Structural cleanup and improvements for the compositor.

Many parts of the compositor are unnecessarily complicated. This patch
aims at reducing the complexity of writing nodes and making the code
more transparent.

== Separating Nodes and Operations ==

Currently these are both mixed in the same graph, even though they have
very different purposes and are used at distinct stages in the
compositing process. The patch introduces dedicated graph classes for
nodes and for operations.

This removes the need for a lot of special case checks (isOperation etc.)
and explicit type casts. It simplifies the code since it becomes clear
at every stage what type of node we are dealing with. The compiler can
use static typing to avoid common bugs from mixing up these types and
fewer runtime sanity checks are needed.

== Simplified Node Conversion ==

Converting nodes to operations was previously based on "relinking", i.e.
nodes would start with by mirroring links in the Blender DNA node trees,
then add operations and redirect these links to them. This was very hard
to follow in many cases and required a lot of attention to avoid invalid
states.

Now there is a helper class called the NodeConverter, which is passed to
nodes and implements a much simpler API for this process. Nodes can add
operations and explicit connections as before, but defining "external"
links to the inputs/outputs of the original node now uses mapping
instead of directly modifying link data. Input data (node graph) and
result (operations graph) are cleanly separated.

== Removed Redundant Data Structures ==

A few redundant data structures have been removed, notably the
SocketConnection. These are only needed temporarily during graph
construction. For executing the compositor operations it is perfectly
sufficient to store only the direct input link pointers. A common
pointer indirection is avoided this way (which might also give a little
performance improvement).

== Avoid virtual recursive functions ==

Recursive virtual functions are evil. They are very hard to follow
during debugging. At least in the parts this patch is concerned with
these functions have been replaced by a non-virtual recursive core
function (which might then call virtual non-recursive functions if
needed). See for example NodeOperationBuilder::group_operations.

1 files changed, 125 insertions, 151 deletions

diff --git a/source/blender/compositor/nodes/COM_KeyingNode.cpp b/source/blender/compositor/nodes/COM_KeyingNode.cpp
index 786530bd3c4..e896b7144e5 100644
--- a/source/blender/compositor/nodes/COM_KeyingNode.cpp
+++ b/source/blender/compositor/nodes/COM_KeyingNode.cpp
@@ -47,83 +47,74 @@ KeyingNode::KeyingNode(bNode *editorNode) : Node(editorNode)
 	/* pass */
 }
 
-OutputSocket *KeyingNode::setupPreBlur(ExecutionSystem *graph, InputSocket *inputImage, int size, OutputSocket **originalImage)
+NodeOperationOutput *KeyingNode::setupPreBlur(NodeConverter &converter, NodeInput *inputImage, int size) const
 {
 	ConvertRGBToYCCOperation *convertRGBToYCCOperation = new ConvertRGBToYCCOperation();
 	convertRGBToYCCOperation->setMode(0);  /* ITU 601 */
-
-	inputImage->relinkConnections(convertRGBToYCCOperation->getInputSocket(0), 0, graph);
-	graph->addOperation(convertRGBToYCCOperation);
-
+	converter.addOperation(convertRGBToYCCOperation);
+	
+	converter.mapInputSocket(inputImage, convertRGBToYCCOperation->getInputSocket(0));
+	
 	CombineChannelsOperation *combineOperation = new CombineChannelsOperation();
-	graph->addOperation(combineOperation);
+	converter.addOperation(combineOperation);
 
