Add p_delta argument to _process_modification() and expose advance()

doc/classes/Skeleton3D.xml

@@ -20,6 +20,14 @@
 				[b]Note:[/b] Bone names should be unique, non empty, and cannot include the [code]:[/code] and [code]/[/code] characters.
 			</description>
 		</method>
+		<method name="advance">
+			<return type="void" />
+			<param index="0" name="delta" type="float" />
+			<description>
+				Manually advance the child [SkeletonModifier3D]s by the specified time (in seconds).
+				[b]Note:[/b] The [param delta] is temporarily accumulated in the [Skeleton3D], and the deferred process uses the accumulated value to process the modification.
+			</description>
+		</method>
 		<method name="clear_bones">
 			<return type="void" />
 			<description>
@@ -420,5 +428,8 @@
 		<constant name="MODIFIER_CALLBACK_MODE_PROCESS_IDLE" value="1" enum="ModifierCallbackModeProcess">
 			Set a flag to process modification during process frames (see [constant Node.NOTIFICATION_INTERNAL_PROCESS]).
 		</constant>
+		<constant name="MODIFIER_CALLBACK_MODE_PROCESS_MANUAL" value="2" enum="ModifierCallbackModeProcess">
+			Do not process modification. Use [method advance] to process the modification manually.
+		</constant>
 	</constants>
 </class>

doc/classes/SkeletonModifier3D.xml

@@ -12,13 +12,22 @@
 		<link title="Design of the Skeleton Modifier 3D">https://godotengine.org/article/design-of-the-skeleton-modifier-3d/</link>
 	</tutorials>
 	<methods>
-		<method name="_process_modification" qualifiers="virtual">
+		<method name="_process_modification" qualifiers="virtual" deprecated="Use [method _process_modification_with_delta] instead.">
 			<return type="void" />
 			<description>
 				Override this virtual method to implement a custom skeleton modifier. You should do things like get the [Skeleton3D]'s current pose and apply the pose here.
 				[method _process_modification] must not apply [member influence] to bone poses because the [Skeleton3D] automatically applies influence to all bone poses set by the modifier.
 			</description>
 		</method>
+		<method name="_process_modification_with_delta" qualifiers="virtual">
+			<return type="void" />
+			<param index="0" name="delta" type="float" />
+			<description>
+				Override this virtual method to implement a custom skeleton modifier. You should do things like get the [Skeleton3D]'s current pose and apply the pose here.
+				[method _process_modification_with_delta] must not apply [member influence] to bone poses because the [Skeleton3D] automatically applies influence to all bone poses set by the modifier.
+				[param delta] is passed from parent [Skeleton3D]. See also [method Skeleton3D.advance].
+			</description>
+		</method>
 		<method name="get_skeleton" qualifiers="const">
 			<return type="Skeleton3D" />
 			<description>

scene/3d/look_at_modifier_3d.cpp

@@ -487,7 +487,7 @@ void LookAtModifier3D::_bind_methods() {
 	BIND_ENUM_CONSTANT(ORIGIN_FROM_EXTERNAL_NODE);
 }
 
-void LookAtModifier3D::_process_modification() {
+void LookAtModifier3D::_process_modification(double p_delta) {
 	if (!is_inside_tree()) {
 		return;
 	}
@@ -570,13 +570,7 @@ void LookAtModifier3D::_process_modification() {
 
 	// Do time-based interpolation.
 	if (remaining > 0) {
-		double delta = 0.0;
+		remaining = MAX(0, remaining - time_step * p_delta);
-		if (skeleton->get_modifier_callback_mode_process() == Skeleton3D::MODIFIER_CALLBACK_MODE_PROCESS_IDLE) {
-			delta = get_process_delta_time();
-		} else {
-			delta = get_physics_process_delta_time();
-		}
-		remaining = MAX(0, remaining - time_step * delta);
 		if (is_flippable) {
 			// Interpolate through the rest same as AnimationTree blending for preventing to penetrate the bone into the body.
 			Quaternion rest = skeleton->get_bone_rest(bone).basis.get_rotation_quaternion();

scene/3d/look_at_modifier_3d.h

@@ -107,7 +107,7 @@ protected:
 
 	static void _bind_methods();
 
