Fix sculpt dyntopo undo leaving PBVH at NULL

1 files changed, 11 insertions, 0 deletions

diff --git a/source/blender/draw/modes/sculpt_mode.c b/source/blender/draw/modes/sculpt_mode.c
index 5053ea47b06..b55e3236ed9 100644
--- a/source/blender/draw/modes/sculpt_mode.c
+++ b/source/blender/draw/modes/sculpt_mode.c
@@ -195,6 +195,17 @@ static void SCULPT_cache_populate(void *vedata, Object *ob)
 
 		if (ob->sculpt && ob == OBACT_NEW) {
 			PBVH *pbvh = ob->sculpt->pbvh;
+
+			/* XXX, needed for dyntopo-undo (which clears).
+			 * probably depsgraph should handlle? in 2.7x getting derived-mesh does this (mesh_build_data) */
+			if (pbvh == NULL) {
+				/* create PBVH immediately (would be created on the fly too,
+				 * but this avoids waiting on first stroke) */
+				Scene *scene = draw_ctx->scene;
+
+				BKE_sculpt_update_mesh_elements(scene, scene->toolsettings->sculpt, ob, false, false);
+			}
+
 			if (pbvh && pbvh_has_mask(pbvh)) {
 				/* Get geometry cache */
 				DRWShadingGroup *shgroup = object_is_flat(ob) ? stl->g_data->group_flat : stl->g_data->group_smooth;