Add node_notify signal for animation trees

doc/classes/AnimationNode.xml

@@ -244,5 +244,11 @@
 		<constant name="FILTER_BLEND" value="3" enum="FilterAction">
 			Paths matching the filter will be blended (by the blend value).
 		</constant>
+		<constant name="NOTIFY_STARTED" value="0" enum="NotifyReason">
+			The node has started playback.
+		</constant>
+		<constant name="NOTIFY_FINISHED" value="1" enum="NotifyReason">
+			The node has finished playback.
+		</constant>
 	</constants>
 </class>

doc/classes/AnimationTree.xml

@@ -45,6 +45,13 @@
 				Emitted when the [member anim_player] is changed.
 			</description>
 		</signal>
+		<signal name="node_notify">
+			<param index="0" name="node" type="StringName" />
+			<param index="1" name="reason" type="int" />
+			<description>
+				Emitted when the [param node] state changes during processing or playback.
+			</description>
+		</signal>
 	</signals>
 	<constants>
 		<constant name="ANIMATION_PROCESS_PHYSICS" value="0" enum="AnimationProcessCallback" deprecated="See [constant AnimationMixer.ANIMATION_CALLBACK_MODE_PROCESS_PHYSICS].">

scene/animation/animation_blend_tree.cpp

@@ -696,6 +696,10 @@ AnimationNode::NodeTimeInfo AnimationNodeOneShot::_process(const AnimationMixer:
 	set_parameter(fade_in_remaining, cur_fade_in_remaining);
 	set_parameter(fade_out_remaining, cur_fade_out_remaining);
 
+	if (cur_active != (bool)get_parameter(active)) {
+		_notify_tree(cur_active ? NOTIFY_FINISHED : NOTIFY_STARTED);
+	}
+
 	return cur_internal_active ? os_nti : main_nti;
 }
 
@@ -1451,6 +1455,7 @@ AnimationNodeOutput::AnimationNodeOutput() {
 void AnimationNodeBlendTree::add_node(const StringName &p_name, Ref<AnimationNode> p_node, const Vector2 &p_position) {
 	ERR_FAIL_COND(nodes.has(p_name));
 	ERR_FAIL_COND(p_node.is_null());
+	ERR_FAIL_COND(node_to_name.has(*p_node));
 	ERR_FAIL_COND(p_name == SceneStringName(output));
 	ERR_FAIL_COND(String(p_name).contains_char('/'));
 
@@ -1459,6 +1464,7 @@ void AnimationNodeBlendTree::add_node(const StringName &p_name, Ref<AnimationNod
 	n.position = p_position;
 	n.connections.resize(n.node->get_input_count());
 	nodes[p_name] = n;
+	node_to_name[*p_node] = p_name;
 
 	emit_changed();
 	emit_signal(SNAME("tree_changed"));
@@ -1476,12 +1482,10 @@ Ref<AnimationNode> AnimationNodeBlendTree::get_node(const StringName &p_name) co
 }
 
 StringName AnimationNodeBlendTree::get_node_name(const Ref<AnimationNode> &p_node) const {
-	for (const KeyValue<StringName, Node> &E : nodes) {
-		if (E.value.node == p_node) {
-			return E.key;
-		}
+	AHashMap<AnimationNode *, StringName>::ConstIterator E = node_to_name.find(*p_node);
+	if (E) {
+		return E->value;
 	}
-
 	ERR_FAIL_V(StringName());
 }
 
@@ -1525,6 +1529,7 @@ void AnimationNodeBlendTree::remove_node(const StringName &p_name) {
 
 	{
 		Ref<AnimationNode> node = nodes[p_name].node;
+		node_to_name.erase(*node);
 		node->disconnect(SNAME("tree_changed"), callable_mp(this, &AnimationNodeBlendTree::_tree_changed));
 		node->disconnect(SNAME("animation_node_renamed"), callable_mp(this, &AnimationNodeBlendTree::_animation_node_renamed));
 		node->disconnect(SNAME("animation_node_removed"), callable_mp(this, &AnimationNodeBlendTree::_animation_node_removed));
@@ -1554,8 +1559,8 @@ void AnimationNodeBlendTree::rename_node(const StringName &p_name, const StringN
 	ERR_FAIL_COND(p_new_name == SceneStringName(output));
 
 	nodes[p_name].node->disconnect_changed(callable_mp(this, &AnimationNodeBlendTree::_node_changed));
-
 	nodes[p_new_name] = nodes[p_name];
+	node_to_name[*(nodes[p_new_name].node)] = p_new_name;
 	nodes.erase(p_name);
 
 	// Rename connections.
@@ -1853,7 +1858,8 @@ void AnimationNodeBlendTree::_initialize_node_tree() {
 	n.node = output;
 	n.position = Vector2(300, 150);
 	n.connections.resize(1);
-	nodes["output"] = n;
+	nodes[SceneStringName(output)] = n;
+	node_to_name[*n.node] = SceneStringName(output);
 }
 
 AnimationNodeBlendTree::AnimationNodeBlendTree() {

scene/animation/animation_blend_tree.h

@@ -411,6 +411,7 @@ class AnimationNodeBlendTree : public AnimationRootNode {
 	};
 
 	AHashMap<StringName, Node> nodes;
+	AHashMap<AnimationNode *, StringName> node_to_name;
 