-	virtual void _process_modification() override;
+	virtual void _process_modification(double p_delta) override;
 
 public:
 	void set_bone_name(const String &p_bone_name);

scene/3d/physics/physical_bone_simulator_3d.cpp

@@ -364,7 +364,7 @@ void PhysicalBoneSimulator3D::set_bone_global_pose(int p_bone, const Transform3D
 	bones.write[p_bone].global_pose = p_pose;
 }
 
-void PhysicalBoneSimulator3D::_process_modification() {
+void PhysicalBoneSimulator3D::_process_modification(double p_delta) {
 	Skeleton3D *skeleton = get_skeleton();
 	if (!skeleton) {
 		return;

scene/3d/physics/physical_bone_simulator_3d.h

@@ -72,7 +72,7 @@ protected:
 	void _pose_updated();
 	void _bone_pose_updated(Skeleton3D *skeleton, int p_bone_id);
 
-	virtual void _process_modification() override;
+	virtual void _process_modification(double p_delta) override;
 
 	virtual void _skeleton_changed(Skeleton3D *p_old, Skeleton3D *p_new) override;
 

scene/3d/retarget_modifier_3d.cpp

@@ -370,7 +370,7 @@ void RetargetModifier3D::_retarget_pose() {
 	}
 }
 
-void RetargetModifier3D::_process_modification() {
+void RetargetModifier3D::_process_modification(double p_delta) {
 	if (use_global_pose) {
 		_retarget_global_pose();
 	} else {

scene/3d/retarget_modifier_3d.h

@@ -96,7 +96,7 @@ protected:
 	virtual void remove_child_notify(Node *p_child) override;
 
 	virtual void _set_active(bool p_active) override;
-	virtual void _process_modification() override;
+	virtual void _process_modification(double p_delta) override;
 
 public:
 	virtual PackedStringArray get_configuration_warnings() const override;

scene/3d/skeleton_3d.cpp

@@ -357,8 +357,10 @@ void Skeleton3D::_notification(int p_what) {
 				// Store dirty flags for global bone poses.
 				bone_global_pose_dirty_backup = bone_global_pose_dirty;
 
+				if (update_flags & UPDATE_FLAG_MODIFIER) {
 					_process_modifiers();
 				}
+			}
 
 			// Abort if pose is not changed.
 			if (!(update_flags & UPDATE_FLAG_POSE)) {
@@ -438,14 +440,21 @@ void Skeleton3D::_notification(int p_what) {
 			updating = false;
 			update_flags = UPDATE_FLAG_NONE;
 		} break;
-		case NOTIFICATION_INTERNAL_PROCESS:
+		case NOTIFICATION_INTERNAL_PROCESS: {
+			advance(get_process_delta_time());
+		} break;
 		case NOTIFICATION_INTERNAL_PHYSICS_PROCESS: {
+			advance(get_physics_process_delta_time());
+		} break;
+	}
+}
+
+void Skeleton3D::advance(double p_delta) {
 	_find_modifiers();
 	if (!modifiers.is_empty()) {
+		update_delta += p_delta; // Accumulate delta for manual advance as it needs to process in deferred update.
 		_update_deferred(UPDATE_FLAG_MODIFIER);
 	}
-		} break;
-	}
 }
 
 void Skeleton3D::set_modifier_callback_mode_process(Skeleton3D::ModifierCallbackModeProcess p_mode) {
@@ -467,6 +476,9 @@ void Skeleton3D::_process_changed() {
 	} else if (modifier_callback_mode_process == MODIFIER_CALLBACK_MODE_PROCESS_PHYSICS) {
 		set_process_internal(false);
 		set_physics_process_internal(true);
+	} else {
+		set_process_internal(false);
+		set_physics_process_internal(false);
 	}
 }
 
