while (1){
   vec_set (camera.x, my.x);
   camera.z += 100;
   camera.tilt = 80;
   wait (1);
}

void sniper()
 {
   while(1)
   {
     if(mouse_right) // right mouse button pressed
     {
       camera.arc = max(camera.arc - time_step, 30);	 // reduce fiel of view
     }
     else
     {
       camera.arc = min(camera.arc + time_step, 60);    // increase fiel of view
     }
     wait(1);
   } 
 }