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

#include "stdcycles.h"

shader node_refraction_bsdf(color Color = 0.8,
                            string distribution = "sharp",
                            float Roughness = 0.2,
                            float IOR = 1.45,
                            normal Normal = N,
                            output closure color BSDF = 0)
{
  float f = max(IOR, 1e-5);
  float eta = backfacing() ? 1.0 / f : f;
  float roughness = Roughness * Roughness;

  if (distribution == "sharp")
    BSDF = Color * refraction(Normal, eta);
  else if (distribution == "beckmann")
    BSDF = Color * microfacet_beckmann_refraction(Normal, roughness, eta);
  else if (distribution == "GGX")
    BSDF = Color * microfacet_ggx_refraction(Normal, roughness, eta);
}