;; this file:
;;   https://dataswamp.org/~incal/common-lisp/general-base/triangle.lisp

(defun draw-triangle (x1 y1 z1 x2 y2 z2 x3 y3 z3)
  (gl:with-primitive :triangles
    (gl:vertex x1 y1 z1)
    (gl:vertex x2 y2 z2)
    (gl:vertex x3 y3 z3) ))

(defun draw-triangle-test (&optional (num 3) (limit 2.0))
  (dotimes (_ num)
    (random-color)
    (draw-triangle
      ;; x1 y1 z1
      (random-limit limit)
      (random-limit limit)
      (random-limit limit)
      ;; x2 y2 z2
      (random-limit limit)
      (random-limit limit)
      (random-limit limit)
      ;; x3 y3 z3
      (random-limit limit)
      (random-limit limit)
      (random-limit limit) )))