ffff

text_rendering/cache.c

@@ -6,6 +6,7 @@
 #include <stdint.h>
 #include <string.h>
 
+#include "cache.h"
 #include "hash.h"
 #include "font.h"
 #include "util.h"
@@ -49,7 +50,7 @@ void cache_destroy(void)
 }
 
 
-struct font_glyph * cache_get(unsigned int code)
+const struct font_glyph * cache_search(unsigned int code)
 {
 	struct hm_entry *r = hm_search(hash_table, code);
 
@@ -63,21 +64,28 @@ struct font_glyph * cache_get(unsigned int code)
 }
 
 
-int cache_insert(struct font_glyph *g)
+// return the first free spot into the cache
+unsigned int cache_get(void)
 {
-	struct font_glyph *spot = NULL;
 	uint32_t x = 0;
 	// find an open spot in the cache
 	// TODO: use __builtin_clz to speed this up
 	for (; x < CACHE_SIZE; x++) {
-//		printf("test: %d\n", x);
 		if (!B_TEST(x))
 			break;
 	}
+	return x;
+}
+
+
+// inserts the font glyph into the cache
+const struct font_glyph * cache_insert(struct font_glyph *g, unsigned int x)
+{
+	struct font_glyph *spot = NULL;
 
 	// allocation in cache failed
 	if (B_TEST(x))
-		return -1;
+		return NULL;
 
 	set_bit(x);
 	spot = &cache_array[x];
@@ -100,7 +108,7 @@ int cache_insert(struct font_glyph *g)
 
 	struct hm_entry e = { .code  = g->codepoint, .data = spot};
 	if (!hm_insert(hash_table, &e))
-		return -1;
+		return NULL;
 
-	return 0;
+	return spot;
 }

text_rendering/cache.h

@@ -1,10 +1,13 @@
 #ifndef _CACHE_H
 #define _CACHE_H
 
+#define CACHE_SIZE 512
+
 void cache_init(void);
 void cache_destroy(void);
-struct font_glyph * cache_get(unsigned int code);
-int cache_insert(struct font_glyph *g);
+const struct font_glyph * cache_search(unsigned int code);
+unsigned int cache_get(void);
+const struct font_glyph * cache_insert(struct font_glyph *g, unsigned int idx);
 
 
 #endif

text_rendering/font.c

@@ -1,17 +1,21 @@
 #define _POSIX_C_SOURCE 200809l
 #define STB_TRUETYPE_IMPLEMENTATION
 #define STBTT_STATIC
+#define MSDF_IMPLEMENTATION
 
 #include <grapheme.h>
+#include <assert.h>
 
+#include "font.h"
 #include "msdf_c/stb_truetype.h"
 #include "msdf_c/msdf.h"
 #include "util.h"
-#include "font.h"
+#include "cache.h"
 
 
 #define UTF8(c) (c&0x80)
-
+#define BDEPTH 3
+#define BORDER 4
 
 // Generates a cached atlas of font glyphs encoded usign a signed distance field
 // https://www.youtube.com/watch?v=1b5hIMqz_wM
@@ -21,13 +25,16 @@
 
 
 struct font_atlas {
-	unsigned int glyphs;
+	unsigned int glyphs, width, height;
 	unsigned char *atlas;
 
 	struct {
-		stbtt_fontinfo info;
+		stbtt_fontinfo stb;
+		msdf_AllocCtx ctx;
+		msdf_Result msdf;
 		float scale;
-	} stb;
+	} priv;
+
 	int file_size;
 	unsigned char *file;
 };
@@ -37,34 +44,115 @@ const unsigned int glyph_w = 32;
 const unsigned int glyph_h = 32;
 
 
+// only useful for msdf_c
+static inline void * _emalloc(size_t x, void *_) { (void)_; return emalloc(x); }
+static inline void _efree(void *x, void *_) { (void)_; efree(x); }
+
+
 // loads a font into memory, storing all the ASCII characters in the atlas
-int load_font(struct font_atlas *atlas, const char *path, int height)
+int font_load(struct font_atlas *atlas, const char *path, int height)
 {
 	if (!atlas || !path)
 		return -1;
 
 	dump_file(path, &(atlas->file), &(atlas->file_size));
 
-	stbtt_InitFont(&(atlas->stb.info), atlas->file, 0);
-	atlas->stb.scale = stbtt_ScaleForPixelHeight(&(atlas->stb.info), height);
+	stbtt_InitFont(&(atlas->priv.stb), atlas->file, 0);
+	atlas->priv.scale = stbtt_ScaleForPixelHeight(&(atlas->priv.stb), height);
 	int ascent, descent, linegap, baseline;
 	int x0,y0,x1,y1;
-	stbtt_GetFontVMetrics(&(atlas->stb.info), &ascent, &descent, &linegap);
-	stbtt_GetFontBoundingBox(&(atlas->stb.info), &x0, &y0, &x1, &y1);
+	stbtt_GetFontVMetrics(&(atlas->priv.stb), &ascent, &descent, &linegap);
+	stbtt_GetFontBoundingBox(&(atlas->priv.stb), &x0, &y0, &x1, &y1);
 