 	for (int channel = 0; channel < 4; channel++) {
 		SeparateChannelOperation *separateOperation = new SeparateChannelOperation();
 		separateOperation->setChannel(channel);
-		addLink(graph, convertRGBToYCCOperation->getOutputSocket(0), separateOperation->getInputSocket(0));
-		graph->addOperation(separateOperation);
-
+		converter.addOperation(separateOperation);
+		
+		converter.addLink(convertRGBToYCCOperation->getOutputSocket(0), separateOperation->getInputSocket(0));
+		
 		if (channel == 0 || channel == 3) {
-			addLink(graph, separateOperation->getOutputSocket(0), combineOperation->getInputSocket(channel));
+			converter.addLink(separateOperation->getOutputSocket(0), combineOperation->getInputSocket(channel));
 		}
 		else {
 			KeyingBlurOperation *blurXOperation = new KeyingBlurOperation();
-			KeyingBlurOperation *blurYOperation = new KeyingBlurOperation();
-
 			blurXOperation->setSize(size);
 			blurXOperation->setAxis(KeyingBlurOperation::BLUR_AXIS_X);
-			blurXOperation->setbNode(this->getbNode());
-
+			converter.addOperation(blurXOperation);
+			
+			KeyingBlurOperation *blurYOperation = new KeyingBlurOperation();
 			blurYOperation->setSize(size);
 			blurYOperation->setAxis(KeyingBlurOperation::BLUR_AXIS_Y);
-			blurYOperation->setbNode(this->getbNode());
-
-			addLink(graph, separateOperation->getOutputSocket(), blurXOperation->getInputSocket(0));
-			addLink(graph, blurXOperation->getOutputSocket(), blurYOperation->getInputSocket(0));
-			addLink(graph, blurYOperation->getOutputSocket(0), combineOperation->getInputSocket(channel));
-
-			graph->addOperation(blurXOperation);
-			graph->addOperation(blurYOperation);
+			converter.addOperation(blurYOperation);
+			
+			converter.addLink(separateOperation->getOutputSocket(), blurXOperation->getInputSocket(0));
+			converter.addLink(blurXOperation->getOutputSocket(), blurYOperation->getInputSocket(0));
+			converter.addLink(blurYOperation->getOutputSocket(0), combineOperation->getInputSocket(channel));
 		}
 	}
-
+	
 	ConvertYCCToRGBOperation *convertYCCToRGBOperation = new ConvertYCCToRGBOperation();
 	convertYCCToRGBOperation->setMode(0);  /* ITU 601 */
-	addLink(graph, combineOperation->getOutputSocket(0), convertYCCToRGBOperation->getInputSocket(0));
-	graph->addOperation(convertYCCToRGBOperation);
-
-	*originalImage = convertRGBToYCCOperation->getInputSocket(0)->getConnection()->getFromSocket();
-
+	converter.addOperation(convertYCCToRGBOperation);
+	
+	converter.addLink(combineOperation->getOutputSocket(0), convertYCCToRGBOperation->getInputSocket(0));
+	
 	return convertYCCToRGBOperation->getOutputSocket(0);
 }
 
-OutputSocket *KeyingNode::setupPostBlur(ExecutionSystem *graph, OutputSocket *postBlurInput, int size)
+NodeOperationOutput *KeyingNode::setupPostBlur(NodeConverter &converter, NodeOperationOutput *postBlurInput, int size) const
 {
 	KeyingBlurOperation *blurXOperation = new KeyingBlurOperation();
-	KeyingBlurOperation *blurYOperation = new KeyingBlurOperation();
-
 	blurXOperation->setSize(size);
 	blurXOperation->setAxis(KeyingBlurOperation::BLUR_AXIS_X);
-	blurXOperation->setbNode(this->getbNode());
-
+	converter.addOperation(blurXOperation);
+	
+	KeyingBlurOperation *blurYOperation = new KeyingBlurOperation();
 	blurYOperation->setSize(size);
 	blurYOperation->setAxis(KeyingBlurOperation::BLUR_AXIS_Y);
-	blurYOperation->setbNode(this->getbNode());
-
-	addLink(graph, postBlurInput, blurXOperation->getInputSocket(0));
-	addLink(graph, blurXOperation->getOutputSocket(), blurYOperation->getInputSocket(0));
-
-	graph->addOperation(blurXOperation);
-	graph->addOperation(blurYOperation);
-
+	converter.addOperation(blurYOperation);
+	
+	converter.addLink(postBlurInput, blurXOperation->getInputSocket(0));
+	converter.addLink(blurXOperation->getOutputSocket(), blurYOperation->getInputSocket(0));
+	
 	return blurYOperation->getOutputSocket();
 }
 
-OutputSocket *KeyingNode::setupDilateErode(ExecutionSystem *graph, OutputSocket *dilateErodeInput, int distance)
+NodeOperationOutput *KeyingNode::setupDilateErode(NodeConverter &converter, NodeOperationOutput *dilateErodeInput, int distance) const
 {
 	DilateDistanceOperation *dilateErodeOperation;
-
 	if (distance > 0) {
 		dilateErodeOperation = new DilateDistanceOperation();
 		dilateErodeOperation->setDistance(distance);
@@ -132,211 +123,194 @@ OutputSocket *KeyingNode::setupDilateErode(ExecutionSystem *graph, OutputSocket
 		dilateErodeOperation = new ErodeDistanceOperation();
 		dilateErodeOperation->setDistance(-distance);
 	}
-	dilateErodeOperation->setbNode(this->getbNode());
-
-	addLink(graph, dilateErodeInput, dilateErodeOperation->getInputSocket(0));
-
-	graph->addOperation(dilateErodeOperation);
-
+	converter.addOperation(dilateErodeOperation);
+	
+	converter.addLink(dilateErodeInput, dilateErodeOperation->getInputSocket(0));
+	
 	return dilateErodeOperation->getOutputSocket(0);
 }
 
