Process NavigationAgent2D/3D avoidance on demand only

Changes NavigationAgent avoidance callback to a toggle that is disabled by default.
Also fixes a few missing descriptions / wrong warnings.

(cherry picked from commit 7f3688603cb3662e425cb7a1dce15459162c1dc6)

doc/classes/NavigationAgent.xml

@@ -48,7 +48,7 @@
 		<method name="get_rid" qualifiers="const">
 			<return type="RID" />
 			<description>
-				Returns the object's [RID].
+				Returns the [RID] of this agent on the [NavigationServer].
 			</description>
 		</method>
 		<method name="get_target_location" qualifiers="const">
@@ -101,6 +101,9 @@
 		<member name="agent_height_offset" type="float" setter="set_agent_height_offset" getter="get_agent_height_offset" default="0.0">
 			The agent height offset to match the navigation mesh height.
 		</member>
+		<member name="avoidance_enabled" type="bool" setter="set_avoidance_enabled" getter="get_avoidance_enabled" default="false">
+			If [code]true[/code] the agent is registered for an RVO avoidance callback on the [NavigationServer]. When [method set_velocity] is used and the processing is completed a [code]safe_velocity[/code] Vector3 is received with a signal connection to [signal velocity_computed]. Avoidance processing with many registered agents has a significant performance cost and should only be enabled on agents that currently require it.
+		</member>
 		<member name="ignore_y" type="bool" setter="set_ignore_y" getter="get_ignore_y" default="true">
 			Ignores collisions on the Y axis. Must be [code]true[/code] to move on a horizontal plane.
 		</member>

doc/classes/NavigationAgent2D.xml

@@ -48,7 +48,7 @@
 		<method name="get_rid" qualifiers="const">
 			<return type="RID" />
 			<description>
-				Returns the object's [RID].
+				Returns the [RID] of this agent on the [Navigation2DServer].
 			</description>
 		</method>
 		<method name="get_target_location" qualifiers="const">
@@ -98,6 +98,9 @@
 		</method>
 	</methods>
 	<members>
+		<member name="avoidance_enabled" type="bool" setter="set_avoidance_enabled" getter="get_avoidance_enabled" default="false">
+			If [code]true[/code] the agent is registered for an RVO avoidance callback on the [Navigation2DServer]. When [method set_velocity] is used and the processing is completed a [code]safe_velocity[/code] Vector2 is received with a signal connection to [signal velocity_computed]. Avoidance processing with many registered agents has a significant performance cost and should only be enabled on agents that currently require it.
+		</member>
 		<member name="max_neighbors" type="int" setter="set_max_neighbors" getter="get_max_neighbors" default="10">
 			The maximum number of neighbors for the agent to consider.
 		</member>

scene/2d/navigation_agent_2d.cpp

@@ -37,6 +37,9 @@
 void NavigationAgent2D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_rid"), &NavigationAgent2D::get_rid);
 
+	ClassDB::bind_method(D_METHOD("set_avoidance_enabled", "enabled"), &NavigationAgent2D::set_avoidance_enabled);
+	ClassDB::bind_method(D_METHOD("get_avoidance_enabled"), &NavigationAgent2D::get_avoidance_enabled);
+
 	ClassDB::bind_method(D_METHOD("set_target_desired_distance", "desired_distance"), &NavigationAgent2D::set_target_desired_distance);
 	ClassDB::bind_method(D_METHOD("get_target_desired_distance"), &NavigationAgent2D::get_target_desired_distance);
 
@@ -82,6 +85,7 @@ void NavigationAgent2D::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::REAL, "time_horizon", PROPERTY_HINT_RANGE, "0.1,10000,0.01"), "set_time_horizon", "get_time_horizon");
 	ADD_PROPERTY(PropertyInfo(Variant::REAL, "max_speed", PROPERTY_HINT_RANGE, "0.1,100000,0.01"), "set_max_speed", "get_max_speed");
 	ADD_PROPERTY(PropertyInfo(Variant::REAL, "path_max_distance", PROPERTY_HINT_RANGE, "10,100,1"), "set_path_max_distance", "get_path_max_distance");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "avoidance_enabled"), "set_avoidance_enabled", "get_avoidance_enabled");
 
 	ADD_SIGNAL(MethodInfo("path_changed"));
 	ADD_SIGNAL(MethodInfo("target_reached"));
@@ -94,7 +98,7 @@ void NavigationAgent2D::_notification(int p_what) {
 		case NOTIFICATION_READY: {
 			agent_parent = Object::cast_to<Node2D>(get_parent());
 
-			Navigation2DServer::get_singleton()->agent_set_callback(agent, this, "_avoidance_done");
+			set_avoidance_enabled(avoidance_enabled);
 
 			// Search the navigation node and set it
 			{
@@ -153,6 +157,7 @@ NavigationAgent2D::NavigationAgent2D() :
 		agent_parent(nullptr),
 		navigation(nullptr),
 		agent(RID()),
+		avoidance_enabled(false),
 		target_desired_distance(1.0),
 		path_max_distance(3.0),
 		velocity_submitted(false),
@@ -171,6 +176,19 @@ NavigationAgent2D::~NavigationAgent2D() {
 	agent = RID(); // Pointless
 }
 
