.gitignore

@@ -1,2 +1,5 @@
+microgui
 *.o
-build/*
+test/test
+**/compile_commands.json
+**/.cache

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "lib/raylib.c3l"]
-	path = lib/raylib.c3l
-	url = https://github.com/NexushasTaken/raylib.c3l

ARCHITECTURE.md

@@ -1,184 +0,0 @@
-## High level overview
-
-Under the hood every element has an id, this id allows the library to store state
-between frames.
-Elements are also cached such that when the ui tree is rebuilt at the beginning of
-every frame the element data structure doesn't have to be rebuilt.
-
-Elements are arranged in a tree, nodes are container elements that can contain other
-elements, leafs are elements that cannot contain other elements.
-
-Every element has a size and a position, containers also have to keep track of their
-layout information and some other state.
-
-Elements can push commands into the draw stack, which is a structure that contains
-all the draw commands that the user application has to perform do display the ui
-correctly, such commands include drawing lines, rectangles, sprites, text, etc.
-
-
-```text
-            +-----------+
-            | ug_init() |
-            +-----+-----+
-                  |
-                  |
-                  |
-        +---------v----------+
-        |ug_input_keyboard() |
-        |ug_input_mouse()    <----+
-        |ug_input_clipboard()|    |
-        |        ...         |    |
-        +---------+----------+    |
-                  |               |
-                  |               |
-          +-------v--------+      |
-          |ug_frame_begin()|      |
-          +-------+--------+      |
-                  |               |
-                  |               |
-        +---------v----------+    |
-        |ug_window_start()   |    |
-   +---->ug_container_start()|    |
-   |    |ug_div_start()      |    |
-   |    |        ...         |    |
-   |    +---------+----------+    |
-   |              |               |
-   |              |               |
-multiple +--------v---------+     |
- times   |ug_layout_row()   |     |
-   |     |ug_layout_column()|     |
-   |     |ug_layout_float() |     |
-   |     |       ...        |     |
-   |     +--------+---------+     |
-   |              |               |
-   |              |               |
-   |       +------v------+        |
-   |       |ug_button()  |        |
-   |       |ug_text_box()|        |
-   |       |ug_slider()  |        |
-   |       |     ...     |        |
-   |       +------+------+        |
-   |              |               |
-   +--------------+               |
-                  |               |
-         +--------v---------+     |
-         |ug_window_end()   |     |
-         |ug_container_end()|     |
-         |ug_div_end()      |     |
-         |       ...        |     |
-         +--------+---------+     |
-                  |               |
-                  |               |
-                  |               |
-           +------v-------+       |
-           |ug_frame_end()|       |
-           +------+-------+       |
-                  |               |
-                  |               |
-                  |               |
-           +------v-------+       |
-           |user draws the|       |
-           |      ui      +-------+
-           +------+-------+
-                  |
-                  |quit
-                  |
-           +------v-------+
-           | ug_destroy() |
-           +--------------+
-```
-
-### Layouting
-
-Layouting happens in a dynamic grid, when a new element is inserted in a non-floating
-manner it reserves a space in the grid, new elements are placed following this grid.
-
-Every div has two points of origin, one for the row layout and one for the column
-layout, named origin_r and origin_c respectively
-
-origin_r is used when the row layout is used and it is used to position the child
-elements one next to the other, as such it always points to the top-right edge
-of the last row element
-
-```text
-Layout: row
-#: lost space
-              Parent div
-x---------------------------------+
-|[origin_c]                       |
-|[origin_r]                       |
-|                                 |
-|                                 |
-|                                 |
-|                                 |
-|                                 |
-|                                 |
-|                                 |
-+---------------------------------+
-
-              Parent div
-+-----x---------------------------+
-|     |[origin_r]                 |
-| E1  |                           |
-|     |                           |
-x-----+---------------------------+
-|[origin_c]                       |
-|     |                           |
-|     |                           |
-|     |                           |
-|     |                           |
-|     |                           |
-+-----+---------------------------+
-
-              Parent div
-+-----+----------+-----x----------+
-|     |    E2    |     |[origin_r]|
-|  E1 +----------+     |          |
-|     |##########| E3  |          |
-+-----+##########|     |          |
-|################|     |          |
-+----------------x-----+----------+
-|                [origin_c]       |
-|                |                |
-|                |                |
-|                |                |
-+----------------+----------------+
-```
-
-TODO: handle when the content overflows the div
-- Use a different concept, like a view or relative space, for example the child
-div could have position `[0,0]` but in reality it is relative to the origin of the
-parent div
-- each div could have a view and a total area of the content, when drawing everything
-is clipped to the view and scrollbars are shown
-- individual elements accept dimensions and the x/y coordinates could be interpreted
-as offset if the layout is row/column or absolute coordinates if the leayout is floating
-
-A div can be marked resizeable or fixed, and static or dynamic. The difference being
-that resizeable adds a resize handle to the div and dynamic lets the content overflow
-causing scrollbars to be drawn
-
-### Notes
-
-How elements determine if they have focus or not
-
-```C
-// in begin_{container} code
-calculate focus
-set has_focus property
-
-
-
-// in the element code
-if(PARENT_HAS_FOCUS()) {
-	update stuff
-} else {
-	fast path to return
-}
-```
-
-How to get ids:
-	1. use a name for each element
-	2. supply an id for each element
-	3. use a macro and the line position as id and then hash it
-	4. use a macro, get the code line and hash it

RENDERER

@@ -0,0 +1,4 @@
+Divide up the OpenGL renderer into three parts, one part that draws simple shapes,
+another that only draws text and one that is responsible for drawing icons and
+mapping sprites in general, this way all the texture atlases are separate and
+everything is done within 3 draw calls

TODO

@@ -1,7 +0,0 @@
-# TODOs, semi-random sorting
-[ ] Implement glyph draw command
-[ ] Implement div.view and scrollbars
-[ ] Port font system from C to C3 (rewrite1)
-[ ] Update ARCHITECTURE.md
-[ ] Write a README.md
-[ ] Use an arena allocator for cache

def_style.h

@@ -0,0 +1,40 @@
+#ifndef _UG_DEF_STYLE_H
+#define _UG_DEF_STYLE_H
+
+#include "ugui.h"
+
+#define SZ_INT(x)            x.size.i
+
+static const ug_style_t default_style = {
+	.color  = {
+		.bg   = RGB_FORMAT(0x131313),
+		.fg   = RGB_FORMAT(0xffffff),
+	},
+	.margin = SIZE_PX(3),
+	.border = {
+		.color = RGB_FORMAT(0xf50a00),
+		.size  = SIZE_PX(2),
+	},
+	.title = {
+		.color = {
+			.bg = RGB_FORMAT(0xbbbbbb),
+			.fg = RGB_FORMAT(0xffff00),
+		},
+		.height    = SIZE_PX(20),
+		.font_size = SIZE_PX(14),
+	},
+	.btn = {
+		.color = {
+			.act = RGB_FORMAT(0x440044),
+			.bg  = RGB_FORMAT(0x006600),
+			.fg  = RGB_FORMAT(0xffff00),
+			.sel = RGB_FORMAT(0x0a0aff),
+			.br  = RGB_FORMAT(0xff00ff),
+		},
+		.font_size = SIZE_PX(10),
+		.border    = SIZE_PX(5),
+	},
+};
+
+
+#endif

font-to-atlas/.gitignore

@@ -0,0 +1,3 @@
+*.ff
+*.png
+font-to-atlas

font-to-atlas/Makefile

@@ -0,0 +1,2 @@
+font-to-atlas: main.c ff.c ff.h
+	cc -lm -g main.c ff.c -o font-to-atlas

font-to-atlas/ff.c

@@ -0,0 +1,118 @@
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <stdio.h>
+
+#include "ff.h"
+
+
+#define MAX(a,b) a>b?a:b
+
+
+struct ff * ff_new(uint32_t width, uint32_t height)
+{
+	uint64_t size = (uint64_t)width*height*sizeof(struct ff);
+	struct ff *image = malloc(sizeof(struct ff) + size);
+	if (!image)
+		return NULL;
+	memcpy(image->magic, "farbfeld", 8);
+	image->width  = htonl(width);
+	image->height = htonl(height);
+
+	// create a transparent image
+	memset(image->pixels, 0, size);
+
+	return image;
+}
+
+
+uint64_t ff_bytes(const struct ff *image)
+{
+	if (!image)
+		return 0;
+	return sizeof(struct ff)+(uint64_t)ntohl(image->width)*ntohl(image->height)*sizeof(struct ff_px);
+}
+
+
+struct ff * ff_resize(struct ff *image, uint32_t width, uint32_t height)
+{
+	struct ff *new = NULL;
+	int64_t size = sizeof(struct ff)+(int64_t)width*height*sizeof(uint64_t);
+	if (image) {
+		int64_t old_size = ff_bytes(image);
+		if (old_size == size)
+			return image;
+
+		new = realloc(image, size);
+		if (!new)
+			return NULL;
+
+		uint32_t old_width = ntohl(new->width);
+		uint32_t old_height = ntohl(new->height);
+		if (size-old_size > 0) {
+			struct ff_px *b = new->pixels;
+			memset(&b[old_width*old_height], 0, size-old_size);
+			for (int64_t c = (int64_t)old_height-1; c >= 0; c--) {
+				memmove(&b[width*c], &b[old_width*c], sizeof(struct ff_px)*old_width);
+				memset(&b[c*old_width], 0, sizeof(struct ff_px)*(c*width-c*old_width));
+			}
+		} else {
+		}
+		new->height = htonl(height);
+		new->width = htonl(width);
+
+	} else {
+		new = ff_new(width, height);
+	}
+
+	return new;
+}
+
+
+int ff_verify (const struct ff *image)
+{
+	if (!image || strncmp("farbfeld", (char*)image->magic, 8))
+		return 1;
+	return 0;
+}
+
+
+int ff_free(struct ff *image)
+{
+	if (!ff_verify(image))
+		free(image);
+	return 0;
+}
+
+
+// overlays the bitmap containing only 1 8bpp channel to the image starting at (x,y)
+// be stands for the data is already big endian
+int ff_overlay_8r(struct ff **image, const uint8_t *bitmap, uint32_t x, uint32_t y, uint32_t w, uint32_t h)
+{
+	if (!image || !*image)
+		return 1;
+
+	uint32_t iw = ntohl((*image)->width), ih = ntohl((*image)->height);
+	*image = ff_resize(*image, MAX(iw, x+w), MAX(ih, y+h));
+	if (!image)
+		return -1;
+	iw = ntohl((*image)->width);
+	ih = ntohl((*image)->height);
+
+	for (uint32_t r = 0; r < h; r++) {
+		for (uint32_t c = 0; c < w; c++) {
+			uint8_t col = bitmap[r*w+c];
+			struct ff_px p = {
+				.r = 0xffff,
+				.g = 0xffff,
+				.b = 0xffff,
+				.a = htons(257*col)
+			};
+			(*image)->pixels[(r+y)*iw + (c+x)] = p;
+		}
+	}
+
+	return 0;
+}

font-to-atlas/ff.h

@@ -0,0 +1,25 @@
+#ifndef _FARBFELD_EZ_H
+#define _FARBFELD_EZ_H
+
+
+#include <stdint.h>
+
+
+struct __attribute__((packed)) ff_px { uint16_t r, g, b, a; };
+
+struct __attribute__((packed)) ff {
+	int8_t magic[8];
+	uint32_t width, height;
+	struct ff_px pixels[];
+};
+
+
+struct ff * ff_new(uint32_t width, uint32_t height);
+int ff_verify (const struct ff *image);
+int ff_free(struct ff *image);
+uint64_t ff_bytes(const struct ff *image);
+struct ff * ff_resize(struct ff *image, uint32_t width, uint32_t height);
+int ff_overlay_8r(struct ff **image, const uint8_t *bitmap, uint32_t x, uint32_t y, uint32_t w, uint32_t h);
+
+
+#endif

font-to-atlas/main.c

@@ -0,0 +1,107 @@
+#define _POSIX_C_SOURCE 200809l
+#define STB_TRUETYPE_IMPLEMENTATION
+#define STBTT_STATIC
+
+#include <sys/mman.h>
+
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <errno.h>
+#include <err.h>
+
+#include "stb_truetype.h"
+#include "ff.h"
+
+
+const int font_size = 32;
+
+
+void map_file(const unsigned char **str, int *size, const char *path)
+{
+	if (!path)
+		err(EXIT_FAILURE, "NULL filename");
+	FILE *fp = fopen(path, "r");
+	if (!fp)
+		err(EXIT_FAILURE, "Cannot open file %s", path);
+	*size = lseek(fileno(fp), 0, SEEK_END);
+	if (*size == (off_t)-1)
+		err(EXIT_FAILURE, "lseek failed");
+	*str = mmap(0, *size, PROT_READ, MAP_PRIVATE, fileno(fp), 0);
+	if (*str == (void*)-1)
+		err(EXIT_FAILURE, "mmap failed");
+	if (fclose(fp))
+		err(EXIT_FAILURE, "Error closing file");
+}
+
+
+int main(int argc, char *argv[])
+{
+	if (argc < 2)
+		return EXIT_FAILURE;
+	int len;
+	const unsigned char *map;
+	map_file(&map, &len, argv[1]);
+
+	stbtt_fontinfo font;
+	stbtt_InitFont(&font, map, stbtt_GetFontOffsetForIndex(map, 0));
+
+	// all this is to get the font bounding box in pixels
+	float font_scale = 1.0;
+	font_scale = stbtt_ScaleForPixelHeight(&font, font_size);
+	int ascent, descent, linegap;
+	stbtt_GetFontVMetrics(&font, &ascent, &descent, &linegap);
+	int x0,y0,x1,y1;
+	int bound_w, bound_h;
+	stbtt_GetFontBoundingBox(&font, &x0, &y0, &x1, &y1);
+
+	printf("font_scale: %f\n", font_scale);
+	printf("x0:%d y0:%d x1:%d y1:%d\n",x0,y0,x1,y1);
+
+	int baseline = font_scale * -y0;
+	bound_h = (baseline+font_scale*y1) - (baseline+font_scale*y0);
+	bound_w = (font_scale*x1) - (font_scale*x0);
+	baseline = bound_h - baseline;
+	unsigned char *bitmap = malloc(bound_h*bound_w);
+	if (!bitmap)
+		err(EXIT_FAILURE, "Cannot allocate bitmap");
+
+	printf("bounding h:%d w:%d\n", bound_h, bound_w);
+	printf("baseline: %d\n", baseline);
+
+	struct ff *image = ff_new(0, 0);
+
+	// get all ascii
+	int x = 0, y = 0, maxwidth = 64*bound_w;
+	for (unsigned int i = 0; i <= 0x7F; i++) {
+		int x0,y0,x1,y1,w,h,l,a, ox,oy;
+		int g = stbtt_FindGlyphIndex(&font, i);
+
+		stbtt_GetGlyphBitmapBoxSubpixel(&font, g, font_scale, font_scale, 0, 0, &x0, &y0, &x1, &y1);
+		w = x1 - x0;
+		h = y1 - y0;
+		//printf("%d\n", y0);
+		stbtt_GetGlyphHMetrics(&font, g, &a, &l);
+		stbtt_MakeGlyphBitmapSubpixel(&font, bitmap, w, h, w, font_scale, font_scale, 0, 0, g);
+		//printf("'%c' -> l*scale:%.0f, y0:%d\n", i, font_scale*l, bound_h+y0);
+		ox = font_scale*l;
+		oy = bound_h+y0;
+		ff_overlay_8r(&image, bitmap, x+ox, y+oy, w, h);
+
+		x += bound_w;
+		if (x >= maxwidth) y += bound_h;
+		x %= maxwidth;
+
+	}
+
+	FILE *fp = fopen("out.ff", "w");
+	if (fp) {
+		fwrite(image, 1, ff_bytes(image), fp);
+		fclose(fp);
+	}
+
+	free(bitmap);
+	ff_free(image);
+	munmap((void *)map, len);
+	return 0;
+}

input.c

@@ -0,0 +1,40 @@
+#include "ugui.h"
+
+/*=============================================================================*
+ *                            Input Handling                                   *
+ *=============================================================================*/
+
+
+#define TEST_CTX(ctx) { if (!ctx) return -1; }
+
+
+int ug_input_mousemove(ug_ctx_t *ctx, int x, int y)
+{
+	TEST_CTX(ctx)
+	if (x < 0 || y < 0)
+		return 0;
+	
+	ctx->mouse.pos = (ug_vec2_t){.x = x, .y = y};
+
+	return 0;
+}
+
+
+int ug_input_mousedown(ug_ctx_t *ctx, unsigned int mask)
+{
+	TEST_CTX(ctx);
+
+	ctx->mouse.update  |= mask;
+
+	return 0;
+}
+
+
+int ug_input_mouseup(ug_ctx_t *ctx, unsigned int mask)
+{
+	TEST_CTX(ctx);
+
+	ctx->mouse.update |= mask;
+
+	return 0;
+}

lib/raylib.c3l

@@ -1 +0,0 @@
-Subproject commit c7ebe054ce16136c1128fab54fcce4921044293e

opengl-ren/.gitignore

@@ -0,0 +1,2 @@
+a.out
+gl

opengl-ren/Makefile

@@ -0,0 +1,5 @@
+CFLAGS  = -Wall -Wextra -Wpedantic -std=c11 -g
+LDFLAGS = -lSDL2 -lGLEW -lGL
+
+gl: main.c
+	gcc ${CFLAGS} ${LDFLAGS} main.c -o gl

opengl-ren/README

@@ -0,0 +1,2 @@
+since I've never worked with opengl I made this folder as a little test environment
+for an SDL-OpenGL renderer

opengl-ren/fragment.glsl

@@ -0,0 +1,12 @@
+#version 330
+
+flat in vec4 out_color;
+in vec2 texture_coord;
+uniform sampler2D texture_sampler;
+
+out vec4 color;
+
+void main()
+{
+	color = texture(texture_sampler, texture_coord) + out_color;
+}

opengl-ren/main.c

@@ -0,0 +1,521 @@
+#define _POSIX_C_SOURCE 200809l
+
+#include <sys/mman.h>
+#include <arpa/inet.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <errno.h>
+#include <err.h>
+
+#include <SDL2/SDL.h>
+#include <GL/glew.h>
+#include <SDL2/SDL_opengl.h>
+
+
+#define GLSL_VERT_SHADER "vertex.glsl"
+#define GLSL_FRAG_SHADER "fragment.glsl"
+#define PACKED __attribute__((packed))
+
+
+const int vertindex = 0;
+const int colindex  = 1;
+const int textindex = 2;
+
+struct {
+	SDL_Window *w;
+	SDL_GLContext *gl;
+	GLuint gl_vertbuffer;
+	GLuint gl_program;
+	GLuint font_texture;
+} ren = {0};
+
+typedef struct PACKED {
+	union { GLfloat x, u; };
+	union { GLfloat y, v; };
+} vec2;
+
+typedef struct PACKED {
+	union { GLfloat x, r; };
+	union { GLfloat y, g; };
+	union { GLfloat z, b; };
+	union { GLfloat w, a; };
+} vec4;
+
+// a vertex has a position and a color
+struct PACKED vertex {
+	vec2 pos;
+	vec2 texture;
+	vec4 color;
+};
+
+
+int w_height(SDL_Window *);
+int w_width(SDL_Window *);
+
+
+// this just descrives a farbfeld image
+// https://tools.suckless.org/farbfeld/
+struct PACKED _ff {
+	uint8_t magic[8];
+	uint32_t w, h;
+	uint64_t bytes[];
+};
+const int gw = 7, gh = 9;
+unsigned int fw, fh;
+
+
+struct {
+	struct vertex *v;
+	int size, idx;
+	int prev_idx;
+	unsigned long int hash, prev_hash;
+} vstack = {0};
+
+
+void grow_stack(int step)
+{
+	vstack.v = realloc(vstack.v, (vstack.size+step)*sizeof(*(vstack.v)));
+	if(!vstack.v)
+		err(-1, "Could not allocate stack #S: %s", strerror(errno));
+	memset(&(vstack.v[vstack.size]), 0, step*sizeof(*(vstack.v)));
+	vstack.size += step;
+}
+
+void push(struct vertex v)
+{
+	if (vstack.idx >= vstack.size)
+		grow_stack(6);
+	vstack.v[vstack.idx++] = v;
+}
+
+
+void update_hash()
+{
+	if (!vstack.idx)
+		return;
+	unsigned int hash = 0x5400F1B3;
+	unsigned char *v = (unsigned char *)vstack.v;
+	int size = vstack.idx;
+
+	for (; size; size--) {
+		hash += v[size-1];
+		hash += hash << 10;
+		hash ^= hash >> 6;
+	}
+	hash += hash << 3;
+  	hash ^= hash >> 11;
+  	hash += hash << 15;
+
+	vstack.hash = hash;
+}
+
+
+void force_changed()
+{
+	vstack.prev_idx = 0;
+}
+
+
+int changed()
+{
+	return vstack.prev_idx != vstack.idx || vstack.prev_hash != vstack.hash;
+}
+
+
+int vstack_push_quad_c(int x, int y, int w, int h, vec4 color)
+{
+	// x4,y4        x3,y3
+	// +-------------+
+	// |(x,y)       /|
+	// |          /  |
+	// |   2    /    |
+	// |      /      |
+	// |    /        |
+	// |  /     1    |
+	// |/            |
+	// +-------------+
+	// x1,y1        x2,y2
+
+	int hw = w_width(ren.w)/2;
+	int hh = w_height(ren.w)/2;
+
+	float x1, x2, x3, x4;
+	float y1, y2, y3, y4;
+
+	x4 = x1 = (float)(x - hw)   / hw;
+	x2 = x3 = (float)(x+w - hw) / hw;
+	y4 = y3 = (float)(hh - y)   / hh;
+	y1 = y2 = (float)(hh - y-h) / hh;
+
+	push((struct vertex){ .pos.x=x1, .pos.y=y1, .color=color });
+	push((struct vertex){ .pos.x=x2, .pos.y=y2, .color=color });
+	push((struct vertex){ .pos.x=x3, .pos.y=y3, .color=color });
+	push((struct vertex){ .pos.x=x1, .pos.y=y1, .color=color });
+	push((struct vertex){ .pos.x=x3, .pos.y=y3, .color=color });
+	push((struct vertex){ .pos.x=x4, .pos.y=y4, .color=color });
+
+	return 0;
+}
+
+
+int vstack_push_quad_t(int x, int y, int w, int h, int u, int v)
+{
+	// x4,y4        x3,y3
+	// +-------------+
+	// |(x,y)       /|
+	// |          /  |
+	// |   2    /    |
+	// |      /      |
+	// |    /        |
+	// |  /     1    |
+	// |/            |
+	// +-------------+
+	// x1,y1        x2,y2
+
+	int hw = w_width(ren.w)/2;
+	int hh = w_height(ren.w)/2;
+
+	float x1, x2, x3, x4;
+	float y1, y2, y3, y4;
+
+	x1 = x4 = (float)(x - hw)   / hw;
+	x2 = x3 = (float)(x+w - hw) / hw;
+	y1 = y2 = (float)(hh - y-h) / hh;
+	y3 = y4 = (float)(hh - y)   / hh;
+
+	float u1, u2, u3, u4;
+	float v1, v2, v3, v4;
+
+	u1 = u4 = (float)(u)    / fw;
+	u2 = u3 = (float)(u+gw) / fw;
+	v1 = v2 = (float)(v+gh) / fh;
+	v3 = v4 = (float)(v)    / fh;
+
+	push((struct vertex){ .pos.x=x1, .pos.y=y1, .texture.x=u1, .texture.y=v1 });
+	push((struct vertex){ .pos.x=x2, .pos.y=y2, .texture.x=u2, .texture.y=v2 });
+	push((struct vertex){ .pos.x=x3, .pos.y=y3, .texture.x=u3, .texture.y=v3 });
+	push((struct vertex){ .pos.x=x1, .pos.y=y1, .texture.x=u1, .texture.y=v1 });
+	push((struct vertex){ .pos.x=x3, .pos.y=y3, .texture.x=u3, .texture.y=v3 });
+	push((struct vertex){ .pos.x=x4, .pos.y=y4, .texture.x=u4, .texture.y=v4 });
+
+	return 0;
+}
+
+
+void vstack_clear(void)
+{
+	vstack.prev_hash = vstack.hash;
+	vstack.prev_idx = vstack.idx;
+	vstack.idx = 0;
+}
+
+
+// copy the vertex buffer from system to video memory
+void ren_initvertbuffer()
+{
+	// generate a buffer id
+	glGenBuffers(1, &ren.gl_vertbuffer);
+	// tell opengl that we want to work on that buffer
+	glBindBuffer(GL_ARRAY_BUFFER, ren.gl_vertbuffer);
+	// copy the vertex data into the gpu memory, GL_STATIC_DRAW tells opengl
+	// that the data will be used for drawing (DRAW) and it will only be modified
+	// every frame (DYNAMIC)
+	glBufferData(GL_ARRAY_BUFFER, vstack.idx*sizeof(struct vertex), vstack.v, GL_DYNAMIC_DRAW);
+	// set the format of each vertex, in this case each vertex is made of 4
+	// coordinates, x y z w, where w is the clip coordinate, stride is
+	// sizeof(vec4) since every postition vertex there is a vector representing
+	// color data
+	// set the position data of the vertex buffer, and bind it as input to the
+	// vertex shader with an index of 0
+	glEnableVertexAttribArray(vertindex);
+	glVertexAttribPointer(vertindex, 2, GL_FLOAT, GL_FALSE, sizeof(struct vertex), 0);
+	// set the color data of the vertex buffer to index 1
+	// vertex attribute is the OpenGL name given to a set of vertices which are
+	// given as input to a vertext shader, in a shader an array of vertices is
+	// always referred to by index and not by pointer or other manners, indices
+	// go from 0 to 15
+	glEnableVertexAttribArray(colindex);
+	glVertexAttribPointer(colindex, 4, GL_FLOAT, GL_FALSE, sizeof(struct vertex), (void*)(2*sizeof(vec2)));
+	// texture uv data
+	glEnableVertexAttribArray(textindex);
+	glVertexAttribPointer(textindex, 2, GL_FLOAT, GL_FALSE, sizeof(struct vertex), (void*)sizeof(vec2));
+	// reset the object bind so not to create errors
+	glBindBuffer(GL_ARRAY_BUFFER, 0);
+}
+
+
+void map_file(const char **str, int *size, const char *fname)
+{
+	FILE *fp = fopen(fname, "r");
+	*size = lseek(fileno(fp), 0, SEEK_END);
+	*str = mmap(0, *size, PROT_READ, MAP_PRIVATE, fileno(fp), 0);
+	fclose(fp);
+}
+
+
+// print shader compilation errors
+int debug_shader(GLuint shader)
+{
+	GLint status;
+	glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
+	if (status != GL_FALSE)
+		return 0;
+
+	GLint log_length;
+	glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &log_length);
+
+	GLchar *log_str = malloc((log_length + 1)*sizeof(GLchar));
+	glGetShaderInfoLog(shader, log_length, NULL, log_str);
+
+	const char *shader_type_str = NULL;
+	GLint shader_type;
+	glGetShaderiv(shader, GL_SHADER_TYPE, &shader_type);
+	switch(shader_type) {
+	case GL_VERTEX_SHADER:   shader_type_str = "vertex";   break;
+	case GL_GEOMETRY_SHADER: shader_type_str = "geometry"; break;
+	case GL_FRAGMENT_SHADER: shader_type_str = "fragment"; break;
+	}
+
+	fprintf(stderr, "Compile failure in %s shader:\n%s\n", shader_type_str, log_str);
+	free(log_str);
+	return -1;
+}
+
+
+// print program compilation errors
+int debug_program(GLuint prog)
+{
+	GLint status;
+	glGetProgramiv (prog, GL_LINK_STATUS, &status);
+	if (status != GL_FALSE)
+		return 0;
+
+	GLint log_length;
+	glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &log_length);
+
+	GLchar *log_str = malloc((log_length + 1)*sizeof(GLchar));
+	glGetProgramInfoLog(prog, log_length, NULL, log_str);
+	fprintf(stderr, "Linker failure: %s\n", log_str);
+	free(log_str);
+
+	return -1;
+}
+
+
+void ren_initshaders()
+{
+	GLuint gl_vertshader, gl_fragshader;
+
+	// initialize the vertex shader and get the corresponding id
+	gl_vertshader = glCreateShader(GL_VERTEX_SHADER);
+	if (!gl_vertshader)
+		err(-1, "Could not create the vertex shader");
+
+	// map the shader file into memory
+	const char *vshader_str = NULL;
+	int vshader_size;
+	map_file(&vshader_str, &vshader_size, GLSL_VERT_SHADER);
+
+	// get the shader into opengl
+	glShaderSource(gl_vertshader, 1, &vshader_str, NULL);
+	// compile the shader
+	glCompileShader(gl_vertshader);
+	if (debug_shader(gl_vertshader))
+		exit(EXIT_FAILURE);
+
+	// do the same for the fragment shader
+	// FIXME: make this a function
+	gl_fragshader = glCreateShader(GL_FRAGMENT_SHADER);
+	if (!gl_fragshader)
+		err(-1, "Could not create the vertex shader");
+
+	// map the shader file into memory
+	const char *fshader_str = NULL;
+	int fshader_size;
+	map_file(&fshader_str, &fshader_size, GLSL_FRAG_SHADER);
+
+	// get the shader into opengl
+	glShaderSource(gl_fragshader, 1, &fshader_str, NULL);
+	// compile the shader
+	glCompileShader(gl_fragshader);
+	if (debug_shader(gl_fragshader))
+		exit(EXIT_FAILURE);
+
+	// create the main program object, it is an amalgamation of all shaders
+	ren.gl_program = glCreateProgram();
+	// attach the shaders to the program (set which shaders are present)
+	glAttachShader(ren.gl_program, gl_vertshader);
+	glAttachShader(ren.gl_program, gl_fragshader);
+	// then link the program (basically the linking stage of the program)
+	glLinkProgram(ren.gl_program);
+	if (debug_program(ren.gl_program))
+		exit(EXIT_FAILURE);
+
+	// after linking the shaders can be detached and the source freed from
+	// memory since the program is ready to use
+	glDetachShader(ren.gl_program, gl_vertshader);
+	glDetachShader(ren.gl_program, gl_fragshader);
+	munmap((void *)vshader_str, vshader_size);
+	munmap((void *)fshader_str, fshader_size);
+
+	// now tell opengl to use the program
+	glUseProgram(ren.gl_program);
+}
+
+
+void ren_drawvertbuffer()
+{
+	if (!changed())
+		return;
+	glClear(GL_COLOR_BUFFER_BIT);
+	glBindBuffer(GL_ARRAY_BUFFER, ren.gl_vertbuffer);
+	// upload vertex data
+	if (vstack.idx != vstack.prev_idx)
+		glBufferData(GL_ARRAY_BUFFER, vstack.idx*sizeof(struct vertex), vstack.v, GL_DYNAMIC_DRAW);
+	else
+	 	glBufferSubData(GL_ARRAY_BUFFER, 0, vstack.idx*sizeof(struct vertex), vstack.v);
+	// draw vertex data
+	glDrawArrays(GL_TRIANGLES, 0, vstack.idx);
+	glBindBuffer(GL_ARRAY_BUFFER, 0);
+	SDL_GL_SwapWindow(ren.w);
+}
+
+
+int w_height(SDL_Window *win)
+{
+	int h;
+	SDL_GetWindowSize(win, NULL, &h);
+	return h;
+}
+
+
+int w_width(SDL_Window *win)
+{
+	int w;
+	SDL_GetWindowSize(win, &w, NULL);
+	return w;
+}
+
+
+void import_font(const char *path)
+{
+	const char *map;
+	int size;
+	const struct _ff *img;
+
+	map_file(&map, &size, path);
+	img = (const struct _ff *)map;
+	fw = ntohl(img->w);
+	fh = ntohl(img->h);
+
+	glGenTextures(1, &ren.font_texture);
+	glBindTexture(GL_TEXTURE_2D, ren.font_texture);
+	// farbfeld image
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, fw, fh, 0, GL_RGBA, GL_UNSIGNED_SHORT, img->bytes);
+
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+	munmap((void *)map, size);
+}
+
+
+void push_text(int x, int y, float scale, const char *s)
+{
+	for (; *s; s++) {
+		int u, v;
+		int idx = *s - ' ';
+		u = idx % (fw / gw);
+		v = (idx / (fw / gw)) % (fh / gh);
+		vstack_push_quad_t(x, y, gw*scale, gh*scale, u*gw, v*gh);
+		x += gw*scale;
+		if (*s == '\n')
+			y += gh;
+	}
+}
+
+
+int main (void)
+{
+	SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS);
+	SDL_SetHint(SDL_HINT_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR, "0");
+	SDL_SetHint(SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, "1");
+
+	ren.w = SDL_CreateWindow("test",
+	SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
+	500, 500, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE );
+
+	// create the OpenGL context
+	ren.gl = SDL_GL_CreateContext(ren.w);
+	if (ren.gl == NULL)
+		err(-1, "Failed to create OpenGL context: %s", SDL_GetError());
+
+	// select some features
+	glEnable(GL_BLEND);
+	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+	glDisable(GL_CULL_FACE);
+	glDisable(GL_DEPTH_TEST);
+	glEnable(GL_SCISSOR_TEST);
+	glEnable(GL_TEXTURE_2D);
+
+	// initialize glew, this library gives us the declarations for most GL
+	// functions, in the future it would be cool to do it manually
+	GLenum glew_err = glewInit();
+	if (glew_err != GLEW_OK)
+		err(-1, "Failed to initialize GLEW: %s", glewGetErrorString(glew_err));
+
+	ren_initshaders();
+	import_font("./charmap.ff");
+
+	vec4 magenta = {.r=1.0, .g=0.0, .b=1.0, .a=1.0};
+
+	ren_initvertbuffer();
+
+	glClearColor(0.3f, 0.3f, 0.3f, 0.f);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	// event loop and drawing
+	SDL_Event ev = {0};
+	int running = 1;
+	do {
+		SDL_WaitEvent(&ev);
+		switch (ev.type) {
+		case SDL_QUIT: running = 0; break;
+		case SDL_WINDOWEVENT:
+			if(ev.window.event == SDL_WINDOWEVENT_SIZE_CHANGED) {
+				glViewport(0, 0, w_width(ren.w), w_height(ren.w));
+				glScissor(0, 0, w_width(ren.w), w_height(ren.w));
+				force_changed();
+			}
+			break;
+		default: break;
+		}
+
+		vstack_push_quad_c(0, 0, 100, 100, magenta);
+		vstack_push_quad_c(200, 0, 10, 10, magenta);
+		vstack_push_quad_c(10, 150, 100, 100, magenta);
+		push_text(250, 250, 1.0f, "Ciao Victoria <3");
+		update_hash();
+
+		ren_drawvertbuffer();
+
+		vstack_clear();
+
+	} while(running);
+
+	glUseProgram(0);
+	glDisableVertexAttribArray(vertindex);
+	glDisableVertexAttribArray(colindex);
+	glDeleteTextures(1, &ren.font_texture);
+	glDeleteBuffers(1, &ren.gl_vertbuffer);
+	SDL_GL_DeleteContext(ren.gl);
+	SDL_DestroyWindow(ren.w);
+	SDL_Quit();
+
+	return 0;
+}

