User Interface: Remove the green background when inside a node group

The current background color and parent nodetrees is too distracting and noisy.
It drastically affect the readability of the nested node-trees.

Other techniques (better bread crumbs) can be used instead to indicate
to users that they are inside a node group.

---

The background drawing was introduced in 4638e5f99a9ba as part of the
Python Nodes branch merge. This made its debut in Blender 2.67
(30/May/2021).

At the time the color used for the background was a light gray. Over the
years the color changed to the current dark green, aggravating the
problem further.

Before that, the (expanded) nodegroup already had the partially
transparent background, mingling with the other nodes. The Python Nodes
branch brought this concept with its changes, and would always draw up
to two levels up in the background (the parent nodetree, and its parent
nodetree).

To read the original inspiration for all the changes introduced then:
https://code.blender.org/2012/01/improving-node-group-interface-editing/

Differential Revision: https://developer.blender.org/D12780

1 files changed, 2 insertions, 48 deletions

diff --git a/source/blender/editors/space_node/node_draw.cc b/source/blender/editors/space_node/node_draw.cc
index 9b243290566..b5e2434f3d8 100644
--- a/source/blender/editors/space_node/node_draw.cc
+++ b/source/blender/editors/space_node/node_draw.cc
@@ -2176,28 +2176,6 @@ static void draw_nodetree(const bContext *C,
   node_draw_nodetree(C, region, snode, ntree, parent_key);
 }
 
-/* Shade the parent node group and add a `uiBlock` to clip mouse events. */
-static void draw_group_overlay(const bContext *C, ARegion *region)
-{
-  const View2D *v2d = &region->v2d;
-  const rctf rect = v2d->cur;
-  float color[4];
-
-  /* Shade node groups to separate them visually. */
-  GPU_blend(GPU_BLEND_ALPHA);
-
-  UI_GetThemeColorShadeAlpha4fv(TH_NODE_GROUP, 0, 0, color);
-  UI_draw_roundbox_corner_set(UI_CNR_NONE);
-  UI_draw_roundbox_4fv(&rect, true, 0, color);
-  GPU_blend(GPU_BLEND_NONE);
-
-  /* Set the block bounds to clip mouse events from underlying nodes. */
-  uiBlock *block = UI_block_begin(C, region, "node tree bounds block", UI_EMBOSS);
-  UI_block_bounds_set_explicit(block, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
-  UI_block_flag_enable(block, UI_BLOCK_CLIP_EVENTS);
-  UI_block_end(C, block);
-}
-
 void node_draw_space(const bContext *C, ARegion *region)
 {
   wmWindow *win = CTX_wm_window(C);
@@ -2237,8 +2215,6 @@ void node_draw_space(const bContext *C, ARegion *region)
 
   /* Draw parent node trees. */
   if (snode->treepath.last) {
-    static const int max_depth = 2;
-
     bNodeTreePath *path = (bNodeTreePath *)snode->treepath.last;
 
     /* Update tree path name (drawn in the bottom left). */
@@ -2259,35 +2235,13 @@ void node_draw_space(const bContext *C, ARegion *region)
       copy_v2_v2(snode->edittree->view_center, center);
     }
 
-    int depth = 0;
-    while (path->prev && depth < max_depth) {
-      path = path->prev;
-      depth++;
-    }
-
-    /* Parent node trees in the background. */
-    for (int curdepth = depth; curdepth > 0; path = path->next, curdepth--) {
-      bNodeTree *ntree = path->nodetree;
-      if (ntree) {
-        snode_setup_v2d(snode, region, path->view_center);
-
-        draw_nodetree(C, region, ntree, path->parent_key);
-
-        draw_group_overlay(C, region);
-      }
-    }
-
     /* Top-level edit tree. */
     bNodeTree *ntree = path->nodetree;
     if (ntree) {
       snode_setup_v2d(snode, region, center);
 
-      /* Grid, uses theme color based on node path depth. */
-      UI_view2d_multi_grid_draw(v2d,
-                                (depth > 0 ? TH_NODE_GROUP : TH_GRID),
-                                ED_node_grid_size(),
-                                NODE_GRID_STEPS,
-                                grid_levels);
+      /* Grid. */
+      UI_view2d_multi_grid_draw(v2d, TH_GRID, ED_node_grid_size(), NODE_GRID_STEPS, grid_levels);
 
       /* Backdrop. */
       draw_nodespace_back_pix(C, region, snode, path->parent_key);