support for negative feather dilate/erode

1 files changed, 9 insertions, 3 deletions

diff --git a/source/blender/compositor/operations/COM_GaussianAlphaYBlurOperation.cpp b/source/blender/compositor/operations/COM_GaussianAlphaYBlurOperation.cpp
index f84f4e3b094..40f74ad4485 100644
--- a/source/blender/compositor/operations/COM_GaussianAlphaYBlurOperation.cpp
+++ b/source/blender/compositor/operations/COM_GaussianAlphaYBlurOperation.cpp
@@ -79,8 +79,14 @@ void GaussianAlphaYBlurOperation::updateGauss(MemoryBuffer **memoryBuffers)
 	}
 }
 
+BLI_INLINE float finv_test(const float f, const bool test)
+{
+	return (LIKELY(test == false)) ? f : 1.0f - f;
+}
+
 void GaussianAlphaYBlurOperation::executePixel(float *color, int x, int y, MemoryBuffer *inputBuffers[], void *data)
 {
+	const bool do_invert = this->do_subtract;
 	MemoryBuffer *inputBuffer = (MemoryBuffer *)data;
 	float *buffer = inputBuffer->getBuffer();
 	int bufferwidth = inputBuffer->getWidth();
@@ -104,14 +110,14 @@ void GaussianAlphaYBlurOperation::executePixel(float *color, int x, int y, Memor
 	float overallmultiplyer = 0.0f;
 
 	/* dilate */
-	float value_max = buffer[(x * 4) + (y * 4 * bufferwidth)]; /* init with the current color to avoid unneeded lookups */
+	float value_max = finv_test(buffer[(x * 4) + (y * 4 * bufferwidth)], do_invert); /* init with the current color to avoid unneeded lookups */
 	float distfacinv_max = 1.0f; /* 0 to 1 */
 
 	for (int ny = miny; ny < maxy; ny += step) {
 		int bufferindex = ((minx - bufferstartx) * 4) + ((ny - bufferstarty) * 4 * bufferwidth);
 
 		const int index = (ny - y) + this->rad;
-		float value = buffer[bufferindex];
+		float value = finv_test(buffer[bufferindex], do_invert);
 		float multiplyer;
 
 		/* gauss */
@@ -140,7 +146,7 @@ void GaussianAlphaYBlurOperation::executePixel(float *color, int x, int y, Memor
 	/* blend between the max value and gauss blue - gives nice feather */
 	const float value_gauss = tempColor / overallmultiplyer;
 	const float value_final = (value_max * distfacinv_max) + (value_gauss * (1.0f - distfacinv_max));
-	color[0] = value_final;
+	color[0] = finv_test(value_final, do_invert);
 }
 
 void GaussianAlphaYBlurOperation::deinitExecution()