Ported: Physics Interpolation - Reset on adding child to SceneTree. For convenience, branches added to the SceneTree now have physics interpolation reset after the first update of the transform to the VisualServer. - lawnjelly

328866ee6a

scene/3d/visual_instance.cpp

@@ -103,6 +103,15 @@ void VisualInstance::_notification(int p_what) {
 				if (!_is_using_identity_transform()) {
 					Transform gt = get_global_transform();
 					VisualServer::get_singleton()->instance_set_transform(instance, gt);
+
+					// For instance when first adding to the tree, when the previous transform is
+					// unset, to prevent streaking from the origin.
+					if (_is_physics_interpolation_reset_requested()) {
+						if (_is_vi_visible()) {
+							_notification(NOTIFICATION_RESET_PHYSICS_INTERPOLATION);
+						}
+						_set_physics_interpolation_reset_requested(false);
+					}
 				}
 			}
 		} break;

scene/main/node.cpp

@@ -225,6 +225,18 @@ void Node::_propagate_physics_interpolated(bool p_interpolated) {
 	data.blocked--;
 }
 
+void Node::_propagate_physics_interpolation_reset_requested() {
+	if (is_physics_interpolated()) {
+		data.physics_interpolation_reset_requested = true;
+	}
+
+	data.blocked++;
+	for (int i = 0; i < data.children.size(); i++) {
+		data.children[i]->_propagate_physics_interpolation_reset_requested();
+	}
+	data.blocked--;
+}
+
 void Node::_propagate_enter_tree() {
 	// this needs to happen to all children before any enter_tree
 
@@ -1018,6 +1030,10 @@ void Node::_set_physics_interpolated_client_side(bool p_enable) {
 	data.physics_interpolated_client_side = p_enable;
 }
 
+void Node::_set_physics_interpolation_reset_requested(bool p_enable) {
+	data.physics_interpolation_reset_requested = p_enable;
+}
+
 void Node::_set_use_identity_transform(bool p_enable) {
 	data.use_identity_transform = p_enable;
 }
@@ -1254,6 +1270,12 @@ void Node::_add_child_nocheck(Node *p_child, const StringName &p_name) {
 	//recognize children created in this node constructor
 	p_child->data.parent_owned = data.in_constructor;
 	add_child_notify(p_child);
+
+	// Allow physics interpolated nodes to automatically reset when added to the tree
+	// (this is to save the user doing this manually each time)
+	if (is_inside_tree() && get_tree()->is_physics_interpolation_enabled()) {
+		p_child->_propagate_physics_interpolation_reset_requested();
+	}
 }
 
 void Node::add_child(Node *p_child, bool p_legible_unique_name) {
@@ -3191,6 +3213,7 @@ Node::Node() {
 	data.inside_tree = false;
 	data.ready_notified = false;
 	data.physics_interpolated = true;
+	data.physics_interpolation_reset_requested = false;
 	data.physics_interpolated_client_side = false;
 	data.use_identity_transform = false;
 

scene/main/node.h

@@ -148,6 +148,9 @@ private:
 		// is switched on.
 		bool physics_interpolated : 1;
 
+		// We can auto-reset physics interpolation when e.g. adding a node for the first time
+		bool physics_interpolation_reset_requested : 1;
+
 		// Most nodes need not be interpolated in the scene tree, physics interpolation
 		// is normally only needed in the VisualServer. However if we need to read the
 		// interpolated transform of a node in the SceneTree, it is necessary to duplicate
@@ -194,6 +197,7 @@ private:
 	void _propagate_exit_tree();
 	void _propagate_after_exit_branch(bool p_exiting_tree);
 	void _propagate_physics_interpolated(bool p_interpolated);
+	void _propagate_physics_interpolation_reset_requested();
 	void _print_stray_nodes();
 	void _propagate_pause_owner(Node *p_owner);
 	Array _get_node_and_resource(const NodePath &p_path);
@@ -253,6 +257,11 @@ protected:
 		return data.physics_interpolated_client_side;
 	}
 
+	void _set_physics_interpolation_reset_requested(bool p_enable);
+	bool _is_physics_interpolation_reset_requested() const {
+		return data.physics_interpolation_reset_requested;
+	}
+
 	void _set_use_identity_transform(bool p_enable);
 	bool _is_using_identity_transform() const {
 		return data.use_identity_transform;