opengl-ren/vertex.glsl

@@ -0,0 +1,17 @@
+#version 330
+
+// use the input ("in") vertices from index zero
+layout(location = 0) in vec2 position;
+layout(location = 1) in vec4 color;
+layout(location = 2) in vec2 uv;
+
+flat out vec4 out_color;
+out vec2 texture_coord;
+
+void main()
+{
+	// simply copy teh output position
+	gl_Position = vec4(position.x, position.y, 0.0f, 1.0f);
+	out_color = color;
+	texture_coord = uv;
+}

opengl/.gitignore

@@ -0,0 +1,2 @@
+a.out
+gl

opengl/Makefile

@@ -0,0 +1,5 @@
+CFLAGS  = -Wall -Wextra -Wpedantic -std=c11 -g
+LDFLAGS = -lSDL2 -lGLEW -lGL
+
+gl: main.c
+	gcc ${CFLAGS} ${LDFLAGS} main.c -o gl

opengl/README

@@ -0,0 +1,2 @@
+since I've never worked with opengl I made this folder as a little test environment
+for an SDL-OpenGL renderer

opengl/fragment.glsl

@@ -0,0 +1,10 @@
+#version 330
+
+smooth in vec4 out_color;
+out vec4 color;
+
+void main()
+{
+	// set the color for each vertex to white
+	color = out_color;
+}

opengl/main.c

@@ -0,0 +1,278 @@
+#define _POSIX_C_SOURCE 200809l
+
+#include <sys/mman.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <err.h>
+
+#include <SDL2/SDL.h>
+#include <GL/glew.h>
+#include <SDL2/SDL_opengl.h>
+
+
+#define GLSL_VERT_SHADER "vertex.glsl"
+#define GLSL_FRAG_SHADER "fragment.glsl"
+#define PACKED __attribute__((packed))
+
+
+const int vertindex = 0;
+const int colindex  = 1;
+
+struct {
+	SDL_Window *w;
+	SDL_GLContext *gl;
+	GLuint gl_vertbuffer;
+	GLuint gl_program;
+} ren = {0};
+
+typedef struct PACKED {
+	union { GLfloat x, r; };
+	union { GLfloat y, g; };
+	union { GLfloat z, b; };
+	union { GLfloat w, a; };
+} vec4;
+
+// a vertex has a position and a color
+struct PACKED vertex { vec4 pos, col; };
+
+#define VNUM(s) (sizeof(s)/sizeof(s[0]))
+struct vertex vertbuffer[] = {
+	{ .pos={.x= 0.75f, .y= 0.75f, .z=0.0f,.w=1.0f}, .col={ .r=1.0f, .g=0.0f, .b=0.0f, .a=1.0f} },
+	{ .pos={.x=-0.75f, .y=-0.75f, .z=0.0f,.w=1.0f}, .col={ .r=1.0f, .g=0.0f, .b=0.0f, .a=1.0f} },
+	{ .pos={.x= 0.75f, .y=-0.75f, .z=0.0f,.w=1.0f}, .col={ .r=1.0f, .g=0.0f, .b=0.0f, .a=1.0f} },
+
+	{ .pos={.x= 0.75f, .y= 0.75f, .z=0.0f,.w=1.0f}, .col={ .r=1.0f, .g=0.0f, .b=0.0f, .a=1.0f} },
+	{ .pos={.x=-0.75f, .y=-0.75f, .z=0.0f,.w=1.0f}, .col={ .r=1.0f, .g=0.0f, .b=0.0f, .a=1.0f} },
+	{ .pos={.x=-0.75f, .y= 0.75f, .z=0.0f,.w=1.0f}, .col={ .r=1.0f, .g=0.0f, .b=0.0f, .a=1.0f} },
+};
+
+
+// copy the vertex buffer from system to video memory
+void ren_initvertbuffer()
+{
+	// generate a buffer id
+	glGenBuffers(1, &ren.gl_vertbuffer);
+	// tell opengl that we want to work on that buffer
+	glBindBuffer(GL_ARRAY_BUFFER, ren.gl_vertbuffer);
+	// copy the vertex data into the gpu memory, GL_STATIC_DRAW tells opengl
+	// that the data will be used for drawing (DRAW) and it will only be modified
+	// once (STATIC)
+	glBufferData(GL_ARRAY_BUFFER, sizeof(vertbuffer), &vertbuffer, GL_STATIC_DRAW);
+	// set the format of each vertex, in this case each vertex is made of 4
+	// coordinates, x y z w, where w is the clip coordinate, stride is
+	// sizeof(vec4) since every postition vertex there is a vector representing
+	// color data
+	// set the position data of the vertex buffer, and bind it as input to the
+	// vertex shader with an index of 0
+	glEnableVertexAttribArray(vertindex);
+	glVertexAttribPointer(vertindex, 4, GL_FLOAT, GL_FALSE, sizeof(struct vertex), 0);
+	// set the color data of the vertex buffer to index 1
+	// vertex attribute is the OpenGL name given to a set of vertices which are
+	// given as input to a vertext shader, in a shader an array of vertices is
+	// always referred to by index and not by pointer or other manners, indices
+	// go from 0 to 15
+	glEnableVertexAttribArray(colindex);
+	glVertexAttribPointer(colindex, 4, GL_FLOAT, GL_FALSE, sizeof(struct vertex), (void*)sizeof(vec4));
+	// reset the object bind so not to create errors
+	glBindBuffer(GL_ARRAY_BUFFER, 0);
+}
+
+
+void map_file(const char **str, int *size, const char *fname)
+{
+	FILE *fp = fopen(fname, "r");
+	*size = lseek(fileno(fp), 0, SEEK_END);
+	*str = mmap(0, *size, PROT_READ, MAP_PRIVATE, fileno(fp), 0);
+	fclose(fp);
+}
+
+
+// print shader compilation errors
+int debug_shader(GLuint shader)
+{
+	GLint status;
+	glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
+	if (status != GL_FALSE)
+		return 0;
+
+	GLint log_length;
+	glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &log_length);
+
+	GLchar *log_str = malloc((log_length + 1)*sizeof(GLchar));
+	glGetShaderInfoLog(shader, log_length, NULL, log_str);
+
+	const char *shader_type_str = NULL;
+	GLint shader_type;
+	glGetShaderiv(shader, GL_SHADER_TYPE, &shader_type);
+	switch(shader_type) {
+	case GL_VERTEX_SHADER:   shader_type_str = "vertex";   break;
+	case GL_GEOMETRY_SHADER: shader_type_str = "geometry"; break;
+	case GL_FRAGMENT_SHADER: shader_type_str = "fragment"; break;
+	}
+
+	fprintf(stderr, "Compile failure in %s shader:\n%s\n", shader_type_str, log_str);
+	free(log_str);
+	return -1;
+}
+
+
+// print program compilation errors
+int debug_program(GLuint prog)
+{
+	GLint status;
+	glGetProgramiv (prog, GL_LINK_STATUS, &status);
+	if (status != GL_FALSE)
+		return 0;
+
+	GLint log_length;
+	glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &log_length);
+
+	GLchar *log_str = malloc((log_length + 1)*sizeof(GLchar));
+	glGetProgramInfoLog(prog, log_length, NULL, log_str);
+	fprintf(stderr, "Linker failure: %s\n", log_str);
+	free(log_str);
+
+	return -1;
+}
+
+
+void ren_initshaders()
+{
+	GLuint gl_vertshader, gl_fragshader;
+
+	// initialize the vertex shader and get the corresponding id
+	gl_vertshader = glCreateShader(GL_VERTEX_SHADER);
+	if (!gl_vertshader)
+		err(-1, "Could not create the vertex shader");
+
+	// map the shader file into memory
+	const char *vshader_str = NULL;
+	int vshader_size;
+	map_file(&vshader_str, &vshader_size, GLSL_VERT_SHADER);
+
+	// get the shader into opengl
+	glShaderSource(gl_vertshader, 1, &vshader_str, NULL);
+	// compile the shader
+	glCompileShader(gl_vertshader);
+	if (debug_shader(gl_vertshader))
+		exit(EXIT_FAILURE);
+
+	// do the same for the fragment shader
+	// FIXME: make this a function
+	gl_fragshader = glCreateShader(GL_FRAGMENT_SHADER);
+	if (!gl_fragshader)
+		err(-1, "Could not create the vertex shader");
+
+	// map the shader file into memory
+	const char *fshader_str = NULL;
+	int fshader_size;
+	map_file(&fshader_str, &fshader_size, GLSL_FRAG_SHADER);
+
+	// get the shader into opengl
+	glShaderSource(gl_fragshader, 1, &fshader_str, NULL);
+	// compile the shader
+	glCompileShader(gl_fragshader);
+	if (debug_shader(gl_fragshader))
+		exit(EXIT_FAILURE);
+
+	// create the main program object, it is an amalgamation of all shaders
+	ren.gl_program = glCreateProgram();
+	// attach the shaders to the program (set which shaders are present)
+	glAttachShader(ren.gl_program, gl_vertshader);
+	glAttachShader(ren.gl_program, gl_fragshader);
+	// then link the program (basically the linking stage of the program)
+	glLinkProgram(ren.gl_program);
+	if (debug_program(ren.gl_program))
+		exit(EXIT_FAILURE);
+
+	// after linking the shaders can be detached and the source freed from
+	// memory since the program is ready to use
+	glDetachShader(ren.gl_program, gl_vertshader);
+	glDetachShader(ren.gl_program, gl_fragshader);
+	munmap((void *)vshader_str, vshader_size);
+	munmap((void *)fshader_str, fshader_size);
+
+	// now tell opengl to use the program
+	glUseProgram(ren.gl_program);
+}
+
+
+void ren_drawvertbuffer()
+{
+	glBindBuffer(GL_ARRAY_BUFFER, ren.gl_vertbuffer);
+	glDrawArrays(GL_TRIANGLES, 0, VNUM(vertbuffer));
+	glBindBuffer(GL_ARRAY_BUFFER, 0);
+}
+
+
+int w_height(SDL_Window *win)
+{
+	int h;
+	SDL_GetWindowSize(win, NULL, &h);
+	return h;
+}
+
+
+int w_width(SDL_Window *win)
+{
+	int w;
+	SDL_GetWindowSize(win, &w, NULL);
+	return w;
+}
+
+
+int main (void)
+{
+	SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS);
+	SDL_SetHint(SDL_HINT_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR, "0");
+	SDL_SetHint(SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, "1");
+
+	ren.w = SDL_CreateWindow("test",
+	SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
+	500, 500, SDL_WINDOW_OPENGL );
+
+	// create the OpenGL context
+	ren.gl = SDL_GL_CreateContext(ren.w);
+	if (ren.gl == NULL)
+		err(-1, "Failed to create OpenGL context: %s", SDL_GetError());
+
+	// initialize glew, this library gives us the declarations for most GL
+	// functions, in the future it would be cool to do it manually
+	GLenum glew_err = glewInit();
+	if (glew_err != GLEW_OK)
+		err(-1, "Failed to initialize GLEW: %s", glewGetErrorString(glew_err));
+
+	ren_initvertbuffer();
+	ren_initshaders();
+
+	// event loop and drawing
+	SDL_Event ev = {0};
+	int running = 1;
+	do {
+		SDL_WaitEvent(&ev);
+		switch (ev.type) {
+		case SDL_QUIT: running = 0; break;
+		default: break;
+		}
+
+		glViewport(0, 0, w_width(ren.w), w_height(ren.w));
+		glClearColor(0.f, 0.f, 0.f, 0.f);
+		glClear(GL_COLOR_BUFFER_BIT);
+
+		ren_drawvertbuffer();
+
+		SDL_GL_SwapWindow(ren.w);
+
+	} while(running);
+
+	glDisableVertexAttribArray(vertindex);
+	glDisableVertexAttribArray(colindex);
+	SDL_GL_DeleteContext(ren.gl);
+	SDL_DestroyWindow(ren.w);
+	SDL_Quit();
+
+	return 0;
+}

opengl/vertex.glsl

@@ -0,0 +1,14 @@
+#version 330
+
+// use the input ("in") vertices from index zero
+layout(location = 0) in vec4 position;
+layout(location = 1) in vec4 color;
+
+smooth out vec4 out_color;
+
+void main()
+{
+	// simply copy teh output position
+	gl_Position = position;
+	out_color = color;
+}

project.json

@@ -1,56 +0,0 @@
-{
-  // Language version of C3.
-  "langrev": "1",
-  // Warnings used for all targets.
-  "warnings": [ "no-unused" ],
-  // Directories where C3 library files may be found.
-  "dependency-search-paths": [ "lib" ],
-  // Libraries to use for all targets.
-  "dependencies": [ "raylib" ],
-  "features": [
-    // See rcore.c3
-    //"SUPPORT_INTERNAL_MEMORY_MANAGEMENT",
-    //"SUPPORT_STANDARD_FILEIO",
-    //"SUPPORT_FILE_SYSTEM_FUNCTIONS",
-    //"SUPPORT_DATA_ENCODER",
-    // See text.c3
-    //"SUPPORT_TEXT_CODEPOINTS_MANAGEMENT",
-    //"SUPPORT_TEXT_C_STRING_MANAGEMENT",
-    //"SUPPORT_RANDOM_GENERATION",
-  
-    "SUPPORT_RAYGUI",
-    //"RAYGUI_NO_ICONS",
-    //"RAYGUI_CUSTOM_ICONS",
-  ],
-  // Authors, optionally with email.
-  "authors": [ "John Doe <john.doe@example.com>" ],
-  // Version using semantic versioning.
-  "version": "0.1.0",
-  // Sources compiled for all targets.
-  "sources": [ "src/**" ],
-  // C sources if the project also compiles C sources
-  // relative to the project file.
-  // "c-sources": [ "csource/**" ],
-  // Include directories for C sources relative to the project file.
-  // "c-include-dirs": [ "csource/include" ],
-  // Output location, relative to project file.
-  "output": "build",
-  // Architecture and OS target.
-  // You can use 'c3c --list-targets' to list all valid targets.
-  // "target": "windows-x64",
-  // Targets.
-  "targets": {
-    "ugui": {
-      // Executable or library.
-      "type": "executable",
-      // Additional libraries, sources
-      // and overrides of global settings here.
-    },
-  },
-  // Global settings.
-  // CPU name, used for optimizations in the LLVM backend.
-  "cpu": "generic",
-  // Optimization: "O0", "O1", "O2", "O3", "O4", "O5", "Os", "Oz".
-  "opt": "O0",
-  // See resources/examples/project_all_settings.json and 'c3c --list-project-properties' to see more properties.
-}

rewrite/generic_stack.h

@@ -0,0 +1,126 @@
+#ifndef _STACK_GENERIC_H
+#define _STACK_GENERIC_H
+
+
+#define STACK_STEP 8
+#define STACK_SALT 0xbabb0cac
+
+// FIXME: find a way to not re-hash the whole stack when removing one item
+
+// incremental hash for every grow
+#define STACK_HASH(p, s, h)                                                    \
+{                                                                              \
+	unsigned char *v = (unsigned char *)(p);                               \
+	for (int x = (s); x; x--) {                                            \
+		(h) += v[x-1];                                                 \
+		(h) += (h) << 10;                                              \
+		(h) ^= (h) >> 6;                                               \
+	}                                                                      \
+	(h) += (h) << 3;                                                       \
+  	(h) ^= (h) >> 11;                                                      \
+  	(h) += (h) << 15;                                                      \
+}
+
+
+// declare just the prototypes
+#define STACK_PROTO(stackname, type)                                           \
+struct stackname {                                                             \
+	type *items;                                                           \
+	int size, idx, old_idx;                                                \
+	unsigned int hash, old_hash;                                           \
+};                                                                             \
+struct stackname stackname##_init(void);                                       \
+int stackname##_grow(struct stackname *stack, int step);                       \
+int stackname##_push(struct stackname *stack, type *e);                        \
+type stackname##_pop(struct stackname *stack);                                 \
+int stackname##_clear(struct stackname *stack);                                \
+int stackname##_changed(struct stackname *stack);                              \
+int stackname##_size_changed(struct stackname *stack);                         \
+int stackname##_free(struct stackname *stack);
+
+
+#define STACK_DEFINE(stackname, type)                                          \
+struct stackname;                                                              \
+\
+\
+struct stackname stackname##_init(void)                                        \
+{                                                                              \
+	return (struct stackname){0, .hash = STACK_SALT};                      \
+}                                                                              \
+\
+\
+int stackname##_grow(struct stackname *stack, int step)                        \
+{                                                                              \
+	if (!stack)                                                            \
+		return -1;                                                     \
+	stack->items = realloc(stack->items, (stack->size+step)*sizeof(type)); \
+	if(!stack->items)                                                      \
+		return -1;                                                     \
+	memset(&(stack->items[stack->size]), 0, step*sizeof(*(stack->items))); \
+	stack->size += step;                                                   \
+	return 0;                                                              \
+}                                                                              \
+\
+\
+int stackname##_push(struct stackname *stack, type *e)                         \
+{                                                                              \
+	if (!stack || !e)                                                      \
+		return -1;                                                     \
+	if (stack->idx >= stack->size)                                         \
+		if (stackname##_grow(stack, STACK_STEP))                       \
+			return -1;                                             \
+	stack->items[stack->idx++] = *e;                                       \
+	STACK_HASH(e, sizeof(type), stack->hash);                              \
+	return 0;                                                              \
+}                                                                              \
+\
+\
+type stackname##_pop(struct stackname *stack)                                  \
+{                                                                              \
+	if (!stack || stack->idx == 0 || stack->size == 0)                     \
+		return (type){0};                                              \
+	stack->hash = STACK_SALT;                                              \
+	STACK_HASH(stack->items, sizeof(type)*(stack->idx-1), stack->hash);    \
+	return stack->items[stack->idx--];                                     \
+}                                                                              \
+\
+\
+int stackname##_clear(struct stackname *stack)                                 \
+{                                                                              \
+	if (!stack)                                                            \
+		return -1;                                                     \
+	stack->old_idx = stack->idx;                                           \
+	stack->old_hash = stack->hash;                                         \
+	stack->hash = STACK_SALT;                                              \
+	stack->idx = 0;                                                        \
+	return 0;                                                              \
+}                                                                              \
+\
+\
+int stackname##_changed(struct stackname *stack)                               \
+{                                                                              \
+	if (!stack)                                                            \
+		return -1;                                                     \
+	return stack->hash != stack->old_hash;                                 \
+}                                                                              \
+\
+\
+int stackname##_size_changed(struct stackname *stack)                          \
+{                                                                              \
+	if (!stack)                                                            \
+		return -1;                                                     \
+	return stack->size != stack->old_idx;                                  \
+}                                                                              \
+\
+\
+int stackname##_free(struct stackname *stack)                                  \
+{                                                                              \
+	if (stack) {                                                           \
+		stackname##_clear(stack);                                      \
+		if (stack->items)                                              \
+			free(stack->items);                                    \
+	}                                                                      \
+	return 0;                                                              \
+}                                                                              \
+
+#endif

