Base class for all objects affected by physics in 2D space. PhysicsBody2D is an abstract base class for implementing a physics body. All *Body2D types inherit from it. Adds a body to the list of bodies that this body can't collide with. Return an individual bit on the collision mask. Return an individual bit on the collision mask. Removes a body from the list of bodies that this body can't collide with. Set/clear individual bits on the layer mask. This makes getting a body in/out of only one layer easier. Set/clear individual bits on the collision mask. This makes selecting the areas scanned easier. The physics layers this area is in. Collidable objects can exist in any of 32 different layers. These layers work like a tagging system, and are not visual. A collidable can use these layers to select with which objects it can collide, using the collision_mask property. 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. The physics layers this area can scan for collisions. Both collision_layer and collision_mask. Returns collision_layer when accessed. Updates collision_layers and collision_mask when modified.