Jolt Physics: Fix default area parameter updates not propagating to bodies

modules/jolt_physics/objects/jolt_area_3d.cpp

@@ -206,9 +206,17 @@ void JoltArea3D::_notify_body_exited(const JPH::BodyID &p_body_id) {
 }
 
 void JoltArea3D::_notify_bodies_updated(bool p_priority_changed) {
-	for (KeyValue<JPH::BodyID, Overlap> &E : bodies_by_id) {
-		if (JoltBody3D *body = space->try_get_body(E.key)) {
-			body->update_area(this, p_priority_changed);
+	if (unlikely(!in_space())) {
+		return;
+	}
+
+	if (space->get_default_area() == this) {
+		space->increment_default_area_changed_count();
+	} else {
+		for (KeyValue<JPH::BodyID, Overlap> &E : bodies_by_id) {
+			if (JoltBody3D *body = space->try_get_body(E.key)) {
+				body->update_area(this, p_priority_changed);
+			}
 		}
 	}
 }

modules/jolt_physics/objects/jolt_body_3d.cpp

@@ -279,6 +279,14 @@ void JoltBody3D::_update_mass_properties() {
 	}
 }
 
+bool JoltBody3D::_needs_update_environmental_properties() const {
+	if (unlikely(!in_space())) {
+		return false;
+	}
+
+	return has_point_gravity || space->get_default_area_changed_count() != default_area_changed_count;
+}
+
 void JoltBody3D::_update_environmental_properties() {
 	if (unlikely(!in_space())) {
 		return;
@@ -349,6 +357,8 @@ void JoltBody3D::_update_environmental_properties() {
 			total_angular_damp = angular_damp;
 		} break;
 	}
+
+	default_area_changed_count = space->get_default_area_changed_count();
 }
 
 void JoltBody3D::_update_kinematic_transform() {
@@ -1104,14 +1114,14 @@ void JoltBody3D::pre_step(float p_step) {
 		} break;
 		case PhysicsServer3D::BODY_MODE_RIGID:
 		case PhysicsServer3D::BODY_MODE_RIGID_LINEAR: {
-			if (has_point_gravity) {
+			if (_needs_update_environmental_properties()) {
 				_update_environmental_properties();
 			}
 
 			_integrate_forces(p_step);
 		} break;
 		case PhysicsServer3D::BODY_MODE_KINEMATIC: {
-			if (has_point_gravity) {
+			if (_needs_update_environmental_properties()) {
 				_update_environmental_properties();
 			}
 

modules/jolt_physics/objects/jolt_body_3d.h

@@ -98,6 +98,8 @@ private:
 
 	uint32_t locked_axes = 0;
 
+	uint16_t default_area_changed_count = 0;
+
 	bool sleep_allowed = true;
 	bool sleep_initially = false;
 	bool custom_center_of_mass = false;
@@ -126,6 +128,7 @@ private:
 	void _on_wake_up();
 
 	void _update_mass_properties();
+	bool _needs_update_environmental_properties() const;
 	void _update_environmental_properties();
 	void _update_kinematic_transform();
 	void _update_group_filter();

modules/jolt_physics/spaces/jolt_space_3d.h

@@ -78,6 +78,8 @@ class JoltSpace3D {
 
 	float last_step = 0.0f;
 
+	uint16_t default_area_changed_count = 0;
+
 	bool active = false;
 	bool stepping = false;
 
@@ -129,6 +131,9 @@ public:
 	JoltArea3D *get_default_area() const { return default_area; }
 	void set_default_area(JoltArea3D *p_area) { default_area = p_area; }
 
+	void increment_default_area_changed_count() { default_area_changed_count++; }
+	uint16_t get_default_area_changed_count() const { return default_area_changed_count; }
+
 	float get_last_step() const { return last_step; }
 
 	JPH::Body *add_object(const JoltObject3D &p_object, const JPH::BodyCreationSettings &p_settings, bool p_sleeping = false);