src/cache.c3

@@ -1,133 +0,0 @@
-module cache(<Key, Value, SIZE>);
-
-/* LRU Cache
- * The cache uses a pool (array) to store all the elements, each element has
- * a key (id) and a value. A HashMap correlates the ids to an index in the pool.
- * To keep track of which items were recently used two bit arrays are kept, one
- * stores the "used" flag for each index and anothe the "present" flag.
- * Every NCYCLES operations the present and used arrays are updated to free up
- * the elements that were not recently used.
- */
-
-// FIXME: this module should really allocate all resources on an arena or temp
-//        allocator, since all memory allocations are connected and freeing
-//        happens at the same time
-
-import std::core::mem;
-import std::collections::bitset;
-import std::collections::map;
-
-def BitArr = bitset::BitSet(<SIZE>) @private;
-def IdTable = map::HashMap(<Key, usz>) @private;
-def IdTableEntry = map::Entry(<Key, usz>) @private;
-
-const usz CACHE_NCYCLES = (usz)(SIZE * 2.0/3.0);
-
-struct Cache {
-    BitArr present, used;
-    IdTable table;
-    Value[] pool;
-    usz cycle_count;
-}
-
-// Every CACHE_CYCLES operations mark as not-present the unused elements
-macro Cache.cycle(&cache) @private {
-    cache.cycle_count++;
-	if (cache.cycle_count > CACHE_NCYCLES) {
-		for (usz i = 0; i < cache.present.data.len; i++) {
-			cache.present.data[i] &= cache.used.data[i];
-			cache.used.data[i] = 0;
-		}
-		cache.cycle_count = 0;
-	}
-}
-
-fn void! Cache.init(&cache)
-{
-    cache.table.new_init(capacity: SIZE);
-    // FIXME: this shit is SLOW
-    foreach (idx, bit : cache.used) { cache.used[idx] = false; }
-    foreach (idx, bit : cache.present) { cache.present[idx] = false; }
-    cache.pool = mem::new_array(Value, SIZE);
-}
-
-fn void Cache.free(&cache)
-{
-    (void)cache.table.free();
-    (void)mem::free(cache.pool);
-}
-
-fn Value*! Cache.search(&cache, Key id)
-{
-    // get_entry() faults on miss
-	IdTableEntry* entry = cache.table.get_entry(id)!;
-
-	/* MISS */
-	if (entry.key != id) {
-	   return SearchResult.MISSING?;
-	}
-
-	/* MISS, the data is not valid (not present) */
-	if (!cache.present[entry.value]) {
-	    // if the data is not present but it is still in the table, remove it
-		cache.table.remove(id)!;
-		return SearchResult.MISSING?;
-	}
-
-	/* HIT, set as recently used */
-	cache.used[entry.value] = true;
-	return &(cache.pool[entry.value]);
-}
-
-/* Look for a free spot in the present bitmap and return its index */
-/* If there is no free space left then just return the first position */
-fn usz Cache.get_free_spot(&cache) @private
-{
-    const BITS = $typeof(cache.present.data[0]).sizeof*8;
-    foreach (idx, d: cache.present.data) {
-		if (d.clz() != BITS) {
-			return idx*BITS + BITS-d.clz();
-		}
-	}
-	return 0;
-}
-
-fn Value*! Cache.insert_at(&cache, Value *g, Key id, usz index) @private
-{
-    // TODO: verify index, g and id
-	Value* spot;
-
-	/* Set used and present */
-	cache.present.set(index);
-	cache.used.set(index);
-	cache.cycle();
-
-	spot = &(cache.pool[index]);
-	*spot = *g;
-	cache.table.set(id, index);
-	return spot;
-}
-
-// Insert an element in the cache, returns the index
-fn Value*! Cache.insert_new(&cache, Value* g, Key id)
-{
-	usz index = cache.get_free_spot();
-	return cache.insert_at(g, id, index);
-}
-
-fn Value*! Cache.get_or_insert(&cache, Value* g, Key id, bool *is_new = null)
-{
-    Value*! c = cache.search(id);
-    if (catch e = c) {
-        if (e != SearchResult.MISSING) {
-            return e?;
-        } else {
-        	// if the element is new (inserted) set the is_new flag
-         	if (is_new) *is_new = true;
-        	return cache.insert_new(g, id);
-        }
-    } else {
-    	if (is_new) *is_new = false;
-        return c;
-    }
-}

src/fifo.c3

@@ -1,49 +0,0 @@
-module fifo(<Type>);
-
-import std::core::mem;
-
-fault FifoErr {
-	FULL,
-	EMPTY,
-}
-
-// TODO: specify the allocator
-
-struct Fifo {
-	Type[] arr;
-	usz out;
-	usz count;
-}
-
-fn void! Fifo.init(&fifo, usz size)
-{
-	fifo.arr = mem::new_array(Type, size);
-	fifo.out = 0;
-	fifo.count = 0;
-}
-
-fn void Fifo.free(&fifo)
-{
-	(void)mem::free(fifo.arr);
-}
-
-fn void! Fifo.enqueue(&fifo, Type *elem)
-{
-	if (fifo.count >= fifo.arr.len) {
-		return FifoErr.FULL?;
-	}
-	usz in = (fifo.out + fifo.count) % fifo.arr.len;
-	fifo.arr[in] = *elem;
-	fifo.count++;
-}
-
-fn Type*! Fifo.dequeue(&fifo)
-{
-	if (fifo.count == 0) {
-		return FifoErr.EMPTY?;
-	}
-	Type *ret = &fifo.arr[fifo.out];
-	fifo.count--;
-	fifo.out = (fifo.out + 1) % fifo.arr.len;
-	return ret;
-}

src/main.c3

@@ -1,166 +0,0 @@
-import std::io;
-import vtree;
-import cache;
-import ugui;
-import rl;
-
-fn int main(String[] args)
-{
-	ugui::Ctx ui;
-	ui.init()!!;
-
-	short width = 800;
-	short height = 450;
-	rl::set_config_flags(rl::FLAG_WINDOW_RESIZABLE);
-	rl::init_window(width, height, "Ugui Test");
-	ui.input_window_size(width, height)!!;
-	rl::set_target_fps(60);
-	rl::enable_event_waiting();
-
-	isz frame;
-
-	// Main loop
-	while (!rl::window_should_close()) {
-		const int PARTIAL_INPUT  = 0;
-		const int PARTIAL_LAYOUT = 1;
-		const int PARTIAL_DRAW   = 2;
-
-		/* Start Input Handling */
-		if (rl::is_window_resized()) {
-			width  = (short)rl::get_screen_width();
-			height = (short)rl::get_screen_height();
-			ui.input_window_size(width, height)!!;
-		}
-
-		ui.input_changefocus(rl::is_window_focused());
-
-		rl::Vector2 mpos = rl::get_mouse_position();
-		ui.input_mouse_abs((short)mpos.x, (short)mpos.y);
-
-		ugui::MouseButtons buttons;
-		buttons.btn_left = rl::is_mouse_button_down(rl::MOUSE_BUTTON_LEFT);
-		buttons.btn_right = rl::is_mouse_button_down(rl::MOUSE_BUTTON_RIGHT);
-		buttons.btn_middle = rl::is_mouse_button_down(rl::MOUSE_BUTTON_MIDDLE);
-		ui.input_mouse_button(buttons);
-		/* End Input Handling */
-
-		/* Start UI Handling */
-		ui.frame_begin()!!;
-
-/*
-		// main div, fill the whole window
-		ui.div_begin("main", ugui::Rect{.w=ui.width/2})!!;
-		{|
-			ui.layout_set_row()!!;
-			if (ui.button("button0", ugui::Rect{0,0,30,30})!!.mouse_press) {
-				io::printn("press button0");
-			}
-			//ui.layout_next_column()!!;
-			if (ui.button("button1", ugui::Rect{0,0,30,30})!!.mouse_press) {
-				io::printn("press button1");
-			}
-			//ui.layout_next_column()!!;
-			if (ui.button("button2", ugui::Rect{0,0,30,30})!!.mouse_release) {
-				io::printn("release button2");
-			}
-			if (ui.slider_ver("slider", ugui::Rect{0,0,30,100})!!.update) {
-				ugui::Elem* e = ui.get_elem_by_label("slider")!!;
-				io::printfn("slider: %f", e.slider.value);
-			}
-		|};
-		ui.div_end()!!;
-*/
-		ui.div_begin("second", ugui::DIV_FILL)!!;
-		ugui::Elem* de = ui.get_elem_by_label("second")!!;
-		de.div.scroll.can_y = true;
-		{|
-			ui.layout_set_column()!!;
-			if (ui.slider_ver("slider_other", ugui::Rect{0,0,30,100})!!.update) {
-				ugui::Elem* e = ui.get_elem_by_label("slider_other")!!;
-				io::printfn("other slider: %f", e.slider.value);
-			}
-			ui.button("button10", ugui::Rect{0,0,50,50})!!;
-			ui.button("button11", ugui::Rect{0,0,50,50})!!;
-			ui.button("button12", ugui::Rect{0,0,50,50})!!;
-			ui.button("button13", ugui::Rect{0,0,50,50})!!;
-			ui.button("button14", ugui::Rect{0,0,50,50})!!;
-			ui.button("button15", ugui::Rect{0,0,50,50})!!;
-			ui.button("button16", ugui::Rect{0,0,50,50})!!;
-			ui.button("button17", ugui::Rect{0,0,50,50})!!;
-		|};
-		ui.div_end()!!;
-
-		ui.frame_end()!!;
-		/* End UI Handling */
-
-		/* Start UI Drawing */
-		rl::begin_drawing();
-		// ClearBackground(BLACK);
-
-		rl::Color c;
-		for (Cmd* cmd; (cmd = ui.cmd_queue.dequeue() ?? null) != null;) {
-			switch (cmd.type) {
-			case ugui::CmdType.CMD_RECT:
-				c = rl::Color{
-				    .r = cmd.rect.color.r,
-				    .g = cmd.rect.color.g,
-				    .b = cmd.rect.color.b,
-				    .a = cmd.rect.color.a,
-				};
-				rl::draw_rectangle(
-				    cmd.rect.rect.x,
-				    cmd.rect.rect.y,
-				    cmd.rect.rect.w,
-				    cmd.rect.rect.h,
-				    c
-				);
-			default:
-				io::printfn("Unknown cmd type: %d", cmd.type);
-			}
-		}
-
-		rl::end_drawing();
-	}
-
-	rl::close_window();
-
-	ui.free();
-	return 0;
-}
-
-/*
-fn void! test_vtree() @test
-{
-    vtree::VTree(<String>) vt;
-    vt.init(10)!!;
-    defer vt.free();
-
-    assert(vt.size() == 10, "Size is incorrect");
-
-    isz ref = vt.add("Ciao Mamma", 0)!!;
-    String s = vt.get(ref)!!;
-    assert(s == "Ciao Mamma", "String is incorrect");
-    isz par = vt.parentof(0)!!;
-    assert(ref == par, "Not Root");
-
-    vt.print();
-}
-
-def StrCache = cache::Cache(<int, String, 256>);
-fn void! test_cache() @test
-{
-	StrCache cc;
-	cc.init()!!;
-	defer cc.free();
-
-	String*! r = cc.search(1);
-	if (catch ex = r) {
-		if (ex != SearchResult.MISSING) {
-			return ex?;
-		}
-	}
-
-	r = cc.get_or_insert(&&"Ciao Mamma", 1)!;
-	assert(*r!! == "Ciao Mamma", "incorrect string");
-}
-*/

src/ugui_button.c3

@@ -1,47 +0,0 @@
-module ugui;
-
-import std::io;
-
-// draw a button, return the events on that button
-fn ElemEvents! Ctx.button(&ctx, String label, Rect size)
-{
-	Id id = label.hash();
-
-	Elem *parent = ctx.get_parent()!;
-	Elem *c_elem = ctx.get_elem(id)!;
-	// add it to the tree
-	ctx.tree.add(id, ctx.active_div)!;
-
-	// 1. Fill the element fields
-	// this resets the flags
-	c_elem.type     = ETYPE_BUTTON;
-	Color bg_color = uint_to_rgba(0x0000ffff);
-
-	// if the element is new or the parent was updated then redo layout
-	if (c_elem.flags.is_new || parent.flags.updated) {
-		// 2. Layout
-		c_elem.bounds = ctx.position_element(parent, size, true);
-
-		// TODO: 3. Fill the button specific fields
-	}
-
-	c_elem.events = ctx.get_elem_events(c_elem);
-	if (parent.flags.has_focus) {
-		if (c_elem.events.mouse_hover) {
-			c_elem.flags.has_focus = true;
-			bg_color = uint_to_rgba(0x00ff00ff);
-		}
-	}
-
-	// Draw the button
-	Cmd cmd = {
-	    .type = CMD_RECT,
-	    .rect =	{
-		    .rect  = c_elem.bounds,
-		    .color = bg_color,
-		},
-	};
-	ctx.cmd_queue.enqueue(&cmd)!;
-
-	return c_elem.events;
-}

src/ugui_data.c3

@@ -1,213 +0,0 @@
-module ugui;
-
-import std::io;
-import std::core::string;
-
-import vtree;
-import cache;
-import fifo;
-
-
-struct Rect {
-	short x, y, w, h;
-}
-
-struct Point {
-	short x, y;
-}
-
-struct Color{
-	char r, g, b, a;
-}
-
-// element ids are just long ints
-def Id = usz;
-
-enum ElemType {
-	ETYPE_NONE,
-	ETYPE_DIV,
-	ETYPE_BUTTON,
-	ETYPE_SLIDER,
-}
-
-bitstruct ElemFlags : uint {
-	bool updated : 0;
-	bool has_focus : 1;
-	bool is_new : 2;
-}
-
-bitstruct ElemEvents : uint {
-	bool key_press     : 0;
-	bool key_release   : 1;
-	bool key_hold      : 2;
-	bool mouse_hover   : 3;
-	bool mouse_press   : 4;
-	bool mouse_release : 5;
-	bool mouse_hold    : 6;
-	bool update        : 7;
-}
-
-enum DivLayout {
-	LAYOUT_ROW,
-	LAYOUT_COLUMN,
-	LAYOUT_FLOATING,
-}
-
-// div element
-struct Div {
-	DivLayout layout;
-	struct scroll {
-		bool can_x;
-		bool can_y;
-		bool on_x;
-		bool on_y;
-		float value_x;
-		float value_y;
-	}
-	Rect children_bounds;
-	Point origin_r, origin_c;
-	Color color_bg;
-}
-
-// slider element
-struct Slider {
-    float value;
-    Rect handle;
-}
-
-// element structure
-struct Elem {
-	Id id;
-	ElemFlags flags;
-	ElemEvents events;
-	Rect bounds;
-	ElemType type;
-	union {
-		Div div;
-		Slider slider;
-	}
-}
-
-
-// relationships between elements are stored in a tree, it stores just the ids
-def IdTree = vtree::VTree(<Id>) @private;
-
-// elements themselves are kept in a cache
-const uint MAX_ELEMENTS = 1024;
-def ElemCache = cache::Cache(<Id, Elem, MAX_ELEMENTS>) @private;
-
-def CmdQueue = fifo::Fifo(<Cmd>);
-
-fault UgError {
-	INVALID_SIZE,
-	EVENT_UNSUPPORTED,
-	UNEXPECTED_ELEMENT,
-}
-
-macro uint_to_rgba(uint u) {
-	return Color{
-		.r = (char)((u >> 24) & 0xff),
-		.g = (char)((u >> 16) & 0xff),
-		.b = (char)((u >> 8) & 0xff),
-		.a = (char)((u >> 0) & 0xff)
-	};
-}
-
-const Rect DIV_FILL = { .x = 0, .y = 0, .w = 0, .h = 0 };
-
-macro abs(a) { return a < 0 ? -a : a; }
-macro clamp(x, min, max) { return x < min ? min : (x > max ? max : x); }
-
-const uint STACK_STEP = 10;
-const uint MAX_ELEMS  = 128;
-const uint MAX_CMDS   = 256;
-const uint ROOT_ID    = 1;
-
-// command type
-enum CmdType {
-	CMD_RECT,
-}
-
-// command to draw a rect
-struct CmdRect {
-	Rect rect;
-	Color color;
-}
-
-// command structure
-struct Cmd {
-	CmdType type;
-	union {
-		CmdRect rect;
-	}
-}
-
-enum Layout {
-	ROW,
-	COLUMN,
-	FLOATING
-}
-
-// global style, similar to the css box model
-struct Style { // css box model
-	Rect  padding;
-	Rect  border;
-	Rect  margin;
-	Color bgcolor; // background color
-	Color fgcolor; // foreground color
-	Color bcolor;  // border color
-}
-
-
-struct Ctx {
-	Layout layout;
-	IdTree tree;
-	ElemCache cache;
-	CmdQueue cmd_queue;
-	// total size in pixels of the context
-	ushort width, height;
-	Style style;
-
-	bool has_focus;
-	struct input {
-		InputEvents events;
-		struct mouse {
-			Point pos, delta;
-			// mouse_down:      bitmap of mouse buttons that are held
-			// mouse_updated:   bitmap of mouse buttons that have been updated
-			// mouse_released = mouse_updated & ~mouse_down
-			// mouse_pressed  = mouse_updated & mouse_down
-			MouseButtons down;
-			MouseButtons updated;
-		}
-	}
-
-	isz active_div; // tree node indicating the current active div
-}
-
-macro point_in_rect(Point p, Rect r)
-{
-	return (p.x >= r.x && p.x <= r.x + r.w) && (p.y >= r.y && p.y <= r.y + r.h);
-}
-
-// return true if rect a contains b
-macro rect_contains(Rect a, Rect b)
-{
-	return (a.x <= b.x && a.y <= b.y && a.x+a.w >= b.x+b.w && a.y+a.h >= b.y+b.h);
-}
-
-macro rect_intersection(Rect a, Rect b)
-{
-	return Rect{
-		.x = (short)max(a.x, b.x),
-		.y = (short)max(a.y, b.y),
-		.w = (short)min(a.x+a.w, b.x+b.w) - (short)max(a.x, b.x),
-		.h = (short)min(a.y+a.h, b.y+b.h) - (short)max(a.y, b.y),
-	};
-}
-
-// rect intersection not null
-macro rect_collision(Rect a, Rect b)
-{
-	return !(a.x > b.x+b.w || a.x+a.w < b.x || a.y > b.y+b.h || a.y+a.h < b.y);
-}

src/ugui_div.c3

@@ -1,131 +0,0 @@
-module ugui;
-
-import std::io;
-
-fn void! Ctx.div_begin(&ctx, String label, Rect size)
-{
-	Id id = label.hash();
-
-	Elem *parent = ctx.get_parent()!;
-	Elem* c_elem = ctx.get_elem(id)!;
-	isz div_node = ctx.tree.add(id, ctx.active_div)!;
-	ctx.active_div = div_node;
-
-	// 1. Fill the element fields
-	c_elem.type  = ETYPE_DIV;
-
-	// do layout and update flags only if the element was updated
-	if (c_elem.flags.is_new || parent.flags.updated) {
-		// 2. layout the element
-		c_elem.bounds = ctx.position_element(parent, size);
-		if (c_elem.flags.is_new) {
-			c_elem.div.children_bounds = c_elem.bounds;
-		}
-
-		// 3. Mark the element as updated
-		c_elem.flags.updated = true;
-		// 4. Fill the div fields
-		c_elem.div.layout   = parent.div.layout;
-		c_elem.div.origin_c = Point{
-		    .x = c_elem.bounds.x,
-		    .y = c_elem.bounds.y,
-		};
-		c_elem.div.origin_r = c_elem.div.origin_c;
-		c_elem.div.color_bg = uint_to_rgba(0xff0000ff);
-		c_elem.div.scroll.can_x = false;
-		c_elem.div.scroll.can_y = false;
-		c_elem.div.scroll.value_x = 0;
-		c_elem.div.scroll.value_y = 0;
-	}
-
-	// Add the background to the draw stack
-	Cmd cmd = {
-		.type = CMD_RECT,
-		.rect = {
-		    .rect  = c_elem.bounds,
-		    .color = c_elem.div.color_bg,
-		},
-	};
-	ctx.cmd_queue.enqueue(&cmd)!;
-
-	// TODO: check active
-	// TODO: check resizeable
-
-	// check and draw scroll bars
-	if (!rect_contains(c_elem.bounds, c_elem.div.children_bounds)) {
-		Point cbc = {
-			.x = c_elem.div.children_bounds.x + c_elem.div.children_bounds.w,
-			.y = c_elem.div.children_bounds.y + c_elem.div.children_bounds.h,
-		};
-		Point bc = {
-			.x = c_elem.bounds.x + c_elem.bounds.w,
-			.y = c_elem.bounds.y + c_elem.bounds.h,
-		};
-		// vertical overflow, check and draw scroll bar
-		if (cbc.y > bc.y && c_elem.div.scroll.can_y) {
-			// set the scrollbar flag, is used in layout
-			c_elem.div.scroll.on_y = true;
-
-			Rect vslider = {
-				.x = c_elem.bounds.x + c_elem.bounds.w - 10,
-				.y = c_elem.bounds.y,
-				.w = 10,
-				.h = c_elem.bounds.h,
-			};
-
-			float vh = max((float)bc.y / cbc.y, (float)0.15);
-			Rect vhandle = {
-				.x = c_elem.bounds.x + c_elem.bounds.w - 10,
-				.y = (short)(c_elem.bounds.y + (int)(c_elem.bounds.h*(1-vh) * c_elem.div.scroll.value_y)),
-				.w = 10,
-				.h = (short)(c_elem.bounds.h * vh),
-			};
-
-			c_elem.events = ctx.get_elem_events(c_elem);
-			if (parent.flags.has_focus && c_elem.events.mouse_hover && c_elem.events.mouse_hold && point_in_rect(ctx.input.mouse.pos, vhandle)) {
-				short y = (short)clamp(ctx.input.mouse.pos.y - vhandle.h/2, vslider.y, vslider.y + vslider.h - vhandle.h);
-				vhandle.y = y;
-				float v = (float)(vhandle.y-vslider.y) / (float)(vslider.h-vhandle.h);
-				c_elem.div.scroll.value_y = v;
-				c_elem.flags.updated = true;
-				c_elem.div.origin_c = Point{
-					.x = c_elem.bounds.x,
-					.y = c_elem.bounds.y,
-				};
-				c_elem.div.origin_r = c_elem.div.origin_c;
-			}
-
-			Cmd scrl = {
-				.type = CMD_RECT,
-				.rect.rect = vslider,
-				.rect.color = uint_to_rgba(0x999999ff),
-			};
-			ctx.cmd_queue.enqueue(&scrl)!;
-
-			scrl.rect.rect = vhandle;
-			scrl.rect.color = uint_to_rgba(0x9999ffff);
-			ctx.cmd_queue.enqueue(&scrl)!;
-
-		} else {
-			c_elem.div.scroll.on_y = false;
-		}
-	}
-
-	// if the bounds are outside of the view then allocate space for scrollbars
-	DivLayout old_layout = c_elem.div.layout;
-	c_elem.div.layout = LAYOUT_FLOATING;
-	c_elem.div.layout = old_layout;
-
-	if (parent.flags.has_focus) {
-		if (point_in_rect(ctx.input.mouse.pos, c_elem.bounds)) {
-			c_elem.flags.has_focus = true;
-		}
-	}
-
-}
-
-fn void! Ctx.div_end(&ctx)
-{
-	// the active_div returns to the parent of the current one
-	ctx.active_div = ctx.tree.parentof(ctx.active_div)!;
-}

src/ugui_impl.c3

@@ -1,139 +0,0 @@
-module ugui;
-
-import std::io;
-
-// return a pointer to the parent of the current active div
-fn Elem*! Ctx.get_parent(&ctx)
-{
-	// FIXME: if the tree held pointers to the elements then no more
-	//        redundant cache search
-	Id parent_id = ctx.tree.get(ctx.active_div)!;
-	return ctx.cache.search(parent_id);
-}
-
-// get or push an element from the cache, return a pointer to it
-// resets all flags except is_new which is set accordingly
-macro Ctx.get_elem(&ctx, Id id)
-{
-	Elem empty_elem;
-	bool is_new;
-	Elem* c_elem;
-	c_elem = ctx.cache.get_or_insert(&empty_elem, id, &is_new)!;
-	c_elem.flags = (ElemFlags)0;
-	c_elem.flags.is_new = is_new;
-	return c_elem;
-}
-
-// this searches an element in the cache by label, it does not create a new element
-// if it does't find one
-macro Ctx.get_elem_by_label(&ctx, String label)
-{
-    Id id = label.hash();
-    return ctx.cache.search(id);
-}
-
-macro Ctx.get_elem_by_tree_idx(&ctx, isz idx) @private
-{
-    Id id = ctx.tree.get(ctx.active_div)!;
-	return ctx.cache.search(id);
-}
-
-fn void! Ctx.init(&ctx)
-{
-	ctx.tree.init(MAX_ELEMENTS)!;
-	defer catch { (void)ctx.tree.free(); }
-	//ug_fifo_init(&ctx.fifo, MAX_CMDS);
-
-	ctx.cache.init()!;
-	defer catch { (void)ctx.cache.free(); }
-
-	ctx.cmd_queue.init(MAX_ELEMENTS)!;
-	defer catch { (void)ctx.cmd_queue.free(); }
-
-	ctx.layout = Layout.ROW;
-	ctx.active_div = 0;
-
-	// TODO: add style config
-	ctx.style.margin  = Rect{1, 1, 1, 1};
-}
-
-fn void Ctx.free(&ctx)
-{
-	(void)ctx.tree.free();
-	(void)ctx.cache.free();
-	(void)ctx.cmd_queue.free();
-}
-
-fn void! Ctx.frame_begin(&ctx)
-{
-
-	// 2. Get the root element from the cache and update it
-	Elem* c_elem = ctx.get_elem(ROOT_ID)!;
-	// The root should have the updated flag only if the size of the window
-	// was changed between frames, this propagates an element size recalculation
-	// down the element tree
-	c_elem.flags.updated = ctx.input.events.resize;
-	// if the window has focus then the root element also has focus, no other
-	// computation needed, child elements need to check the mouse positon and
-	// other stuff
-	c_elem.flags.has_focus = ctx.has_focus;
-
-	if (c_elem.flags.is_new || c_elem.flags.updated) {
-	Elem def_root = {
-		.id = ROOT_ID,
-		.type = ETYPE_DIV,
-		.bounds = {
-			.w = ctx.width,
-			.h = ctx.height,
-		},
-		.div = {
-			.layout = LAYOUT_ROW,
-			.children_bounds = {
-				.w = ctx.width,
-				.h = ctx.height,
-			}
-		},
-		.flags = c_elem.flags,
-	};
-
-	*c_elem = def_root;
-	}
-
-	// 3. Push the root element into the element tree
-	ctx.active_div = ctx.tree.add(ROOT_ID, 0)!;
-
-	// The root element does not push anything to the stack
-	// TODO: add a background color taken from a theme or config
-}
-
-fn void! Ctx.frame_end(&ctx)
-{
-	// 1. clear the tree
-	ctx.tree.prune(0)!;
-
-	// 2. clear input fields
-	ctx.input.events = (InputEvents)0;
-
-	// draw mouse position
-$if 1:
-	Cmd cmd = {
-	    .type = CMD_RECT,
-	    .rect.rect = {
-		    .x = ctx.input.mouse.pos.x - 2,
-		    .y = ctx.input.mouse.pos.y - 2,
-		    .w = 4,
-		    .h = 4,
-		},
-		.rect.color = uint_to_rgba(0xff00ffff)
-	};
-	ctx.cmd_queue.enqueue(&cmd)!;
-$endif
-}
-
-/**
- * @ensure elem != null
-**/
-fn bool Ctx.is_hovered(&ctx, Elem *elem)
-{
-	return point_in_rect(ctx.input.mouse.pos, elem.bounds);
-}