@@ -1194,7 +1206,7 @@ void Skeleton3D::_process_modifiers() {
 			for (int i = 0; i < get_bone_count(); i++) {
 				old_poses.push_back(get_bone_pose(i));
 			}
-			mod->process_modification();
+			mod->process_modification(update_delta);
 			LocalVector<Transform3D> new_poses;
 			for (int i = 0; i < get_bone_count(); i++) {
 				new_poses.push_back(get_bone_pose(i));
@@ -1206,10 +1218,11 @@ void Skeleton3D::_process_modifiers() {
 				set_bone_pose(i, old_poses[i].interpolate_with(new_poses[i], influence));
 			}
 		} else {
-			mod->process_modification();
+			mod->process_modification(update_delta);
 		}
 		force_update_all_dirty_bones();
 	}
+	update_delta = 0; // Reset accumulated delta.
 }
 
 void Skeleton3D::add_child_notify(Node *p_child) {
@@ -1297,11 +1310,13 @@ void Skeleton3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_modifier_callback_mode_process", "mode"), &Skeleton3D::set_modifier_callback_mode_process);
 	ClassDB::bind_method(D_METHOD("get_modifier_callback_mode_process"), &Skeleton3D::get_modifier_callback_mode_process);
 
+	ClassDB::bind_method(D_METHOD("advance", "delta"), &Skeleton3D::advance);
+
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "motion_scale", PROPERTY_HINT_RANGE, "0.001,10,0.001,or_greater"), "set_motion_scale", "get_motion_scale");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "show_rest_only"), "set_show_rest_only", "is_show_rest_only");
 
 	ADD_GROUP("Modifier", "modifier_");
-	ADD_PROPERTY(PropertyInfo(Variant::INT, "modifier_callback_mode_process", PROPERTY_HINT_ENUM, "Physics,Idle"), "set_modifier_callback_mode_process", "get_modifier_callback_mode_process");
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "modifier_callback_mode_process", PROPERTY_HINT_ENUM, "Physics,Idle,Manual"), "set_modifier_callback_mode_process", "get_modifier_callback_mode_process");
 
 	ADD_SIGNAL(MethodInfo("rest_updated"));
 	ADD_SIGNAL(MethodInfo("pose_updated"));
@@ -1313,6 +1328,7 @@ void Skeleton3D::_bind_methods() {
 	BIND_CONSTANT(NOTIFICATION_UPDATE_SKELETON);
 	BIND_ENUM_CONSTANT(MODIFIER_CALLBACK_MODE_PROCESS_PHYSICS);
 	BIND_ENUM_CONSTANT(MODIFIER_CALLBACK_MODE_PROCESS_IDLE);
+	BIND_ENUM_CONSTANT(MODIFIER_CALLBACK_MODE_PROCESS_MANUAL);
 
 #ifndef DISABLE_DEPRECATED
 	ClassDB::bind_method(D_METHOD("clear_bones_global_pose_override"), &Skeleton3D::clear_bones_global_pose_override);

scene/3d/skeleton_3d.h

@@ -79,6 +79,7 @@ public:
 	enum ModifierCallbackModeProcess {
 		MODIFIER_CALLBACK_MODE_PROCESS_PHYSICS,
 		MODIFIER_CALLBACK_MODE_PROCESS_IDLE,
+		MODIFIER_CALLBACK_MODE_PROCESS_MANUAL,
 	};
 
 private:
@@ -93,6 +94,7 @@ private:
 	void _update_deferred(UpdateFlag p_update_flag = UPDATE_FLAG_POSE);
 	uint8_t update_flags = UPDATE_FLAG_NONE;
 	bool updating = false; // Is updating now?
+	double update_delta = 0.0;
 
 	struct Bone {
 		String name;
@@ -294,6 +296,8 @@ public:
 	void set_modifier_callback_mode_process(ModifierCallbackModeProcess p_mode);
 	ModifierCallbackModeProcess get_modifier_callback_mode_process() const;
 