-	baseline = atlas->stb.scale * -y0;
-	//atlas->glyph_max_w = (atlas->stb.scale*x1) - (atlas->stb.scale*x0);
-	//atlas->glyph_max_h = (baseline+atlas->stb.scale*y1) - (baseline+atlas->stb.scale*y0);
+	baseline = atlas->priv.scale * -y0;
+	//atlas->glyph_max_w = (atlas->priv.scale*x1) - (atlas->priv.scale*x0);
+	//atlas->glyph_max_h = (baseline+atlas->priv.scale*y1) - (baseline+atlas->priv.scale*y0);
 	//atlas->atlas = emalloc(atlas->glyph_max_w*atlas->glyph_max_h*CACHE_SIZE);
-	atlas->atlas
+	atlas->atlas  = ecalloc(CACHE_SIZE, BDEPTH*glyph_h*glyph_w);
+	atlas->width  = glyph_w*CACHE_SIZE;
+	atlas->height = glyph_h*CACHE_SIZE;
+
+	atlas->priv.ctx = (msdf_AllocCtx){_emalloc, _efree, NULL};
+
+	cache_init();
 
 	return 0;
 }
 
 
-int free_font(struct font_atlas *atlas)
+int font_free(struct font_atlas *atlas)
 {
 	efree(atlas->atlas);
 	efree(atlas->file);
 	return 0;
 }
+
+
+// FIXME: when generating the sdf I only use the height, so to not encounter memory
+//        errors height and width must be equal
+static unsigned int insert(struct font_atlas *atlas)
+{
+	unsigned char *a = atlas->atlas;
+	msdf_Result  res = atlas->priv.msdf;
+
+	float s  = glyph_h;
+	float tw = ((s * 0.7f) + s) / (s * 2.0f);
+	float ta = tw - 0.5f;
+	float ts = 0.5 - ta / 2;
+	float te = ts + ta;
+
+	unsigned int spot = cache_get();
+	unsigned int off = spot * glyph_h * glyph_w * BDEPTH;
+
+	#define NORMALIZE(x) x = x > ts ? (x > te ? 1.0f : (x-ts)/ta+0.0f) : (0.0f)
+
+	for (int y = 0; y < res.height; y++) {
+	        int yPos = res.width * 3 * y;
+		for (int x = 0; x < res.width; x++) {
+
+			int i = yPos + (x * 3);
+			float r = res.rgb[i+0];
+			float g = res.rgb[i+1];
+			float b = res.rgb[i+2];
+
+			r = (r + s) / (s * 2.0f);
+			g = (g + s) / (s * 2.0f);
+			b = (b + s) / (s * 2.0f);
+
+			NORMALIZE(r);
+			NORMALIZE(g);
+			NORMALIZE(b);
+
+			a[off + glyph_w*y + x + 0] = r * 255.0f; // (r > 0.5f) ? 255.0f : r * 255.0f;
+			a[off + glyph_w*y + x + 0] = g * 255.0f; // (g > 0.5f) ? 255.0f : g * 255.0f;
+			a[off + glyph_w*y + x + 0] = b * 255.0f; // (b > 0.5f) ? 255.0f : b * 255.0f;
+		}
+	}
+
+	return spot;
+}
+
+
+struct font_glyph * font_get_glyph_texture(struct font_atlas *atlas, unsigned int code)
+{
+	struct font_glyph *r;
+	if ((r = cache_search(code)) != NULL)
+		return r;
+
+	// generate the sdf and put it into the cache
+	// TODO: generate the whole block at once
+	int idx = stbtt_FindGlyphIndex(&atlas->priv.stb, code);
+	// FIXME: what happens if I change the range?
+	int s;
+	s = msdf_genGlyph(&atlas->priv.msdf,
+		&atlas->priv.stb,
+		idx,
+		BORDER,
+		atlas->priv.scale,
+		2.0f/glyph_h,
+		&atlas->priv.ctx);
+	if (!s)
+		return NULL;
+	unsigned int spot = insert(atlas);
+
+}

text_rendering/font.h

@@ -1,7 +1,6 @@
 #ifndef _FONT_H
 #define _FONT_H
 
-#define CACHE_SIZE 512
 
 /* width and height of a glyph contain the kering advance
  * (u,v)
@@ -28,13 +27,7 @@ struct font_glyph {
 
 struct font_atlas;
 
-int load_font(struct font_atlas *atlas, const char *path, int height);
-int free_font(struct font_atlas *atlas);
-
-void cache_init(void);
-void cache_destroy(void);
-struct font_glyph * cache_get(unsigned int code);
-int cache_insert(struct font_glyph *g);
-
+int font_load(struct font_atlas *atlas, const char *path, int height);
+int font_free(struct font_atlas *atlas);
 
 #endif

text_rendering/msdf_c/CMakeLists.txt

@@ -1,8 +0,0 @@
-cmake_minimum_required(VERSION 3.19)
-project(engine)
-
-add_definitions(-DSAMPLE_ROOT="${PROJECT_SOURCE_DIR}/sample")
-
-set(CMAKE_C_STANDARD 11)
-
-add_executable(msdf_sample sample/sample.c)

text_rendering/msdf_c/LICENSE

@@ -1,22 +0,0 @@
-MIT License
-
-Copyright (c) 2023 Peter Jakobs
-Copyright (c) 2018 exezin
-
-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.