src/ugui_input.c3

@@ -1,135 +0,0 @@
-module ugui;
-
-import std::io;
-
-// TODO: this could be a bitstruct
-bitstruct InputEvents : uint {
-	bool resize : 0; // window size was changed
-	bool change_focus : 1; // window focus changed
-	bool mouse_move : 2; // mouse was moved
-	bool mouse_btn : 3; // mouse button pressed or released
-}
-
-// Window size was changed
-fn void! Ctx.input_window_size(&ctx, short width, short height)
-{
-	if (width <= 0 || height <= 0) {
-		return UgError.INVALID_SIZE?;
-	}
-	ctx.width = width;
-	ctx.height = height;
-	ctx.input.events.resize = true;
-}
-
-// Window gained/lost focus
-fn void Ctx.input_changefocus(&ctx, bool has_focus)
-{
-	// FIXME: raylib only has an API to query the focus status so we have to
-	//        update the input flag only if the focus changed
-	if (ctx.has_focus != has_focus) {
-		ctx.input.events.change_focus = true;
-	}
-	ctx.has_focus = has_focus;
-}
-
-bitstruct MouseButtons : uint {
-	bool btn_left : 0;
-	bool btn_middle : 1;
-	bool btn_right : 2;
-	bool btn_4 : 3;
-	bool btn_5 : 4;
-}
-
-macro Ctx.mouse_pressed(&ctx)
-{
-    return ctx.input.mouse.updated & ctx.input.mouse.down;
-}
-
-macro Ctx.mouse_released(&ctx)
-{
-    return ctx.input.mouse.updated & ~ctx.input.mouse.down;
-}
-
-macro Ctx.mouse_down(&ctx)
-{
-    return ctx.input.mouse.down;
-}
-
-const MouseButtons BTN_NONE = (MouseButtons)0u;
-const MouseButtons BTN_ANY = (MouseButtons)(uint.max);
-const MouseButtons BTN_LEFT = {.btn_left = true};
-const MouseButtons BTN_MIDDLE = {.btn_middle = true};
-const MouseButtons BTN_RIGHT = {.btn_right = true};
-const MouseButtons BTN_4 = {.btn_4 = true};
-const MouseButtons BTN_5 = {.btn_5 = true};
-
-// FIXME: hthis compairson could be done with a cast using MouseButtons.inner
-// property but I could not figure out how
-macro Ctx.is_mouse_pressed(&ctx, MouseButtons btn)
-{
-    return (ctx.mouse_pressed() & btn) != BTN_NONE;
-}
-
-macro Ctx.is_mouse_released(&ctx, MouseButtons btn)
-{
-    return (ctx.mouse_released() & btn) != BTN_NONE;
-}
-
-macro Ctx.is_mouse_down(&ctx, MouseButtons btn)
-{
-    return (ctx.mouse_down() & btn) != BTN_NONE;
-}
-
-macro ElemEvents Ctx.get_elem_events(&ctx, Elem *elem)
-{
-    // TODO: add the other events
-    // FIXME: active should be elsewhere
-    bool active = elem.events.mouse_hold || ctx.is_hovered(elem);
-    ElemEvents ev = {
-        .mouse_hover = ctx.is_hovered(elem),
-        .mouse_press = active & ctx.is_mouse_pressed(BTN_ANY),
-		.mouse_release = active & ctx.is_mouse_released(BTN_ANY),
-		.mouse_hold = active & ctx.is_mouse_down(BTN_ANY),
-    };
-    return ev;
-}
-
-// Mouse Button moved
-fn void Ctx.input_mouse_button(&ctx, MouseButtons buttons)
-{
-	ctx.input.mouse.updated = ctx.input.mouse.down ^ buttons;
-	ctx.input.mouse.down = buttons;
-	ctx.input.events.mouse_btn = true;
-}
-
-// Mouse was moved, report absolute position
-fn void Ctx.input_mouse_abs(&ctx, short x, short y)
-{
-	ctx.input.mouse.pos.x = clamp(x, 0u16, ctx.width);
-	ctx.input.mouse.pos.y = clamp(y, 0u16, ctx.height);
-
-	short dx, dy;
-	dx = x - ctx.input.mouse.pos.x;
-	dy = y - ctx.input.mouse.pos.y;
-
-	ctx.input.mouse.delta.x = dx;
-	ctx.input.mouse.delta.y = dy;
-
-	ctx.input.events.mouse_move = true;
-}
-
-// Mouse was moved, report relative motion
-fn void Ctx.input_mouse_delta(&ctx, short dx, short dy)
-{
-	ctx.input.mouse.delta.x = dx;
-	ctx.input.mouse.delta.y = dy;
-
-	short mx, my;
-	mx = ctx.input.mouse.pos.x + dx;
-	my = ctx.input.mouse.pos.y + dy;
-
-	ctx.input.mouse.pos.x = clamp(mx, 0u16, ctx.width);
-	ctx.input.mouse.pos.y = clamp(my, 0u16, ctx.height);
-
-	ctx.input.events.mouse_move = true;
-}

src/ugui_layout.c3

@@ -1,177 +0,0 @@
-module ugui;
-
-
-fn void! Ctx.layout_set_row(&ctx)
-{
-	Id parent_id = ctx.tree.get(ctx.active_div)!;
-	Elem *parent = ctx.cache.search(parent_id)!;
-
-	if (parent.type != ETYPE_DIV) {
-		// what?
-		return UgError.UNEXPECTED_ELEMENT?;
-	}
-
-	parent.div.layout = LAYOUT_ROW;
-}
-
-fn void! Ctx.layout_set_column(&ctx)
-{
-	Id parent_id = ctx.tree.get(ctx.active_div)!;
-	Elem *parent = ctx.cache.search(parent_id)!;
-
-	if (parent.type != ETYPE_DIV) {
-		// what?
-		return UgError.UNEXPECTED_ELEMENT?;
-	}
-
-	parent.div.layout = LAYOUT_COLUMN;
-}
-
-fn void! Ctx.layout_set_floating(&ctx)
-{
-	Id parent_id = ctx.tree.get(ctx.active_div)!;
-	Elem *parent = ctx.cache.search(parent_id)!;
-
-	if (parent.type != ETYPE_DIV) {
-		// what?
-		return UgError.UNEXPECTED_ELEMENT?;
-	}
-
-	parent.div.layout = LAYOUT_FLOATING;
-}
-
-fn void! Ctx.layout_next_row(&ctx)
-{
-	Id parent_id = ctx.tree.get(ctx.active_div)!;
-	Elem *parent = ctx.cache.search(parent_id)!;
-
-	if (parent.type != ETYPE_DIV) {
-		// what?
-		return UgError.UNEXPECTED_ELEMENT?;
-	}
-
-	parent.div.origin_r = Point{
-	    .x = parent.bounds.x,
-	    .y = parent.div.origin_c.y,
-	};
-	parent.div.origin_c = parent.div.origin_r;
-}
-
-fn void! Ctx.layout_next_column(&ctx)
-{
-	Id parent_id = ctx.tree.get(ctx.active_div)!;
-	Elem *parent = ctx.cache.search(parent_id)!;
-
-	if (parent.type != ETYPE_DIV) {
-		// what?
-		return UgError.UNEXPECTED_ELEMENT?;
-	}
-
-	parent.div.origin_c = Point{
-	    .x = parent.div.origin_r.x,
-	    .y = parent.bounds.y,
-	};
-	parent.div.origin_r = parent.div.origin_c;
-}
-
-// position the rectangle inside the parent according to the layout
-// parent: parent div
-// rect: the requested size
-// style: apply style
-<*
-@require ctx != null
-@require parent.type == ETYPE_DIV
-*>
-fn Rect Ctx.position_element(&ctx, Elem *parent, Rect rect, bool style = false)
-{
-	Rect  placement;
-	Point origin;
-	Div* div = &parent.div;
-
-	// 1. Select the right origin
-	switch (div.layout) {
-	case LAYOUT_ROW:
-		origin = div.origin_r;
-	case LAYOUT_COLUMN:
-		origin = div.origin_c;
-	case LAYOUT_FLOATING: // none
-	default:
-		// Error
-	}
-
-	// the bottom-right border of the element box
-	Point pl_corner;
-
-	// 2. Calculate the placement
-	placement.x = (short)max(origin.x + rect.x, 0);
-	placement.y = (short)max(origin.y + rect.y, 0);
-	placement.w = rect.w > 0 ? rect.w : (short)max(parent.bounds.w - (placement.x - parent.bounds.x), 0);
-	placement.h = rect.h > 0 ? rect.h : (short)max(parent.bounds.h - (placement.y - parent.bounds.y), 0);
-
-	pl_corner.x = placement.x + placement.w;
-	pl_corner.y = placement.y + placement.h;
-
-	// 2.1 apply style, css box model
-	if (style) {
-	    Rect margin = ctx.style.margin;
-	    Rect border = ctx.style.border;
-		Rect padding = ctx.style.padding;
-
-		placement.x += margin.x;
-		placement.y += margin.y;
-		if (rect.w != 0) { placement.w += margin.x+margin.w + padding.x+padding.w; }
-		if (rect.h != 0) { placement.h += margin.y+margin.h + padding.y+padding.h; }
-
-		pl_corner.x = placement.x + placement.w + margin.w;
-		pl_corner.y = placement.y + placement.h + margin.h;
-	}
-
-	// 3. Update the origins of the parent
-	div.origin_r = Point{
-	    .x = pl_corner.x,
-	    .y = origin.y,
-	};
-	div.origin_c = Point{
-	    .x = origin.x,
-	    .y = pl_corner.y,
-	};
-
-	// 4. Calculate the "scrolled" view
-	Point off;
-	Rect* cb = &div.children_bounds;
-	if (div.scroll.can_x && div.scroll.on_x) {
-		off.x = (short)(cb.w * div.scroll.value_x);
-	}
-	if (div.scroll.can_y && div.scroll.on_y) {
-		off.y = (short)((float)(cb.h - parent.bounds.h) * div.scroll.value_y);
-	}
-	Rect view = {
-		.x = parent.bounds.x + off.x,
-		.y = parent.bounds.y + off.y,
-		.w = parent.bounds.w,
-		.h = parent.bounds.h,
-	};
-
-	// 5. check if the placement overflows the children ounds, if so update them
-	if (!point_in_rect(pl_corner, *cb)) {
-		if (pl_corner.y > cb.y+cb.h) {
-			cb.h = pl_corner.y - cb.y;
-		}
-		if (pl_corner.x > cb.x+cb.w) {
-			cb.w += pl_corner.x - (cb.x + cb.w);
-		}
-	}
-
-	// 6. check if the placement is inside the view
-	if (rect_collision(placement, view)) {
-		return Rect{
-			.x = placement.x - off.x,
-			.y = placement.y - off.y,
-			.w = placement.w,
-			.h = placement.h,
-		};
-	} else {
-		return Rect{};
-	}
-}
-

src/ugui_slider.c3

@@ -1,140 +0,0 @@
-module ugui;
-
-import std::io;
-
-/*       handle
- * +----+-----+---------------------+
- * |    |#####|                     |
- * +----+-----+---------------------+
- */
-fn ElemEvents! Ctx.slider_hor(&ctx, String label, Rect size)
-{
-    Id id = label.hash();
-
-	Elem *parent = ctx.get_parent()!;
-	Elem *c_elem = ctx.get_elem(id)!;
-	// add it to the tree
-	ctx.tree.add(id, ctx.active_div)!;
-
-	// 1. Fill the element fields
-	c_elem.type = ETYPE_SLIDER;
-
-	// if the element is new or the parent was updated then redo layout
-	if (c_elem.flags.is_new || parent.flags.updated) {
-		// 2. Layout
-		c_elem.bounds = ctx.position_element(parent, size, true);
-		c_elem.slider.handle = Rect{
-			.x = (short)(c_elem.bounds.x + (int)(c_elem.bounds.w * c_elem.slider.value)),
-			.y = c_elem.bounds.y,
-			.w = (short)(c_elem.bounds.w * 0.25),
-			.h = c_elem.bounds.h,
-		};
-	}
-
-	c_elem.events = ctx.get_elem_events(c_elem);
-	if (parent.flags.has_focus && c_elem.events.mouse_hover) {
-	    if (point_in_rect(ctx.input.mouse.pos, c_elem.slider.handle) && c_elem.events.mouse_hold) {
-			short x = (short)clamp(ctx.input.mouse.pos.x - c_elem.slider.handle.w/2, c_elem.bounds.x, c_elem.bounds.x + c_elem.bounds.w - c_elem.slider.handle.w);
-			float v = (float)(c_elem.slider.handle.x-c_elem.bounds.x) / (float)(c_elem.bounds.w-c_elem.slider.handle.w);
-			c_elem.slider.handle.x = x;
-			c_elem.slider.value = v;
-			c_elem.events.update = true;
-		}
-	}
-
-	// Draw the button
-	Color bg_color = uint_to_rgba(0x0000ffff);
-	Color handle_color = uint_to_rgba(0x0ff000ff);
-
-	Cmd cmd = {
-	    .type = CMD_RECT,
-	    .rect =	{
-		    .rect  = c_elem.bounds,
-		    .color = bg_color,
-		},
-	};
-	ctx.cmd_queue.enqueue(&cmd)!;
-
-	cmd = Cmd{
-	    .type = CMD_RECT,
-	    .rect =	{
-		    .rect  = c_elem.slider.handle,
-		    .color = handle_color,
-		},
-	};
-	ctx.cmd_queue.enqueue(&cmd)!;
-
-	return c_elem.events;
-}
-
-/*
- * +-+
- * | |
- * | |
- * +-+
- * |#| handle
- * |#|
- * +-+
- * | |
- * | |
- * +-+
- */
-fn ElemEvents! Ctx.slider_ver(&ctx, String label, Rect size)
-{
-	Id id = label.hash();
-
-	Elem *parent = ctx.get_parent()!;
-	Elem *c_elem = ctx.get_elem(id)!;
-	// add it to the tree
-	ctx.tree.add(id, ctx.active_div)!;
-
-	// 1. Fill the element fields
-	c_elem.type = ETYPE_SLIDER;
-
-	// if the element is new or the parent was updated then redo layout
-	if (c_elem.flags.is_new || parent.flags.updated) {
-		// 2. Layout
-		c_elem.bounds = ctx.position_element(parent, size, true);
-		c_elem.slider.handle = Rect{
-			.x = c_elem.bounds.x,
-			.y = (short)(c_elem.bounds.y + (int)(c_elem.bounds.h * c_elem.slider.value)),
-			.w = c_elem.bounds.w,
-			.h = (short)(c_elem.bounds.h * 0.25),
-		};
-	}
-
-	c_elem.events = ctx.get_elem_events(c_elem);
-	if (parent.flags.has_focus && c_elem.events.mouse_hover) {
-	    if (point_in_rect(ctx.input.mouse.pos, c_elem.slider.handle) && c_elem.events.mouse_hold) {
-			short y = (short)clamp(ctx.input.mouse.pos.y - c_elem.slider.handle.h/2, c_elem.bounds.y, c_elem.bounds.y + c_elem.bounds.h - c_elem.slider.handle.h);
-			float v = (float)(c_elem.slider.handle.y-c_elem.bounds.y) / (float)(c_elem.bounds.h-c_elem.slider.handle.h);
-			c_elem.slider.handle.y = y;
-			c_elem.slider.value = v;
-			c_elem.events.update = true;
-		}
-	}
-
-	// Draw the button
-	Color bg_color = uint_to_rgba(0x0000ffff);
-	Color handle_color = uint_to_rgba(0x0ff000ff);
-
-	Cmd cmd = {
-	    .type = CMD_RECT,
-	    .rect =	{
-		    .rect  = c_elem.bounds,
-		    .color = bg_color,
-		},
-	};
-	ctx.cmd_queue.enqueue(&cmd)!;
-
-	cmd = Cmd{
-	    .type = CMD_RECT,
-	    .rect =	{
-		    .rect  = c_elem.slider.handle,
-		    .color = handle_color,
-		},
-	};
-	ctx.cmd_queue.enqueue(&cmd)!;
-
-	return c_elem.events;
-}

src/vtree.c3

@@ -1,333 +0,0 @@
-module vtree(<ElemType>);
-
-import std::core::mem;
-import std::io;
-
-struct VTree {
-	usz elements;
-	ElemType[] vector; // vector of element ids
-	isz[] refs, ordered_refs;
-}
-
-fault VTreeError {
-    CANNOT_SHRINK,
-    INVALID_REFERENCE,
-    TREE_FULL,
-    REFERENCE_NOT_PRESENT,
-    INVALID_ARGUMENT,
-}
-
-macro VTree.ref_is_valid(&tree, isz ref) { return (ref >= 0 && ref < tree.refs.len); }
-macro VTree.ref_is_present(&tree, isz ref) { return tree.refs[ref] >= 0; }
-macro VTree.size(&tree) { return tree.refs.len; }
-
-// macro to zero an elemen
-macro @zero()
-{
-	$if $assignable(0, ElemType):
-		return 0;
-	$else
-		return ElemType{0};
-	$endif
-}
-
-fn void! VTree.init(&tree, usz size)
-{
-	tree.vector = mem::new_array(ElemType, size);
-	defer catch { (void)mem::free(tree.vector); }
-
-	tree.refs = mem::new_array(isz, size);
-	defer catch { (void)mem::free(tree.refs); }
-
-	tree.ordered_refs = mem::new_array(isz, size);
-	defer catch { (void)mem::free(tree.ordered_refs); }
-
-	// set all refs to -1, meaning invalid (free) element
-	tree.refs[..] = -1;
-
-	tree.elements = 0;
-}
-
-fn void VTree.free(&tree)
-{
-	(void)mem::free(tree.vector);
-	(void)mem::free(tree.refs);
-	(void)mem::free(tree.ordered_refs);
-}
-
-fn void VTree.pack(&tree)
-{
-	// TODO: add a PACKED flag to skip this
-
-	isz free_spot = -1;
-	for (usz i = 0; i < tree.size(); i++) {
-		if (tree.refs[i] == -1) {
-			free_spot = i;
-			continue;
-		}
-
-		// find a item that can be packed
-		if (free_spot >= 0 && tree.refs[i] >= 0) {
-			isz old_ref = i;
-
-			// move the item
-			tree.vector[free_spot] = tree.vector[i];
-			tree.refs[free_spot]   = tree.refs[i];
-
-			tree.vector[i] = @zero();
-			tree.refs[i]   = -1;
-
-			// and move all references
-			for (usz j = 0; j < tree.size(); j++) {
-				if (tree.refs[j] == old_ref) {
-				    tree.refs[j] = free_spot;
-				}
-			}
-
-			// mark the free spot as used
-			free_spot = -1;
-		}
-	}
-}
-
-fn void! VTree.resize(&tree, usz newsize)
-{
-	// return error when shrinking with too many elements
-	if (newsize < tree.elements) {
-		return VTreeError.CANNOT_SHRINK?;
-	}
-
-	// pack the vector when shrinking to avoid data loss
-	if ((int)newsize < tree.size()) {
-		// FIXME: packing destroys all references to elements of vec
-		//        so shrinking may cause dangling pointers
-		return VTreeError.CANNOT_SHRINK?;
-	}
-
-	usz old_size = tree.size();
-
-	tree.vector = ((ElemType*)mem::realloc(tree.vector, newsize*ElemType.sizeof))[:newsize];
-	defer catch { (void)mem::free(tree.vector); }
-
-	tree.refs = ((isz*)mem::realloc(tree.refs, newsize*isz.sizeof))[:newsize];
-	defer catch { (void)mem::free(tree.refs); }
-
-	tree.ordered_refs = ((isz*)mem::realloc(tree.ordered_refs, newsize*isz.sizeof))[:newsize];
-	defer catch { (void)mem::free(tree.ordered_refs); }
-
-	if (newsize > tree.size()) {
-	   tree.vector[old_size..newsize-1] = @zero();
-	   tree.refs[old_size..newsize-1] = -1;
-	}
-}
-
-// add an element to the tree, return it's ref
-fn isz! VTree.add(&tree, ElemType elem, isz parent)
-{
-	// invalid parent
-	if (!tree.ref_is_valid(parent)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	// no space left
-	if (tree.elements >= tree.size()) {
-	   return VTreeError.TREE_FULL?;
-	}
-
-	// check if the parent exists
-	// if there are no elements in the tree the first add will set the root
-	if (!tree.ref_is_present(parent) && tree.elements != 0) {
-	   return VTreeError.REFERENCE_NOT_PRESENT?;
-	}
-
-	// get the first free spot
-	isz free_spot = -1;
-	for (usz i = 0; i < tree.size(); i++) {
-		if (tree.refs[i] == -1) {
-			free_spot = i;
-			break;
-		}
-	}
-	if (free_spot < 0) {
-		return VTreeError.TREE_FULL?;
-	}
-
-	// finally add the element
-	tree.vector[free_spot] = elem;
-	tree.refs[free_spot]   = parent;
-	tree.elements++;
-
-	return free_spot;
-}
-
-// prune the tree starting from the ref
-// returns the number of pruned elements
-fn usz! VTree.prune(&tree, isz ref)
-{
-    if (!tree.ref_is_valid(ref)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	if (!tree.ref_is_present(ref)) {
-		return 0;
-	}
-
-	tree.vector[ref] = @zero();
-	tree.refs[ref]   = -1;
-	tree.elements--;
-
-	usz count = 1;
-	for (usz i = 0; tree.elements > 0 && i < tree.size(); i++) {
-		if (tree.refs[i] == ref) {
-			count += tree.prune(i)!;
-		}
-	}
-
-	return count;
-}
-
-// find the size of the subtree starting from ref
-fn usz! VTree.subtree_size(&tree, isz ref)
-{
-    if (!tree.ref_is_valid(ref)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	if (!tree.ref_is_present(ref)) {
-		return 0;
-	}
-
-	usz count = 1;
-	for (usz i = 0; i < tree.size(); i++) {
-		// only root has the reference to itself
-		if (tree.refs[i] == ref && ref != i) {
-			count += tree.subtree_size(i)!;
-		}
-	}
-
-	return count;
-}
-
-// iterate through the first level children, use a cursor like strtok_r
-fn isz! VTree.children_it(&tree, isz parent, isz *cursor)
-{
-	if (cursor == null) {
-		return VTreeError.INVALID_ARGUMENT?;
-	}
-
-	// if the cursor is out of bounds then we are done for sure
-	if (!tree.ref_is_valid(*cursor)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	// same for the parent, if it's invalid it can't have children
-	if (!tree.ref_is_valid(parent) || !tree.ref_is_present(parent)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	// find the first child, update the cursor and return the ref
-	for (isz i = *cursor; i < tree.size(); i++) {
-		if (tree.refs[i] == parent) {
-			*cursor = i + 1;
-			return i;
-		}
-	}
-
-	// if no children are found return -1
-	*cursor = -1;
-	return -1;
-}
-
-/* iterates trough every leaf of the subtree in the following manner
- * node [x], x: visit order
- *              [0]
- *             / | \
- *            / [2] [3]
- *          [1]      |
- *         /   \    [6]
- *       [4]   [5]
- */
-fn isz! VTree.level_order_it(&tree, isz ref, isz *cursor)
-{
-	if (cursor == null) {
-	   return VTreeError.INVALID_ARGUMENT?;
-	}
-
-	isz[] queue = tree.ordered_refs;
-
-	// TODO: this could also be done when adding or removing elements
-	// first call, create a ref array ordered like we desire
-	if (*cursor == -1) {
-		*cursor = 0;
-		queue[..] = -1;
-
-		// iterate through the queue appending found children
-		isz pos, off;
-		do {
-			// printf ("ref=%d\n", ref);
-			for (isz i = 0; i < tree.size(); i++) {
-				if (tree.refs[i] == ref) {
-					queue[pos++] = i;
-				}
-			}
-
-			for (; ref == queue[off] && off < tree.size(); off++);
-			ref = queue[off];
-
-		} while (tree.ref_is_valid(ref));
-		// This line is why tree.ordered_refs has to be size+1
-		queue[off + 1] = -1;
-	}
-
-	// PRINT_ARR(queue, tree.size());
-	// return -1;
-
-	// on successive calls just iterate through the queue until we find an
-	// invalid ref, if the user set the cursor to -1 it means it has found what
-	// he needed, so free
-	if (*cursor < 0) {
-		return -1;
-	} else if (tree.ref_is_valid(*cursor)) {
-		return queue[(*cursor)++];
-	}
-
-	return -1;
-}
-
-fn isz! VTree.parentof(&tree, isz ref)
-{
-	if (!tree.ref_is_valid(ref)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	if (!tree.ref_is_present(ref)) {
-	   return VTreeError.REFERENCE_NOT_PRESENT?;
-	}
-
-	return tree.refs[ref];
-}
-
-fn ElemType! VTree.get(&tree, isz ref)
-{
-    if (!tree.ref_is_valid(ref)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	if (!tree.ref_is_present(ref)) {
-	   return VTreeError.REFERENCE_NOT_PRESENT?;
-	}
-
-	return tree.vector[ref];
-}
-
-fn void VTree.print(&tree)
-{
-	for (isz i = 0; i < tree.size(); i++) {
-		if (tree.refs[i] == -1) {
-			continue;
-		}
-		io::printf("[%d] {parent=%d, data=", i, tree.refs[i]);
-		io::print(tree.vector[i]);
-		io::printn("}");
-	}
-}

test/Makefile

@@ -0,0 +1,11 @@
+CFLAGS  = -Wall -Wextra -Wpedantic -std=c11 -g
+LDFLAGS = -lSDL2 -lm
+
+test: main.c ../ugui.c ../ugui.h ../def_style.h ../input.c
+	gcc ${CFLAGS} -c ../ugui.c -o ugui.o
+	gcc ${CFLAGS} -c ../input.c -o input.o
+	gcc ${CFLAGS} -c main.c    -o main.o
+	gcc ${LDFLAGS} main.o ugui.o input.o -o test
+
+clean:
+	rm -f main.o ugui.o

