fix font alpha channel

TODO

@@ -1,32 +1,38 @@
 # TODOs, semi-random sorting
+
 [x] Implement glyph draw command
 [x] Implement div.view and scrollbars
-[ ] Port font system from C to C3 (rewrite1)
+[x] Port font system from C to C3 (rewrite1)
 [ ] Update ARCHITECTURE.md
 [ ] Write a README.md
 [ ] Use an arena allocator for cache
 [ ] Do not redraw if there was no update (no layout and no draw)
 [ ] Better handling of the active and focused widgets, try
-    to maintain focus until mouse release (fix scroll bars)
+to maintain focus until mouse release (fix scroll bars)
 
 ## Commands
+
 [x] rect commads should have:
-	* border width
-	* border radius
+_ border width
+_ border radius
 [x] add a command to update an atlas
 
 ## Atlases
+
 [ ] Add an interface to create, destroy, update and get atlases based on their ids
 [ ] Implement multiple font atlases
 
 ## Fonts
-[ ] Fix the missing alpha channel
+
+[x] Fix the missing alpha channel
 [x] Fix the alignment
 
 ## Raylib
+
 [ ] Implement type (Rect, Color, Point) conversion functions between rl:: and ugui::
 [x] Implement pixel radius rounding for border radius
 
 ## Widgets
+
 [ ] Dynamic text box to implement an fps counter
 [ ] Button with label

src/main.c3

@@ -23,6 +23,28 @@ fn void Times.print_stats(&times)
 	io::printfn("min=%s, max=%s, avg=%s", min, max, avg);
 }
 
+const ZString FONT_FS = `
+#version 330
+
+// Input vertex attributes (from vertex shader)
+in vec2 fragTexCoord;
+in vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+// Output fragment color
+out vec4 finalColor;
+
+void main()
+{
+    vec4 alpha = texture(texture0, fragTexCoord);
+    finalColor = colDiffuse*fragColor;
+    finalColor.a *= alpha.r;
+}
+`;
+
 fn int main(String[] args)
 {
 	ugui::Ctx ui;
@@ -42,6 +64,7 @@ fn int main(String[] args)
 	time::Clock clock;
 	Times ui_times;
 	Times draw_times;
+	rl::Shader font_shader = rl::load_shader_from_memory(null, FONT_FS);
 
 	// Main loop
 	while (!rl::window_should_close()) {
@@ -173,8 +196,9 @@ fn int main(String[] args)
 					.x = cmd.sprite.rect.x,
 					.y = cmd.sprite.rect.y,
 				};
-
+				rl::begin_shader_mode(font_shader);
 				rl::draw_texture_rec(font_texture, source, position, rl::WHITE);
+				rl::end_shader_mode();
 			case ugui::CmdType.CMD_SCISSOR:
 				if (cmd.scissor.rect.w == 0 && cmd.scissor.rect.h == 0) {
 					rl::end_scissor_mode();

src/ugui_font.c3

@@ -61,7 +61,7 @@ struct Font {
 	bool should_update; // should send update_atlas command, resets at frame_end()
 }
 
-fn void! Font.load(&font, String name, String path, uint height, float scale)
+fn void! Font.load(&font, String name, ZString path, uint height, float scale)
 {
 	font.table.new_init(capacity: FONT_CACHED);
 	font.id = name.hash();
@@ -161,7 +161,7 @@ fn void Font.free(&font)
 	schrift::freefont(font.sft.font);
 }
 
-fn void! Ctx.load_font(&ctx, String name, String path, uint height, float scale = 1.0)
+fn void! Ctx.load_font(&ctx, String name, ZString path, uint height, float scale = 1.0)
 {
 	return ctx.font.load(name, path, height, scale);
 }