Update

2 files changed, 49 insertions, 0 deletions

diff --git a/src/assets/shaders/truetype/frag.glsl b/src/assets/shaders/truetype/frag.glsl
new file mode 100644
index 0000000..b0e25bf
--- /dev/null
+++ b/src/assets/shaders/truetype/frag.glsl
@@ -0,0 +1,23 @@
+#version 300 es
+precision highp float;
+
+uniform sampler2D texture_data;
+uniform int text[256];
+uniform int atlas_width;
+uniform int cell_width;
+uniform int text_width;
+
+in vec2 vertex_texcoord;
+out vec4 frag_color;
+
+void main()
+{
+    vec2 inverted_texcoord = vec2(vertex_texcoord.x, 1.0 - vertex_texcoord.y);
+    float texcoord_pixels_x = inverted_texcoord.x * float(text_width);
+    int char_idx = int(floor(texcoord_pixels_x)) / cell_width;
+    int offset = text[char_idx];
+    float cbase = float(offset);
+    float coff = mod(texcoord_pixels_x, float(cell_width));
+    float val = texture(texture_data, vec2((cbase + coff) / float(atlas_width), inverted_texcoord.y)).r;
+    frag_color = vec4(val, val, val, 1.0);
+} 
diff --git a/src/assets/shaders/truetype/vert.glsl b/src/assets/shaders/truetype/vert.glsl
new file mode 100644
index 0000000..4005d75
--- /dev/null
+++ b/src/assets/shaders/truetype/vert.glsl
@@ -0,0 +1,26 @@
+#version 300 es
+precision highp float;
+
+uniform mat4 view;
+uniform mat4 position;
+
+out vec2 vertex_texcoord;
+
+void main() {
+    const vec2 positions[4] = vec2[](
+        vec2(-1, -1),
+        vec2(+1, -1),
+        vec2(-1, +1),
+        vec2(+1, +1)
+    );
+    const vec2 coords[4] = vec2[](
+        vec2(0, 0),
+        vec2(1, 0),
+        vec2(0, 1),
+        vec2(1, 1)
+    );
+    vec4 vertex = vec4(positions[gl_VertexID], 0.0, 1.0);
+
+    vertex_texcoord = coords[gl_VertexID];
+    gl_Position = view * position * vertex;
+}