// use a gun to produce mole-hills in terrain
function mole_gun()
{
  while (1)
  {
// calculate the target vector
    VECTOR trace_target;
    vec_set(trace_target,vector(5000,0,0)); // firing range 5000 quants
    vec_rotate(trace_target, camera.pan);
    vec_add(trace_target, camera.x);
    
// display a red spot at the target position
    if (c_trace(camera.x,trace_target, IGNORE_PASSABLE | USE_POLYGON| SCAN_TEXTURE) > 0) // hit something?
      draw_point3d(hit.x,vector(50,50,255),100,3);

    if (key_ctrl && HIT_TARGET && you && ent_type(you) == 4) // fire onto terrain
    {
// create a mole-hill by elevating the closest terrain vertex       var vertex_num = ent_nextvertex(you,hit.x); 
     CONTACT* contact = ent_getvertex(you,NULL,vertex_num); 
     c.z += 10;  // increase the vertex height
      c.v = NULL; // c.x,y,z was changed, instead of c.v      ent_setvertex(you,c,vertex_num);    // update the mesh
      wait(-0.5); // reload
    }

    wait(1); 
  }
}