don't draw text outiside the bounding box

text_rendering/main.c

@@ -15,7 +15,7 @@ SDL_Window *win;
 void draw(void)
 {
 	ren_clear();
-	ren_render_text(str, 0, 0, 200, 100, 12);
+	ren_render_text(str, 0, 0, 100, 50, 12);
 	ren_render_box(100, 300, 50, 50, 0xffff0000);
 	SDL_GL_SwapWindow(win);
 }

text_rendering/ren.c

@@ -515,11 +515,8 @@ int ren_set_scissor(int x, int y, int w, int h)
 }
 
 
-
-// TODO: implement font size
-int ren_render_text(const char *str, int x, int y, int w, int h, int size)
+static int ren_push_glyph(const struct font_glyph *g, int gx, int gy)
 {
-	
 	/* x4,y4        x3,y3
 	 * +-------------+
 	 * |(x,y)       /|
@@ -531,32 +528,8 @@ int ren_render_text(const char *str, int x, int y, int w, int h, int size)
 	 * |/            |
 	 * +-------------+
 	 * x1,y1        x2,y2 */
-
-	// TODO: stop drawing when outside the bounding box
-	// TODO: check size, if the current font is not of the same size then load 
-	//       load a new font and use that texture instead, this implies making
-	//       a system to store and use different fonts, like:
-	//           struct font_atlas * font_by_size(int size);
-	// FIXME: the bounding box (scissor) logic does not work
-	// TODO: create a method for calculating the total bounding box of a string
-	//       given the box size
-
-	const struct font_glyph *g;
-	struct font_glyph c;
-	size_t ret, off;
-	uint_least32_t cp;
-	int updated, gx = x, gy = y;
 	struct v_text v;
-	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)
-		// FIXME: handle tab
-		if (iscntrl(cp)) goto skip_render;
-		g = font_get_glyph_texture(ren.font, cp, &updated);
-		if (!g) REN_RET(-1, REN_FONT);
-		if (updated) {
-			if (update_font_texture())
-				REN_RET(-1, REN_TEXTURE);
-		}
+	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);
@@ -597,10 +570,42 @@ int ren_render_text(const char *str, int x, int y, int w, int h, int size)
 	};
 	vtstack_push(&ren.font_stack, &v);
 
+	return 0;
+}
+
+
+// TODO: implement font size
+int ren_render_text(const char *str, int x, int y, int w, int h, int size)
+{
+	// TODO: check size, if the current font is not of the same size then load
+	//       load a new font and use that texture instead, this implies making
+	//       a system to store and use different fonts, like:
+	//           struct font_atlas * font_by_size(int size);
+	// FIXME: the bounding box (scissor) logic does not work
+	// TODO: create a method for calculating the total bounding box of a string
+	//       given the box size
+	const struct font_glyph *g;
+	size_t ret, off;
+	uint_least32_t cp;
+	int updated, gx = x, gy = y;
+	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)
+		// FIXME: handle tab
+		if (iscntrl(cp)) goto skip_render;
+		g = font_get_glyph_texture(ren.font, cp, &updated);
+		if (!g) REN_RET(-1, REN_FONT);
+		if (updated) {
+			if (update_font_texture())
+				REN_RET(-1, REN_TEXTURE);
+		}
+
+		// 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 += c.x + c.a;
+		gx += g->x + g->a;
 		skip_render:
 		switch (cp) {
 		case '\r':
@@ -632,6 +637,17 @@ int ren_render_text(const char *str, int x, int y, int w, int h, int size)
 #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
+	 * +-------------+
+	 * |(x,y)       /|
+	 * |          /  |
+	 * |   2    /    |
+	 * |      /      |
+	 * |    /        |
+	 * |  /     1    |
+	 * |/            |
+	 * +-------------+
+	 * x1,y1        x2,y2 */
 	struct v_col v;
 	vec4_i c = {
 		.r = RENORM(R(color)),