Merge pull request #77326 from BastiaanOlij/fix_material_dependencies

Properly clear material slots on mesh instance when material is freed

servers/rendering/renderer_scene_cull.cpp

@@ -34,7 +34,6 @@
 #include "core/object/worker_thread_pool.h"
 #include "core/os/os.h"
 #include "rendering_server_default.h"
-#include "rendering_server_globals.h"
 
 #include <new>
 

servers/rendering/renderer_scene_cull.h

@@ -42,6 +42,7 @@
 #include "servers/rendering/renderer_scene_occlusion_cull.h"
 #include "servers/rendering/renderer_scene_render.h"
 #include "servers/rendering/rendering_method.h"
+#include "servers/rendering/rendering_server_globals.h"
 #include "servers/rendering/storage/utilities.h"
 #include "servers/xr/xr_interface.h"
 
@@ -516,6 +517,29 @@ public:
 			} else if (p_dependency == instance->skeleton) {
 				singleton->instance_attach_skeleton(instance->self, RID());
 			} else {
+				// It's possible the same material is used in multiple slots,
+				// so we check whether we need to clear them all.
+				if (p_dependency == instance->material_override) {
+					singleton->instance_geometry_set_material_override(instance->self, RID());
+				}
+				if (p_dependency == instance->material_overlay) {
+					singleton->instance_geometry_set_material_overlay(instance->self, RID());
+				}
+				for (int i = 0; i < instance->materials.size(); i++) {
+					if (p_dependency == instance->materials[i]) {
+						singleton->instance_set_surface_override_material(instance->self, i, RID());
+					}
+				}
+				if (instance->base_type == RS::INSTANCE_PARTICLES) {
+					RID particle_material = RSG::particles_storage->particles_get_process_material(instance->base);
+					if (p_dependency == particle_material) {
+						RSG::particles_storage->particles_set_process_material(instance->base, RID());
+					}
+				}
+
+				// Even if no change is made we still need to call `_instance_queue_update`.
+				// This dependency could also be a result of the freed material being used
+				// by the mesh this mesh instance uses.
 				singleton->_instance_queue_update(instance, false, true);
 			}
 		}