-OutputSocket *KeyingNode::setupFeather(ExecutionSystem *graph, CompositorContext *context,
-                                       OutputSocket *featherInput, int falloff, int distance)
+NodeOperationOutput *KeyingNode::setupFeather(NodeConverter &converter, const CompositorContext &context,
+                                   NodeOperationOutput *featherInput, int falloff, int distance) const
 {
 	/* this uses a modified gaussian blur function otherwise its far too slow */
-	CompositorQuality quality = context->getQuality();
+	CompositorQuality quality = context.getQuality();
 
 	/* initialize node data */
-	NodeBlurData *data = &this->m_alpha_blur;
-	memset(data, 0, sizeof(*data));
-	data->filtertype = R_FILTER_GAUSS;
-
+	NodeBlurData data;
+	memset(&data, 0, sizeof(NodeBlurData));
+	data.filtertype = R_FILTER_GAUSS;
 	if (distance > 0) {
-		data->sizex = data->sizey = distance;
+		data.sizex = data.sizey = distance;
 	}
 	else {
-		data->sizex = data->sizey = -distance;
+		data.sizex = data.sizey = -distance;
 	}
 
 	GaussianAlphaXBlurOperation *operationx = new GaussianAlphaXBlurOperation();
-	operationx->setData(data);
+	operationx->setData(&data);
 	operationx->setQuality(quality);
 	operationx->setSize(1.0f);
 	operationx->setSubtract(distance < 0);
 	operationx->setFalloff(falloff);
-	operationx->setbNode(this->getbNode());
-	graph->addOperation(operationx);
+	converter.addOperation(operationx);
 	
 	GaussianAlphaYBlurOperation *operationy = new GaussianAlphaYBlurOperation();
-	operationy->setData(data);
+	operationy->setData(&data);
 	operationy->setQuality(quality);
 	operationy->setSize(1.0f);
 	operationy->setSubtract(distance < 0);
 	operationy->setFalloff(falloff);
-	operationy->setbNode(this->getbNode());
-	graph->addOperation(operationy);
+	converter.addOperation(operationy);
 
-	addLink(graph, featherInput, operationx->getInputSocket(0));
-	addLink(graph, operationx->getOutputSocket(), operationy->getInputSocket(0));
+	converter.addLink(featherInput, operationx->getInputSocket(0));
+	converter.addLink(operationx->getOutputSocket(), operationy->getInputSocket(0));
 
 	return operationy->getOutputSocket();
 }
 
-OutputSocket *KeyingNode::setupDespill(ExecutionSystem *graph, OutputSocket *despillInput, OutputSocket *inputScreen,
-                                       float factor, float colorBalance)
+NodeOperationOutput *KeyingNode::setupDespill(NodeConverter &converter, NodeOperationOutput *despillInput, NodeInput *inputScreen,
+                                   float factor, float colorBalance) const
 {
 	KeyingDespillOperation *despillOperation = new KeyingDespillOperation();
-
 	despillOperation->setDespillFactor(factor);
 	despillOperation->setColorBalance(colorBalance);
-
-	addLink(graph, despillInput, despillOperation->getInputSocket(0));
-	addLink(graph, inputScreen, despillOperation->getInputSocket(1));
-
-	graph->addOperation(despillOperation);
-
+	converter.addOperation(despillOperation);
+	
+	converter.addLink(despillInput, despillOperation->getInputSocket(0));
+	converter.mapInputSocket(inputScreen, despillOperation->getInputSocket(1));
+	
 	return despillOperation->getOutputSocket(0);
 }
 
-OutputSocket *KeyingNode::setupClip(ExecutionSystem *graph, OutputSocket *clipInput, int kernelRadius, float kernelTolerance,
-                                    float clipBlack, float clipWhite, bool edgeMatte)
+NodeOperationOutput *KeyingNode::setupClip(NodeConverter &converter, NodeOperationOutput *clipInput, int kernelRadius, float kernelTolerance,
+                                float clipBlack, float clipWhite, bool edgeMatte) const
 {
 	KeyingClipOperation *clipOperation = new KeyingClipOperation();
-
 	clipOperation->setKernelRadius(kernelRadius);
 	clipOperation->setKernelTolerance(kernelTolerance);
-
 	clipOperation->setClipBlack(clipBlack);
 	clipOperation->setClipWhite(clipWhite);
 	clipOperation->setIsEdgeMatte(edgeMatte);
-
-	addLink(graph, clipInput, clipOperation->getInputSocket(0));
-
-	graph->addOperation(clipOperation);
-
+	converter.addOperation(clipOperation);
+	
+	converter.addLink(clipInput, clipOperation->getInputSocket(0));
+	
 	return clipOperation->getOutputSocket(0);
 }
 
