function loads the PhysX engine and returns a pointer to it. Automatically called by physX_open; otherwise put it at the beginning
of your main function.
Pointer to the NxPhysicsSDK for possible user extensions, or NULL when the PhysX engine could not be loaded.
- Must be called before the first call to physX_run or any other PhysX function.
- If warn_level is set at 1 or above, an error message is issued when the PhysX engine could not be loaded.
void* NxPhysicsSDK = physX_load();