Adding some rigid bodies

Now, we will create individual bodies and set their properties and put them into our dynamics world, as follows:

   modelbuilder.begin();
MeshPartBuilder mpb = modelbuilder.part("parts", GL20.GL_TRIANGLES, Usage.Position | Usage.Normal | Usage.Color, new Material(ColorAttribute.createDiffuse(Color.WHITE)));
   mpb.setColor(1f, 1f, 1f, 1f);
   mpb.box(0, 0, 0, 40, 1, 40);
   Model model = modelbuilder.end();
groundInstance = new ModelInstance(model);


   btCollisionShape groundshape = new btBoxShape(new Vector3(20, 1 / 2f, 20));
   btRigidBodyConstructionInfo bodyInfo = new btRigidBodyConstructionInfo(0, null, groundshape, Vector3.Zero);
   btRigidBody body = new btRigidBody(bodyInfo);
   world.addRigidBody(body);

The preceding steps are to create the ground. In our program, the ground is simply a box with very low height. Using the mesh builder, we create a box with width, height, and depth as 40, 1, and 40 units respectively. Remember, this is simply a...