/*
  To render box { <0,0,0> <1,1,0> }:
    Render_Plane(<0.5,0.5,0>, <1,0,0>, <0,1,0>)

  To render box { <-10,-1,-1> <-10,1,1> }:
    Render_Plane(<-10,0,0> <0,0,2> <0,2,0>)

  You might need to turn off the vista buffer for a non-perpendicular camera.
*/

#macro Render_Plane(plane_center, plane_right, plane_up)
  #local plane_out = vnormalize(vcross(plane_right, plane_up));

  Render_Plane_From(plane_center + plane_out,
    plane_center, plane_right, plane_up)
#end

#macro Render_Plane_From(cam_loc, plane_center, plane_right, plane_up)
  camera {
    location  cam_loc
    direction plane_center - cam_loc
    right     plane_right
    up        plane_up
  }
#end