improvement to the DOF node, after blurring the radius buffer (derived from the depth), overlay with the original so pixels in focus are not mixed with out of focus pixels.

source/blender/compositor/nodes/COM_DefocusNode.cpp

@@ -73,11 +73,14 @@ void DefocusNode::convertToOperations(ExecutionSystem *graph, CompositorContext
 		this->getInputSocket(1)->relinkConnections(converter->getInputSocket(0), 1, graph);
 		graph->addOperation(converter);
 		
-		FastGaussianBlurValueOperation * blur = new FastGaussianBlurValueOperation();
+		FastGaussianBlurValueOperation *blur = new FastGaussianBlurValueOperation();
 		addLink(graph, converter->getOutputSocket(0), blur->getInputSocket(0));
 		graph->addOperation(blur);
 		radiusOperation = blur;
 		converter->setPostBlur(blur);
+
+		/* maintain close pixels so far Z values don't bleed into the foreground */
+		blur->setOverlay(FAST_GAUSS_OVERLAY_MIN);
 	}
 	
 	BokehImageOperation *bokeh = new BokehImageOperation();

source/blender/compositor/operations/COM_FastGaussianBlurOperation.cpp

@@ -277,6 +277,28 @@ void *FastGaussianBlurValueOperation::initializeTileData(rcti *rect)
 		MemoryBuffer *newBuf = (MemoryBuffer *)this->m_inputprogram->initializeTileData(rect);
 		MemoryBuffer *copy = newBuf->duplicate();
 		FastGaussianBlurOperation::IIR_gauss(copy, this->m_sigma, 0, 3);
+
+		if (this->m_overlay == FAST_GAUSS_OVERLAY_MIN) {
+			float *src = newBuf->getBuffer();
+			float *dst = copy->getBuffer();
+			for (int i = copy->getWidth() * copy->getHeight() * COM_NUMBER_OF_CHANNELS; i != 0; i--, src++, dst++) {
+				if (*src < *dst) {
+					*dst = *src;
+				}
+			}
+		}
+		else if (this->m_overlay == FAST_GAUSS_OVERLAY_MAX) {
+			float *src = newBuf->getBuffer();
+			float *dst = copy->getBuffer();
+			for (int i = copy->getWidth() * copy->getHeight() * COM_NUMBER_OF_CHANNELS; i != 0; i--, src++, dst++) {
+				if (*src > *dst) {
+					*dst = *src;
+				}
+			}
+		}
+
+//		newBuf->
+
 		this->m_iirgaus = copy;
 	}
 	unlockMutex();

source/blender/compositor/operations/COM_FastGaussianBlurOperation.h

@@ -42,11 +42,23 @@ public:
 	void initExecution();
 };
 
+enum {
+	FAST_GAUSS_OVERLAY_MIN  = -1,
+	FAST_GAUSS_OVERLAY_NONE =  0,
+	FAST_GAUSS_OVERLAY_MAX  =  1
+};
+
 class FastGaussianBlurValueOperation : public NodeOperation {
 private:
 	float m_sigma;
 	MemoryBuffer *m_iirgaus;
 	SocketReader *m_inputprogram;
+
+	/**
+	 * -1: re-mix with darker
+	 *  0: do nothing
+	 *  1 re-mix with lighter */
+	int m_overlay;
 public:
 	FastGaussianBlurValueOperation();
 	bool determineDependingAreaOfInterest(rcti *input, ReadBufferOperation *readOperation, rcti *output);
@@ -56,6 +68,9 @@ public:
 	void deinitExecution();
 	void initExecution();
 	void setSigma(float sigma) { this->m_sigma = sigma; }
+
+	/* used for DOF blurring ZBuffer */
+	void setOverlay(int overlay) { this->m_overlay = overlay; }
 };
 
 #endif