Fix #36050, backdrop not working. The compositor backdrop requires a restart of the compositing job, which does not happen if just enabling backdrop after adding a viewer node. To fix this added the appropriate notifiers in a update callback for the show_backdrop property.

1 files changed, 7 insertions, 1 deletions

diff --git a/source/blender/makesrna/intern/rna_space.c b/source/blender/makesrna/intern/rna_space.c
index 38ada7bf74f..2555e925eed 100644
--- a/source/blender/makesrna/intern/rna_space.c
+++ b/source/blender/makesrna/intern/rna_space.c
@@ -1249,6 +1249,12 @@ void rna_SpaceNodeEditor_path_pop(SpaceNode *snode, bContext *C)
 	ED_node_tree_update(C);
 }
 
+static void rna_SpaceNodeEditor_show_backdrop_update(Main *UNUSED(bmain), Scene *UNUSED(scene), PointerRNA *UNUSED(ptr))
+{
+	WM_main_add_notifier(NC_NODE | NA_EDITED, NULL);
+	WM_main_add_notifier(NC_SCENE | ND_NODES, NULL);
+}
+
 static void rna_SpaceClipEditor_clip_set(PointerRNA *ptr, PointerRNA value)
 {
 	SpaceClip *sc = (SpaceClip *)(ptr->data);
@@ -3369,7 +3375,7 @@ static void rna_def_space_node(BlenderRNA *brna)
 	prop = RNA_def_property(srna, "show_backdrop", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "flag", SNODE_BACKDRAW);
 	RNA_def_property_ui_text(prop, "Backdrop", "Use active Viewer Node output as backdrop for compositing nodes");
-	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_NODE_VIEW, NULL);
+	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_NODE_VIEW, "rna_SpaceNodeEditor_show_backdrop_update");
 
 	prop = RNA_def_property(srna, "show_grease_pencil", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "flag", SNODE_SHOW_GPENCIL);