Expose local center of mass in physics servers

Center of mass in body's local space is more useful than the transformed
one in some cases, like drawing its position for debug.

It's especially useful to get the generated local center of mass when
in auto mode (by default).

Physics Server BODY_PARAM_CENTER_OF_MASS:
Now always returns the local center of mass, instead of setting a local
center of mass and getting a transformed one.
This causes compatibility breaking, but it makes more sense for the
parameter to be consistent between getter and setter.

Direct Body State:
There are now two properties, because both of them can be useful in
different situations.
center_of_mass: relative position in global coordinates (same as before)
center_of_mass_local: position in local coordinates

4 files changed, 7 insertions, 1 deletions

diff --git a/servers/physics_3d/godot_body_3d.cpp b/servers/physics_3d/godot_body_3d.cpp
index 768c9e6572..acf60d61c2 100644
--- a/servers/physics_3d/godot_body_3d.cpp
+++ b/servers/physics_3d/godot_body_3d.cpp
@@ -267,7 +267,7 @@ Variant GodotBody3D::get_param(PhysicsServer3D::BodyParameter p_param) const {
 			}
 		} break;
 		case PhysicsServer3D::BODY_PARAM_CENTER_OF_MASS: {
-			return center_of_mass;
+			return center_of_mass_local;
 		} break;
 		case PhysicsServer3D::BODY_PARAM_GRAVITY_SCALE: {
 			return gravity_scale;
diff --git a/servers/physics_3d/godot_body_3d.h b/servers/physics_3d/godot_body_3d.h
index 4993ea6a1b..7fc2f58168 100644
--- a/servers/physics_3d/godot_body_3d.h
+++ b/servers/physics_3d/godot_body_3d.h
@@ -200,6 +200,7 @@ public:
 
 	_FORCE_INLINE_ Basis get_principal_inertia_axes() const { return principal_inertia_axes; }
 	_FORCE_INLINE_ Vector3 get_center_of_mass() const { return center_of_mass; }
+	_FORCE_INLINE_ Vector3 get_center_of_mass_local() const { return center_of_mass_local; }
 	_FORCE_INLINE_ Vector3 xform_local_to_principal(const Vector3 &p_pos) const { return principal_inertia_axes_local.xform(p_pos - center_of_mass_local); }
 
 	_FORCE_INLINE_ void set_linear_velocity(const Vector3 &p_velocity) { linear_velocity = p_velocity; }
diff --git a/servers/physics_3d/godot_body_direct_state_3d.cpp b/servers/physics_3d/godot_body_direct_state_3d.cpp
index 9c234a5752..a929cab6f9 100644
--- a/servers/physics_3d/godot_body_direct_state_3d.cpp
+++ b/servers/physics_3d/godot_body_direct_state_3d.cpp
@@ -49,6 +49,10 @@ Vector3 GodotPhysicsDirectBodyState3D::get_center_of_mass() const {
 	return body->get_center_of_mass();
 }
 
+Vector3 GodotPhysicsDirectBodyState3D::get_center_of_mass_local() const {
+	return body->get_center_of_mass_local();
+}
+
 Basis GodotPhysicsDirectBodyState3D::get_principal_inertia_axes() const {
 	return body->get_principal_inertia_axes();
 }
diff --git a/servers/physics_3d/godot_body_direct_state_3d.h b/servers/physics_3d/godot_body_direct_state_3d.h
index 6c584a2634..35fd1543b0 100644
--- a/servers/physics_3d/godot_body_direct_state_3d.h
+++ b/servers/physics_3d/godot_body_direct_state_3d.h
@@ -46,6 +46,7 @@ public:
 	virtual real_t get_total_linear_damp() const override;
 
 	virtual Vector3 get_center_of_mass() const override;
+	virtual Vector3 get_center_of_mass_local() const override;
 	virtual Basis get_principal_inertia_axes() const override;
 
 	virtual real_t get_inverse_mass() const override;