(defun project-with-perspective (&key (field-of-view *field-of-view*) (depth *z-far*))
  (gl:enable :depth-test)
  (gl:clear-depth 1.0)
  (gl:clear :color-buffer-bit)
  (gl:enable :texture-2d :blend)
  (set-blending-mode :alpha)
  (gl:matrix-mode :projection)
  (gl:load-identity)
  (glu:perspective field-of-view (/ *gl-screen-width* *gl-screen-height*) *z-near* depth)
  (gl:hint :perspective-correction-hint :nicest))