Fix crash on RigidBody _direct_state_changed

[rafallus]

Fixes: #46003 for master branch

[madmiraal]

Three points:

1. As mentioned in Executing RigidBody.new()._direct_state_changed(BoxShape.new()) crashes Godot #46003 (comment), unless there is a reason this method is exposed, the better solution would be to unexpose this method.
2. This method also exists in KinematicBody, VehicleBody and the equivalents in 2D; so whatever solution is agreed on, those should be updated too.
3. This will prevent the crash identified in Fix crash on RigidBody _direct_state_changed #47485 in debug mode only i.e. when run from the editor.

[rafallus]

@madmiraal

1. I agree that's a decision to be made.
2. Thanks for pointing this out.
3. The comment for the non-debug section says to trust it. So I just leave it as is. I guess for release you are supposed to have already tested your code.

[pouleyKetchoupp]

I agree we should just unexpose the method on master. The method binding seems to be used only because of an internal call (see #46003 (comment)).

@rafallus If you're up for refactoring this fix, the proper changes are:

• Modify body_set_force_integration_callback in the physics server to use a callable:
  

  godot/servers/physics_server_3d.h

  Line 489 in 35066f3

  virtual void body_set_force_integration_callback(RID p_body, Object *p_receiver, const StringName &p_method, const Variant &p_udata = Variant()) = 0;

virtual void body_set_force_integration_callback(RID p_body, const Callable &p_callable, const Variant &p_udata = Variant()) = 0; 

• Modify how it's stored in the body inside the physics server:
  

  godot/servers/physics_3d/body_3d_sw.h

  Lines 129 to 133 in 35066f3

  	struct ForceIntegrationCallback {
  	ObjectID id;
  	StringName method;
  	Variant udata;
  	};

struct ForceIntegrationCallback {
	Callable callable;
	Variant udata;
};

• Modify the call to use Callable::get_object() and Callable::call():
  

  godot/servers/physics_3d/body_3d_sw.cpp

  Lines 696 to 705 in 35066f3

  	Object *obj = ObjectDB::get_instance(fi_callback->id);
  	if (!obj) {
  	set_force_integration_callback(ObjectID(), StringName());
  	} else {
  	const Variant *vp[2] = { &v, &fi_callback->udata };
  	Callable::CallError ce;
  	int argc = (fi_callback->udata.get_type() == Variant::NIL) ? 1 : 2;
  	obj->call(fi_callback->method, vp, argc, ce);
  	}

• Make the same changes in Bullet module and Godot Physics 2D
• Use callable_mp macro in calls to body_set_force_integration_callback
• Remove all the _direct_state_changed bindings

[pouleyKetchoupp]

@rafallus Thanks for refactoring the PR! I haven't reviewed or tested yet, but for info some checks are failing because of compilation errors in test code:

tests/test_physics_2d.cpp: In member function 'RID TestPhysics2DMainLoop::_add_body(PhysicsServer2D::ShapeType, const Transform2D&)':
tests/test_physics_2d.cpp:246:76: error: no matching function for call to 'PhysicsServer2D::body_set_force_integration_callback(RID&, TestPhysics2DMainLoop*, const char [12], RID&)'
  246 |   ps->body_set_force_integration_callback(body, this, "_body_moved", sprite);
      |                                                                            ^
In file included from tests/test_physics_2d.cpp:39:
./servers/physics_server_2d.h:480:15: note: candidate: 'virtual void PhysicsServer2D::body_set_force_integration_callback(RID, const Callable&, const Variant&)'
  480 |  virtual void body_set_force_integration_callback(RID p_body, const Callable &p_callable, const Variant &p_udata = Variant()) = 0;
      |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./servers/physics_server_2d.h:480:15: note:   candidate expects 3 arguments, 4 provided

It seems there are some more cases in test_physics_3d.cpp as well.

[rafallus]

Still there are some tests that haven't passed. I'll check that later

[rafallus]

Ok, the PR is ready for review

[pouleyKetchoupp]

Looks good except for 2 things:

• There are currently errors when starting the editor or game because of body_set_force_integration_callback in physics servers has different arguments now. The method binding needs to be updated here:
  

  godot/servers/physics_server_2d.cpp

  Line 650 in 5c8505c

  ClassDB::bind_method(D_METHOD("body_set_force_integration_callback", "body", "receiver", "method", "userdata"), &PhysicsServer2D::body_set_force_integration_callback, DEFVAL(Variant()));

  
  (and the same in the 3d physics server)

• The documentation for physics servers needs to be updated too:
  

  godot/doc/classes/PhysicsServer2D.xml

  Lines 657 to 671 in 5c8505c

  	<method name="body_set_force_integration_callback">
  	<return type="void">
  	</return>
  	<argument index="0" name="body" type="RID">
  	</argument>
  	<argument index="1" name="receiver" type="Object">
  	</argument>
  	<argument index="2" name="method" type="StringName">
  	</argument>
  	<argument index="3" name="userdata" type="Variant" default="null">
  	</argument>
  	<description>
  	Sets the function used to calculate physics for an object, if that object allows it (see [method body_set_omit_force_integration]).
  	</description>
  	</method>

  
  (again, for the 3d version as well)

[akien-mga]

Suggested a couple additional cleanups, but looks great overall. Thanks!

[madmiraal]

It looks good. Just, as suggested below, the original check this PR suggested either needs to be applied consistently or not at all.

[akien-mga]

Thanks!

[YuriSizov]

@twocountriestrus Please don't spam PRs with "Thanks"