1 files changed, 52 insertions, 0 deletions
diff --git a/source/blender/compositor/realtime_compositor/shaders/library/gpu_shader_compositor_channel_matte.glsl b/source/blender/compositor/realtime_compositor/shaders/library/gpu_shader_compositor_channel_matte.glsl
new file mode 100644
index 00000000000..f2dcc9543f2
--- /dev/null
+++ b/source/blender/compositor/realtime_compositor/shaders/library/gpu_shader_compositor_channel_matte.glsl
@@ -0,0 +1,52 @@
+#pragma BLENDER_REQUIRE(gpu_shader_common_color_utils.glsl)
+
+#define CMP_NODE_CHANNEL_MATTE_CS_RGB 1.0
+#define CMP_NODE_CHANNEL_MATTE_CS_HSV 2.0
+#define CMP_NODE_CHANNEL_MATTE_CS_YUV 3.0
+#define CMP_NODE_CHANNEL_MATTE_CS_YCC 4.0
+
+void node_composite_channel_matte(vec4 color,
+                                  const float color_space,
+                                  const float matte_channel,
+                                  const vec2 limit_channels,
+                                  float max_limit,
+                                  float min_limit,
+                                  out vec4 result,
+                                  out float matte)
+{
+  vec4 channels;
+  if (color_space == CMP_NODE_CHANNEL_MATTE_CS_HSV) {
+    rgb_to_hsv(color, channels);
+  }
+  else if (color_space == CMP_NODE_CHANNEL_MATTE_CS_YUV) {
+    rgba_to_yuva_itu_709(color, channels);
+  }
+  else if (color_space == CMP_NODE_CHANNEL_MATTE_CS_YCC) {
+    rgba_to_ycca_itu_709(color, channels);
+  }
+  else {
+    channels = color;
+  }
+
+  float matte_value = channels[int(matte_channel)];
+  float limit_value = max(channels[int(limit_channels.x)], channels[int(limit_channels.y)]);
+
+  float alpha = 1.0 - (matte_value - limit_value);
+  if (alpha > max_limit) {
+    alpha = color.a;
+  }
+  else if (alpha < min_limit) {
+    alpha = 0.0;
+  }
+  else {
+    alpha = (alpha - min_limit) / (max_limit - min_limit);
+  }
+
+  matte = min(alpha, color.a);
+  result = color * matte;
+}
+
+#undef CMP_NODE_CHANNEL_MATTE_CS_RGB
+#undef CMP_NODE_CHANNEL_MATTE_CS_HSV
+#undef CMP_NODE_CHANNEL_MATTE_CS_YUV
+#undef CMP_NODE_CHANNEL_MATTE_CS_YCC