Fix T72593 Blender crashes when modifier change the material count

Instead of changing the modifiers behavior, we make sure to always use
the data->totcol instead of the ob->totcol. Also we centralize getting
this number to avoid future issues.

Fix T72593 Blender crashes when separating mesh
Fix T72017 Crash on set visibility change

1 files changed, 19 insertions, 0 deletions

diff --git a/source/blender/draw/intern/draw_cache.c b/source/blender/draw/intern/draw_cache.c
index f2e43e032a9..083901c9ebe 100644
--- a/source/blender/draw/intern/draw_cache.c
+++ b/source/blender/draw/intern/draw_cache.c
@@ -824,6 +824,25 @@ GPUBatch *DRW_cache_object_surface_get(Object *ob)
   }
 }
 
+int DRW_cache_object_material_count_get(struct Object *ob)
+{
+  short type = (ob->runtime.mesh_eval != NULL) ? OB_MESH : ob->type;
+
+  switch (type) {
+    case OB_MESH:
+      return DRW_mesh_material_count_get(ob->data);
+    case OB_CURVE:
+    case OB_SURF:
+    case OB_FONT:
+      return DRW_curve_material_count_get(ob->data);
+    case OB_MBALL:
+      return DRW_metaball_material_count_get(ob->data);
+    default:
+      BLI_assert(0);
+      return 0;
+  }
+}
+
 GPUBatch **DRW_cache_object_surface_material_get(struct Object *ob,
                                                  struct GPUMaterial **gpumat_array,
                                                  uint gpumat_array_len,