+	void advance(double p_delta);
+
 #ifndef DISABLE_DEPRECATED
 	Transform3D get_bone_global_pose_no_override(int p_bone) const;
 	void clear_bones_global_pose_override();

scene/3d/skeleton_ik_3d.cpp

@@ -366,7 +366,7 @@ void SkeletonIK3D::_bind_methods() {
 #endif
 }
 
-void SkeletonIK3D::_process_modification() {
+void SkeletonIK3D::_process_modification(double p_delta) {
 	if (!internal_active) {
 		return;
 	}
@@ -485,7 +485,7 @@ bool SkeletonIK3D::is_running() {
 void SkeletonIK3D::start(bool p_one_time) {
 	if (p_one_time) {
 		internal_active = true;
-		SkeletonModifier3D::process_modification();
+		SkeletonModifier3D::process_modification(0);
 		internal_active = false;
 	} else {
 		internal_active = true;

scene/3d/skeleton_ik_3d.h

@@ -144,7 +144,7 @@ protected:
 	static void _bind_methods();
 	virtual void _notification(int p_what);
 
-	virtual void _process_modification() override;
+	virtual void _process_modification(double p_delta) override;
 
 public:
 	SkeletonIK3D();

scene/3d/skeleton_modifier_3d.cpp

@@ -113,16 +113,23 @@ real_t SkeletonModifier3D::get_influence() const {
 	return influence;
 }
 
-void SkeletonModifier3D::process_modification() {
+void SkeletonModifier3D::process_modification(double p_delta) {
 	if (!active) {
 		return;
 	}
-	_process_modification();
+	_process_modification(p_delta);
 	emit_signal(SNAME("modification_processed"));
 }
 
-void SkeletonModifier3D::_process_modification() {
+void SkeletonModifier3D::_process_modification(double p_delta) {
-	GDVIRTUAL_CALL(_process_modification);
+	if (GDVIRTUAL_CALL(_process_modification_with_delta, p_delta)) {
+		return;
+	}
+#ifndef DISABLE_DEPRECATED
+	if (GDVIRTUAL_CALL(_process_modification)) {
+		return;
+	}
+#endif // DISABLE_DEPRECATED
 }
 
 void SkeletonModifier3D::_notification(int p_what) {
@@ -151,7 +158,10 @@ void SkeletonModifier3D::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "influence", PROPERTY_HINT_RANGE, "0,1,0.001"), "set_influence", "get_influence");
 
 	ADD_SIGNAL(MethodInfo("modification_processed"));
+	GDVIRTUAL_BIND(_process_modification_with_delta, "delta");
+#ifndef DISABLE_DEPRECATED
 	GDVIRTUAL_BIND(_process_modification);
+#endif
 
 	BIND_ENUM_CONSTANT(BONE_AXIS_PLUS_X);
 	BIND_ENUM_CONSTANT(BONE_AXIS_MINUS_X);

scene/3d/skeleton_modifier_3d.h

@@ -68,8 +68,12 @@ protected:
 
 	virtual void _set_active(bool p_active);
 
-	virtual void _process_modification();
+	virtual void _process_modification(double p_delta);
+	// TODO: In Godot 5, should obsolete old GDVIRTUAL0(_process_modification); and replace it with _process_modification_with_delta as GDVIRTUAL1(_process_modification, double).
+	GDVIRTUAL1(_process_modification_with_delta, double);
+#ifndef DISABLE_DEPRECATED
 	GDVIRTUAL0(_process_modification);
+#endif
 
 public:
 	virtual PackedStringArray get_configuration_warnings() const override;
@@ -83,7 +87,7 @@ public:
 