test/main.c

@@ -0,0 +1,268 @@
+#define _POSIX_C_SOURCE 200809l
+
+#include <stdio.h>
+#include <SDL2/SDL.h>
+
+#include "../ugui.h"
+
+#define STB_RECT_PACK_IMPLEMENTATION
+#define STB_TRUETYPE_IMPLEMENTATION
+#define STBTTF_IMPLEMENTATION
+#include "stbttf.h"
+
+
+SDL_Window *w;
+SDL_Renderer *r;
+ug_ctx_t *ctx;
+STBTTF_Font *font;
+
+void cleanup(void);
+
+int main(void)
+{
+	SDL_DisplayMode dm;
+
+	SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS);
+	SDL_EnableScreenSaver();
+	SDL_EventState(SDL_DROPFILE, SDL_ENABLE);
+	SDL_EventState(SDL_DROPTEXT, SDL_ENABLE);
+
+	SDL_GetDesktopDisplayMode(0, &dm);
+
+#ifdef SDL_HINT_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR /* Available since 2.0.8 */
+	SDL_SetHint(SDL_HINT_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR, "0");
+#endif
+
+#if SDL_VERSION_ATLEAST(2, 0, 5)
+	SDL_SetHint(SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, "1");
+#endif
+
+	w = SDL_CreateWindow("test",
+	                     SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
+	                     dm.w*0.8, dm.h*0.8,
+			     SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI |
+	                     SDL_WINDOW_OPENGL );
+
+	//SDL_Surface *s;
+	//s = SDL_GetWindowSurface(w);
+	r = SDL_CreateRenderer(w, -1, SDL_RENDERER_ACCELERATED);
+	SDL_SetRenderDrawBlendMode(r, SDL_BLENDMODE_BLEND);
+
+	ug_vec2_t size, dsize;
+	SDL_GetWindowSize(w, &size.w, &size.h);
+	SDL_GL_GetDrawableSize(w, &dsize.w, &dsize.h);
+	float scale = 1.0;
+	scale = ((float)(size.w+size.h)/2)/((float)(dsize.w+dsize.h)/2);
+
+	float dpi;
+	int idx;
+	idx = SDL_GetWindowDisplayIndex(w);
+	SDL_GetDisplayDPI(idx, &dpi, NULL, NULL);
+
+
+	ctx = ug_ctx_new();
+	ug_ctx_set_displayinfo(ctx, scale, dpi);
+	ug_ctx_set_drawableregion(ctx, dsize);
+
+	// open font
+	font = STBTTF_OpenFont(r, "monospace.ttf", ctx->style_px->title.font_size.size.i);
+
+//	atexit(cleanup);
+
+	SDL_Event event;
+
+	char button_map[] = {
+		[SDL_BUTTON_LEFT   & 0xff] = UG_BTN_LEFT,
+		[SDL_BUTTON_MIDDLE & 0xff] = UG_BTN_MIDDLE,
+		[SDL_BUTTON_RIGHT  & 0xff] = UG_BTN_RIGHT,
+		[SDL_BUTTON_X1     & 0xff] = UG_BTN_4,
+		[SDL_BUTTON_X2     & 0xff] = UG_BTN_5,
+	};
+
+	do {
+	SDL_WaitEvent(&event);
+
+		switch (event.type) {
+		case SDL_WINDOWEVENT:
+	        	switch (event.window.event) {
+			case SDL_WINDOWEVENT_SHOWN:
+				(SDL_Log("Window %d shown", event.window.windowID));
+				break;
+			case SDL_WINDOWEVENT_HIDDEN:
+				(SDL_Log("Window %d hidden", event.window.windowID));
+				break;
+			case SDL_WINDOWEVENT_EXPOSED:
+				(SDL_Log("Window %d exposed", event.window.windowID));
+				break;
+			case SDL_WINDOWEVENT_MOVED:
+				(SDL_Log("Window %d moved to %d,%d",
+				event.window.windowID, event.window.data1,
+				event.window.data2));
+				break;
+			case SDL_WINDOWEVENT_RESIZED:
+				(SDL_Log("Window %d resized to %dx%d",
+				event.window.windowID, event.window.data1,
+				event.window.data2));
+				break;
+			case SDL_WINDOWEVENT_SIZE_CHANGED:
+				(SDL_Log("Window %d size changed to %dx%d",
+				event.window.windowID, event.window.data1,
+				event.window.data2));
+
+				size.w = event.window.data1;
+				size.h = event.window.data2;
+				// surface is invalidated every time the window
+				// is resized
+				//s = SDL_GetWindowSurface(w);
+				ug_ctx_set_drawableregion(ctx, size);
+
+				break;
+			case SDL_WINDOWEVENT_MINIMIZED:
+				(SDL_Log("Window %d minimized", event.window.windowID));
+				break;
+			case SDL_WINDOWEVENT_MAXIMIZED:
+				(SDL_Log("Window %d maximized", event.window.windowID));
+				break;
+			case SDL_WINDOWEVENT_RESTORED:
+				(SDL_Log("Window %d restored", event.window.windowID));
+				break;
+			case SDL_WINDOWEVENT_ENTER:
+				(SDL_Log("Mouse entered window %d",
+					event.window.windowID));
+				break;
+			case SDL_WINDOWEVENT_LEAVE:
+				(SDL_Log("Mouse left window %d", event.window.windowID));
+				break;
+			case SDL_WINDOWEVENT_FOCUS_GAINED:
+				(SDL_Log("Window %d gained keyboard focus",
+				event.window.windowID));
+				break;
+			case SDL_WINDOWEVENT_FOCUS_LOST:
+				(SDL_Log("Window %d lost keyboard focus",
+				event.window.windowID));
+				break;
+			case SDL_WINDOWEVENT_CLOSE:
+				(SDL_Log("Window %d closed", event.window.windowID));
+				break;
+#if SDL_VERSION_ATLEAST(2, 0, 5)
+			case SDL_WINDOWEVENT_TAKE_FOCUS:
+				(SDL_Log("Window %d is offered a focus", event.window.windowID));
+				break;
+			case SDL_WINDOWEVENT_HIT_TEST:
+				(SDL_Log("Window %d has a special hit test", event.window.windowID));
+				break;
+#endif
+			default:
+				(SDL_Log("Window %d got unknown event %d",
+				event.window.windowID, event.window.event));
+				break;
+			}
+			break;
+		case SDL_QUIT:
+			(printf("Quitting\n"));
+			break;
+		case SDL_MOUSEMOTION:
+
+			ug_input_mousemove(ctx, event.motion.x, event.motion.y);
+
+			break;
+		case SDL_MOUSEBUTTONDOWN:
+			ug_input_mousemove(ctx, event.button.x, event.button.y);
+			ug_input_mousedown(ctx, button_map[event.button.button & 0xff]);
+
+			break;
+		case SDL_MOUSEBUTTONUP:
+
+			ug_input_mousemove(ctx, event.button.x, event.button.y);
+			ug_input_mouseup(ctx, button_map[event.button.button & 0xff]);
+
+			break;
+		default:
+			(printf("Unknown event: %d\n", event.type));
+			break;
+		}
+
+
+		ug_frame_begin(ctx);
+
+		//if (ctx->frame < 5000) {
+		//	ug_container_menu_bar(ctx, "Menu fichissimo", (ug_size_t)SIZE_PX(24));
+		//} else if (ctx->frame == 5000) {
+		//	ug_container_remove(ctx, "Menu fichissimo");
+		//}
+
+		ug_container_floating(ctx, "stupid name", (ug_div_t){.x=SIZE_PX(0), .y=SIZE_PX(0), .w=SIZE_PX(100), .h=SIZE_MM(75.0)});
+		ug_element_button(ctx, "float", "X", (ug_div_t){SQUARE(SIZE_MM(5))});
+		//ug_container_floating(ctx, "floating windoooooooow", (ug_div_t){.x=SIZE_PX(100), .y=SIZE_PX(0), .w=SIZE_PX(100), .h=SIZE_MM(75.0)});
+
+		//ug_container_sidebar(ctx, "Right Sidebar", (ug_size_t)SIZE_PX(300), UG_SIDE_RIGHT);
+		//ug_container_sidebar(ctx, "Left Sidebar", (ug_size_t)SIZE_PX(200), UG_SIDE_LEFT);
+		//ug_container_sidebar(ctx, "Bottom Sidebar", (ug_size_t)SIZE_MM(10), UG_SIDE_BOTTOM);
+		ug_container_sidebar(ctx, "Top Sidebar", (ug_size_t)SIZE_MM(40), UG_SIDE_TOP);
+
+		// ug_container_popup(ctx, "Annoying popup", (ug_div_t){.x=SIZE_MM(150), .y=SIZE_MM(150), .w=SIZE_PX(100), .h=SIZE_MM(75.0)});
+
+		//ug_container_body(ctx, "Main Body");
+		//if (ug_container_body(ctx, "Other Body"))
+		//	printf("No space!\n");
+
+		ug_layout_row(ctx);
+
+		ug_layout_column(ctx);
+		ug_element_button(ctx, "button 1", "hey", (ug_div_t){SQUARE(SIZE_MM(10))});
+		//ug_element_button(ctx, "button 2", "lol", (ug_div_t){SQUARE(SIZE_MM(10))});
+		//ug_layout_next_row(ctx);
+		//ug_element_button(ctx, "button 3", "L", (ug_div_t){SQUARE(SIZE_MM(10))});
+		//ug_element_button(ctx, "button 4", "69", (ug_div_t){SQUARE(SIZE_MM(10))});
+		ug_layout_next_column(ctx);
+		ug_element_button(ctx, "button 5", "lmao", (ug_div_t){SQUARE(SIZE_MM(10))});
+		//ug_element_textbtn(ctx, "text button 1", "foo", (ug_div_t){.w = 0, .h = SIZE_PX(30)});
+		//ug_element_button(ctx, "button 6", "", (ug_div_t){SQUARE(SIZE_MM(10)),.x=SIZE_PX(-10)});
+
+		ug_container_body(ctx, "fill body");
+
+		ug_frame_end(ctx);
+
+		// fill background
+		// solid purple makes it easy to identify, same color as hl missing texture
+		SDL_SetRenderDrawColor(r, 0xff, 0, 0xdc, 0xff);
+		SDL_RenderClear(r);
+		for (ug_cmd_t *cmd = NULL; (cmd = ug_cmd_next(ctx));) {
+			switch (cmd->type) {
+			case UG_CMD_RECT:
+				{
+				ug_color_t col = cmd->rect.color;
+				SDL_Rect sr = {
+					.x = cmd->rect.x,
+					.y = cmd->rect.y,
+					.w = cmd->rect.w,
+					.h = cmd->rect.h,
+				};
+				SDL_SetRenderDrawColor(r, col.r, col.g, col.b, col.a);
+				SDL_RenderFillRect(r, &sr);
+				}
+				break;
+			case UG_CMD_TEXT:
+			SDL_SetRenderDrawColor(r, cmd->text.color.r, cmd->text.color.g, cmd->text.color.b, cmd->text.color.a);
+				STBTTF_RenderText(r, font, cmd->text.x, cmd->text.y, cmd->text.str);
+				break;
+			default: break;
+			}
+		}
+		SDL_RenderPresent(r);
+
+	} while (event.type != SDL_QUIT);
+
+	cleanup();
+
+	return 0;
+}
+
+void cleanup(void)
+{
+	ug_ctx_free(ctx);
+	STBTTF_CloseFont(font);
+	SDL_DestroyRenderer(r);
+	SDL_DestroyWindow(w);
+	SDL_Quit();
+}

test/stb_rect_pack.h

@@ -0,0 +1,623 @@
+// stb_rect_pack.h - v1.01 - public domain - rectangle packing
+// Sean Barrett 2014
+//
+// Useful for e.g. packing rectangular textures into an atlas.
+// Does not do rotation.
+//
+// Before #including,
+//
+//    #define STB_RECT_PACK_IMPLEMENTATION
+//
+// in the file that you want to have the implementation.
+//
+// Not necessarily the awesomest packing method, but better than
+// the totally naive one in stb_truetype (which is primarily what
+// this is meant to replace).
+//
+// Has only had a few tests run, may have issues.
+//
+// More docs to come.
+//
+// No memory allocations; uses qsort() and assert() from stdlib.
+// Can override those by defining STBRP_SORT and STBRP_ASSERT.
+//
+// This library currently uses the Skyline Bottom-Left algorithm.
+//
+// Please note: better rectangle packers are welcome! Please
+// implement them to the same API, but with a different init
+// function.
+//
+// Credits
+//
+//  Library
+//    Sean Barrett
+//  Minor features
+//    Martins Mozeiko
+//    github:IntellectualKitty
+//
+//  Bugfixes / warning fixes
+//    Jeremy Jaussaud
+//    Fabian Giesen
+//
+// Version history:
+//
+//     1.01  (2021-07-11)  always use large rect mode, expose STBRP__MAXVAL in public section
+//     1.00  (2019-02-25)  avoid small space waste; gracefully fail too-wide rectangles
+//     0.99  (2019-02-07)  warning fixes
+//     0.11  (2017-03-03)  return packing success/fail result
+//     0.10  (2016-10-25)  remove cast-away-const to avoid warnings
+//     0.09  (2016-08-27)  fix compiler warnings
+//     0.08  (2015-09-13)  really fix bug with empty rects (w=0 or h=0)
+//     0.07  (2015-09-13)  fix bug with empty rects (w=0 or h=0)
+//     0.06  (2015-04-15)  added STBRP_SORT to allow replacing qsort
+//     0.05:  added STBRP_ASSERT to allow replacing assert
+//     0.04:  fixed minor bug in STBRP_LARGE_RECTS support
+//     0.01:  initial release
+//
+// LICENSE
+//
+//   See end of file for license information.
+
+//////////////////////////////////////////////////////////////////////////////
+//
+//       INCLUDE SECTION
+//
+
+#ifndef STB_INCLUDE_STB_RECT_PACK_H
+#define STB_INCLUDE_STB_RECT_PACK_H
+
+#define STB_RECT_PACK_VERSION  1
+
+#ifdef STBRP_STATIC
+#define STBRP_DEF static
+#else
+#define STBRP_DEF extern
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct stbrp_context stbrp_context;
+typedef struct stbrp_node    stbrp_node;
+typedef struct stbrp_rect    stbrp_rect;
+
+typedef int            stbrp_coord;
+
+#define STBRP__MAXVAL  0x7fffffff
+// Mostly for internal use, but this is the maximum supported coordinate value.
+
+STBRP_DEF int stbrp_pack_rects (stbrp_context *context, stbrp_rect *rects, int num_rects);
+// Assign packed locations to rectangles. The rectangles are of type
+// 'stbrp_rect' defined below, stored in the array 'rects', and there
+// are 'num_rects' many of them.
+//
+// Rectangles which are successfully packed have the 'was_packed' flag
+// set to a non-zero value and 'x' and 'y' store the minimum location
+// on each axis (i.e. bottom-left in cartesian coordinates, top-left
+// if you imagine y increasing downwards). Rectangles which do not fit
+// have the 'was_packed' flag set to 0.
+//
+// You should not try to access the 'rects' array from another thread
+// while this function is running, as the function temporarily reorders
+// the array while it executes.
+//
+// To pack into another rectangle, you need to call stbrp_init_target
+// again. To continue packing into the same rectangle, you can call
+// this function again. Calling this multiple times with multiple rect
+// arrays will probably produce worse packing results than calling it
+// a single time with the full rectangle array, but the option is
+// available.
+//
+// The function returns 1 if all of the rectangles were successfully
+// packed and 0 otherwise.
+
+struct stbrp_rect
+{
+   // reserved for your use:
+   int            id;
+
+   // input:
+   stbrp_coord    w, h;
+
+   // output:
+   stbrp_coord    x, y;
+   int            was_packed;  // non-zero if valid packing
+
+}; // 16 bytes, nominally
+
+
+STBRP_DEF void stbrp_init_target (stbrp_context *context, int width, int height, stbrp_node *nodes, int num_nodes);
+// Initialize a rectangle packer to:
+//    pack a rectangle that is 'width' by 'height' in dimensions
+//    using temporary storage provided by the array 'nodes', which is 'num_nodes' long
+//
+// You must call this function every time you start packing into a new target.
+//
+// There is no "shutdown" function. The 'nodes' memory must stay valid for
+// the following stbrp_pack_rects() call (or calls), but can be freed after
+// the call (or calls) finish.
+//
+// Note: to guarantee best results, either:
+//       1. make sure 'num_nodes' >= 'width'
+//   or  2. call stbrp_allow_out_of_mem() defined below with 'allow_out_of_mem = 1'
+//
+// If you don't do either of the above things, widths will be quantized to multiples
+// of small integers to guarantee the algorithm doesn't run out of temporary storage.
+//
+// If you do #2, then the non-quantized algorithm will be used, but the algorithm
+// may run out of temporary storage and be unable to pack some rectangles.
+
+STBRP_DEF void stbrp_setup_allow_out_of_mem (stbrp_context *context, int allow_out_of_mem);
+// Optionally call this function after init but before doing any packing to
+// change the handling of the out-of-temp-memory scenario, described above.
+// If you call init again, this will be reset to the default (false).
+
+
+STBRP_DEF void stbrp_setup_heuristic (stbrp_context *context, int heuristic);
+// Optionally select which packing heuristic the library should use. Different
+// heuristics will produce better/worse results for different data sets.
+// If you call init again, this will be reset to the default.
+
+enum
+{
+   STBRP_HEURISTIC_Skyline_default=0,
+   STBRP_HEURISTIC_Skyline_BL_sortHeight = STBRP_HEURISTIC_Skyline_default,
+   STBRP_HEURISTIC_Skyline_BF_sortHeight
+};
+
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// the details of the following structures don't matter to you, but they must
+// be visible so you can handle the memory allocations for them
+
+struct stbrp_node
+{
+   stbrp_coord  x,y;
+   stbrp_node  *next;
+};
+
+struct stbrp_context
+{
+   int width;
+   int height;
+   int align;
+   int init_mode;
+   int heuristic;
+   int num_nodes;
+   stbrp_node *active_head;
+   stbrp_node *free_head;
+   stbrp_node extra[2]; // we allocate two extra nodes so optimal user-node-count is 'width' not 'width+2'
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
+//////////////////////////////////////////////////////////////////////////////
+//
+//     IMPLEMENTATION SECTION
+//
+
+#ifdef STB_RECT_PACK_IMPLEMENTATION
+#ifndef STBRP_SORT
+#include <stdlib.h>
+#define STBRP_SORT qsort
+#endif
+
+#ifndef STBRP_ASSERT
+#include <assert.h>
+#define STBRP_ASSERT assert
+#endif
+
+#ifdef _MSC_VER
+#define STBRP__NOTUSED(v)  (void)(v)
+#define STBRP__CDECL       __cdecl
+#else
+#define STBRP__NOTUSED(v)  (void)sizeof(v)
+#define STBRP__CDECL
+#endif
+
+enum
+{
+   STBRP__INIT_skyline = 1
+};
+
+STBRP_DEF void stbrp_setup_heuristic(stbrp_context *context, int heuristic)
+{
+   switch (context->init_mode) {
+      case STBRP__INIT_skyline:
+         STBRP_ASSERT(heuristic == STBRP_HEURISTIC_Skyline_BL_sortHeight || heuristic == STBRP_HEURISTIC_Skyline_BF_sortHeight);
+         context->heuristic = heuristic;
+         break;
+      default:
+         STBRP_ASSERT(0);
+   }
+}
+
+STBRP_DEF void stbrp_setup_allow_out_of_mem(stbrp_context *context, int allow_out_of_mem)
+{
+   if (allow_out_of_mem)
+      // if it's ok to run out of memory, then don't bother aligning them;
+      // this gives better packing, but may fail due to OOM (even though
+      // the rectangles easily fit). @TODO a smarter approach would be to only
+      // quantize once we've hit OOM, then we could get rid of this parameter.
+      context->align = 1;
+   else {
+      // if it's not ok to run out of memory, then quantize the widths
+      // so that num_nodes is always enough nodes.
+      //
+      // I.e. num_nodes * align >= width
+      //                  align >= width / num_nodes
+      //                  align = ceil(width/num_nodes)
+
+      context->align = (context->width + context->num_nodes-1) / context->num_nodes;
+   }
+}
+
+STBRP_DEF void stbrp_init_target(stbrp_context *context, int width, int height, stbrp_node *nodes, int num_nodes)
+{
+   int i;
+
+   for (i=0; i < num_nodes-1; ++i)
+      nodes[i].next = &nodes[i+1];
+   nodes[i].next = NULL;
+   context->init_mode = STBRP__INIT_skyline;
+   context->heuristic = STBRP_HEURISTIC_Skyline_default;
+   context->free_head = &nodes[0];
+   context->active_head = &context->extra[0];
+   context->width = width;
+   context->height = height;
+   context->num_nodes = num_nodes;
+   stbrp_setup_allow_out_of_mem(context, 0);
+
+   // node 0 is the full width, node 1 is the sentinel (lets us not store width explicitly)
+   context->extra[0].x = 0;
+   context->extra[0].y = 0;
+   context->extra[0].next = &context->extra[1];
+   context->extra[1].x = (stbrp_coord) width;
+   context->extra[1].y = (1<<30);
+   context->extra[1].next = NULL;
+}
+
+// find minimum y position if it starts at x1
+static int stbrp__skyline_find_min_y(stbrp_context *c, stbrp_node *first, int x0, int width, int *pwaste)
+{
+   stbrp_node *node = first;
+   int x1 = x0 + width;
+   int min_y, visited_width, waste_area;
+
+   STBRP__NOTUSED(c);
+
+   STBRP_ASSERT(first->x <= x0);
+
+   #if 0
+   // skip in case we're past the node
+   while (node->next->x <= x0)
+      ++node;
+   #else
+   STBRP_ASSERT(node->next->x > x0); // we ended up handling this in the caller for efficiency
+   #endif
+
+   STBRP_ASSERT(node->x <= x0);
+
+   min_y = 0;
+   waste_area = 0;
+   visited_width = 0;
+   while (node->x < x1) {
+      if (node->y > min_y) {
+         // raise min_y higher.
+         // we've accounted for all waste up to min_y,
+         // but we'll now add more waste for everything we've visted
+         waste_area += visited_width * (node->y - min_y);
+         min_y = node->y;
+         // the first time through, visited_width might be reduced
+         if (node->x < x0)
+            visited_width += node->next->x - x0;
+         else
+            visited_width += node->next->x - node->x;
+      } else {
+         // add waste area
+         int under_width = node->next->x - node->x;
+         if (under_width + visited_width > width)
+            under_width = width - visited_width;
+         waste_area += under_width * (min_y - node->y);
+         visited_width += under_width;
+      }
+      node = node->next;
+   }
+
+   *pwaste = waste_area;
+   return min_y;
+}
+
+typedef struct
+{
+   int x,y;
+   stbrp_node **prev_link;
+} stbrp__findresult;
+
+static stbrp__findresult stbrp__skyline_find_best_pos(stbrp_context *c, int width, int height)
+{
+   int best_waste = (1<<30), best_x, best_y = (1 << 30);
+   stbrp__findresult fr;
+   stbrp_node **prev, *node, *tail, **best = NULL;
+
+   // align to multiple of c->align
+   width = (width + c->align - 1);
+   width -= width % c->align;
+   STBRP_ASSERT(width % c->align == 0);
+
+   // if it can't possibly fit, bail immediately
+   if (width > c->width || height > c->height) {
+      fr.prev_link = NULL;
+      fr.x = fr.y = 0;
+      return fr;
+   }
+
+   node = c->active_head;
+   prev = &c->active_head;
+   while (node->x + width <= c->width) {
+      int y,waste;
+      y = stbrp__skyline_find_min_y(c, node, node->x, width, &waste);
+      if (c->heuristic == STBRP_HEURISTIC_Skyline_BL_sortHeight) { // actually just want to test BL
+         // bottom left
+         if (y < best_y) {
+            best_y = y;
+            best = prev;
+         }
+      } else {
+         // best-fit
+         if (y + height <= c->height) {
+            // can only use it if it first vertically
+            if (y < best_y || (y == best_y && waste < best_waste)) {
+               best_y = y;
+               best_waste = waste;
+               best = prev;
+            }
+         }
+      }
+      prev = &node->next;
+      node = node->next;
+   }
+
+   best_x = (best == NULL) ? 0 : (*best)->x;
+
+   // if doing best-fit (BF), we also have to try aligning right edge to each node position
+   //
+   // e.g, if fitting
+   //
+   //     ____________________
+   //    |____________________|
+   //
+   //            into
+   //
+   //   |                         |
+   //   |             ____________|
+   //   |____________|
+   //
+   // then right-aligned reduces waste, but bottom-left BL is always chooses left-aligned
+   //
+   // This makes BF take about 2x the time
+
+   if (c->heuristic == STBRP_HEURISTIC_Skyline_BF_sortHeight) {
+      tail = c->active_head;
+      node = c->active_head;
+      prev = &c->active_head;
+      // find first node that's admissible
+      while (tail->x < width)
+         tail = tail->next;
+      while (tail) {
+         int xpos = tail->x - width;
+         int y,waste;
+         STBRP_ASSERT(xpos >= 0);
+         // find the left position that matches this
+         while (node->next->x <= xpos) {
+            prev = &node->next;
+            node = node->next;
+         }
+         STBRP_ASSERT(node->next->x > xpos && node->x <= xpos);
+         y = stbrp__skyline_find_min_y(c, node, xpos, width, &waste);
+         if (y + height <= c->height) {
+            if (y <= best_y) {
+               if (y < best_y || waste < best_waste || (waste==best_waste && xpos < best_x)) {
+                  best_x = xpos;
+                  STBRP_ASSERT(y <= best_y);
+                  best_y = y;
+                  best_waste = waste;
+                  best = prev;
+               }
+            }
+         }
+         tail = tail->next;
+      }
+   }
+
+   fr.prev_link = best;
+   fr.x = best_x;
+   fr.y = best_y;
+   return fr;
+}
+
+static stbrp__findresult stbrp__skyline_pack_rectangle(stbrp_context *context, int width, int height)
+{
+   // find best position according to heuristic
+   stbrp__findresult res = stbrp__skyline_find_best_pos(context, width, height);
+   stbrp_node *node, *cur;
+
+   // bail if:
+   //    1. it failed
+   //    2. the best node doesn't fit (we don't always check this)
+   //    3. we're out of memory
+   if (res.prev_link == NULL || res.y + height > context->height || context->free_head == NULL) {
+      res.prev_link = NULL;
+      return res;
+   }
+
+   // on success, create new node
+   node = context->free_head;
+   node->x = (stbrp_coord) res.x;
+   node->y = (stbrp_coord) (res.y + height);
+
+   context->free_head = node->next;
+
+   // insert the new node into the right starting point, and
+   // let 'cur' point to the remaining nodes needing to be
+   // stiched back in
+
+   cur = *res.prev_link;
+   if (cur->x < res.x) {
+      // preserve the existing one, so start testing with the next one
+      stbrp_node *next = cur->next;
+      cur->next = node;
+      cur = next;
+   } else {
+      *res.prev_link = node;
+   }
+
+   // from here, traverse cur and free the nodes, until we get to one
+   // that shouldn't be freed
+   while (cur->next && cur->next->x <= res.x + width) {
+      stbrp_node *next = cur->next;
+      // move the current node to the free list
+      cur->next = context->free_head;
+      context->free_head = cur;
+      cur = next;
+   }
+
+   // stitch the list back in
+   node->next = cur;
+
+   if (cur->x < res.x + width)
+      cur->x = (stbrp_coord) (res.x + width);
+
+#ifdef _DEBUG
+   cur = context->active_head;
+   while (cur->x < context->width) {
+      STBRP_ASSERT(cur->x < cur->next->x);
+      cur = cur->next;
+   }
+   STBRP_ASSERT(cur->next == NULL);
+
+   {
+      int count=0;
+      cur = context->active_head;
+      while (cur) {
+         cur = cur->next;
+         ++count;
+      }
+      cur = context->free_head;
+      while (cur) {
+         cur = cur->next;
+         ++count;
+      }
+      STBRP_ASSERT(count == context->num_nodes+2);
+   }
+#endif
+
+   return res;
+}
+
+static int STBRP__CDECL rect_height_compare(const void *a, const void *b)
+{
+   const stbrp_rect *p = (const stbrp_rect *) a;
+   const stbrp_rect *q = (const stbrp_rect *) b;
+   if (p->h > q->h)
+      return -1;
+   if (p->h < q->h)
+      return  1;
+   return (p->w > q->w) ? -1 : (p->w < q->w);
+}
+
+static int STBRP__CDECL rect_original_order(const void *a, const void *b)
+{
+   const stbrp_rect *p = (const stbrp_rect *) a;
+   const stbrp_rect *q = (const stbrp_rect *) b;
+   return (p->was_packed < q->was_packed) ? -1 : (p->was_packed > q->was_packed);
+}
+
+STBRP_DEF int stbrp_pack_rects(stbrp_context *context, stbrp_rect *rects, int num_rects)
+{
+   int i, all_rects_packed = 1;
+
+   // we use the 'was_packed' field internally to allow sorting/unsorting
+   for (i=0; i < num_rects; ++i) {
+      rects[i].was_packed = i;
+   }
+
+   // sort according to heuristic
+   STBRP_SORT(rects, num_rects, sizeof(rects[0]), rect_height_compare);
+
+   for (i=0; i < num_rects; ++i) {
+      if (rects[i].w == 0 || rects[i].h == 0) {
+         rects[i].x = rects[i].y = 0;  // empty rect needs no space
+      } else {
+         stbrp__findresult fr = stbrp__skyline_pack_rectangle(context, rects[i].w, rects[i].h);
+         if (fr.prev_link) {
+            rects[i].x = (stbrp_coord) fr.x;
+            rects[i].y = (stbrp_coord) fr.y;
+         } else {
+            rects[i].x = rects[i].y = STBRP__MAXVAL;
+         }
+      }
+   }
+
+   // unsort
+   STBRP_SORT(rects, num_rects, sizeof(rects[0]), rect_original_order);
+
+   // set was_packed flags and all_rects_packed status
+   for (i=0; i < num_rects; ++i) {
+      rects[i].was_packed = !(rects[i].x == STBRP__MAXVAL && rects[i].y == STBRP__MAXVAL);
+      if (!rects[i].was_packed)
+         all_rects_packed = 0;
+   }
+
+   // return the all_rects_packed status
+   return all_rects_packed;
+}
+#endif
+
+/*
+------------------------------------------------------------------------------
+This software is available under 2 licenses -- choose whichever you prefer.
+------------------------------------------------------------------------------
+ALTERNATIVE A - MIT License
+Copyright (c) 2017 Sean Barrett
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+------------------------------------------------------------------------------
+ALTERNATIVE B - Public Domain (www.unlicense.org)
+This is free and unencumbered software released into the public domain.
+Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
+software, either in source code form or as a compiled binary, for any purpose,
+commercial or non-commercial, and by any means.
+In jurisdictions that recognize copyright laws, the author or authors of this
+software dedicate any and all copyright interest in the software to the public
+domain. We make this dedication for the benefit of the public at large and to
+the detriment of our heirs and successors. We intend this dedication to be an
+overt act of relinquishment in perpetuity of all present and future rights to
+this software under copyright law.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+------------------------------------------------------------------------------
+*/

