Fix T70614 EEVEE: Bump with texture connected to other branches don't work

Was caused by the bump node not being evaluated because the other branch
was evaluated before.

To fix this, we use fromnode instead of tonode.

Also we fix a potential issue with recursiveness because
ntree_shader_copy_branch() also use nodeChainIterBackwards() which would
reset the iter_flag in the middle of the parent iteration. Use iter_flag
as a bitflag for each iteration to fix this.

1 files changed, 6 insertions, 6 deletions

diff --git a/source/blender/nodes/shader/node_shader_tree.c b/source/blender/nodes/shader/node_shader_tree.c
index b2d979074fe..4bcd77496c1 100644
--- a/source/blender/nodes/shader/node_shader_tree.c
+++ b/source/blender/nodes/shader/node_shader_tree.c
@@ -629,7 +629,7 @@ static bNode *ntree_shader_copy_branch(bNodeTree *ntree,
   /* Count and tag all nodes inside the displacement branch of the tree. */
   start_node->tmp_flag = 0;
   int node_count = 1;
-  nodeChainIterBackwards(ntree, start_node, ntree_branch_count_and_tag_nodes, &node_count);
+  nodeChainIterBackwards(ntree, start_node, ntree_branch_count_and_tag_nodes, &node_count, 1);
   /* Make a full copy of the branch */
   bNode **nodes_copy = MEM_mallocN(sizeof(bNode *) * node_count, __func__);
   LISTBASE_FOREACH (bNode *, node, &ntree->nodes) {
@@ -763,13 +763,13 @@ static void node_tag_branch_as_derivative(bNode *node, int dx)
   }
 }
 
-static bool ntree_shader_bump_branches(bNode *UNUSED(fromnode), bNode *tonode, void *userdata)
+static bool ntree_shader_bump_branches(bNode *fromnode, bNode *UNUSED(tonode), void *userdata)
 {
   bNodeTree *ntree = (bNodeTree *)userdata;
 
-  if (tonode->type == SH_NODE_BUMP) {
+  if (fromnode->type == SH_NODE_BUMP) {
     bNodeSocket *height_dx_sock, *height_dy_sock, *bump_socket, *bump_dx_socket, *bump_dy_socket;
-    bNode *bump = tonode;
+    bNode *bump = fromnode;
     bump_socket = ntree_shader_node_find_input(bump, "Height");
     bump_dx_socket = ntree_shader_node_find_input(bump, "Height_dx");
     bump_dy_socket = ntree_shader_node_find_input(bump, "Height_dy");
@@ -832,7 +832,7 @@ void ntree_shader_tag_nodes(bNodeTree *ntree, bNode *output_node, nTreeTags *tag
   /* Make sure sockets links pointers are correct. */
   ntreeUpdateTree(G.main, ntree);
 
-  nodeChainIterBackwards(ntree, output_node, ntree_tag_bsdf_cb, tags);
+  nodeChainIterBackwards(ntree, output_node, ntree_tag_bsdf_cb, tags, 0);
 }
 
 /* This one needs to work on a local tree. */
@@ -861,7 +861,7 @@ void ntreeGPUMaterialNodes(bNodeTree *localtree,
 
   /* Duplicate bump height branches for manual derivatives.
    */
-  nodeChainIterBackwards(localtree, output, ntree_shader_bump_branches, localtree);
+  nodeChainIterBackwards(localtree, output, ntree_shader_bump_branches, localtree, 0);
 
   /* TODO(fclem): consider moving this to the gpu shader tree evaluation. */
   nTreeTags tags = {