Fix T39799: Backdrop (compositor) ignores alpha.

This issue is because of a somewhat "special" behavior in old code, which got lost during rB09874df:

There was a variant of the `relinkConnections` function which would leave the socket completely unconnected. This is not a valid state really (given that each unconnected input must otherwise connected to a constant `Set` type node), but was used as a way to distinguish connected alpha/depth sockets in composite and viewer output nodes.
https://developer.blender.org/diffusion/B/browse/master/source/blender/compositor/intern/COM_InputSocket.cpp;28a829893c702918afc5ac1945a06eaefa611594$69

After the large cleanup patch ({D309}) every socket is now automatically connected to a constant, such that `getInputSocketReader` will never return a NULL pointer. This breaks the previous test method, which needs to be replaced by more explicit flags. Luckily this was done only for very few output nodes (Composite, Viewer, Output-File). These now use the regular SetValueOperation default in case "use alpha" is disabled, but set this to an explicit 1.0 value instead of mapping to the node socket.

1 files changed, 27 insertions, 0 deletions

diff --git a/source/blender/compositor/intern/COM_NodeConverter.cpp b/source/blender/compositor/intern/COM_NodeConverter.cpp
index 833fcedbc53..5965eade389 100644
--- a/source/blender/compositor/intern/COM_NodeConverter.cpp
+++ b/source/blender/compositor/intern/COM_NodeConverter.cpp
@@ -103,6 +103,33 @@ NodeOperationInput *NodeConverter::addOutputProxy(NodeOutput *output)
 	return proxy->getInputSocket(0);
 }
 
+void NodeConverter::addInputValue(NodeOperationInput *input, float value)
+{
+	SetValueOperation *operation = new SetValueOperation();
+	operation->setValue(value);
+	
+	m_builder->addOperation(operation);
+	m_builder->addLink(operation->getOutputSocket(), input);
+}
+
+void NodeConverter::addInputColor(NodeOperationInput *input, const float value[4])
+{
+	SetColorOperation *operation = new SetColorOperation();
+	operation->setChannels(value);
+	
+	m_builder->addOperation(operation);
+	m_builder->addLink(operation->getOutputSocket(), input);
+}
+
+void NodeConverter::addInputVector(NodeOperationInput *input, const float value[3])
+{
+	SetVectorOperation *operation = new SetVectorOperation();
+	operation->setVector(value);
+	
+	m_builder->addOperation(operation);
+	m_builder->addLink(operation->getOutputSocket(), input);
+}
+
 void NodeConverter::addOutputValue(NodeOutput *output, float value)
 {
 	SetValueOperation *operation = new SetValueOperation();