test/stbttf.h

@@ -0,0 +1,212 @@
+#ifndef __STBTTF_H__
+#define __STBTTF_H__
+
+#include <SDL2/SDL.h>
+
+#include "stb_rect_pack.h"
+#include "stb_truetype.h"
+
+/* STBTTF: A quick and dirty SDL2 text renderer based on stb_truetype and stdb_rect_pack.
+ * Benoit Favre 2019
+ *
+ * This header-only addon to the stb_truetype library allows to draw text with SDL2 from
+ * TTF fonts with a similar API to SDL_TTF without the bloat.
+ * The renderer is however limited by the integral positioning of SDL blit functions.
+ * It also does not parse utf8 text and only prints ASCII characters.
+ *
+ * This code is public domain.
+ */
+
+typedef struct {
+	stbtt_fontinfo* info;
+	stbtt_packedchar* chars;
+	SDL_Texture* atlas;
+	int texture_size;
+	float size;
+	float scale;
+	int ascent;
+	int baseline;
+} STBTTF_Font;
+
+/* Release the memory and textures associated with a font */
+void STBTTF_CloseFont(STBTTF_Font* font);
+
+/* Open a TTF font given a SDL abstract IO handler, for a given renderer and a given font size.
+ * Returns NULL on failure. The font must be deallocated with STBTTF_CloseFont when not used anymore.
+ * This function creates a texture atlas with prerendered ASCII characters (32-128).
+ */ 
+STBTTF_Font* STBTTF_OpenFontRW(SDL_Renderer* renderer, SDL_RWops* rw, float size);
+
+/* Open a TTF font given a filename, for a given renderer and a given font size.
+ * Convinience function which calls STBTTF_OpenFontRW.
+ */
+STBTTF_Font* STBTTF_OpenFont(SDL_Renderer* renderer, const char* filename, float size);
+
+/* Draw some text using the renderer draw color at location (x, y).
+ * Characters are copied from the texture atlas using the renderer SDL_RenderCopy function.
+ * Since that function only supports integral coordinates, the result is not great.
+ * Only ASCII characters (32 <= c < 128) are supported. Anything outside this range is ignored.
+ */
+void STBTTF_RenderText(SDL_Renderer* renderer, STBTTF_Font* font, float x, float y, const char *text);
+
+/* Return the length in pixels of a text. 
+ * You can get the height of a line by using font->baseline.
+ */
+float STBTTF_MeasureText(STBTTF_Font* font, const char *text);
+
+#ifdef STBTTF_IMPLEMENTATION
+
+void STBTTF_CloseFont(STBTTF_Font* font) {
+	if(font->atlas) SDL_DestroyTexture(font->atlas);
+	if(font->info) free(font->info);
+	if(font->chars) free(font->chars);
+	free(font);
+}
+
+STBTTF_Font* STBTTF_OpenFontRW(SDL_Renderer* renderer, SDL_RWops* rw, float size) {
+	Sint64 file_size = SDL_RWsize(rw);
+	unsigned char* buffer = malloc(file_size);
+	if(SDL_RWread(rw, buffer, file_size, 1) != 1) return NULL;
+	SDL_RWclose(rw);
+
+	STBTTF_Font* font = calloc(sizeof(STBTTF_Font), 1);
+	font->info = malloc(sizeof(stbtt_fontinfo));
+	font->chars = malloc(sizeof(stbtt_packedchar) * 96);
+
+	if(stbtt_InitFont(font->info, buffer, 0) == 0) {
+		free(buffer);
+		STBTTF_CloseFont(font);
+		return NULL;
+	}
+
+	// fill bitmap atlas with packed characters
+	unsigned char* bitmap = NULL;
+	font->texture_size = 32;
+	while(1) {
+		bitmap = malloc(font->texture_size * font->texture_size);
+		stbtt_pack_context pack_context;
+		stbtt_PackBegin(&pack_context, bitmap, font->texture_size, font->texture_size, 0, 1, 0);
+		stbtt_PackSetOversampling(&pack_context, 1, 1);
+		if(!stbtt_PackFontRange(&pack_context, buffer, 0, size, 32, 95, font->chars)) {
+			// too small
+			free(bitmap);
+			stbtt_PackEnd(&pack_context);
+			font->texture_size *= 2;
+		} else {
+			stbtt_PackEnd(&pack_context);
+			break;
+		}
+	}
+
+	// convert bitmap to texture
+	font->atlas = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_STATIC, font->texture_size, font->texture_size);
+	SDL_SetTextureBlendMode(font->atlas, SDL_BLENDMODE_BLEND);
+
+	Uint32* pixels = malloc(font->texture_size * font->texture_size * sizeof(Uint32));
+	static SDL_PixelFormat* format = NULL;
+	if(format == NULL) format = SDL_AllocFormat(SDL_PIXELFORMAT_RGBA32);
+	for(int i = 0; i < font->texture_size * font->texture_size; i++) {
+		pixels[i] = SDL_MapRGBA(format, 0xff, 0xff, 0xff, bitmap[i]);
+	}
+	SDL_UpdateTexture(font->atlas, NULL, pixels, font->texture_size * sizeof(Uint32));
+	free(pixels);
+	free(bitmap);
+
+	// setup additional info
+  font->scale = stbtt_ScaleForPixelHeight(font->info, size);
+	stbtt_GetFontVMetrics(font->info, &font->ascent, 0, 0);
+  font->baseline = (int) (font->ascent * font->scale);
+
+	free(buffer);
+
+	return font;
+}
+
+STBTTF_Font* STBTTF_OpenFont(SDL_Renderer* renderer, const char* filename, float size) {
+	SDL_RWops *rw = SDL_RWFromFile(filename, "rb");
+	if(rw == NULL) return NULL;
+	return STBTTF_OpenFontRW(renderer, rw, size);
+}
+
+void STBTTF_RenderText(SDL_Renderer* renderer, STBTTF_Font* font, float x, float y, const char *text) {
+	Uint8 r, g, b, a;
+	SDL_GetRenderDrawColor(renderer, &r, &g, &b, &a);
+	SDL_SetTextureColorMod(font->atlas, r, g, b);
+	SDL_SetTextureAlphaMod(font->atlas, a);
+	for(int i = 0; text[i]; i++) {
+		if (text[i] >= 32 && text[i] < 128) {
+			//if(i > 0) x += stbtt_GetCodepointKernAdvance(font->info, text[i - 1], text[i]) * font->scale;
+
+			stbtt_packedchar* info = &font->chars[text[i] - 32];
+			SDL_Rect src_rect = {info->x0, info->y0, info->x1 - info->x0, info->y1 - info->y0};
+			SDL_Rect dst_rect = {x + info->xoff, y + info->yoff, info->x1 - info->x0, info->y1 - info->y0};
+
+			SDL_RenderCopy(renderer, font->atlas, &src_rect, &dst_rect);
+			x += info->xadvance;
+		}
+	}
+}
+
+float STBTTF_MeasureText(STBTTF_Font* font, const char *text) {
+	float width = 0;
+	for(int i = 0; text[i]; i++) {
+		if (text[i] >= 32 && text[i] < 128) {
+			//if(i > 0) width += stbtt_GetCodepointKernAdvance(font->info, text[i - 1], text[i]) * font->scale;
+
+			stbtt_packedchar* info = &font->chars[text[i] - 32];
+			width += info->xadvance;
+		}
+	}
+	return width;
+}
+
+/*******************
+ * Example program *
+ *******************
+
+#include <stdio.h>
+
+#define STB_RECT_PACK_IMPLEMENTATION
+#define STB_TRUETYPE_IMPLEMENTATION
+#define STBTTF_IMPLEMENTATION
+
+#include "stbttf.h"
+
+int main(int argc, char** argv) {
+	if(argc != 2) {
+		fprintf(stderr, "usage: %s <font>\n", argv[0]);
+		exit(1);
+	}
+	SDL_Init(SDL_INIT_VIDEO);
+	SDL_Window* window = SDL_CreateWindow("stbttf", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 640, 480, SDL_WINDOW_SHOWN | SDL_WINDOW_OPENGL);
+	SDL_Renderer* renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
+	SDL_RenderSetLogicalSize(renderer, 640, 480);
+	SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_BLEND);
+
+	STBTTF_Font* font = STBTTF_OpenFont(renderer, argv[1], 32);
+
+	while(1) {
+		SDL_Event event;
+		while(SDL_PollEvent(&event)) {
+			if(event.type == SDL_QUIT) exit(0);
+		}
+		SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
+		SDL_RenderClear(renderer);
+		// set color and render some text
+		SDL_SetRenderDrawColor(renderer, 128, 0, 0, 255);
+		STBTTF_RenderText(renderer, font, 50, 50, "This is a test");
+		// render the atlas to check its content
+		//SDL_Rect dest = {0, 0, font->texturesize, font->texturesize};
+		//SDL_RenderCopy(renderer, font->atlas, &dest, &dest);
+		SDL_RenderPresent(renderer);
+		SDL_Delay(1000 / 60);
+	}
+	STBTTF_CloseFont(font);
+	SDL_Quit();
+}
+
+*/
+
+#endif
+
+#endif

test/test_bitsruct.c3

@@ -1,14 +0,0 @@
-bitstruct Bits : uint {
-	bool a : 0;
-	bool b : 1;
-	bool c : 2;
-}
-
-fn int main()
-{
-	Bits a = {false, true, false};
-	Bits b = {true, true, false};
-	Bits c = a | b;
-
-	return 0;
-}

test/test_bittype.c3

@@ -1,10 +0,0 @@
-import std::io;
-import std::collections::bitset;
-
-def Bits = bitset::BitSet(<128>);
-
-fn void main()
-{
-    Bits b;
-	io::printn($typeof(b.data[0]).sizeof);
-}

test/test_custom_hash.c3

@@ -1,14 +0,0 @@
-import std::collections::map;
-
-def Codepoint = uint;
-fn uint Codepoint.hash(Codepoint code) => code < 128 ? code : ((uint)code).hash();
-def CodeMap = map::HashMap(<Codepoint, Codepoint>);
-
-
-fn int main()
-{
-    CodeMap m;
-    m.new_init();
-    m.free();
-    return 0;
-}

test/test_union.c3

@@ -1,26 +0,0 @@
-
-struct CmdA {
-	int a, b;
-}
-
-struct CmdB {
-	float a, b;
-}
-
-union AnyCmd {
-	CmdA a;
-	CmdB b;
-}
-
-struct Cmd {
-	int type;
-	AnyCmd cmd;
-}
-
-fn int main()
-{
-	Cmd c;
-	c.type = 1;
-	c.cmd.a = {.a = 1, .b = 2};
-	return 0;
-}

test/test_vtree.c3

@@ -1,7 +0,0 @@
-import std::io;
-import vtree;
-
-fn int main()
-{
-    return 0;
-}

text_rendering/.gitignore

@@ -0,0 +1,4 @@
+*.png
+test
+obj/**
+objlist

text_rendering/Makefile

@@ -0,0 +1,18 @@
+CC      = gcc
+# instrumentation flags
+INFLAGS = -fsanitize=address,builtin,undefined
+LDFLAGS = -lm -lgrapheme -lSDL2 -lGLEW -lGL ${INFLAGS}
+CFLAGS  = -ggdb3 -Wall -Wextra -pedantic -std=c11 -Wno-unused-function -fno-omit-frame-pointer ${INFLAGS}
+
+.PHONY: clean all
+all: test
+
+font.o: font.c font.h stb_truetype.h stb_image_write.h util.h \
+ generic_cache.h generic_hash.h
+main.o: main.c ren.h util.h
+ren.o: ren.c util.h font.h ren.h generic_stack.h
+util.o: util.c util.h
+test:  font.o main.o ren.o util.o
+	${CC} ${LDFLAGS} -o test  font.o main.o ren.o util.o
+clean:
+	rm -f test  font.o main.o ren.o util.o

text_rendering/box_fragshader.glsl

@@ -0,0 +1,8 @@
+#version 330 core
+
+in vec4 col;
+
+void main()
+{
+	gl_FragColor = col;
+}

text_rendering/box_vertshader.glsl

@@ -0,0 +1,19 @@
+#version 330 core
+
+uniform ivec2 viewsize;
+
+layout(location = 0) in vec2 position;
+layout(location = 2) in vec4 color;
+
+out vec4 col;
+
+
+void main()
+{
+	vec2 v = vec2(float(viewsize.x), float(viewsize.y));
+	vec2 p = vec2(position.x*2.0/v.x - 1.0, 1.0 - position.y*2.0/v.y);
+	vec4 pos = vec4(p.x, p.y, 0.0f, 1.0f);
+
+	gl_Position = pos;
+	col = color;
+}

text_rendering/font.c

@@ -1,72 +1,41 @@
-module ugui;
+#define _POSIX_C_SOURCE 200809l
-
+#define STB_TRUETYPE_IMPLEMENTATION
-import cache;
+#define STBTT_STATIC
-//#include <grapheme.h>
+#define STB_IMAGE_WRITE_IMPLEMENTATION
-//#include <assert.h>
-
-//#include "stb_truetype.h"
-//#include "stbimage_write.h"
-
-// unicode code point, different type for a different hash
-def Codepoint = uint;
-
-/* width and height of a glyph contain the kering advance
- * (u,v)
- *   +-------------*---+ -
- *   |       ^     |   | ^
- *   |       |oy   |   | |
- *   |       v     |   | |
- *   |      .ii.   |   | |
- *   |     @@@@@@. |<->| |
- *   |    V@Mio@@o |adv| |h
- *   |    :i.  V@V |   | |
- *   |      :oM@@M |   | |
- *   |    :@@@MM@M |   | |
- *   |    @@o  o@M |   | |
- *   |<->:@@.  M@M |   | |
- *   |ox  @@@o@@@@ |   | |
- *   |    :M@@V:@@.|   | v
- *   +-------------*---+ -
- *   |<------------->|
- *           w
- */
-struct Glyph {
-    Codepoint code;
-	uint u, v;
-	ushort w, h, a, x, y;
-}
 
-def GlyphCache = cache::Cache(<Codepoint, Glyph, 1024>);
+#include <grapheme.h>
+#include <assert.h>
 
-// identity map the ASCII range
+#include "font.h"
-fn uint Codepoint.hash(Codepoint code) => code < 128 ? code : ((uint)code).hash();
+#include "stb_truetype.h"
+#include "stb_image_write.h"
+#include "util.h"
 
-struct FontAtlas {
+#include "generic_cache.h"
-	uint width, height;
+static inline unsigned int hash(unsigned int code)
-	char* atlas;
+{
-	uint glyph_max_w, glyph_max_h;
+	// identity map the ascii range
-	int size;
+	return code < 128 ? code : hash_u32(code);
-	int file_size;
-	char *file;
-	void *priv;
 }
+CACHE_DECL(cache, struct font_glyph, hash, hash_cmp_u32)
 
 
-macro is_utf8(char c) => c & 0x80;
+#define UTF8(c) (c&0x80)
-const uint BDEPTH = 1;
+#define BDEPTH 1
-const uint BORDER = 4;
+#define BORDER 4
 
-// FIXME: as of now only monospaced fonts look decent since no
+// FIXME: as of now only monospaced fonts work correctly since no kerning information
-//        kerning information is stored
+// is stored
 
-struct Priv @private {
+
+struct priv {
 	stbtt_fontinfo stb;
 	float scale;
 	int baseline;
 	unsigned char *bitmap;
 	struct cache c;
-}
+};
-//#define PRIV(x) ((struct priv *)x->priv)
+#define PRIV(x) ((struct priv *)x->priv)
 
 
 struct font_atlas * font_init(void)

text_rendering/font.h

@@ -0,0 +1,50 @@
+#ifndef _FONT_H
+#define _FONT_H
+
+#include <stdint.h>
+
+/* width and height of a glyph contain the kering advance
+ * (u,v)
+ *   +-------------*---+ -
+ *   |       ^     |   | ^
+ *   |       |oy   |   | |
+ *   |       v     |   | |
+ *   |      .ii.   |   | |
+ *   |     @@@@@@. |<->| |
+ *   |    V@Mio@@o |adv| |
+ *   |    :i.  V@V |   | |
+ *   |      :oM@@M |   | |
+ *   |    :@@@MM@M |   | |
+ *   |    @@o  o@M |   | |
+ *   |<->:@@.  M@M |   | |
+ *   |ox  @@@o@@@@ |   | |
+ *   |    :M@@V:@@.|   | v
+ *   +-------------*---+ -
+ *   |<------------->|
+ *           w
+ */
+// TODO: the advance isn't unique for every pair of characters
+struct font_glyph {
+	uint32_t codepoint;
+	uint32_t u, v;
+	uint16_t w, h, a, x, y;
+};
+
+struct font_atlas {
+	unsigned int width, height;
+	unsigned char *atlas;
+	unsigned int glyph_max_w, glyph_max_h;
+	int size;
+	int file_size;
+	char *file;
+	void *priv;
+};
+
+
+struct font_atlas * font_init(void);
+int font_load(struct font_atlas *atlas, const char *path, int size);
+int font_free(struct font_atlas *atlas);
+const struct font_glyph * font_get_glyph_texture(struct font_atlas *atlas, unsigned int code, int *updated);
+void font_dump(const struct font_atlas *atlas, const char *path);
+
+#endif

text_rendering/font_fragshader.glsl

@@ -0,0 +1,18 @@
+#version 330 core
+
+// viewsize.x = viewport width in pixels; viewsize.y = viewport height in pixels
+uniform ivec2 viewsize;
+uniform ivec2 texturesize;
+
+// texture uv coordinate in texture space
+in vec2 uv;
+uniform sampler2DRect ts;
+
+const vec3 textcolor = vec3(1.0, 1.0, 1.0);
+
+
+void main()
+{
+	//gl_FragColor = vec4(1.0f,0.0f,0.0f,1.0f);
+	gl_FragColor = vec4(textcolor, texture(ts, uv));
+}

text_rendering/font_vertshader.glsl

@@ -0,0 +1,26 @@
+#version 330 core
+
+// viewsize.x = viewport width in pixels; viewsize.y = viewport height in pixels
+uniform ivec2 viewsize;
+uniform ivec2 texturesize;
+
+// both position and and uv are in pixels, they where converted to floats when 
+// passed to the shader
+layout(location = 0) in vec2 position;
+layout(location = 1) in vec2 txcoord;
+
+out vec2 uv;
+
+void main()
+{
+	vec2 v = vec2(float(viewsize.x), float(viewsize.y));
+	
+//	vec2 p = vec2(position.x*2.0f/v.x - 1.0f, position.y*2.0f/v.y - 1.0f);
+	vec2 p = vec2(position.x*2.0/v.x - 1.0, 1.0 - position.y*2.0/v.y);
+	vec4 pos = vec4(p.x, p.y, 0.0f, 1.0f);
+
+	gl_Position = pos;
+	// since the texture is a GL_TEXTURE_RECTANGLE the coordintes do not need to
+	// be normalized
+	uv = vec2(txcoord.x, txcoord.y);
+}

text_rendering/generic_cache.h

@@ -0,0 +1,126 @@
+#ifndef CACHE_GENERIC_H
+#define CACHE_GENERIC_H
+
+
+#include "generic_hash.h"
+
+#define CACHE_SIZE 512
+#define CACHE_NCYCLES (CACHE_SIZE*2/3)
+#define CACHE_BSIZE (((CACHE_SIZE+0x3f)&(~0x3f))>>6)
+#define CACHE_BRESET(b)   for (int i = 0; i < CACHE_BSIZE; b[i++] = 0);
+#define CACHE_BSET(b, x)  b[(x)>>6] |= (uint64_t)1<<((x)&63)
+#define CACHE_BTEST(b, x) (b[(x)>>6]&((uint64_t)1<<((x)&63)))
+
+// FIXME: this cache implementation is not really generic since it expects an unsigned
+//        as the code and not a generic type
+
+
+#define CACHE_CYCLE(c)                                                         \
+{                                                                              \
+	if (++(c->cycles) > CACHE_NCYCLES) {                                   \
+		for (int i = 0; i < CACHE_BSIZE; i++) {                        \
+			c->present[i] &= c->used[i];                           \
+			c->used[i] = 0;                                        \
+		}                                                              \
+		c->cycles = 0;                                                 \
+	}                                                                      \
+}
+
+
+#define CACHE_DECL(name, type, hashfn, cmpfn)                                  \
+HASH_DECL(name##table, uint32_t, uint32_t, hashfn, cmpfn)                      \
+struct name {                                                                  \
+	struct name##table_ref *table;                                         \
+	type *array;                                                           \
+	uint64_t *present, *used;                                              \
+	int cycles;                                                            \
+};                                                                             \
+\
+\
+/* FIXME: check for allocation errors */                                       \
+struct name name##_init(void)                                                  \
+{                                                                              \
+	struct name##table_ref *t = name##table_create(CACHE_SIZE);            \
+	type *a = malloc(sizeof(type)*CACHE_SIZE);                             \
+	uint64_t *p = malloc(sizeof(uint64_t)*CACHE_BSIZE);                    \
+	uint64_t *u = malloc(sizeof(uint64_t)*CACHE_BSIZE);                    \
+	CACHE_BRESET(p);                                                       \
+	CACHE_BRESET(u);                                                       \
+	return (struct name){.table=t, .array=a, .present=p, .used=u, 0};      \
+}                                                                              \
+\
+\
+void name##_free(struct name *cache)                                           \
+{                                                                              \
+	if (cache) {                                                           \
+		name##table_destroy(cache->table);                             \
+		free(cache->array);                                            \
+		free(cache->present);                                          \
+		free(cache->used);                                             \
+	}                                                                      \
+}                                                                              \
+\
+\
+const type * name##_search(struct name *cache, uint32_t code)                  \
+{                                                                              \
+	if (!cache) return NULL;                                               \
+	struct name##table_entry *r;                                           \
+	r = name##table_search(cache->table, code);                            \
+	/* MISS */                                                             \
+	if (!r || !cmpfn(code, r->code))                                       \
+		return NULL;                                                   \
+	/* MISS, the data is not valid (not present) */                        \
+	if (!CACHE_BTEST(cache->present, r->data))                             \
+		return NULL;                                                   \
+	/* HIT, set as recently used */                                        \
+	CACHE_BSET(cache->used, r->data);                                      \
+	return (&cache->array[r->data]);                                       \
+}                                                                              \
+\
+\
+/* Look for a free spot in the present bitmap and return its index */          \
+/* If there is no free space left then just return the first position */       \
+int name##_get_free_spot(struct name *cache)                                   \
+{                                                                              \
+	if (!cache) return -1;                                                 \
+	int x = 0;                                                             \
+	for (int b = 0; b < CACHE_BSIZE; b++) {                                \
+		if (cache->present[b] == 0) x = 64;                            \
+		else x = __builtin_clzll(cache->present[b]);                   \
+		x = 64-x;                                                      \
+		if (!CACHE_BTEST(cache->present, x+64*b))                      \
+			return x+64*b;                                         \
+	}                                                                      \
+	return 0;                                                              \
+}                                                                              \
+\
+\
+const type * name##_insert_at(struct name *cache, const type *g, uint32_t code, int x)\
+{                                                                              \
+	if (!cache) return NULL;                                               \
+	type *spot = NULL;                                                     \
+	/* check if the spot is valid */                                       \
+	if (x < 0) return NULL;                                                \
+	/* Set used and present */                                             \
+	CACHE_BSET(cache->present, x);                                         \
+	CACHE_BSET(cache->used, x);                                            \
+	CACHE_CYCLE(cache)                                                     \
+	spot = &(cache->array[x]);                                             \
+	*spot = *g;                                                            \
+	struct name##table_entry e = { .code = code, .data = x};               \
+	if (!name##table_insert(cache->table, &e))                             \
+		return NULL;                                                   \
+	return spot;                                                           \
+}                                                                              \
+\
+\
+const type * name##_insert(struct name *cache, const type *g, uint32_t code, int *x)\
+{                                                                              \
+	int y;                                                                 \
+	if (!x) x = &y;                                                        \
+	*x = name##_get_free_spot(cache);                                      \
+	return name##_insert_at(cache, g, code, *x);                           \
+}                                                                              \
+
+
+#endif

text_rendering/generic_hash.h

@@ -0,0 +1,134 @@
+#ifndef _HASH_GENERIC
+#define _HASH_GENERIC
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+
+#define HASH_MAXSIZE 4096
+// for fibonacci hashing, 2^{32,64}/<golden ratio>
+#define HASH_RATIO32 ((uint64_t)2654435769u)
+#define HASH_RATIO64 ((uint64_t)11400714819322457583u)
+// salt for string hashing
+#define HASH_SALT ((uint64_t)0xbabb0cac)
+
+
+/* Ready-made compares */
+static inline int hash_cmp_u32(uint32_t a, uint32_t b) { return a == b; }
+static inline int hash_cmp_u64(uint64_t a, uint64_t b) { return a == b; }
+static inline int hash_cmp_str(const char *a, const char *b) { return strcmp(a, b) == 0; }
+
+
+/* Ready-made hashes */
+static inline uint32_t hash_u64(uint64_t c)
+{
+	return (uint64_t)((((uint64_t)c+HASH_SALT)*HASH_RATIO64)>>32);
+}
+static inline uint32_t hash_u32(uint32_t c)
+{
+	return (uint32_t)((((uint64_t)c<<31)*HASH_RATIO64)>>32);
+}
+static inline uint32_t hash_str(const char *s)
+{
+	uint32_t h = HASH_SALT;
+	const uint8_t *v = (const uint8_t *)(s);
+	for (int x = *s; x; x--) {
+		h += v[x-1];
+		h += h << 10;
+		h ^= h >> 6;
+	}
+	h += h << 3;
+  	h ^= h >> 11;
+  	h += h << 15;
+	return h;
+}
+
+
+#define HASH_DECL(htname, codetype, datatype, hashfn, cmpfn)                   \
+struct htname##_entry {                                                        \
+	codetype code;                                                         \
+	datatype data;                                                         \
+};                                                                             \
+\
+struct htname##_ref {                                                          \
+	uint32_t items, size, exp;                                             \
+	struct htname##_entry bucket[];                                        \
+};                                                                             \
+\
+\
+struct htname##_ref * htname##_create(uint32_t size)                           \
+{                                                                              \
+	if (!size || size > HASH_MAXSIZE)                                      \
+		return NULL;                                                   \
+	/* round to the greater power of two */                                \
+	/* FIXME: check for intger overflow here */                            \
+	uint32_t exp = 32-__builtin_clz(size-1);                               \
+	size = 1<<(exp);                                                       \
+	/* FIXME: check for intger overflow here */                            \
+	struct htname##_ref *ht = malloc(sizeof(struct htname##_ref)+sizeof(struct htname##_entry)*size); \
+	if (ht) {                                                              \
+		ht->items = 0;                                                 \
+		ht->size  = size;                                              \
+		ht->exp   = exp;                                               \
+		memset(ht->bucket, 0, sizeof(struct htname##_entry)*size);     \
+	}                                                                      \
+	return ht;                                                             \
+}                                                                              \
+\
+\
+void htname##_destroy(struct htname##_ref *ht)                                 \
+{                                                                              \
+	if (ht) free(ht);                                                      \
+}                                                                              \
+\
+\
+static uint32_t htname##_lookup(struct htname##_ref *ht, uint32_t hash, uint32_t idx) \
+{                                                                              \
+	if (!ht) return 0;                                                     \
+	uint32_t mask = ht->size-1;                                            \
+	uint32_t step = (hash >> (32 - ht->exp)) | 1;                          \
+	return (idx + step) & mask;                                            \
+}                                                                              \
+\
+\
+/* Find and return the element by code */                                      \
+struct htname##_entry * htname##_search(struct htname##_ref *ht, codetype code)\
+{                                                                              \
+	if (!ht) return NULL;                                                  \
+	uint32_t h = hashfn(code);                                             \
+	for (uint32_t i=h, x=0; ; x++) {                                       \
+		i = htname##_lookup(ht, h, i);                                 \
+		if (x > (ht->size<<1)   ||                                     \
+		    !ht->bucket[i].code ||                                     \
+		    cmpfn(ht->bucket[i].code, code)                            \
+		) {                                                            \
+			return &(ht->bucket[i]);                               \
+		}                                                              \
+	}                                                                      \
+	return NULL;                                                           \
+}                                                                              \
+\
+\
+/* FIXME: this simply overrides the found item */                              \
+struct htname##_entry * htname##_insert(struct htname##_ref *ht, struct htname##_entry *entry) \
+{                                                                              \
+	struct htname##_entry *r = htname##_search(ht, entry->code);           \
+	if (r) {                                                               \
+		if (!r->code)                                                  \
+			ht->items++;                                           \
+		*r = *entry;                                                   \
+	}                                                                      \
+	return r;                                                              \
+}                                                                              \
+\
+\
+struct htname##_entry * htname##_remove(struct htname##_ref *ht, codetype code)\
+{                                                                              \
+	if (!ht) return NULL;                                                  \
+	struct htname##_entry *r = htname##_search(ht, code);                  \
+	if (r) r->code = 0;                                                    \
+	return r;                                                              \
+}                                                                              \
+
+#endif

