1 files changed, 25 insertions, 0 deletions
diff --git a/gsk/gl/resources/color_matrix.glsl b/gsk/gl/resources/color_matrix.glsl
new file mode 100644
index 0000000000..79cb36434e
--- /dev/null
+++ b/gsk/gl/resources/color_matrix.glsl
@@ -0,0 +1,25 @@
+// VERTEX_SHADER:
+void main() {
+  gl_Position = u_projection * u_modelview * vec4(aPosition, 0.0, 1.0);
+
+  vUv = vec2(aUv.x, aUv.y);
+}
+
+// FRAGMENT_SHADER:
+uniform mat4 u_color_matrix;
+uniform vec4 u_color_offset;
+
+void main() {
+  vec4 color = GskTexture(u_source, vUv);
+
+  // Un-premultilpy
+  if (color.a != 0.0)
+    color.rgb /= color.a;
+
+  color = u_color_matrix * color + u_color_offset;
+  color = clamp(color, 0.0, 1.0);
+
+  color.rgb *= color.a;
+
+  gskSetOutputColor(color * u_alpha);
+}