#define MOUSE_SENSITIVITY 10.0   // set mouse sensitivity
#define CAMERA_SPEED 10.0        // set camera speed

ENTITY* soldier;

void FPS_camera(ENTITY* soldier)
{
   VECTOR vMove = {_VAR(0), _VAR(0), _VAR(0)};
   VECTOR vForce = {_VAR(0), _VAR(0), _VAR(0)};   // temp variables for moving and rotating the camera

   // update camera rotation variables based on mouse input, and multiply by mouse sensitivity
   vForce.x = _VAR(-1 * MOUSE_SENSITIVITY * _FLOAT(v(mouse_force).x) * FLOATV(time_frame));	  // set pan angle variable
   vForce.y = _VAR(MOUSE_SENSITIVITY * _FLOAT(v(mouse_force).y) * FLOATV(time_frame));	      // set tilt angle variable

   // update camera position variables based on keyboard input W, A, S, D, home, end keys
   vMove.x = _VAR(CAMERA_SPEED * (FLOATV(key_w) - FLOATV(key_s)) * FLOATV(time_frame));	       // set forward variable
   vMove.y = _VAR(CAMERA_SPEED * (FLOATV(key_a) - FLOATV(key_d)) * FLOATV(time_frame));	       // set sideways variable
   vMove.z = _VAR(CAMERA_SPEED * (FLOATV(key_home) - FLOATV(key_end)) * FLOATV(time_frame));   // set upward variable
  
   // update the camera's rotation and position
   vec_add((VECTOR*)&v(camera).pan, &vForce);    // rotate camera based on vForce variable
   vec_rotate(&vMove, (ANGLE*)&v(camera).pan);   // rotate vMove variable in direction of camera

   c_move(soldier, (VECTOR*)&vMove, NULL, GLIDE);   // entity, relative dist, global dist, mode

   v(camera).x = soldier->x;
   v(camera).y = soldier->y;
   v(camera).z = _VAR(70);
}

int APIENTRY WinMain(HINSTANCE hInstance,	
                     HINSTANCE hPrevInstance,
                     LPTSTR    lpCmdLine,	
                     int       nCmdShow)	
{
   engine_init();
   v(camera).pan = _VAR(90);
   vec_set((VECTOR*)&v(camera).x, _vec(0, 0, 70));
   v(camera).arc = _VAR(NORMAL_FOV);
   soldier = ent_create("soldier.mdl", _vec(0, 0, 70), NULL);
      phent_settype(soldier,_VAR(PH_RIGID),_VAR(PH_BOX));
      phent_setmass(soldier,_VAR(1.0),_VAR(PH_BOX));
      phent_setfriction(soldier,_VAR(90.0));
      phent_setelasticity(soldier,_VAR(0.0),_VAR(100.0));
      phent_setdamping(soldier,_VAR(30.0),_VAR(30.0));

... BLAH BLAH BLAH ...

   while(engine_frame()) 
   {
      FPS_camera(soldier);
   }
   engine_close();
   return 0;
}