generate_random_vao   xtlang

(bind-func generate_random_vao
  (lambda (tris)
    (let ((num (* 3 tris))
          (verts:float* (alloc (* 4 num)))
          (normals:float* (alloc (* 3 num)))
          (uvws:float* (alloc (* 3 num)))
          (colours:float* (alloc (* 4 num)))
          (vbo_verts (VBO verts (* 4 num)))
          (vbo_normals (VBO normals (* 3 num)))
          (vbo_uvws (VBO uvws (* 3 num)))
          (vbo_colours (VBO colours (* 4 num)))
          (i 0) (j 0) (k 0))
      ;; random verts
      (dotimes (i num)
        (set! j (* i 4))
        (set! k (* i 3))
        (pset! verts (+ j 0) (- (* (random) 4.0) 2.0))
        (pset! verts (+ j 1) (- (* (random) 4.0) 2.0))
        (pset! verts (+ j 2) (- (* (random) 2.0) 1.0))
        (pset! verts (+ j 3) 1.0))
      ;; generate normals
      (generate_tri_normals verts (* 4 num) normals (* 3 num))
      ;; generate uvws
      (generate_tri_uvws uvws (* 3 num))
      ;; white colour
      (dotimes (i (* 4 num)) (pset! colours i 1.0))
      (set_attribute testVAO vbo_verts 0 4)
      (set_attribute testVAO vbo_normals 1 3)
      (set_attribute testVAO vbo_uvws 2 3)
      (set_attribute testVAO vbo_colours 3 4)
      (update vbo_verts)
      (update vbo_normals)
      (update vbo_uvws)
      (update vbo_colours)
      void)))