/* 
 * Adapted from Open Shading Language with this license: 
 * 
 * Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al. 
 * All Rights Reserved. 
 * 
 * Modifications Copyright 2011, Blender Foundation. 
 *  
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are 
 * met: 
 * * Redistributions of source code must retain the above copyright 
 *   notice, this list of conditions and the following disclaimer. 
 * * Redistributions in binary form must reproduce the above copyright 
 *   notice, this list of conditions and the following disclaimer in the 
 *   documentation and/or other materials provided with the distribution. 
 * * Neither the name of Sony Pictures Imageworks nor the names of its 
 *   contributors may be used to endorse or promote products derived from 
 *   this software without specific prior written permission. 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
*/

#ifndef __BSDF_REFRACTION_H__
#define __BSDF_REFRACTION_H__

CCL_NAMESPACE_BEGIN

/* REFRACTION */

typedef struct BsdfRefractionClosure {
	float m_eta;
} BsdfRefractionClosure;

__device void bsdf_refraction_setup(ShaderData *sd, ShaderClosure *sc, float eta)
{
	sc->data0 = eta;

	sc->type = CLOSURE_BSDF_REFRACTION_ID;
	sd->flag |= SD_BSDF;
}

__device void bsdf_refraction_blur(ShaderClosure *sc, float roughness)
{
}

__device float3 bsdf_refraction_eval_reflect(const ShaderData *sd, const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
{
	return make_float3(0.0f, 0.0f, 0.0f);
}

__device float3 bsdf_refraction_eval_transmit(const ShaderData *sd, const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
{
	return make_float3(0.0f, 0.0f, 0.0f);
}

__device float bsdf_refraction_albedo(const ShaderData *sd, const ShaderClosure *sc, const float3 I)
{
	return 1.0f;
}

__device int bsdf_refraction_sample(const ShaderData *sd, const ShaderClosure *sc, float randu, float randv, float3 *eval, float3 *omega_in, float3 *domega_in_dx, float3 *domega_in_dy, float *pdf)
{
	float m_eta = sc->data0;
	float3 m_N = sd->N;

	float3 R, T;
#ifdef __RAY_DIFFERENTIALS__
	float3 dRdx, dRdy, dTdx, dTdy;
#endif
	bool inside;
	fresnel_dielectric(m_eta, m_N, sd->I, &R, &T,
#ifdef __RAY_DIFFERENTIALS__
		sd->dI.dx, sd->dI.dy, &dRdx, &dRdy, &dTdx, &dTdy,
#endif
		&inside);
	
	if(!inside) {
		*pdf = 1;
		*eval = make_float3(1.0f, 1.0f, 1.0f);
		*omega_in = T;
#ifdef __RAY_DIFFERENTIALS__
		*domega_in_dx = dTdx;
		*domega_in_dy = dTdy;
#endif
	}
	return LABEL_TRANSMIT|LABEL_SINGULAR;
}

CCL_NAMESPACE_END

#endif /* __BSDF_REFRACTION_H__ */

