Cycles: Fix displacement code creating cyclic dependencies in graph

Bump result was passed to set_normal node and then set_node was connected
to all unconnected Normal inputs, including the one from original Bump
node, causing cycles.

1 files changed, 10 insertions, 2 deletions

diff --git a/intern/cycles/render/graph.cpp b/intern/cycles/render/graph.cpp
index 9896eaba89b..5b81a2ccb9e 100644
--- a/intern/cycles/render/graph.cpp
+++ b/intern/cycles/render/graph.cpp
@@ -727,10 +727,18 @@ void ShaderGraph::bump_from_displacement()
 	/* connect bump output to normal input nodes that aren't set yet. actually
 	 * this will only set the normal input to the geometry node that we created
 	 * and connected to all other normal inputs already. */
-	foreach(ShaderNode *node, nodes)
-		foreach(ShaderInput *input, node->inputs)
+	foreach(ShaderNode *node, nodes) {
+		/* Don't connect normal to the bump node we're coming from,
+		 * otherwise it'll be a cycle in graph.
+		 */
+		if(node == bump) {
+			continue;
+		}
+		foreach(ShaderInput *input, node->inputs) {
 			if(!input->link && input->default_value == ShaderInput::NORMAL)
 				connect(set_normal->output("Normal"), input);
+		}
+	}
 
 	/* for displacement bump, clear the normal input in case the above loop
 	 * connected the setnormal out to the bump normalin */