text_rendering/generic_stack.h

@@ -0,0 +1,118 @@
+#ifndef _STACK_GENERIC_H
+#define _STACK_GENERIC_H
+
+
+#define STACK_STEP 8
+#define STACK_SALT 0xbabb0cac
+
+// FIXME: find a way to not re-hash the whole stack when removing one item
+
+// incremental hash for every grow
+#if STACK_DISABLE_HASH
+#define STACK_HASH(p, s, h) {}
+#else
+#define STACK_HASH(p, s, h)                                                    \
+{                                                                              \
+	unsigned char *v = (unsigned char *)(p);                               \
+	for (int x = (s); x; x--) {                                            \
+		(h) += v[x-1];                                                 \
+		(h) += (h) << 10;                                              \
+		(h) ^= (h) >> 6;                                               \
+	}                                                                      \
+	(h) += (h) << 3;                                                       \
+  	(h) ^= (h) >> 11;                                                      \
+  	(h) += (h) << 15;                                                      \
+}
+#endif
+
+
+// TODO: add a rolling hash
+#define STACK_DECL(stackname, type)                                            \
+struct stackname {                                                             \
+	type *items;                                                           \
+	int size, idx, old_idx;                                                \
+	unsigned int hash, old_hash;                                           \
+};                                                                             \
+\
+\
+struct stackname stackname##_init(void)                                        \
+{                                                                              \
+	return (struct stackname){0, .hash = STACK_SALT};                      \
+}                                                                              \
+\
+\
+int stackname##_grow(struct stackname *stack, int step)                        \
+{                                                                              \
+	if (!stack)                                                            \
+		return -1;                                                     \
+	stack->items = realloc(stack->items, (stack->size+step)*sizeof(type)); \
+	if(!stack->items)                                                      \
+		return -1;                                                     \
+	memset(&(stack->items[stack->size]), 0, step*sizeof(*(stack->items))); \
+	stack->size += step;                                                   \
+	return 0;                                                              \
+}                                                                              \
+\
+\
+int stackname##_push(struct stackname *stack, type *e)                         \
+{                                                                              \
+	if (!stack || !e)                                                      \
+		return -1;                                                     \
+	if (stack->idx >= stack->size)                                         \
+		if (stackname##_grow(stack, STACK_STEP))                       \
+			return -1;                                             \
+	stack->items[stack->idx++] = *e;                                       \
+	STACK_HASH(e, sizeof(type), stack->hash);                              \
+	return 0;                                                              \
+}                                                                              \
+\
+\
+type stackname##_pop(struct stackname *stack)                                  \
+{                                                                              \
+	if (!stack || stack->idx == 0 || stack->size == 0)                     \
+		return (type){0};                                              \
+	stack->hash = STACK_SALT;                                              \
+	STACK_HASH(stack->items, sizeof(type)*(stack->idx-1), stack->hash);    \
+	return stack->items[stack->idx--];                                     \
+}                                                                              \
+\
+\
+int stackname##_clear(struct stackname *stack)                                 \
+{                                                                              \
+	if (!stack)                                                            \
+		return -1;                                                     \
+	stack->old_idx = stack->idx;                                           \
+	stack->old_hash = stack->hash;                                         \
+	stack->hash = STACK_SALT;                                              \
+	stack->idx = 0;                                                        \
+	return 0;                                                              \
+}                                                                              \
+\
+\
+int stackname##_changed(struct stackname *stack)                               \
+{                                                                              \
+	if (!stack)                                                            \
+		return -1;                                                     \
+	return stack->hash != stack->old_hash;                                 \
+}                                                                              \
+\
+\
+int stackname##_size_changed(struct stackname *stack)                          \
+{                                                                              \
+	if (!stack)                                                            \
+		return -1;                                                     \
+	return stack->size != stack->old_idx;                                  \
+}                                                                              \
+\
+\
+int stackname##_free(struct stackname *stack)                                  \
+{                                                                              \
+	if (stack) {                                                           \
+		stackname##_clear(stack);                                      \
+		if (stack->items)                                              \
+			free(stack->items);                                    \
+	}                                                                      \
+	return 0;                                                              \
+}                                                                              \
+
+#endif

text_rendering/genmake.sh

@@ -0,0 +1,46 @@
+#!/bin/sh
+
+genobj() {
+	#echo "$1" | sed -e 's/^/obj\//' -e 's/\.c/\.o/'
+	echo "$1" | sed -e 's/\.c/\.o/'
+}
+
+genrule() {
+	#gcc -MM "$1" | sed 's/^/obj\//'
+	gcc -MM "$1"
+}
+
+
+rm -f objlist
+
+cat > Makefile << EOF
+CC      = gcc
+# instrumentation flags
+INFLAGS = -fsanitize=address,builtin,undefined
+LDFLAGS = -lm -lgrapheme -lSDL2 -lGLEW -lGL \${INFLAGS}
+CFLAGS  = -ggdb3 -Wall -Wextra -pedantic -std=c11 \
+-Wno-unused-function -fno-omit-frame-pointer \${INFLAGS}
+
+.PHONY: clean all
+all: test
+
+EOF
+
+for f in *.c; do
+	genrule $f >> Makefile
+	genobj $f >> objlist
+done
+
+mainrule='test: '
+linkcmd='	${CC} ${LDFLAGS} -o test '
+cleanrule='clean:
+	rm -f test '
+while IFS="" read -r line; do
+	mainrule="$mainrule $line"
+	linkcmd="$linkcmd $line"
+	cleanrule="$cleanrule $line"
+done < objlist
+
+echo "$mainrule"  >> Makefile
+echo "$linkcmd"   >> Makefile
+echo "$cleanrule" >> Makefile

text_rendering/main.c

@@ -0,0 +1,96 @@
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_events.h>
+#include <SDL2/SDL_video.h>
+#include <stdlib.h>
+#include <locale.h>
+#include <stdio.h>
+
+#include "ren.h"
+#include "util.h"
+
+
+//const char *str1 = "Ciao Mamma!\nprova: òçà°ù§|¬³¼$£ì\t";
+const char *str1 = "ciao\tmamma";
+const char *str2 = "The quick brown fox jumps over the lazy dog\n"
+	"чащах юга жил бы цитрус? Да, но фальшивый экземпляр!\n"
+	"Pijamalı hasta, yağız şoföre çabucak güvendi\n"
+	"Pchnąć w tę łódź jeża lub ośm skrzyń fig\n"
+	"イロハニホヘト チリヌルヲ ワカヨタレソ ツネナラム ウヰノオクヤマ ケフコエテ アサキユメミシ ヱヒモセスン\n"
+	"Kæmi ný öxi hér ykist þjófum nú bæði víl og ádrepa";
+SDL_Window *win;
+
+
+#define red  0xff0000ff
+#define blue 0xffff0000
+void draw(void)
+{
+	static unsigned int frame = 0;
+	printf("frame: %d\n", frame++);
+	ren_clear();
+	//ren_render_box(10, 10, 400, 50, blue);
+	//if (ren_render_text(str1, 10, 10, 400, 50, 20))
+	//	printf("text: %s\n", ren_strerror());
+	int w, h;
+	ren_get_text_box(str2, &w, &h, 20);
+	//printf("box for: %s -> (%d, %d)\n", str2, w, h);
+	ren_render_box(0, 0, w, h, blue);
+	ren_render_text(str2, 0, 0, w, h, 20);
+
+	// fixme: this causes a bug
+	const char *s = "ciao mamma";
+	ren_get_text_box(s, &w, &h, 12);
+	s = "stuff that was not in font size 12 -> чащаx";
+	ren_render_box(0, 200, w, h, red);
+	if (ren_render_text(s, 0, 200, 0xffff, 0xffff, 12))
+		printf("BUG\n");
+
+	SDL_GL_SwapWindow(win);
+}
+
+
+int main(void)
+{
+	setlocale(LC_ALL, "en_US.UTF-8");
+
+	SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS);
+	SDL_SetHint(SDL_HINT_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR, "0");
+	SDL_SetHint(SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, "1");
+	SDL_SetHint(SDL_HINT_VIDEO_HIGHDPI_DISABLED, "0");
+
+	win = SDL_CreateWindow(
+		"test render",
+		SDL_WINDOWPOS_UNDEFINED,
+		SDL_WINDOWPOS_UNDEFINED,
+		500,
+		500,
+		SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
+	if (ren_init(win)) {
+		printf("renderer init error: %s\n", ren_strerror());
+		return 1;
+	}
+
+	SDL_Event e;
+	while(1) {
+		SDL_WaitEvent(&e);
+		if (e.type == SDL_QUIT)
+			break;
+		if (e.type == SDL_WINDOWEVENT) {
+			switch (e.window.event) {
+			case SDL_WINDOWEVENT_RESIZED:
+			case SDL_WINDOWEVENT_SIZE_CHANGED:
+				ren_update_viewport(e.window.data1, e.window.data2);
+				draw();
+				break;
+			case SDL_WINDOWEVENT_EXPOSED:
+				draw();
+				break;
+			default: break;
+			}
+		}
+	}
+
+	ren_free();
+	SDL_DestroyWindow(win);
+	SDL_Quit();
+	return 0;
+}

text_rendering/ren.c

@@ -0,0 +1,826 @@
+#include <SDL2/SDL.h>
+#include <GL/glew.h>
+#include <SDL2/SDL_opengl.h>
+#include <SDL2/SDL_video.h>
+#include <ctype.h>
+#include <grapheme.h>
+#include <stdio.h>
+
+#include "util.h"
+#include "font.h"
+#include "ren.h"
+
+
+#define GLERR(x)                                                               \
+{                                                                              \
+	int a = glGetError();                                                  \
+	if (a != GL_NO_ERROR)                                                  \
+		printf("(%s:%d %s:%s) glError: 0x%x %s\n",                     \
+			__FILE__, __LINE__, __func__, x, a, glerr[a&0xff]);    \
+}
+#define GL(f) f; GLERR(#f)
+#define REN_RET(a,b) {ren_errno = b; return a;}
+
+
+enum REN_ERR {
+	REN_SUCCESS = 0,
+	REN_ERRNO,
+	REN_INVAL,
+	REN_VERTEX,
+	REN_FRAGMENT,
+	REN_PROGRAM,
+	REN_COMPILE,
+	REN_LINK,
+	REN_TEXTURE,
+	REN_CONTEXT,
+	REN_GLEW,
+	REN_FONT,
+	REN_BUFFER,
+	REN_UNIFORM,
+};
+
+
+// TODO: make a macro for enum-associated string arrays
+const char * ren_err_msg[] = {
+	[REN_SUCCESS]  = "Success",
+	[REN_ERRNO]    = "Look at errno",
+	[REN_INVAL]    = "Invalid or NULL arguments",
+	[REN_VERTEX]   = "Failed to create opengl vertex shader",
+	[REN_FRAGMENT] = "Failed to create opengl fragment shader",
+	[REN_PROGRAM]  = "Failed to create opengl program",
+	[REN_COMPILE]  = "Failed to compile shaders",
+	[REN_LINK]     = "Failed to link shaders",
+	[REN_TEXTURE]  = "Failed to create texture",
+	[REN_CONTEXT]  = "Failed to create SDL OpenGL context",
+	[REN_GLEW]     = "GLEW Error",
+	[REN_FONT]     = "Font Error",
+	[REN_BUFFER]   = "Failed to create opengl buffer",
+	[REN_UNIFORM]  = "Failed to get uniform location",
+};
+
+#define ELEM(x) [x&0xff] = #x,
+const char *glerr[] = {
+	ELEM(GL_INVALID_ENUM)
+	ELEM(GL_INVALID_VALUE)
+	ELEM(GL_INVALID_OPERATION)
+	ELEM(GL_OUT_OF_MEMORY)
+};
+#undef ELEM
+
+
+// different stacks
+#include "generic_stack.h"
+STACK_DECL(vtstack, struct v_text)
+STACK_DECL(vcstack, struct v_col)
+
+
+struct ren_font {
+	struct font_atlas *font;
+	GLuint texture;
+};
+
+struct {
+	SDL_GLContext *gl;
+	struct ren_font *fonts;
+	int fonts_no;
+	GLuint font_prog;
+	GLuint box_prog;
+	GLuint font_buffer;
+	GLuint box_buffer;
+	GLint  viewsize_loc;
+	GLint  box_viewsize_loc;
+	GLint texturesize_loc;
+	struct vtstack font_stack;
+	struct vcstack box_stack;
+	int width, height;
+	int s_x, s_y, s_w, s_h;
+	int tabsize;
+} ren = {0};
+
+
+static int ren_errno;
+
+
+// print shader compilation errors
+static int shader_compile_error(GLuint shader, const char *path)
+{
+	GLint status;
+	GL(glGetShaderiv(shader, GL_COMPILE_STATUS, &status))
+	if (status != GL_FALSE)
+		return 0;
+
+	GLint log_length;
+	GL(glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &log_length))
+
+	GLchar *log_str = emalloc((log_length + 1)*sizeof(GLchar));
+	GL(glGetShaderInfoLog(shader, log_length, NULL, log_str))
+
+	const char *shader_type_str = NULL;
+	GLint shader_type;
+	GL(glGetShaderiv(shader, GL_SHADER_TYPE, &shader_type))
+	switch(shader_type) {
+	case GL_VERTEX_SHADER:   shader_type_str = "vertex";   break;
+	case GL_GEOMETRY_SHADER: shader_type_str = "geometry"; break;
+	case GL_FRAGMENT_SHADER: shader_type_str = "fragment"; break;
+	}
+
+	fprintf(stderr, "Compile failure in %s shader %s:\n%s\n", shader_type_str, path, log_str);
+	efree(log_str);
+	return -1;
+}
+
+
+// print shader link errors
+static int shader_link_error(GLuint prog)
+{
+	GLint status;
+	GL(glGetProgramiv(prog, GL_LINK_STATUS, &status))
+	if (status != GL_FALSE)
+		return 0;
+
+	GLint log_length;
+	GL(glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &log_length))
+
+	GLchar *log_str = emalloc((log_length + 1)*sizeof(GLchar));
+	GL(glGetProgramInfoLog(prog, log_length, NULL, log_str))
+	fprintf(stderr, "Linker failure: %s\n", log_str);
+	efree(log_str);
+
+	return -1;
+}
+
+
+static GLuint shader_compile(const char *path, const char *shader, GLuint type)
+{
+	GLuint s;
+	// initialize the vertex shader and get the corresponding id
+	s = GL(glCreateShader(type))
+	if (!s) REN_RET(0, REN_VERTEX)
+	// get the shader into opengl
+	GL(glShaderSource(s, 1, &shader, NULL))
+	GL(glCompileShader(s))
+	if (shader_compile_error(s, path))
+		REN_RET(0, REN_COMPILE)
+	return s;
+}
+
+
+const char * ren_strerror(void)
+{
+	return ren_err_msg[ren_errno % (sizeof(ren_err_msg)/sizeof(char *))];
+}
+
+
+// compile a vertex shader (vs_path) and a fragment shader (fs_path) into an opengl
+// program and return it's index
+static GLuint ren_compile_program(const char *vs_path, const char *fs_path)
+{
+	GLuint gl_vertshader, gl_fragshader, prog;
+
+	if (!vs_path || !fs_path)
+		REN_RET(0, REN_INVAL)
+
+	char *str = NULL;
+
+	dump_file(vs_path, &str, NULL);
+	if (!str) REN_RET(0, REN_ERRNO)
+	gl_vertshader = shader_compile(vs_path, str, GL_VERTEX_SHADER);
+	efree(str);
+	if (!gl_vertshader)
+		return 0;
+
+	dump_file(fs_path, &str, NULL);
+	if (!str) REN_RET(0, REN_ERRNO)
+	gl_fragshader = shader_compile(fs_path, str, GL_FRAGMENT_SHADER);
+	efree(str);
+	if (!gl_fragshader)
+		return 0;
+
+
+	// create the main program object, it is an amalgamation of all shaders
+	prog = GL(glCreateProgram())
+	if (!prog) REN_RET(0, REN_PROGRAM)
+
+	// attach the shaders to the program (set which shaders are present)
+	GL(glAttachShader(prog, gl_vertshader))
+	GL(glAttachShader(prog, gl_fragshader))
+	// then link the program (basically the linking stage of the program)
+	GL(glLinkProgram(prog))
+	if (shader_link_error(prog))
+		REN_RET(0, REN_LINK)
+
+	// after linking the shaders can be detached and the source freed from
+	// memory since the program is ready to use
+	GL(glDetachShader(prog, gl_vertshader))
+	GL(glDetachShader(prog, gl_fragshader))
+
+	return prog;
+}
+
+
+static void set_texture_parameters(GLuint type, GLuint wrap_s, GLuint wrap_t, GLuint upscale, GLuint downscale)
+{
+	GL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, wrap_s))
+	GL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, wrap_t))
+	GL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, upscale))
+	GL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, downscale))
+}
+
+
+static GLuint ren_texturergb_2d(const char *buf, int w, int h, int upscale, int downscale)
+{
+	GLuint t;
+
+	if (!buf || w <= 0 || h <= 0)
+		REN_RET(0, REN_INVAL)
+
+	GL(glGenTextures(1, &t))
+	if (!t) REN_RET(0, REN_TEXTURE)
+
+	GL(glBindTexture(GL_TEXTURE_2D, t))
+	GL(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_RGB, GL_UNSIGNED_BYTE, buf))
+
+	set_texture_parameters(GL_TEXTURE_2D, GL_REPEAT, GL_REPEAT, upscale, downscale);
+
+	return t;
+}
+
+
+static GLuint ren_texturergba_2d(const char *buf, int w, int h, int upscale, int downscale)
+{
+	GLuint t;
+
+	if (!buf || w <= 0 || h <= 0)
+		REN_RET(0, REN_INVAL)
+
+	GL(glGenTextures(1, &t))
+	if (!t) REN_RET(0, REN_TEXTURE)
+
+	GL(glBindTexture(GL_TEXTURE_2D, t))
+	GL(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, buf))
+	set_texture_parameters(GL_TEXTURE_2D, GL_REPEAT, GL_REPEAT, upscale, downscale);
+
+	return t;
+}
+
+
+static GLuint ren_texturer_2d(const char *buf, int w, int h, int upscale, int downscale)
+{
+	GLuint t;
+
+	if (!buf || w <= 0 || h <= 0)
+		REN_RET(0, REN_INVAL)
+
+	GL(glGenTextures(1, &t))
+	if (!t) REN_RET(0, REN_TEXTURE)
+
+	GL(glBindTexture(GL_TEXTURE_2D, t))
+	GL(glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, w, h, 0, GL_RED, GL_UNSIGNED_BYTE, buf))
+	set_texture_parameters(GL_TEXTURE_2D, GL_REPEAT, GL_REPEAT, upscale, downscale);
+
+	return t;
+}
+
+
+static GLuint ren_texturer_rect(const char *buf, int w, int h, int upscale, int downscale)
+{
+	GLuint t;
+
+	if (!buf || w <= 0 || h <= 0)
+		REN_RET(0, REN_INVAL)
+
+	GL(glGenTextures(1, &t))
+	if (!t) REN_RET(0, REN_TEXTURE)
+
+	GL(glBindTexture(GL_TEXTURE_RECTANGLE, t))
+	GL(glTexImage2D(GL_TEXTURE_RECTANGLE, 0, GL_RED, w, h, 0, GL_RED, GL_UNSIGNED_BYTE, buf))
+	// a limitation of recatngle textures is that the wrapping mode is limited
+	// to either clamp-to-edge or clamp-to-border
+	set_texture_parameters(GL_TEXTURE_RECTANGLE, GL_CLAMP_TO_EDGE, GL_CLAMP_TO_EDGE, upscale, downscale);
+
+	return t;
+}
+
+
+// FIXME: update only the newly generated character instead of the whole texture
+static int update_font_texture(int idx)
+{
+	GL(glUseProgram(ren.font_prog))
+	GL(glTexSubImage2D(
+		GL_TEXTURE_RECTANGLE,
+		0, 0, 0,
+		ren.fonts[idx].font->width,
+		ren.fonts[idx].font->height,
+		GL_RED,
+		GL_UNSIGNED_BYTE,
+		ren.fonts[idx].font->atlas))
+	//font_dump(ren.fonts[idx].font, "./atlas.png");
+	GL(glUseProgram(0));
+	return 0;
+}
+
+
+// loads a font and returns it's index in the fonts array
+static int ren_load_font(int size, const char *path)
+{
+	int idx = ren.fonts_no;
+	struct font_atlas *f;
+	ren.fonts = erealloc(ren.fonts, sizeof(struct ren_font)*(idx+1));
+	ren.fonts[idx].font = font_init();
+	f = ren.fonts[idx].font;
+	if (!f)
+		REN_RET(-1, REN_FONT)
+
+	if (!path)
+		path = DEFAULT_FONT;
+
+	if (font_load(f, path, size))
+		REN_RET(-1, REN_FONT)
+	//font_dump(f, "./atlas.png");
+
+	// load font texture (atlas)
+	ren.fonts[idx].texture = ren_texturer_rect(
+		(const char *)f->atlas,
+		f->width,
+		f->height,
+		GL_LINEAR, GL_LINEAR);
+	if (!ren.fonts[idx].texture)
+		return -1;
+
+	ren.fonts_no = idx+1;
+	return idx;
+}
+
+
+// returns the index to the ren.fonts array to the font with the correct size
+// return -1 on errror
+static int ren_get_font(int size)
+{
+	for (int i = 0; i < ren.fonts_no; i++) {
+		if (ren.fonts[i].font->size == size)
+			return i;
+	}
+	// TODO: add a way to change font family
+	return ren_load_font(size, NULL);
+}
+
+
+int ren_init(SDL_Window *w)
+{
+	// Initialize OpenGL
+	if (!w)
+		REN_RET(-1, REN_INVAL)
+	// using version 3 does not allow to use glVertexAttribPointer() without
+	// vertex buffer objects, so use compatibility mode
+	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_COMPATIBILITY);
+	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
+	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
+	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
+	ren.gl = SDL_GL_CreateContext(w);
+	if (!ren.gl) {
+		printf("SDL: %s\n", SDL_GetError());
+		REN_RET(-1, REN_CONTEXT)
+	}
+
+	GL(glEnable(GL_BLEND))
+	GL(glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA))
+	GL(glDisable(GL_CULL_FACE))
+	GL(glDisable(GL_DEPTH_TEST))
+	GL(glEnable(GL_SCISSOR_TEST))
+	GL(glEnable(GL_TEXTURE_2D))
+	GL(glEnable(GL_TEXTURE_RECTANGLE))
+
+	GLenum glew_err = glewInit();
+	if (glew_err != GLEW_OK)
+		REN_RET(glew_err, REN_GLEW);
+
+	// Create stacks
+	ren.font_stack = vtstack_init();
+	ren.box_stack  = vcstack_init();
+	// generate the font buffer object
+	GL(glGenBuffers(1, &ren.font_buffer))
+	if (!ren.font_buffer) REN_RET(-1, REN_BUFFER)
+	GL(glGenBuffers(1, &ren.box_buffer))
+	if (!ren.box_buffer) REN_RET(-1, REN_BUFFER)
+
+	// Compile font shaders
+	ren.font_prog = ren_compile_program(FONT_VERSHADER, FONT_FRAGSHADER);
+	if (!ren.font_prog) return -1;
+	// create the uniforms, if the returned value is -1 then the uniform may have
+	// been optimized away, in any case do not return, just give a warning
+	ren.viewsize_loc = GL(glGetUniformLocation(ren.font_prog, "viewsize"))
+	if (ren.viewsize_loc == -1)
+		printf("uniform %s was optimized away\n", "viewsize");
+	ren.texturesize_loc = GL(glGetUniformLocation(ren.font_prog, "texturesize"))
+	if (ren.texturesize_loc == -1)
+		printf("uniform %s was optimized away\n", "texturesize");
+
+	// Compile box shaders
+	ren.box_prog = ren_compile_program(BOX_VERSHADER, BOX_FRAGSHADER);
+	if (!ren.box_prog) return -1;
+	ren.box_viewsize_loc = GL(glGetUniformLocation(ren.box_prog, "viewsize"))
+	if (ren.box_viewsize_loc == -1)
+		printf("uniform %s was optimized away\n", "viewsize");
+
+	// Finishing touches
+	ren.tabsize = REN_TABSIZE;
+	int width, height;
+	SDL_GetWindowSize(w, &width, &height);
+	ren_update_viewport(width, height);
+	GL(glClearColor(0.3f, 0.3f, 0.3f, 0.f))
+	GL(glClear(GL_COLOR_BUFFER_BIT))
+
+	return 0;
+}
+
+
+int ren_clear(void)
+{
+	GL(glScissor(0, 0, ren.width, ren.height))
+	GL(glClear(GL_COLOR_BUFFER_BIT));
+	return 0;
+}
+
+
+// idx refers to the fonts array index, this means that when drawing the font stack
+// only one font size at the time can be used
+static int ren_draw_font_stack(int idx)
+{
+	struct font_atlas *font = ren.fonts[idx].font;
+	GLuint font_texture = ren.fonts[idx].texture;
+
+	GL(glUseProgram(ren.font_prog))
+	GL(glBindTexture(GL_TEXTURE_RECTANGLE, font_texture))
+
+	GL(glViewport(0, 0, ren.width, ren.height))
+	// this has caused me some trouble, convert from image coordiates to viewport
+	GL(glScissor(ren.s_x, ren.height-ren.s_y-ren.s_h, ren.s_w, ren.s_h))
+	GL(glUniform2i(ren.viewsize_loc, ren.width, ren.height))
+	GL(glUniform2i(ren.texturesize_loc, font->width, font->height))
+
+	GL(glBindBuffer(GL_ARRAY_BUFFER, ren.font_buffer))
+	if (vtstack_changed(&ren.font_stack)) {
+		if (vtstack_size_changed(&ren.font_stack)) {
+			GL(glBufferData(
+				GL_ARRAY_BUFFER,
+				ren.font_stack.idx*sizeof(struct v_text),
+				ren.font_stack.items,
+				GL_DYNAMIC_DRAW))
+		} else {
+			GL(glBufferSubData(
+				GL_ARRAY_BUFFER,
+				0,
+				ren.font_stack.idx*sizeof(struct v_text),
+				ren.font_stack.items))
+		}
+	}
+	// when passing ints to glVertexAttribPointer they are automatically
+	// converted to floats
+	GL(glVertexAttribPointer(
+		REN_VERTEX_IDX,
+		2,
+		GL_INT,
+		GL_FALSE,
+		sizeof(struct v_text),
+		0))
+	GL(glVertexAttribPointer(
+		REN_UV_IDX,
+		2,
+		GL_INT,
+		GL_FALSE,
+		sizeof(struct v_text),
+		(void*)sizeof(vec2_i)))
+	GL(glEnableVertexAttribArray(REN_VERTEX_IDX))
+	GL(glEnableVertexAttribArray(REN_UV_IDX))
+
+	GL(glDrawArrays(GL_TRIANGLES, 0, ren.font_stack.idx))
+
+	GL(glDisableVertexAttribArray(REN_VERTEX_IDX))
+	GL(glDisableVertexAttribArray(REN_UV_IDX))
+	GL(glBindBuffer(GL_ARRAY_BUFFER, 0))
+	GL(glBindTexture(GL_TEXTURE_RECTANGLE, 0))
+	GL(glUseProgram(0))
+
+	vtstack_clear(&ren.font_stack);
+	return 0;
+}
+
+
+static int ren_draw_box_stack(void)
+{
+	GL(glUseProgram(ren.box_prog))
+
+	GL(glViewport(0, 0, ren.width, ren.height))
+	GL(glScissor(0, 0, ren.width, ren.height))
+	GL(glUniform2i(ren.box_viewsize_loc, ren.width, ren.height))
+
+	GL(glBindBuffer(GL_ARRAY_BUFFER, ren.box_buffer))
+	if(vcstack_changed(&ren.box_stack)) {
+		if (vcstack_size_changed(&ren.box_stack)) {
+			GL(glBufferData(
+				GL_ARRAY_BUFFER,
+				ren.box_stack.idx*sizeof(struct v_col),
+				ren.box_stack.items,
+				GL_DYNAMIC_DRAW))
+		} else {
+			GL(glBufferSubData(
+				GL_ARRAY_BUFFER,
+				0,
+				ren.box_stack.idx*sizeof(struct v_col),
+				ren.box_stack.items))
+		}
+	}
+	// when passing ints to glVertexAttribPointer they are automatically
+	// converted to floats
+	GL(glVertexAttribPointer(
+		REN_VERTEX_IDX,
+		2,
+		GL_INT,
+		GL_FALSE,
+		sizeof(struct v_col),
+		0))
+	// the color gets normalized
+	GL(glVertexAttribPointer(
+		REN_COLOR_IDX,
+		4,
+		GL_INT,
+		GL_TRUE,
+		sizeof(struct v_col),
+		(void*)sizeof(vec2_i)))
+	GL(glEnableVertexAttribArray(REN_VERTEX_IDX))
+	GL(glEnableVertexAttribArray(REN_COLOR_IDX))
+
+	GL(glDrawArrays(GL_TRIANGLES, 0, ren.box_stack.idx))
+
+	GL(glDisableVertexAttribArray(REN_VERTEX_IDX))
+	GL(glDisableVertexAttribArray(REN_COLOR_IDX))
+	GL(glBindBuffer(GL_ARRAY_BUFFER, 0))
+	GL(glUseProgram(0))
+
+	vcstack_clear(&ren.box_stack);
+	return 0;
+}
+
+
+int ren_update_viewport(int w, int h)
+{
+	ren.width = w;
+	ren.height = h;
+	return 0;
+}
+
+
+int ren_set_scissor(int x, int y, int w, int h)
+{
+	ren.s_x = x;
+	ren.s_y = y;
+	ren.s_w = w;
+	ren.s_h = h;
+	return 0;
+}
+
+
+static int ren_push_glyph(const struct font_glyph *g, int gx, int gy)
+{
+	/* x4,y4        x3,y3
+	 * o-------------+
+	 * |(x,y)       /|
+	 * |          /  |
+	 * |   2    /    |
+	 * |      /      |
+	 * |    /        |
+	 * |  /     1    |
+	 * |/            |
+	 * +-------------+
+	 * x1,y1        x2,y2 */
+	struct v_text v;
+	struct font_glyph c;
+	c = *g;
+	//printf("g: u=%d v=%d w=%d h=%d a=%d x=%d y=%d\n", c.u, c.v, c.w, c.h, c.a, c.x, c.y);
+	//printf("v: x=%d y=%d u=%d v=%d\n", v.pos.x, v.pos.y, v.uv.u, v.uv.v);
+	// x1,y1
+	v = (struct v_text){
+		.pos = { .x = gx+c.x, .y = gy+c.y+c.h   },
+		.uv  = { .u = c.u,    .v = c.v+c.h },
+	};
+	vtstack_push(&ren.font_stack, &v);
+	// x2,y2
+	v = (struct v_text){
+		.pos = { .x = gx+c.x+c.w, .y = gy+c.y+c.h },
+		.uv  = { .u = c.u+c.w,    .v = c.v+c.h },
+	};
+	vtstack_push(&ren.font_stack, &v);
+	// x3,y3
+	v = (struct v_text){
+		.pos = { .x = gx+c.x+c.w, .y = gy+c.y },
+		.uv  = { .u = c.u+c.w,    .v = c.v },
+	};
+	vtstack_push(&ren.font_stack, &v);
+	// x1,y1
+	v = (struct v_text){
+		.pos = { .x = gx+c.x, .y = gy+c.y+c.h },
+		.uv  = { .u = c.u,    .v = c.v+c.h },
+	};
+	vtstack_push(&ren.font_stack, &v);
+	// x3,y3
+	v = (struct v_text){
+		.pos = { .x = gx+c.x+c.w, .y = gy+c.y },
+		.uv  = { .u = c.u+c.w,    .v = c.v },
+	};
+	vtstack_push(&ren.font_stack, &v);
+	// x4,y4
+	v = (struct v_text){
+		.pos = { .x = gx+c.x, .y = gy+c.y },
+		.uv  = { .u = c.u,    .v = c.v },
+	};
+	vtstack_push(&ren.font_stack, &v);
+
+	return 0;
+}
+
+
+static const struct font_glyph * get_glyph(unsigned int code, int idx)
+{
+	const struct font_glyph *g;
+	int updated;
+	g = font_get_glyph_texture(ren.fonts[idx].font, code, &updated);
+	if (!g)
+		REN_RET(NULL, REN_FONT);
+	if (updated) {
+		if (update_font_texture(idx))
+			REN_RET(NULL, REN_TEXTURE);
+	}
+	return g;
+}
+
+
+// TODO: reduce repeating patterns in ren_get_text_box() and ren_render_text()
+int ren_get_text_box(const char *str, int *rw, int *rh, int size)
+{
+	int w = 0, h = 0, x = 0, y = 0;
+	const struct font_glyph *g;
+	size_t off, ret;
+	uint32_t cp;
+	int idx = ren_get_font(size);
+	if (idx < 0)
+		return -1;
+
+	h = y = ren.fonts[idx].font->glyph_max_h;
+	for (off = 0; (ret = grapheme_decode_utf8(str+off, SIZE_MAX, &cp)) > 0 && cp != 0; off += ret) {
+		if (iscntrl(cp)) goto skip_get;
+		if (!(g = get_glyph(cp, idx)))
+			return -1;
+
+		x += g->x + g->a;
+		// FIXME: generalize this thing
+		skip_get:
+		switch (cp) {
+		case '\t': {
+			const struct font_glyph *sp = get_glyph(' ', idx);
+			if (!sp) return -1;
+			x += (sp->x + sp->a)*ren.tabsize;
+		}
+		break;
+		case '\r':
+			x = 0;
+			break;
+		case '\n':
+			// TODO: encode and/or store line height
+			y += ren.fonts[idx].font->glyph_max_h;
+			x = 0;
+			break;
+		default: break;
+		}
+
+		if (x > w) w = x;
+		if (y > h) h = y;
+	}
+
+	if (rw) *rw = w;
+	if (rh) *rh = h;
+
+	return 0;
+}
+
+
+int ren_render_text(const char *str, int x, int y, int w, int h, int size)
+{
+	const struct font_glyph *g;
+	size_t ret, off;
+	uint32_t cp;
+	int gx = x, gy = y;
+	int idx = ren_get_font(size);
+	if (idx < 0)
+		return -1;
+	for (off = 0; (ret = grapheme_decode_utf8(str+off, SIZE_MAX, &cp)) > 0 && cp != 0; off += ret) {
+		// skip special characters that render a box (not present in font)
+		if (iscntrl(cp)) goto skip_render;
+		if (!(g = get_glyph(cp, idx)))
+			return -1;
+
+		// only push the glyph if it is inside the bounding box
+		if (gx <= x+w && gy <= y+h)
+			ren_push_glyph(g, gx, gy);
+		// TODO: possible kerning needs to be applied here
+		// TODO: handle other unicode control characters such as the
+		//       right-to-left isolate (\u2067)
+		gx += g->x + g->a;
+		skip_render:
+		switch (cp) {
+		case '\t': {
+			const struct font_glyph *sp = get_glyph(' ', idx);
+			if (!sp) return -1;
+			gx += (sp->x + sp->a)*ren.tabsize;
+		}
+		break;
+		case '\r':
+			gx = x;
+			break;
+		case '\n':
+			gy += ren.fonts[idx].font->glyph_max_h;
+			gx = x;
+			break;
+		default: break;
+		}
+	}
+
+	ren_set_scissor(x, y, w, h);
+	ren_draw_font_stack(idx);
+
+	return 0;
+}
+
+
+// re-normalize color from 0-255 to 0-0x7fffffff, technically i'm dividing by 256 here
+#define RENORM(x) (((unsigned long long)(x)*0x7fffffff)>>8)
+#define R(x) (x&0xff)
+#define G(x) ((x>>8)&0xff)
+#define B(x) ((x>>16)&0xff)
+#define A(x) ((x>>24)&0xff)
+static int ren_push_box(int x, int y, int w, int h, unsigned int color)
+{
+	/* x4,y4        x3,y3
+	 * o-------------+
+	 * |(x,y)       /|
+	 * |          /  |
+	 * |   2    /    |
+	 * |      /      |
+	 * |    /        |
+	 * |  /     1    |
+	 * |/            |
+	 * +-------------+
+	 * x1,y1        x2,y2 */
+	struct v_col v;
+	vec4_i c = {
+		.r = RENORM(R(color)),
+		.g = RENORM(G(color)),
+		.b = RENORM(B(color)),
+		.a = RENORM(A(color)),
+	};
+	// x1, y1
+	v = (struct v_col){ .pos = { .x = x, .y = y+h }, .col = c };
+	vcstack_push(&ren.box_stack, &v);
+	// x2, y2
+	v = (struct v_col){ .pos = { .x = x+w, .y = y+h }, .col = c };
+	vcstack_push(&ren.box_stack, &v);
+	// x3, y3
+	v = (struct v_col){ .pos = { .x = x+w, .y = y }, .col = c };
+	vcstack_push(&ren.box_stack, &v);
+	// x1, y1
+	v = (struct v_col){ .pos = { .x = x, .y = y+h }, .col = c };
+	vcstack_push(&ren.box_stack, &v);
+	// x3, y3
+	v = (struct v_col){ .pos = { .x = x+w, .y = y }, .col = c };
+	vcstack_push(&ren.box_stack, &v);
+	// x4, y4
+	v = (struct v_col){ .pos = { .x = x, .y = y }, .col = c };
+	vcstack_push(&ren.box_stack, &v);
+
+	return 0;
+}
+
+
+int ren_render_box(int x, int y, int w, int h, unsigned int color)
+{
+	ren_push_box(x, y, w, h, color);
+	ren_draw_box_stack();
+	return 0;
+}
+
+
+int ren_free(void)
+{
+	GL(glUseProgram(0))
+	GL(glBindBuffer(GL_ARRAY_BUFFER, 0))
+	GL(glDeleteProgram(ren.box_prog));
+	GL(glDeleteProgram(ren.font_prog));
+	GL(glDeleteBuffers(1, &ren.font_buffer))
+	for (int i = 0; i < ren.fonts_no; i++) {
+		GL(glDeleteTextures(1, &ren.fonts[i].texture))
+		font_free(ren.fonts[i].font);
+	}
+	SDL_GL_DeleteContext(ren.gl);
+	vtstack_free(&ren.font_stack);
+	vcstack_free(&ren.box_stack);
+	return 0;
+}

