Collision between CSGPolygon and ConcavePolygonShape not working

[BraindeadBZH]

Godot version:
3.1.1.stable

OS/device including version:
Windows 10. Geforce 970M

Issue description:
I have a RigidBody with ConcavePolygonShape for collision. I also have a CSGPolygon extruded along a path with collision activated. The RigidBody is able to collide with another StaticBody with a CubeShape but not with the CSGPolygon. Another RigidBody with a CapsuleShape is able to collide with the CSGPolygon.

Steps to reproduce:

1. Create a CSGPolygonextruded along a path
2. Create a RigidBody with a ConcavePolygonShape
3. The RigidBody goes through the CSGPolygon

CSGCollisionTest.zip

[rhossack]

I ran into this problem with a SphereShape. I have a RigidBody with a ConcavePolygonShape that collides with RayCasts and ConvexPolygonShapes, but not SphereShapes.

The workaround was to create a convex collision sibling instead of a Trimesh collision sibling.

[pete3000a]

Still happens in 3.2

[KoBeWi]

Still valid in 3.2.4 beta4

[Calinou]

I believe this is expected, as RigidBodies can't use trimesh collision shapes. See this warning for RigidBodies in Kinematic mode:

godot/modules/bullet/rigid_body_bullet.cpp

Lines 245 to 257 in 0c7c640

	switch (shape_wrapper->shape->get_type()) {
	case PhysicsServer::SHAPE_SPHERE:
	case PhysicsServer::SHAPE_BOX:
	case PhysicsServer::SHAPE_CAPSULE:
	case PhysicsServer::SHAPE_CYLINDER:
	case PhysicsServer::SHAPE_CONVEX_POLYGON:
	case PhysicsServer::SHAPE_RAY: {
	shapes.write[i].shape = static_cast<btConvexShape *>(shape_wrapper->shape->create_bt_shape(owner_scale * shape_wrapper->scale, safe_margin));
	} break;
	default:
	WARN_PRINT("This shape is not supported to be kinematic!");
	shapes.write[i].shape = nullptr;
	}

In the MRP, there's a node configuration warning appearing:

Running the MRP won't print a warning message though, as the RigidBody isn't using Kinematic mode. We could print a warning message at run-time to complement this node configuration warning, but this may have a non-negligible performance cost. If checking turns out to be expensive, the check could be enabled in debug builds only.

Therefore, I'll close this as a duplicate of #4159.

[rhossack]

RigidBodies can't use trimesh collision shapes

Then the button that creates trimesh collision shapes should be disabled if there are RigidBodies in the current selection.

At least, that's vaguely how I remember running into the issue 2 years ago