Fix T98879: PBVH active attrs only optimization is buggy

PBVH draw has an optimization where it only sends the
active attribute to the GPU in workbench mode.  This
fails if multiple viewports are open with a mix of
workbench and EEVEE mode; it also causes severe lag
if any workbench viewport is in material mode.

There are two solutions: either add the code in sculpt-dev
that checks for EEVEE viewports at the beginning of each frame,
or integrate pbvh draw properly inside the draw manager
and let it handle which attributes should go to the GPU.

1 files changed, 8 insertions, 2 deletions

diff --git a/source/blender/blenkernel/intern/pbvh.c b/source/blender/blenkernel/intern/pbvh.c
index 3a69a33105e..fabc74464ab 100644
--- a/source/blender/blenkernel/intern/pbvh.c
+++ b/source/blender/blenkernel/intern/pbvh.c
@@ -1419,8 +1419,14 @@ static void pbvh_check_draw_layout(PBVH *pbvh, bool full_render)
       break;
   }
 
-  /* rebuild all draw buffers if attribute layout changed */
-  if (GPU_pbvh_attribute_names_update(pbvh->type, pbvh->vbo_id, vdata, ldata, !full_render)) {
+  /* Rebuild all draw buffers if attribute layout changed.
+   *
+   * NOTE: The optimization where we only send active attributes
+   * to the GPU in workbench mode is disabled due to bugs
+   * (there's no guarantee there isn't another EEVEE viewport which would
+   *  free the draw buffers and corrupt the draw cache).
+   */
+  if (GPU_pbvh_attribute_names_update(pbvh->type, pbvh->vbo_id, vdata, ldata, false)) {
     /* attribute layout changed; force rebuild */
     for (int i = 0; i < pbvh->totnode; i++) {
       PBVHNode *node = pbvh->nodes + i;