+void NavigationAgent2D::set_avoidance_enabled(bool p_enabled) {
+	avoidance_enabled = p_enabled;
+	if (avoidance_enabled) {
+		Navigation2DServer::get_singleton()->agent_set_callback(agent, this, "_avoidance_done");
+	} else {
+		Navigation2DServer::get_singleton()->agent_set_callback(agent, nullptr, "_avoidance_done");
+	}
+}
+
+bool NavigationAgent2D::get_avoidance_enabled() const {
+	return avoidance_enabled;
+}
+
 void NavigationAgent2D::set_navigation(Navigation2D *p_nav) {
 	if (navigation == p_nav) {
 		return; // Pointless
@@ -297,7 +315,7 @@ void NavigationAgent2D::_avoidance_done(Vector3 p_new_velocity) {
 
 String NavigationAgent2D::get_configuration_warning() const {
 	if (!Object::cast_to<Node2D>(get_parent())) {
-		return TTR("The NavigationAgent2D can be used only under a Node2D node.");
+		return TTR("The NavigationAgent2D can be used only under a Node2D inheriting parent node.");
 	}
 
 	return String();

scene/2d/navigation_agent_2d.h

@@ -46,6 +46,8 @@ class NavigationAgent2D : public Node {
 	RID agent;
 	RID map_before_pause;
 
+	bool avoidance_enabled;
+
 	real_t target_desired_distance;
 	real_t radius;
 	real_t neighbor_dist;
@@ -87,6 +89,9 @@ public:
 		return agent;
 	}
 
+	void set_avoidance_enabled(bool p_enabled);
+	bool get_avoidance_enabled() const;
+
 	void set_target_desired_distance(real_t p_dd);
 	real_t get_target_desired_distance() const {
 		return target_desired_distance;

scene/3d/navigation_agent.cpp

@@ -37,6 +37,9 @@
 void NavigationAgent::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_rid"), &NavigationAgent::get_rid);
 
+	ClassDB::bind_method(D_METHOD("set_avoidance_enabled", "enabled"), &NavigationAgent::set_avoidance_enabled);
+	ClassDB::bind_method(D_METHOD("get_avoidance_enabled"), &NavigationAgent::get_avoidance_enabled);
+
 	ClassDB::bind_method(D_METHOD("set_target_desired_distance", "desired_distance"), &NavigationAgent::set_target_desired_distance);
 	ClassDB::bind_method(D_METHOD("get_target_desired_distance"), &NavigationAgent::get_target_desired_distance);
 
@@ -90,6 +93,7 @@ void NavigationAgent::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::REAL, "max_speed", PROPERTY_HINT_RANGE, "0.1,10000,0.01"), "set_max_speed", "get_max_speed");
 	ADD_PROPERTY(PropertyInfo(Variant::REAL, "path_max_distance", PROPERTY_HINT_RANGE, "0.01,100,0.1"), "set_path_max_distance", "get_path_max_distance");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "ignore_y"), "set_ignore_y", "get_ignore_y");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "avoidance_enabled"), "set_avoidance_enabled", "get_avoidance_enabled");
 
 	ADD_SIGNAL(MethodInfo("path_changed"));
 	ADD_SIGNAL(MethodInfo("target_reached"));
@@ -102,7 +106,7 @@ void NavigationAgent::_notification(int p_what) {
 		case NOTIFICATION_READY: {
 			agent_parent = Object::cast_to<Spatial>(get_parent());
 
-			NavigationServer::get_singleton()->agent_set_callback(agent, this, "_avoidance_done");
+			set_avoidance_enabled(avoidance_enabled);
 
 			// Search the navigation node and set it
 			{
@@ -161,6 +165,7 @@ NavigationAgent::NavigationAgent() :
 		agent_parent(nullptr),
 		navigation(nullptr),
 		agent(RID()),
+		avoidance_enabled(false),
 		target_desired_distance(1.0),
 		navigation_height_offset(0.0),
 		path_max_distance(3.0),
@@ -181,6 +186,19 @@ NavigationAgent::~NavigationAgent() {
 	agent = RID(); // Pointless
 }
 
+void NavigationAgent::set_avoidance_enabled(bool p_enabled) {
+	avoidance_enabled = p_enabled;
+	if (avoidance_enabled) {
+		NavigationServer::get_singleton()->agent_set_callback(agent, this, "_avoidance_done");
+	} else {
+		NavigationServer::get_singleton()->agent_set_callback(agent, nullptr, "_avoidance_done");
+	}
+}
+
+bool NavigationAgent::get_avoidance_enabled() const {
+	return avoidance_enabled;
+}
+
 void NavigationAgent::set_navigation(Navigation *p_nav) {
 	if (navigation == p_nav) {
 		return; // Pointless
@@ -315,7 +333,7 @@ void NavigationAgent::_avoidance_done(Vector3 p_new_velocity) {
 
 String NavigationAgent::get_configuration_warning() const {
 	if (!Object::cast_to<Spatial>(get_parent())) {
-		return TTR("The NavigationAgent can be used only under a spatial node.");
+		return TTR("The NavigationAgent can be used only under a Spatial inheriting parent node.");
 	}
 
 	return String();

scene/3d/navigation_agent.h

@@ -46,6 +46,8 @@ class NavigationAgent : public Node {
 	RID agent;
 	RID map_before_pause;
 
+	bool avoidance_enabled;
+
 	real_t target_desired_distance;
 	real_t radius;
 	real_t navigation_height_offset;
@@ -89,6 +91,9 @@ public:
 		return agent;
 	}
 
+	void set_avoidance_enabled(bool p_enabled);
+	bool get_avoidance_enabled() const;
+
 	void set_target_desired_distance(real_t p_dd);
 	real_t get_target_desired_distance() const {
 		return target_desired_distance;