PhysX is a proprietary physics programming library made by the graphics card specialist nVidia that simulates the behavior of rigid bodies. One of the library's major features is its ability to leverage the computing abilities of a graphics card to accelerate the calculation of the internal physics formulas used for the simulation. If a suitable graphics adapter cannot be found, the physics engine falls back to the system's CPU so that nobody's left behind.
This recipe will give you some insight into the wrapper that the Panda3D developers have created around this physics API.
This recipe builds upon the framework created in Setting up the game structure found in Chapter 1.
Additionally, you need to have the PhysX SDK installed on your system. For more information on licensing and how to download, see this website: http://developer.nvidia.com/object/physx_downloads.html.