-void KeyingNode::convertToOperations(ExecutionSystem *graph, CompositorContext *context)
+void KeyingNode::convertToOperations(NodeConverter &converter, const CompositorContext &context) const
 {
-	InputSocket *inputImage = this->getInputSocket(0);
-	InputSocket *inputScreen = this->getInputSocket(1);
-	InputSocket *inputGarbageMatte = this->getInputSocket(2);
-	InputSocket *inputCoreMatte = this->getInputSocket(3);
-	OutputSocket *outputImage = this->getOutputSocket(0);
-	OutputSocket *outputMatte = this->getOutputSocket(1);
-	OutputSocket *outputEdges = this->getOutputSocket(2);
-	OutputSocket *postprocessedMatte = NULL, *postprocessedImage = NULL, *originalImage = NULL, *edgesMatte = NULL;
-
 	bNode *editorNode = this->getbNode();
 	NodeKeyingData *keying_data = (NodeKeyingData *) editorNode->storage;
-
+	
+	NodeInput *inputImage = this->getInputSocket(0);
+	NodeInput *inputScreen = this->getInputSocket(1);
+	NodeInput *inputGarbageMatte = this->getInputSocket(2);
+	NodeInput *inputCoreMatte = this->getInputSocket(3);
+	NodeOutput *outputImage = this->getOutputSocket(0);
+	NodeOutput *outputMatte = this->getOutputSocket(1);
+	NodeOutput *outputEdges = this->getOutputSocket(2);
+	NodeOperationOutput *postprocessedMatte = NULL, *postprocessedImage = NULL, *edgesMatte = NULL;
+	
 	/* keying operation */
 	KeyingOperation *keyingOperation = new KeyingOperation();
-
 	keyingOperation->setScreenBalance(keying_data->screen_balance);
-
-	inputScreen->relinkConnections(keyingOperation->getInputSocket(1), 1, graph);
-
+	converter.addOperation(keyingOperation);
+	
+	converter.mapInputSocket(inputScreen, keyingOperation->getInputSocket(1));
+	
 	if (keying_data->blur_pre) {
 		/* chroma preblur operation for input of keying operation  */
-		OutputSocket *preBluredImage = setupPreBlur(graph, inputImage, keying_data->blur_pre, &originalImage);
-		addLink(graph, preBluredImage, keyingOperation->getInputSocket(0));
+		NodeOperationOutput *preBluredImage = setupPreBlur(converter, inputImage, keying_data->blur_pre);
+		converter.addLink(preBluredImage, keyingOperation->getInputSocket(0));
 	}
 	else {
-		inputImage->relinkConnections(keyingOperation->getInputSocket(0), 0, graph);
-		originalImage = keyingOperation->getInputSocket(0)->getConnection()->getFromSocket();
+		converter.mapInputSocket(inputImage, keyingOperation->getInputSocket(0));
 	}
-
-	graph->addOperation(keyingOperation);
-
+	
 	postprocessedMatte = keyingOperation->getOutputSocket();
-
+	
 	/* black / white clipping */
 	if (keying_data->clip_black > 0.0f || keying_data->clip_white < 1.0f) {
-		postprocessedMatte = setupClip(graph, postprocessedMatte,
+		postprocessedMatte = setupClip(converter, postprocessedMatte,
 		                               keying_data->edge_kernel_radius, keying_data->edge_kernel_tolerance,
 		                               keying_data->clip_black, keying_data->clip_white, false);
 	}
-
+	
 	/* output edge matte */
-	if (outputEdges->isConnected()) {
-		edgesMatte = setupClip(graph, postprocessedMatte,
-		                       keying_data->edge_kernel_radius, keying_data->edge_kernel_tolerance,
-		                       keying_data->clip_black, keying_data->clip_white, true);
-	}
-
+	edgesMatte = setupClip(converter, postprocessedMatte,
+	                       keying_data->edge_kernel_radius, keying_data->edge_kernel_tolerance,
+	                       keying_data->clip_black, keying_data->clip_white, true);
+	
 	/* apply garbage matte */
-	if (inputGarbageMatte->isConnected()) {
+	if (inputGarbageMatte->isLinked()) {
 		SetValueOperation *valueOperation = new SetValueOperation();
+		valueOperation->setValue(1.0f);
+		converter.addOperation(valueOperation);
+		
 		MathSubtractOperation *subtractOperation = new MathSubtractOperation();
+		converter.addOperation(subtractOperation);
+		
 		MathMinimumOperation *minOperation = new MathMinimumOperation();
-
-		valueOperation->setValue(1.0f);
-
-		addLink(graph, valueOperation->getOutputSocket(), subtractOperation->getInputSocket(0));
-		inputGarbageMatte->relinkConnections(subtractOperation->getInputSocket(1), 0, graph);
-
-		addLink(graph, subtractOperation->getOutputSocket(), minOperation->getInputSocket(0));
-		addLink(graph, postprocessedMatte, minOperation->getInputSocket(1));
-
+		converter.addOperation(minOperation);
+		
+		converter.addLink(valueOperation->getOutputSocket(), subtractOperation->getInputSocket(0));
+		converter.mapInputSocket(inputGarbageMatte, subtractOperation->getInputSocket(1));
+		
+		converter.addLink(subtractOperation->getOutputSocket(), minOperation->getInputSocket(0));
+		converter.addLink(postprocessedMatte, minOperation->getInputSocket(1));
+		
 		postprocessedMatte = minOperation->getOutputSocket();
-
-		graph->addOperation(valueOperation);
-		graph->addOperation(subtractOperation);
-		graph->addOperation(minOperation);
 	}
-
+	
 	/* apply core matte */
-	if (inputCoreMatte->isConnected()) {
+	if (inputCoreMatte->isLinked()) {
 		MathMaximumOperation *maxOperation = new MathMaximumOperation();
-
-		inputCoreMatte->relinkConnections(maxOperation->getInputSocket(0), 0, graph);
-
-		addLink(graph, postprocessedMatte, maxOperation->getInputSocket(1));
-
+		converter.addOperation(maxOperation);
+		
+		converter.mapInputSocket(inputCoreMatte, maxOperation->getInputSocket(0));
+		converter.addLink(postprocessedMatte, maxOperation->getInputSocket(1));
+		
 		postprocessedMatte = maxOperation->getOutputSocket();
-
-		graph->addOperation(maxOperation);
 	}
-
+	
 	/* apply blur on matte if needed */
 	if (keying_data->blur_post)
-		postprocessedMatte = setupPostBlur(graph, postprocessedMatte, keying_data->blur_post);
+		postprocessedMatte = setupPostBlur(converter, postprocessedMatte, keying_data->blur_post);
 