 	Skeleton3D *get_skeleton() const;
 
-	void process_modification();
+	void process_modification(double p_delta);
 
 	// Utility APIs.
 	static Vector3 get_vector_from_bone_axis(BoneAxis p_axis);

scene/3d/spring_bone_simulator_3d.cpp

@@ -1496,7 +1496,7 @@ void SpringBoneSimulator3D::_set_active(bool p_active) {
 	}
 }
 
-void SpringBoneSimulator3D::_process_modification() {
+void SpringBoneSimulator3D::_process_modification(double p_delta) {
 	if (!is_inside_tree()) {
 		return;
 	}
@@ -1514,10 +1514,9 @@ void SpringBoneSimulator3D::_process_modification() {
 	}
 #endif //TOOLS_ENABLED
 
-	double delta = skeleton->get_modifier_callback_mode_process() == Skeleton3D::MODIFIER_CALLBACK_MODE_PROCESS_IDLE ? skeleton->get_process_delta_time() : skeleton->get_physics_process_delta_time();
 	for (int i = 0; i < settings.size(); i++) {
 		_init_joints(skeleton, settings[i]);
-		_process_joints(delta, skeleton, settings[i]->joints, get_valid_collision_instance_ids(i), settings[i]->cached_center, settings[i]->cached_inverted_center, settings[i]->cached_inverted_center.basis.get_rotation_quaternion());
+		_process_joints(p_delta, skeleton, settings[i]->joints, get_valid_collision_instance_ids(i), settings[i]->cached_center, settings[i]->cached_inverted_center, settings[i]->cached_inverted_center.basis.get_rotation_quaternion());
 	}
 }
 

scene/3d/spring_bone_simulator_3d.h

@@ -153,7 +153,7 @@ protected:
 	static void _bind_methods();
 
 	virtual void _set_active(bool p_active) override;
-	virtual void _process_modification() override;
+	virtual void _process_modification(double p_delta) override;
 	void _init_joints(Skeleton3D *p_skeleton, SpringBone3DSetting *p_setting);
 	void _process_joints(double p_delta, Skeleton3D *p_skeleton, Vector<SpringBone3DJointSetting *> &p_joints, const LocalVector<ObjectID> &p_collisions, const Transform3D &p_center_transform, const Transform3D &p_inverted_center_transform, const Quaternion &p_inverted_center_rotation);
 

scene/3d/xr/xr_body_modifier_3d.cpp

@@ -238,7 +238,7 @@ void XRBodyModifier3D::_get_joint_data() {
 	}
 }
 
-void XRBodyModifier3D::_process_modification() {
+void XRBodyModifier3D::_process_modification(double p_delta) {
 	Skeleton3D *skeleton = get_skeleton();
 	if (!skeleton) {
 		return;

scene/3d/xr/xr_body_modifier_3d.h

@@ -71,7 +71,7 @@ protected:
 	static void _bind_methods();
 
 	virtual void _skeleton_changed(Skeleton3D *p_old, Skeleton3D *p_new) override;
-	virtual void _process_modification() override;
+	virtual void _process_modification(double p_delta) override;
 
 private:
 	struct JointData {

scene/3d/xr/xr_hand_modifier_3d.cpp

@@ -183,7 +183,7 @@ void XRHandModifier3D::_get_joint_data() {
 	}
 }
 
-void XRHandModifier3D::_process_modification() {
+void XRHandModifier3D::_process_modification(double p_delta) {
 	Skeleton3D *skeleton = get_skeleton();
 	if (!skeleton) {
 		return;

scene/3d/xr/xr_hand_modifier_3d.h

@@ -62,7 +62,7 @@ protected:
 	static void _bind_methods();
 
 	virtual void _skeleton_changed(Skeleton3D *p_old, Skeleton3D *p_new) override;
-	virtual void _process_modification() override;
+	virtual void _process_modification(double p_delta) override;
 
 private:
 	struct JointData {