Fix T92080: Background of Node editors appear brighter than before

In the original code depth=0 meant that there was no parents. But with
BLI_listbase_count we have depth 1 in those cases.

Differential Revision: https://developer.blender.org/D12817

1 files changed, 7 insertions, 2 deletions

diff --git a/source/blender/editors/space_node/node_draw.cc b/source/blender/editors/space_node/node_draw.cc
index c864f6c34d6..4332302159c 100644
--- a/source/blender/editors/space_node/node_draw.cc
+++ b/source/blender/editors/space_node/node_draw.cc
@@ -2181,10 +2181,15 @@ static void draw_nodetree(const bContext *C,
  */
 static void draw_background_color(const SpaceNode *snode)
 {
-  const int max_depth = 2;
+  const int max_tree_length = 3;
   const float bright_factor = 0.25f;
 
-  const int depth = BLI_listbase_count_at_most(&snode->treepath, max_depth);
+  /* We ignore the first element of the path since it is the top-most tree and it doesn't need to
+   * be brighter. We also set a cap to how many levels we want to set apart, to avoid the
+   * background from getting too bright. */
+  const int clamped_tree_path_length = BLI_listbase_count_at_most(&snode->treepath,
+                                                                  max_tree_length);
+  const int depth = max_ii(0, clamped_tree_path_length - 1);
 
   float color[3];
   UI_GetThemeColor3fv(TH_BACK, color);