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

#include "stdcycles.h"

shader node_geometry(string bump_offset = "center",

                     output point Position = point(0.0, 0.0, 0.0),
                     output normal Normal = normal(0.0, 0.0, 0.0),
                     output normal Tangent = normal(0.0, 0.0, 0.0),
                     output normal TrueNormal = normal(0.0, 0.0, 0.0),
                     output vector Incoming = vector(0.0, 0.0, 0.0),
                     output point Parametric = point(0.0, 0.0, 0.0),
                     output float Backfacing = 0.0,
                     output float Pointiness = 0.0,
                     output float RandomPerIsland = 0.0)
{
  Position = P;
  Normal = N;
  TrueNormal = Ng;
  Incoming = I;
  Parametric = point(1.0 - u - v, u, 0.0);
  Backfacing = backfacing();

  if (bump_offset == "dx") {
    Position += Dx(Position);
    Parametric += Dx(Parametric);
  }
  else if (bump_offset == "dy") {
    Position += Dy(Position);
    Parametric += Dy(Parametric);
  }

  /* first try to get tangent attribute */
  point generated;

  /* try to create spherical tangent from generated coordinates */
  if (getattribute("geom:generated", generated)) {
    normal data = normal(-(generated[1] - 0.5), (generated[0] - 0.5), 0.0);
    vector T = transform("object", "world", data);
    Tangent = cross(Normal, normalize(cross(T, Normal)));
  }
  else {
    /* otherwise use surface derivatives */
    Tangent = normalize(dPdu);
  }

  getattribute("geom:pointiness", Pointiness);
  if (bump_offset == "dx") {
    Pointiness += Dx(Pointiness);
  }
  else if (bump_offset == "dy") {
    Pointiness += Dy(Pointiness);
  }

  getattribute("geom:random_per_island", RandomPerIsland);
}