fixme: naming in debayer is confusing.

data/debayer.vert

@@ -18,7 +18,7 @@ main()
 {
     top_left_uv = tex_coord - pixel_size / 2.0;
     bottom_right_uv = tex_coord + pixel_size / 2.0;
-    top_right_uv = vec2(top_left_uv.x, bottom_right_uv.y);
+    top_right_uv = vec2(top_left_uv.x, bottom_right_uv.y); // FIXME: this is bottom right
     bottom_left_uv = vec2(bottom_right_uv.x, top_left_uv.y);
 
     gl_Position = vec4(transform * vec3(vert, 1), 1);