RemoteTransform2D may fail to update AnimatableBody2D's position or rotation

[Rindbee]

Godot version

v4.1.dev.custom_build [c29866d], v4.0.1.stable.official [cacf499]

System information

Linux Mint 21.1, Vulkan API 1.3.205, NVIDIA GeForce GTX 1050 Ti

Issue description

When update_position, update_rotation, update_scale are not enabled at the same time, for an AnimatableBody2D with sync_to_physics enabled, RemoteTransform2D may not be able to update the position or rotation of the AnimatableBody2D.

This is related to the following code:

godot/scene/2d/remote_transform_2d.cpp

Lines 79 to 85 in c29866d

	n->set_global_transform(our_trans);
	if (update_remote_scale) {
	n->set_scale(get_global_scale());
	} else {
	n->set_scale(n_scale);
	}

For an AnimatableBody2D with sync_to_physics enabled, after setting the transform, and then calling a method (here, it's set_scale()) that may issue a NOTIFICATION_LOCAL_TRANSFORM_CHANGED notification, the following code will be called twice.

godot/scene/2d/physics_body_2d.cpp

Lines 298 to 308 in c29866d

	case NOTIFICATION_LOCAL_TRANSFORM_CHANGED: {
	// Used by sync to physics, send the new transform to the physics...
	Transform2D new_transform = get_global_transform();
	PhysicsServer2D::get_singleton()->body_set_state(get_rid(), PhysicsServer2D::BODY_STATE_TRANSFORM, new_transform);
	// ... but then revert changes.
	set_notify_local_transform(false);
	set_global_transform(last_valid_transform);
	set_notify_local_transform(true);
	} break;

In the second call, line 302 sets the physics state with an outdated value. It may cause jitter or even failure.

It will become a duplicate of #58269 when use_global_coordinates is disabled. It may be appropriate to use NOTIFICATION_TRANSFORM_CHANGED instead of NOTIFICATION_LOCAL_TRANSFORM_CHANGED in AnimatableBody2D.

Steps to reproduce

1. Download the MRP project and import it;
2. Run the scene and observe;
3. You can use other combinations, then run the scene and observe.

Minimal reproduction project

fail-to-update.zip

[Rindbee]

Disabling use_global_coordinates in RemoteTransform2D will cause the following code not to be called, not sure why. 🤔

godot/scene/2d/remote_transform_2d.cpp

Lines 120 to 128 in c29866d

	case NOTIFICATION_TRANSFORM_CHANGED: {
	if (!is_inside_tree()) {
	break;
	}
	if (cache.is_valid()) {
	_update_remote();
	}
	} break;

Can be related to the following code.

godot/scene/main/canvas_item.cpp

Lines 787 to 799 in c29866d

	if (/*p_node->xform_change.in_list() &&*/ p_node->global_invalid) {
	return; //nothing to do
	}
	p_node->global_invalid = true;
	if (p_node->notify_transform && !p_node->xform_change.in_list()) {
	if (!p_node->block_transform_notify) {
	if (p_node->is_inside_tree()) {
	get_tree()->xform_change_list.add(&p_node->xform_change);
	}
	}
	}

godot/scene/main/canvas_item.cpp

Line 169 in c29866d

global_invalid = false;

global_invalid will be reset to false only after get_global_transform() is called. This may not be appropriate.

The condition on line 787 is commented out, is there any reason? Adding this condition makes it more complete.