text_rendering/ren.h

@@ -0,0 +1,54 @@
+#ifndef _RENDERER_H
+#define _RENDERER_H
+
+#include <SDL2/SDL.h>
+
+
+#define DEFAULT_FONT   "/usr/share/fonts/TTF/FiraCode-Regular.ttf"
+#define FONT_VERSHADER "./font_vertshader.glsl"
+#define FONT_FRAGSHADER "./font_fragshader.glsl"
+#define BOX_VERSHADER "./box_vertshader.glsl"
+#define BOX_FRAGSHADER "./box_fragshader.glsl"
+#define REN_VERTEX_IDX 0
+#define REN_UV_IDX     1
+#define REN_COLOR_IDX  2
+#define REN_TABSIZE    8
+
+
+typedef struct {
+	union { int x, u; };
+	union { int y, v; };
+} vec2_i;
+
+typedef struct {
+	union { int x, r; };
+	union { int y, g; };
+	union { int z, b; };
+	union { int w, a; };
+} vec4_i;
+
+// textured vertex
+struct v_text {
+	vec2_i pos;
+	vec2_i uv;
+};
+
+// colored vertex
+struct v_col {
+	vec2_i pos;
+	vec4_i col;
+};
+
+
+int ren_init(SDL_Window *sdl_window);
+int ren_free(void);
+const char * ren_strerror(void);
+int ren_update_viewport(int w, int h);
+int ren_set_scissor(int x, int y, int w, int h);
+int ren_get_text_box(const char *str, int *rw, int *rh, int size);
+int ren_render_text(const char *str, int x, int y, int w, int h, int size);
+int ren_render_box(int x, int y, int w, int h, unsigned int color);
+int ren_clear(void);
+
+
+#endif

text_rendering/util.c

@@ -0,0 +1,126 @@
+#define _POSIX_C_SOURCE 200809l
+
+#include <sys/mman.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <err.h>
+#include <time.h>
+
+#include "util.h"
+
+
+const char *bit_rep[16] = {
+    [ 0] = "0000", [ 1] = "0001", [ 2] = "0010", [ 3] = "0011",
+    [ 4] = "0100", [ 5] = "0101", [ 6] = "0110", [ 7] = "0111",
+    [ 8] = "1000", [ 9] = "1001", [10] = "1010", [11] = "1011",
+    [12] = "1100", [13] = "1101", [14] = "1110", [15] = "1111",
+};
+
+
+
+void * emalloc(unsigned long int size)
+{
+	void *r = malloc(size);
+	if (!r)
+		err(EXIT_FAILURE, "malloc() of size %ld", size);
+	return r;
+}
+
+
+void * ecalloc(unsigned long int nmemb, unsigned long int size)
+{
+	void *r = calloc(nmemb, size);
+	if (!r)
+		err(EXIT_FAILURE, "calloc() of size %ld, nmemb %ld", size, nmemb);
+	return r;
+}
+
+void * erealloc(void *ptr, unsigned long int size)
+{
+	void *r = realloc(ptr, size);
+	if (!r)
+		err(EXIT_FAILURE, "ralloc() of 0x%lx, to size %ld", (unsigned long)ptr, size);
+	return r;
+}
+
+
+void efree(void *ptr)
+{
+	if (ptr)
+		free(ptr);
+}
+
+
+void map_file(const unsigned char **str, int *size, const char *path)
+{
+	if (!path) {
+		errno = EINVAL;
+		err(EXIT_FAILURE, "NULL filename");
+	}
+	FILE *fp = fopen(path, "r");
+	if (!fp)
+		err(EXIT_FAILURE, "Cannot open file %s", path);
+	*size = lseek(fileno(fp), 0, SEEK_END);
+	if (*size == (off_t)-1)
+		err(EXIT_FAILURE, "lseek() failed");
+	*str = mmap(0, *size, PROT_READ, MAP_PRIVATE, fileno(fp), 0);
+	if (*str == (void*)-1)
+		err(EXIT_FAILURE, "mmap() failed");
+	if (fclose(fp))
+		err(EXIT_FAILURE, "Error closing file");
+}
+
+
+void dump_file(const char *path, char **buf, int *buf_len)
+{
+	if (!path) {
+		errno = EINVAL;
+		err(EXIT_FAILURE, "NULL filename");
+	}
+	if (!buf) {
+		errno = EINVAL;
+		err(EXIT_FAILURE, "No buffer specified");
+	}
+	int m = 0;
+	if (!buf_len)
+		buf_len = &m;
+	FILE *fp = fopen(path, "r");
+	if (!fp)
+		err(EXIT_FAILURE, "Cannot open file %s", path);
+	*buf_len = lseek(fileno(fp), 0, SEEK_END);
+	rewind(fp);
+	if (*buf_len == (off_t)-1)
+		err(EXIT_FAILURE, "lseek() failed");
+	*buf = emalloc(*buf_len+1);
+	memset(*buf, 0, *buf_len+1);
+	int ret = fread(*buf, 1, *buf_len, fp);
+	if (ret != *buf_len)
+		err(EXIT_FAILURE, "fread() returned short %s", ferror(fp) ? "stream error" : feof(fp) ? "EOF reached" : "unknown error");
+	if (fclose(fp))
+		err(EXIT_FAILURE, "Error closing file");
+}
+
+
+void print_byte(unsigned char byte)
+{
+	printf("%s%s", bit_rep[byte >> 4], bit_rep[byte & 0x0F]);
+}
+
+
+static struct timespec clock_start, clock_stop;
+
+void stopwatch_start(void)
+{
+	clock_gettime(CLOCK_MONOTONIC_COARSE, &clock_start);
+}
+
+
+double stopwatch_get(void)
+{
+	clock_gettime(CLOCK_MONOTONIC_COARSE, &clock_stop);
+	return (clock_stop.tv_sec-clock_start.tv_sec)+(double)(clock_stop.tv_nsec-clock_start.tv_nsec)/(double)1000000000L;
+}

text_rendering/util.h

@@ -0,0 +1,34 @@
+#ifndef _UTIL_H
+#define _UTIL_H
+
+#include <stdio.h>
+
+
+void * emalloc(unsigned long int size);
+void * ecalloc(unsigned long int nmemb, unsigned long int size);
+void * erealloc(void *ptr, unsigned long int size);
+void efree(void *ptr);
+
+void map_file(const unsigned char **str, int *size, const char *path);
+void dump_file(const char *path, char **buf, int *buf_len);
+
+void print_byte(unsigned char byte);
+
+void stopwatch_start(void);
+double stopwatch_get(void);
+
+#define TIME_SEC(f)                                                            \
+{                                                                              \
+	stopwatch_start();                                                     \
+	f;                                                                     \
+	printf("\"%s\" took %f seconds", #f, stopwatch_get());                 \
+}
+
+#define TIME_MS(f)                                                             \
+{                                                                              \
+	stopwatch_start();                                                     \
+	f;                                                                     \
+	printf("\"%s\" took %f ms", #f, stopwatch_get()*1000.0f);              \
+}
+
+#endif

ugui.h

@@ -0,0 +1,285 @@
+#ifndef _UG_HEADER
+#define _UG_HEADER
+
+#define UG_STACK(T)    struct { T *items; int idx, size, sorted; }
+#define BIT(n)         (1 << n)
+#define RGBA_FORMAT(x) { .a=x&0xff, .b=(x>>8)&0xff, .g=(x>>16)&0xff, .r=(x>>24)&0xff }
+#define RGB_FORMAT(x)  { .a=0xff, .b=x&0xff, .g=(x>>8)&0xff, .r=(x>>16)&0xff }
+#define SIZE_PX(x)     { .size.i=x, .unit=UG_UNIT_PX }
+#define SIZE_MM(x)     { .size.f=x, .unit=UG_UNIT_MM }
+#define SIZE_PT(x)     { .size.f=x, .unit=UG_UNIT_PT }
+#define SQUARE(x)      .w = x, .h = x
+
+// basic types
+typedef unsigned int                                       ug_id_t;
+typedef struct { union {int x, w;}; union {int y, h;}; }   ug_vec2_t;
+typedef struct { unsigned char a, b, g, r; }               ug_color_t;
+typedef struct { int x, y, w, h; }                         ug_rect_t;
+typedef struct { union {int i; float f;} size; int unit; } ug_size_t;
+// div has information about the phisical dimension
+typedef struct { ug_size_t x, y, w, h;}                    ug_div_t;
+
+typedef enum {
+	UG_UNIT_PX = 0,
+	UG_UNIT_MM,
+	UG_UNIT_PT,
+} ug_unit_t;
+
+
+// element type
+typedef struct {
+	ug_id_t id;
+	unsigned short int type;
+	unsigned short int flags;
+	ug_rect_t rect, rca;
+	const char *name;
+	union {
+		struct {
+			const char *txt;
+		} btn;
+	};
+} ug_element_t;
+
+enum {
+	UG_ELEM_BUTTON,    // button
+	UG_ELEM_TXTBTN,    // textual button, a button but without frame
+	UG_ELEM_CHECK,     // checkbox
+	UG_ELEM_RADIO,     // radio button
+	UG_ELEM_TOGGLE,    // toggle button
+	UG_ELEM_LABEL,     // simple text
+	UG_ELEM_UPDOWN,    // text with two buttons up and down
+	UG_ELEM_TEXTINPUT, // text input box
+	UG_ELEM_TEXTBOX,   // text surrounded by a box
+	UG_ELEM_IMG,       // image, icon
+	UG_ELEM_SPACE,     // takes up space
+};
+
+enum {
+	ELEM_CLIPPED = BIT(0),
+};
+
+
+// container type, a container is an entity that contains layouts, a container has
+// a haight a width and their maximum values, in essence a container is a rectangular
+// area that can be resized and sits somewhere on the drawable region
+// the z index of a container is determined by it's position on the stack
+typedef struct {
+	ug_id_t id;
+	const char *name;
+	ug_rect_t rect;
+	// absolute position rect
+	ug_rect_t rca;
+	unsigned int flags;
+	// layouting and elements
+	// total space used by elements, x and y are the starting coordinates
+	// for elements
+	ug_rect_t space;
+	// origin for in-row and in-column elements
+	ug_vec2_t c_orig, r_orig;
+	UG_STACK(ug_element_t) elem_stack;
+	ug_id_t selected_elem, hover_elem;
+} ug_container_t;
+
+// the container flags
+enum {
+	UG_CNT_FLOATING      = BIT(0), // is on top of everything else
+	UG_CNT_RESIZE_RIGHT  = BIT(1), // can be resized from the right border
+	UG_CNT_RESIZE_BOTTOM = BIT(2), // can be resized from the bottom border
+	UG_CNT_RESIZE_LEFT   = BIT(3), // can be resized from the left border
+	UG_CNT_RESIZE_TOP    = BIT(4), // can be resized from the top border
+	UG_CNT_SCROLL_X      = BIT(5), // can have horizontal scrolling
+	UG_CNT_SCROLL_Y      = BIT(6), // can have vertical scrolling
+	UG_CNT_MOVABLE       = BIT(7), // can be moved around
+	// container state
+	CNT_STATE_NONE       = BIT(30),
+	CNT_STATE_MOVING     = BIT(29),
+	CNT_STATE_RESIZE_T   = BIT(28),
+	CNT_STATE_RESIZE_B   = BIT(27),
+	CNT_STATE_RESIZE_L   = BIT(26),
+	CNT_STATE_RESIZE_R   = BIT(25),
+	CNT_STATE_RESIZE_D   = BIT(24),
+	CNT_STATE_DELETE     = BIT(23), // The container is marked for removal
+	// layouting
+	CNT_LAYOUT_COLUMN    = BIT(22),
+};
+
+// style, defines default height, width, color, margins, borders, etc
+// all dimensions should be taken as a reference when doing the layout since
+// ultimately it's the layout that decides them. For example when deciding how to
+// allocate space one can say that the default size of a region that allocates a
+// slider has the style's default dimensions for a slider
+typedef struct {
+	struct { ug_color_t bg, fg; } color;
+	ug_size_t margin;
+	struct {
+		ug_color_t color;
+		ug_size_t  size;
+	} border;
+	struct {
+		struct { ug_color_t bg, fg; } color;
+		ug_size_t  height, font_size;
+	} title;
+	struct {
+		struct { ug_color_t act, bg, fg, sel, br; } color;
+		ug_size_t font_size, border;
+	} btn;
+} ug_style_t;
+
+
+// render commands
+struct ug_cmd_rect { int x, y, w, h; ug_color_t color; };
+struct ug_cmd_text { int x, y, size; ug_color_t color; const char *str; };
+
+typedef struct {
+	unsigned int type;
+	union {
+		struct ug_cmd_rect rect;
+		struct ug_cmd_text text;
+	};
+} ug_cmd_t;
+
+typedef enum {
+	UG_CMD_NULL = 0,
+	UG_CMD_RECT,
+	UG_CMD_TEXT,
+} ug_cmd_type_t;
+
+// window side
+enum {
+	UG_SIDE_TOP = 0,
+	UG_SIDE_BOTTOM,
+	UG_SIDE_LEFT,
+	UG_SIDE_RIGHT,
+};
+
+// mouse buttons
+enum {
+	UG_BTN_LEFT   = BIT(0),
+	UG_BTN_MIDDLE = BIT(1),
+	UG_BTN_RIGHT  = BIT(2),
+	UG_BTN_4      = BIT(3),
+	UG_BTN_5      = BIT(4),
+};
+
+// context
+typedef struct {
+	// some style information
+	const ug_style_t *style;
+	// style_px is a style cache where all measurements are already in pixels
+	const ug_style_t *style_px;
+	// ppi: pixels per inch
+	// ppm: pixels per millimeter
+	// ppd: pixels per dot
+	float ppi, ppm, ppd;
+	float last_ppi, last_ppm, last_ppd;
+	// containers need to know how big the "main container" is so that all
+	// the relative positioning work
+	ug_vec2_t size;
+	ug_rect_t origin;
+	// which context and element we are hovering
+	ug_id_t hover_cnt;
+	// active is updated on mousedown and released on mouseup
+	// the id of the "active" element, active means different things for
+	// different elements, for exaple active for a button means to be pressed,
+	// and for a text box it means to be focused
+	ug_id_t active_cnt, last_active_cnt;
+	// id of the selected container, used for layout
+	// NOTE: since the stacks can be relocated with realloc it is better not
+	//       to use a pointer here, even tough it would be better for efficiency
+	ug_id_t selected_cnt;
+	// count the frames for fun
+	unsigned long int frame;
+	// mouse data
+	struct {
+		ug_vec2_t pos;
+		ug_vec2_t last_pos;
+		ug_vec2_t delta;
+		ug_vec2_t scroll_delta;
+		// mouse.update: a mask of the mouse buttons that are being updated
+		unsigned char update;
+		// mouse.hold: a mask of the buttons that are being held
+		unsigned char hold;
+	} mouse;
+	// keyboard key pressed
+	struct {
+		unsigned char update;
+		unsigned char hold;
+	} key;
+	// input text buffer
+	char input_text[32];
+	// stacks
+	UG_STACK(ug_container_t) cnt_stack;
+	UG_STACK(ug_cmd_t) cmd_stack;
+	// command stack iterator
+	int cmd_it;
+} ug_ctx_t;
+
+
+// context initialization
+ug_ctx_t * ug_ctx_new(void);
+void ug_ctx_free(ug_ctx_t *ctx);
+// updates the context with user information
+// ppi: pixels per inch, the scale used for all em/mm to pixel calculations
+// scale: it is the scale between the physical pixels on the screen and the pixels
+//        on the buffer, if unsure set to 1.0
+int ug_ctx_set_displayinfo(ug_ctx_t *ctx, float scale, float ppi);
+int ug_ctx_set_drawableregion(ug_ctx_t *ctx, ug_vec2_t size);
+int ug_ctx_set_style(ug_ctx_t *ctx, const ug_style_t *style);
+
+
+// define containers, name is used as a salt for the container id, all sizes are
+// the default ones, resizing is done automagically with internal state
+
+// a floating container can be placed anywhere and can be resized, acts like a
+// window inside another window
+int ug_container_floating(ug_ctx_t *ctx, const char *name, ug_div_t div);
+// like a floating container but cannot be resized
+int ug_container_popup(ug_ctx_t *ctx, const char *name, ug_div_t div);
+// a menu bar is a container of fixed height, cannot be resized and sits at the
+// top of the window
+int ug_container_menu_bar(ug_ctx_t *ctx, const char *name, ug_size_t height);
+// a sidebar is a variable size container anchored to one side of the window
+int ug_container_sidebar(ug_ctx_t *ctx, const char *name, ug_size_t size, int side);
+// a body is a container that scales with the window, sits at it's center and cannot
+// be resized, it also fills all the available space
+int ug_container_body(ug_ctx_t *ctx, const char *name);
+// mark a conatiner for removal, it will be freed at the next frame beginning if
+// name is NULL then use the selected container
+int ug_container_remove(ug_ctx_t *ctx, const char *name);
+// get the drawable area of the container, if name is NULL then use the selected
+// container
+ug_rect_t ug_container_get_rect(ug_ctx_t *ctx, const char *name);
+
+// layouting, the following functions define how different ui elements are placed
+// inside the selected container. A new element is aligned respective to the
+// previous element and/or to the container, particularly elements can be placed
+// in a row or a column.
+int ug_layout_row(ug_ctx_t *ctx);
+int ug_layout_column(ug_ctx_t *ctx);
+int ug_layout_next_row(ug_ctx_t *ctx);
+int ug_layout_next_column(ug_ctx_t *ctx);
+
+// elements
+int ug_element_button(ug_ctx_t *ctx, const char *name, const char *txt, ug_div_t dim);
+int ug_element_textbtn(ug_ctx_t *ctx, const char *name, const char *txt, ug_div_t dim);
+
+// Input functions
+int ug_input_mousemove(ug_ctx_t *ctx, int x, int y);
+int ug_input_mousedown(ug_ctx_t *ctx, unsigned int mask);
+int ug_input_mouseup(ug_ctx_t *ctx, unsigned int mask);
+int ug_input_scroll(ug_ctx_t *ctx, int x, int y);
+// TODO: other input functions
+
+// Frame handling
+int ug_frame_begin(ug_ctx_t *ctx);
+int ug_frame_end(ug_ctx_t *ctx);
+
+// Commands
+// get the next command, save iteration state inside 'iterator'
+ug_cmd_t * ug_cmd_next(ug_ctx_t *ctx);
+
+
+#undef UG_STACK
+#undef BIT
+
+#endif