 	Vector2 graph_offset;
 

scene/animation/animation_node_state_machine.cpp

@@ -194,6 +194,7 @@ AnimationNodeStateMachineTransition::AnimationNodeStateMachineTransition() {
 
 void AnimationNodeStateMachinePlayback::_set_current(AnimationNodeStateMachine *p_state_machine, const StringName &p_state) {
 	current = p_state;
+
 	if (current == StringName()) {
 		group_start_transition = Ref<AnimationNodeStateMachineTransition>();
 		group_end_transition = Ref<AnimationNodeStateMachineTransition>();
@@ -490,6 +491,7 @@ void AnimationNodeStateMachinePlayback::_start(AnimationNodeStateMachine *p_stat
 	teleport_request = true;
 	stop_request = false;
 	start_request = StringName();
+	p_state_machine->_notify_tree(AnimationNode::NOTIFY_STARTED);
 }
 
 bool AnimationNodeStateMachinePlayback::_travel(AnimationTree *p_tree, AnimationNodeStateMachine *p_state_machine, bool p_is_allow_transition_to_self, bool p_test_only) {
@@ -719,6 +721,7 @@ AnimationNode::NodeTimeInfo AnimationNodeStateMachinePlayback::_process(const St
 		travel_request = StringName();
 		path.clear();
 		playing = false;
+		p_state_machine->_notify_tree(AnimationNode::NOTIFY_FINISHED);
 		return AnimationNode::NodeTimeInfo();
 	}
 
@@ -883,8 +886,14 @@ AnimationNode::NodeTimeInfo AnimationNodeStateMachinePlayback::_process(const St
 	if (will_end || ((p_state_machine->get_state_machine_type() == AnimationNodeStateMachine::STATE_MACHINE_TYPE_NESTED) && !p_state_machine->has_transition_from(current))) {
 		// There is no next transition.
 		if (fading_from != StringName()) {
+			if (MAX(current_nti.get_remain(), fadeing_from_nti.get_remain()) <= 0) {
+				p_state_machine->_notify_tree(AnimationNode::NOTIFY_FINISHED);
+			}
 			return Animation::is_greater_approx(current_nti.get_remain(), fadeing_from_nti.get_remain()) ? current_nti : fadeing_from_nti;
 		}
+		if (current_nti.get_remain() <= 0) {
+			p_state_machine->_notify_tree(AnimationNode::NOTIFY_FINISHED);
+		}
 		return current_nti;
 	}
 

scene/animation/animation_tree.cpp

@@ -587,6 +587,19 @@ void AnimationNode::_bind_methods() {
 	BIND_ENUM_CONSTANT(FILTER_PASS);
 	BIND_ENUM_CONSTANT(FILTER_STOP);
 	BIND_ENUM_CONSTANT(FILTER_BLEND);
+
+	BIND_ENUM_CONSTANT(NOTIFY_STARTED);
+	BIND_ENUM_CONSTANT(NOTIFY_FINISHED);
+}
+
+void AnimationNode::_notify_tree(AnimationNode::NotifyReason p_reason) {
+	AnimationNodeBlendTree *blend_tree = Object::cast_to<AnimationNodeBlendTree>(node_state.parent);
+	if (blend_tree) {
+		StringName node_name = blend_tree->get_node_name(this);
+		if (!node_name.is_empty()) {
+			process_state->tree->emit_signal(SceneStringName(node_notify), node_name, p_reason);
+		}
+	}
 }
 
 AnimationNode::AnimationNode() {
@@ -991,6 +1004,7 @@ void AnimationTree::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::NODE_PATH, "anim_player", PROPERTY_HINT_NODE_PATH_VALID_TYPES, "AnimationPlayer"), "set_animation_player", "get_animation_player");
 
 	ADD_SIGNAL(MethodInfo(SNAME("animation_player_changed")));
+	ADD_SIGNAL(MethodInfo(SceneStringName(node_notify), PropertyInfo(Variant::STRING_NAME, "node"), PropertyInfo(Variant::INT, "reason")));
 }
 
 AnimationTree::AnimationTree() {

scene/animation/animation_tree.h

@@ -54,6 +54,11 @@ public:
 		FILTER_BLEND
 	};
 
+	enum NotifyReason {
+		NOTIFY_STARTED,
+		NOTIFY_FINISHED
+	};
+
 	struct Input {
 		String name;
 	};
@@ -181,6 +186,8 @@ protected:
 
 	void _validate_property(PropertyInfo &p_property) const;
 
+	void _notify_tree(AnimationNode::NotifyReason p_reason);
+
 	GDVIRTUAL0RC(Dictionary, _get_child_nodes)
 	GDVIRTUAL0RC(Array, _get_parameter_list)
 	GDVIRTUAL1RC(Ref<AnimationNode>, _get_child_by_name, StringName)
@@ -243,6 +250,7 @@ public:
 };
 
 VARIANT_ENUM_CAST(AnimationNode::FilterAction)
+VARIANT_ENUM_CAST(AnimationNode::NotifyReason)
 
 // Root node does not allow inputs.
 class AnimationRootNode : public AnimationNode {

scene/scene_string_names.h

@@ -85,6 +85,7 @@ public:
 	const StringName sort_children = StaticCString::create("sort_children");
 
 	const StringName finished = StaticCString::create("finished");
+	const StringName node_notify = StaticCString::create("node_notify");
 	const StringName animation_finished = StaticCString::create("animation_finished");
 	const StringName animation_changed = StaticCString::create("animation_changed");
 	const StringName animation_started = StaticCString::create("animation_started");