Update CanvasItem when MultiMesh instance transform changes

(cherry picked from commit b54d4a93be231344940a2aee16ca1dbe3dc3e2b6)

scene/2d/multimesh_instance_2d.cpp

@@ -29,6 +29,7 @@
 /*************************************************************************/
 
 #include "multimesh_instance_2d.h"
+#include "core/core_string_names.h"
 
 void MultiMeshInstance2D::_notification(int p_what) {
 	if (p_what == NOTIFICATION_DRAW) {
@@ -56,7 +57,16 @@ void MultiMeshInstance2D::_bind_methods() {
 }
 
 void MultiMeshInstance2D::set_multimesh(const Ref<MultiMesh> &p_multimesh) {
+	// Cleanup previous connection if any.
+	if (multimesh.is_valid()) {
+		multimesh->disconnect(CoreStringNames::get_singleton()->changed, this, "update");
+	}
 	multimesh = p_multimesh;
+
+	// Connect to the multimesh so the AABB can update when instance transforms are changed.
+	if (multimesh.is_valid()) {
+		multimesh->connect(CoreStringNames::get_singleton()->changed, this, "update");
+	}
 	update();
 }
 

scene/resources/multimesh.cpp

@@ -29,6 +29,7 @@
 /*************************************************************************/
 
 #include "multimesh.h"
+
 #include "servers/visual_server.h"
 
 void MultiMesh::_set_transform_array(const PoolVector<Vector3> &p_array) {
@@ -225,6 +226,7 @@ void MultiMesh::set_instance_transform(int p_instance, const Transform &p_transf
 
 void MultiMesh::set_instance_transform_2d(int p_instance, const Transform2D &p_transform) {
 	VisualServer::get_singleton()->multimesh_instance_set_transform_2d(multimesh, p_instance, p_transform);
+	emit_changed();
 }
 
 Transform MultiMesh::get_instance_transform(int p_instance) const {