Added option for group node buffering in the compositor.

Justa cluster did not have enough memory to handle all Mango 4k scenes.
Option is default disabled and can be enabled in the performance panel.

 - At Mind -

5 files changed, 14 insertions, 5 deletions

diff --git a/release/scripts/startup/bl_ui/space_node.py b/release/scripts/startup/bl_ui/space_node.py
index c46b1c20738..104c1500756 100644
--- a/release/scripts/startup/bl_ui/space_node.py
+++ b/release/scripts/startup/bl_ui/space_node.py
@@ -252,6 +252,7 @@ class NODE_PT_quality(bpy.types.Panel):
 
         col = layout.column()
         col.prop(tree, "use_opencl")
+        col.prop(tree, "use_groupnode_buffer")
         col.prop(tree, "two_pass")
         col.prop(snode, "show_highlight")
         col.prop(snode, "use_hidden_preview")
diff --git a/source/blender/compositor/intern/COM_CompositorContext.h b/source/blender/compositor/intern/COM_CompositorContext.h
index 2f5e8c0648d..840a9e59584 100644
--- a/source/blender/compositor/intern/COM_CompositorContext.h
+++ b/source/blender/compositor/intern/COM_CompositorContext.h
@@ -74,7 +74,7 @@ private:
 	 * @brief does this system have active opencl devices?
 	 */
 	bool m_hasActiveOpenCLDevices;
-	
+
 	/**
 	 * @brief Skip slow nodes
 	 */
@@ -178,6 +178,7 @@ public:
 	
 	void setFastCalculation(bool fastCalculation) {this->m_fastCalculation = fastCalculation;}
 	bool isFastCalculation() {return this->m_fastCalculation;}
+	inline bool isGroupnodeBufferEnabled() {return this->getbNodeTree()->flag & NTREE_COM_GROUPNODE_BUFFER;}
 };
 
 
diff --git a/source/blender/compositor/nodes/COM_GroupNode.cpp b/source/blender/compositor/nodes/COM_GroupNode.cpp
index 4cef337d994..05c749345d5 100644
--- a/source/blender/compositor/nodes/COM_GroupNode.cpp
+++ b/source/blender/compositor/nodes/COM_GroupNode.cpp
@@ -64,11 +64,12 @@ void GroupNode::ungroup(ExecutionSystem &system)
 		}
 	}
 
+	const bool groupnodeBuffering = system.getContext().isGroupnodeBufferEnabled();
 	for (index = 0; index < outputsockets.size(); index++) {
 		OutputSocket *outputSocket = outputsockets[index];
 		bNodeSocket *editorOutput = outputSocket->getbNodeSocket();
 		if (editorOutput->groupsock) {
-			SocketProxyNode *proxy = new SocketProxyNode(bnode, editorOutput->groupsock, editorOutput, true);
+			SocketProxyNode *proxy = new SocketProxyNode(bnode, editorOutput->groupsock, editorOutput, groupnodeBuffering);
 			outputSocket->relinkConnections(proxy->getOutputSocket(0));
 			ExecutionSystemHelper::addNode(system.getNodes(), proxy);
 		}
diff --git a/source/blender/makesdna/DNA_node_types.h b/source/blender/makesdna/DNA_node_types.h
index 7f2e388cd69..5aaf46a541f 100644
--- a/source/blender/makesdna/DNA_node_types.h
+++ b/source/blender/makesdna/DNA_node_types.h
@@ -309,9 +309,11 @@ typedef struct bNodeTree {
 #define NTREE_TYPE_INIT		1
 
 /* ntree->flag */
-#define NTREE_DS_EXPAND		1	/* for animation editors */
-#define NTREE_COM_OPENCL	2	/* use opencl */
-#define NTREE_TWO_PASS		4	/* two pass */
+#define NTREE_DS_EXPAND				1	/* for animation editors */
+#define NTREE_COM_OPENCL			2	/* use opencl */
+#define NTREE_TWO_PASS				4	/* two pass */
+#define NTREE_COM_GROUPNODE_BUFFER	8	/* use groupnode buffers */
+
 /* XXX not nice, but needed as a temporary flags
  * for group updates after library linking.
  */
diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index 397e05b6a97..2140f90664e 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -4971,6 +4971,10 @@ static void rna_def_composite_nodetree(BlenderRNA *brna)
 	RNA_def_property_boolean_sdna(prop, NULL, "flag", NTREE_COM_OPENCL);
 	RNA_def_property_ui_text(prop, "OpenCL", "Enable GPU calculations");
 
+	prop = RNA_def_property(srna, "use_groupnode_buffer", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "flag", NTREE_COM_GROUPNODE_BUFFER);
+	RNA_def_property_ui_text(prop, "Buffer Groups", "Enable buffering of group nodes");
+
 	prop = RNA_def_property(srna, "two_pass", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "flag", NTREE_TWO_PASS);
 	RNA_def_property_ui_text(prop, "Two Pass", "Use two pass execution during editing: first calculate fast nodes, "