 	/* matte dilate/erode */
 	if (keying_data->dilate_distance != 0) {
-		postprocessedMatte = setupDilateErode(graph, postprocessedMatte, keying_data->dilate_distance);
+		postprocessedMatte = setupDilateErode(converter, postprocessedMatte, keying_data->dilate_distance);
 	}
 
 	/* matte feather */
 	if (keying_data->feather_distance != 0) {
-		postprocessedMatte = setupFeather(graph, context, postprocessedMatte, keying_data->feather_falloff,
+		postprocessedMatte = setupFeather(converter, context, postprocessedMatte, keying_data->feather_falloff,
 		                                  keying_data->feather_distance);
 	}
 
 	/* set alpha channel to output image */
 	SetAlphaOperation *alphaOperation = new SetAlphaOperation();
-	addLink(graph, originalImage, alphaOperation->getInputSocket(0));
-	addLink(graph, postprocessedMatte, alphaOperation->getInputSocket(1));
+	converter.addOperation(alphaOperation);
+	
+	converter.mapInputSocket(inputImage, alphaOperation->getInputSocket(0));
+	converter.addLink(postprocessedMatte, alphaOperation->getInputSocket(1));
 
 	postprocessedImage = alphaOperation->getOutputSocket();
 
 	/* despill output image */
 	if (keying_data->despill_factor > 0.0f) {
-		postprocessedImage = setupDespill(graph, postprocessedImage,
-		                                  keyingOperation->getInputSocket(1)->getConnection()->getFromSocket(),
+		postprocessedImage = setupDespill(converter, postprocessedImage,
+		                                  inputScreen,
 		                                  keying_data->despill_factor,
 		                                  keying_data->despill_balance);
 	}
 
 	/* connect result to output sockets */
-	outputImage->relinkConnections(postprocessedImage);
-	outputMatte->relinkConnections(postprocessedMatte);
+	converter.mapOutputSocket(outputImage, postprocessedImage);
+	converter.mapOutputSocket(outputMatte, postprocessedMatte);
 
 	if (edgesMatte)
-		outputEdges->relinkConnections(edgesMatte);
-
-	graph->addOperation(alphaOperation);
+		converter.mapOutputSocket(outputEdges, edgesMatte);
 }