1 files changed, 11 insertions, 14 deletions

diff --git a/source/blender/compositor/operations/COM_LuminanceMatteOperation.cpp b/source/blender/compositor/operations/COM_LuminanceMatteOperation.cpp
index 3be5447db3b..1401ab56fbd 100644
--- a/source/blender/compositor/operations/COM_LuminanceMatteOperation.cpp
+++ b/source/blender/compositor/operations/COM_LuminanceMatteOperation.cpp
@@ -22,6 +22,10 @@
 #include "COM_LuminanceMatteOperation.h"
 #include "BLI_math.h"
 
+extern "C" {
+#include "IMB_colormanagement.h"
+}
+
 LuminanceMatteOperation::LuminanceMatteOperation() : NodeOperation()
 {
 	addInputSocket(COM_DT_COLOR);
@@ -43,41 +47,34 @@ void LuminanceMatteOperation::deinitExecution()
 void LuminanceMatteOperation::executePixelSampled(float output[4], float x, float y, PixelSampler sampler)
 {
 	float inColor[4];
+	this->m_inputImageProgram->readSampled(inColor, x, y, sampler);
 
 	const float high = this->m_settings->t1;
 	const float low = this->m_settings->t2;
+	const float luminance = IMB_colormanagement_get_luminance(inColor);
 
 	float alpha;
-
-	this->m_inputImageProgram->readSampled(inColor, x, y, sampler);
 	
 	/* one line thread-friend algorithm:
-	 * output[0] = max(inputValue[3], min(high, max(low, ((inColor[0] - low) / (high - low))));
+	 * output[0] = min(inputValue[3], min(1.0f, max(0.0f, ((luminance - low) / (high - low))));
 	 */
 		
 	/* test range */
-	if (inColor[0] > high) {
+	if (luminance > high) {
 		alpha = 1.0f;
 	}
-	else if (inColor[0] < low) {
+	else if (luminance < low) {
 		alpha = 0.0f;
 	}
 	else { /*blend */
-		alpha = (inColor[0] - low) / (high - low);
+		alpha = (luminance - low) / (high - low);
 	}
 
-
 	/* store matte(alpha) value in [0] to go with
 	 * COM_SetAlphaOperation and the Value output
 	 */
 
 	/* don't make something that was more transparent less transparent */
-	if (alpha < inColor[3]) {
-		output[0] = alpha;
-	}
-	else {
-		/* leave now it was before */
-		output[0] = inColor[3];
-	}
+	output[0] = min_ff(alpha, inColor[3]);
 }