Usability

- Cycles materials now render in Blender Internal too, skipping the nodes.
  Not very useful, but at least things then show up on renders and in
  previews.

- Node editor: if wrong shader nodes are in a tree, they draw with thene
  color RED ALERT headers now. (Switching render engine will show it).

3 files changed, 17 insertions, 4 deletions

diff --git a/source/blender/nodes/intern/node_exec.c b/source/blender/nodes/intern/node_exec.c
index 1889fd9a38e..061ec71d1e2 100644
--- a/source/blender/nodes/intern/node_exec.c
+++ b/source/blender/nodes/intern/node_exec.c
@@ -287,7 +287,7 @@ void ntreeReleaseThreadStack(bNodeThreadStack *nts)
 	nts->used = 0;
 }
 
-void ntreeExecThreadNodes(bNodeTreeExec *exec, bNodeThreadStack *nts, void *callerdata, int thread)
+int ntreeExecThreadNodes(bNodeTreeExec *exec, bNodeThreadStack *nts, void *callerdata, int thread)
 {
 	bNodeStack *nsin[MAX_SOCKET];	/* arbitrary... watch this */
 	bNodeStack *nsout[MAX_SOCKET];	/* arbitrary... watch this */
@@ -305,10 +305,17 @@ void ntreeExecThreadNodes(bNodeTreeExec *exec, bNodeThreadStack *nts, void *call
 			 * If the mute func is not set, assume the node should never be muted,
 			 * and hence execute it!
 			 */
+			if (node->typeinfo->compatibility != NODE_OLD_SHADING)
+				break;
 			if (node->typeinfo->execfunc)
 				node->typeinfo->execfunc(callerdata, node, nsin, nsout);
 			else if (node->typeinfo->newexecfunc)
 				node->typeinfo->newexecfunc(callerdata, thread, node, nodeexec->data, nsin, nsout);
 		}
 	}
+	
+	/* signal to switch back to no-node render */
+	if (node)
+		return 0;
+	return 1;
 }
diff --git a/source/blender/nodes/intern/node_exec.h b/source/blender/nodes/intern/node_exec.h
index 92ab0813bb1..679439ef12e 100644
--- a/source/blender/nodes/intern/node_exec.h
+++ b/source/blender/nodes/intern/node_exec.h
@@ -79,6 +79,6 @@ void ntree_exec_end(struct bNodeTreeExec *exec);
 
 struct bNodeThreadStack *ntreeGetThreadStack(struct bNodeTreeExec *exec, int thread);
 void ntreeReleaseThreadStack(struct bNodeThreadStack *nts);
-void ntreeExecThreadNodes(struct bNodeTreeExec *exec, struct bNodeThreadStack *nts, void *callerdata, int thread);
+int ntreeExecThreadNodes(struct bNodeTreeExec *exec, struct bNodeThreadStack *nts, void *callerdata, int thread);
 
 #endif
diff --git a/source/blender/nodes/shader/node_shader_tree.c b/source/blender/nodes/shader/node_shader_tree.c
index b7dc83d7d79..74a64f186cb 100644
--- a/source/blender/nodes/shader/node_shader_tree.c
+++ b/source/blender/nodes/shader/node_shader_tree.c
@@ -248,7 +248,8 @@ void ntreeShaderEndExecTree(bNodeTreeExec *exec, int use_tree_data)
 	}
 }
 
-void ntreeShaderExecTree(bNodeTree *ntree, ShadeInput *shi, ShadeResult *shr)
+/* only for Blender internal */
+int ntreeShaderExecTree(bNodeTree *ntree, ShadeInput *shi, ShadeResult *shr)
 {
 	ShaderCallData scd;
 	/**
@@ -258,6 +259,7 @@ void ntreeShaderExecTree(bNodeTree *ntree, ShadeInput *shi, ShadeResult *shr)
 	Material *mat = shi->mat;
 	bNodeThreadStack *nts = NULL;
 	bNodeTreeExec *exec = ntree->execdata;
+	int compat;
 	
 	/* convert caller data to struct */
 	scd.shi = shi;
@@ -277,13 +279,17 @@ void ntreeShaderExecTree(bNodeTree *ntree, ShadeInput *shi, ShadeResult *shr)
 	}
 	
 	nts = ntreeGetThreadStack(exec, shi->thread);
-	ntreeExecThreadNodes(exec, nts, &scd, shi->thread);
+	compat = ntreeExecThreadNodes(exec, nts, &scd, shi->thread);
 	ntreeReleaseThreadStack(nts);
 	
 	// \note: set material back to preserved material
 	shi->mat = mat;
+		
 	/* better not allow negative for now */
 	if (shr->combined[0] < 0.0f) shr->combined[0] = 0.0f;
 	if (shr->combined[1] < 0.0f) shr->combined[1] = 0.0f;
 	if (shr->combined[2] < 0.0f) shr->combined[2] = 0.0f;
+	
+	/* if compat is zero, it has been using non-compatible nodes */
+	return compat;
 }