1 files changed, 33 insertions, 0 deletions
diff --git a/gsk/vulkan/resources/color-matrix.frag b/gsk/vulkan/resources/color-matrix.frag
new file mode 100644
index 0000000000..8787eb443f
--- /dev/null
+++ b/gsk/vulkan/resources/color-matrix.frag
@@ -0,0 +1,33 @@
+#version 420 core
+
+#include "clip.frag.glsl"
+
+layout(location = 0) in vec2 inPos;
+layout(location = 1) in vec2 inTexCoord;
+layout(location = 2) in flat mat4 inColorMatrix;
+layout(location = 6) in flat vec4 inColorOffset;
+
+layout(set = 0, binding = 0) uniform sampler2D inTexture;
+
+layout(location = 0) out vec4 color;
+
+vec4
+color_matrix (vec4 color, mat4 color_matrix, vec4 color_offset)
+{
+  /* unpremultiply */
+  if (color.a != 0.0)
+    color.rgb /= color.a;
+
+  color = color_matrix * color + color_offset;
+  color = clamp(color, 0.0, 1.0);
+
+  /* premultiply */
+  color.rgb *= color.a;
+
+  return color;
+}
+
+void main()
+{
+  color = clip (inPos, color_matrix (texture (inTexture, inTexCoord), inColorMatrix, inColorOffset));
+}