Base class for all objects affected by physics. PhysicsBody2D is an abstract base class for implementing a physics body. All *Body2D types inherit from it. Return the physics layer this area is in. Return an individual bit on the collision mask. Return the physics layers this area can scan for collisions. Return an individual bit on the collision mask. Set the physics layers this area is in. Collidable objects can exist in any of 32 different layers. These layers are not visual, but more of a tagging system instead. A collidable can use these layers/tags to select with which objects it can collide, using [method set_collision_mask]. A contact is detected if object A is in any of the layers that object B scans, or object B is in any layer scanned by object A. Set/clear individual bits on the layer mask. This makes getting a body in/out of only one layer easier. Set the physics layers this area can scan for collisions. Set/clear individual bits on the collision mask. This makes selecting the areas scanned easier.