Fix T78242: Crash when using a Sculpt color tools that needs connectivity for the first time

When there is no color layer available,
BKE_sculpt_update_object_for_edit creates a new one and tags the mesh
with ID_RECLAC_GEOMETRY, so this layer is inmediatly available when the
tool starts. This also deletes the PBVH and when it is created again in
BKE_sculpt_update_object_after_eval, the pmap is not initialized, making
the tool crash.

This moves the color layer creation to a separate function outside
BKE_sculpt_update_object_for_edit, which now runs after the color
layer is available, so it won't need to update again and the pmap will
still be available when the tool is used.

Reviewed By: sergey

Maniphest Tasks: T78242

Differential Revision: https://developer.blender.org/D8135

1 files changed, 8 insertions, 1 deletions

diff --git a/source/blender/editors/sculpt_paint/sculpt.c b/source/blender/editors/sculpt_paint/sculpt.c
index da5d6588dc8..aa8161836f9 100644
--- a/source/blender/editors/sculpt_paint/sculpt.c
+++ b/source/blender/editors/sculpt_paint/sculpt.c
@@ -7140,7 +7140,6 @@ static void sculpt_brush_init_tex(const Scene *scene, Sculpt *sd, SculptSession
 
 static void sculpt_brush_stroke_init(bContext *C, wmOperator *op)
 {
-  Depsgraph *depsgraph = CTX_data_ensure_evaluated_depsgraph(C);
   Scene *scene = CTX_data_scene(C);
   Object *ob = CTX_data_active_object(C);
   Sculpt *sd = CTX_data_tool_settings(C)->sculpt;
@@ -7163,6 +7162,14 @@ static void sculpt_brush_stroke_init(bContext *C, wmOperator *op)
 
   is_smooth = sculpt_needs_connectivity_info(sd, brush, ss, mode);
   needs_colors = ELEM(brush->sculpt_tool, SCULPT_TOOL_PAINT, SCULPT_TOOL_SMEAR);
+
+  if (needs_colors) {
+    BKE_sculpt_color_layer_create_if_needed(ob);
+  }
+
+  /* CTX_data_ensure_evaluated_depsgraph should be used at the end to include the updates of
+   * earlier steps modifying the data. */
+  Depsgraph *depsgraph = CTX_data_ensure_evaluated_depsgraph(C);
   BKE_sculpt_update_object_for_edit(depsgraph, ob, is_smooth, need_mask, needs_colors);
 }