/* SPDX-License-Identifier: Apache-2.0
 * Copyright 2011-2022 Blender Foundation */

#include "oslutil.h"
#include "stdcycles.h"

shader node_wireframe(string bump_offset = "center",
                      int use_pixel_size = 0,
                      float Size = 0.01,
                      output float Fac = 0.0)
{
  Fac = wireframe("triangles", Size, use_pixel_size);
  /* TODO(sergey): Since we can't use autodiff here we do algebraic
   * calculation of derivatives by definition. We could probably
   * optimize this a bit by doing some extra calculation in wireframe().
   */
  if (bump_offset == "dx") {
    point dx = Dx(P);
    P -= dx;
    Fac += (Fac - wireframe("triangles", Size, use_pixel_size)) / length(dx);
  }
  else if (bump_offset == "dy") {
    point dy = Dy(P);
    P -= dy;
    Fac += (Fac - wireframe("triangles", Size, use_pixel_size)) / length(dy);
  }
}