//  Camera placement for the MP logo
//  Last edited on 2010-03-31 11:54:18 by stolfi

#macro put_camera(focus,wd,ht,dir,dist,upp)
  //    focus =  point of interest in scene.
  //    wd =     nominal width of scene around {focus}.
  //    ht =     nominal height of scene around {focus}.
  //    dir =    direction of camera from {focus} (length is immaterial).
  //    dist =   distance from focus along {dir}.
  //    upp =    sky direction.
  
  // If {dist = 0} the camera is 

  #local udir = vnormalize(dir);
  #local pos = focus + dist * udir;

  #local slop = 1.10;

  #if (wd/image_width > ht/image_height)
    #local cwd = wd/dist;
    #local cht = cwd*image_height/image_width;
  #else
    #local cht = ht/dist;
    #local cwd = cht*image_width/image_height;
  #end

  camera {
    location  pos
    right     - slop * cwd * x
    up        + slop * cht * y
    sky       upp
    look_at   focus
  } 
#end