Fix MultiMesh buffer cache in transforms-only case

drivers/gles3/storage/mesh_storage.cpp

@@ -1936,6 +1936,11 @@ void MeshStorage::multimesh_set_buffer(RID p_multimesh, const Vector<float> &p_b
 		glBindBuffer(GL_ARRAY_BUFFER, 0);
 
 	} else {
+		// If we have a data cache, just update it.
+		if (multimesh->data_cache.size()) {
+			multimesh->data_cache = p_buffer;
+		}
+
 		// Only Transform is being used, so we can upload directly.
 		ERR_FAIL_COND(p_buffer.size() != (multimesh->instances * (int)multimesh->stride_cache));
 		const float *r = p_buffer.ptr();
@@ -1947,16 +1952,12 @@ void MeshStorage::multimesh_set_buffer(RID p_multimesh, const Vector<float> &p_b
 	multimesh->buffer_set = true;
 
 	if (multimesh->data_cache.size() || multimesh->uses_colors || multimesh->uses_custom_data) {
-		//if we have a data cache, just update it
-		multimesh->data_cache = multimesh->data_cache;
-		{
-			//clear dirty since nothing will be dirty anymore
-			uint32_t data_cache_dirty_region_count = Math::division_round_up(multimesh->instances, MULTIMESH_DIRTY_REGION_SIZE);
-			for (uint32_t i = 0; i < data_cache_dirty_region_count; i++) {
-				multimesh->data_cache_dirty_regions[i] = false;
-			}
-			multimesh->data_cache_used_dirty_regions = 0;
+		// Clear dirty since nothing will be dirty anymore.
+		uint32_t data_cache_dirty_region_count = Math::division_round_up(multimesh->instances, MULTIMESH_DIRTY_REGION_SIZE);
+		for (uint32_t i = 0; i < data_cache_dirty_region_count; i++) {
+			multimesh->data_cache_dirty_regions[i] = false;
 		}
+		multimesh->data_cache_used_dirty_regions = 0;
 
 		_multimesh_mark_all_dirty(multimesh, false, true); //update AABB
 	} else if (multimesh->mesh.is_valid()) {