how you can create a simple world, and display it with WorldView, and how to provide custom Renderers. Now we’re going to add some user input. We’ll create a control that behaves like a flipper in a pinball machine.
To do that we’ll create a Joint. In JBox2D Joints are used to constrain bodies to the world or to each other. We’ll create a static circular Body that will serve as the axis for our flipper, and bind a Box to it via a RevoluteJoint.
To simplify the code, we’ll first define a JointBuilder base class and a RevoluteJointBuilder: