function physX_level_load()
{
  if (level_ent)
    pXent_settype(level_ent,PH_STATIC,PH_POLY);
  for (you = ent_next(NULL); you; you = ent_next(you))
  { 
    if (you.emask&DYNAMIC) continue;  // only register static ents
    if (you.flags&PASSABLE) continue;	    var type = ent_type(you);
    if (type >= 2 && type <= 5)  // blocks, models, or terrain
      pXent_settype(you,PH_STATIC,PH_POLY);
  }
}

function physX_ent_remove(ENTITY* ent)
{
  if (ent.body) // unregister entity before removal
    pXent_settype(ent,0,0);
}

function physX_open()
{
  physX_load();
  pX_setsteprate(60,8,0);
  pX_setunit(1/40);

  on_exit = physX_destroy;
  on_level_load = physX_level_load;
  on_ent_remove = physX_ent_remove;
 
  while(1) {
    physX_run(time_step/16);
    wait(1);
  }
}

function physX_level_load()
{
	if (!NxPhysicsSDK) return;
	if (level_ent)
		pXent_settype(level_ent,PH_STATIC,PH_POLY);
	for (you = ent_next(NULL); you; you = ent_next(you))
	{ 
		if (you.flags & PASSABLE) continue;	
		var type = ent_type(you);
		if (type == 5 && (you.emask & DYNAMIC)) continue;	// only register static models
		if (type < 2 && type > 5)  continue; // blocks, models, or terrain only
		pXent_settype(you,PH_STATIC,PH_POLY);
 	}
	on_level_load_px();
}

function physX_ent_remove(ENTITY* ent)
{
	if (!NxPhysicsSDK) return;
	if (ent.body)
		pXent_settype(ent,0,0);
	on_ent_remove_px(ent);
}

function physX_open()
{
	if (NxPhysicsSDK) return; // already initialized
	if (version < 8) {
		error("PhysX only supported in A8!");
		return;
	}
	if (level_ent) // level already loaded?
		error("Open PhysX before loading level!");
		
	NxPhysicsSDK = physX_load();
  NxScene = physX_run(0);
	pX_setsteprate(60,8,0);
	pX_setunit(1/40);

	on_exit_px = on_exit;	// store previous on_exit function
	on_exit = physX_close;
	on_level_load_px = on_level_load;
	on_level_load = physX_level_load;
	on_ent_remove_px = on_ent_remove;
	on_ent_remove = physX_ent_remove;

	while(NxPhysicsSDK) {
#ifdef FIXED_TIME
//This for-loop fixes the physX framerate to 60 when the frame rate is below 60 fps
		int loc_n = integer(time_step * 60 / 16) + 1;
		int loc_i = 0;
		if (freeze_mode <= 0)		
			for (; loc_i < loc_n; loc_i++)
			   physX_run(0);
#else
		if (freeze_mode <= 0)		
			physX_run(time_step/16);
#endif
		wait(1);
	}	
}