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/* SPDX-License-Identifier: BSD-3-Clause
*
* Adapted from Open Shading Language
* Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
* All Rights Reserved.
*
* Modifications Copyright 2011-2022 Blender Foundation. */
#pragma once
#include "kernel/sample/mapping.h"
#include "kernel/util/color.h"
CCL_NAMESPACE_BEGIN
#ifdef __OSL__
typedef struct DiffuseRampBsdf {
SHADER_CLOSURE_BASE;
ccl_private float3 *colors;
} DiffuseRampBsdf;
static_assert(sizeof(ShaderClosure) >= sizeof(DiffuseRampBsdf), "DiffuseRampBsdf is too large!");
ccl_device float3 bsdf_diffuse_ramp_get_color(const float3 colors[8], float pos)
{
int MAXCOLORS = 8;
float npos = pos * (float)(MAXCOLORS - 1);
int ipos = float_to_int(npos);
if (ipos < 0)
return colors[0];
if (ipos >= (MAXCOLORS - 1))
return colors[MAXCOLORS - 1];
float offset = npos - (float)ipos;
return colors[ipos] * (1.0f - offset) + colors[ipos + 1] * offset;
}
ccl_device int bsdf_diffuse_ramp_setup(DiffuseRampBsdf *bsdf)
{
bsdf->type = CLOSURE_BSDF_DIFFUSE_RAMP_ID;
return SD_BSDF | SD_BSDF_HAS_EVAL;
}
ccl_device void bsdf_diffuse_ramp_blur(ccl_private ShaderClosure *sc, float roughness)
{
}
ccl_device Spectrum bsdf_diffuse_ramp_eval_reflect(ccl_private const ShaderClosure *sc,
const float3 I,
const float3 omega_in,
ccl_private float *pdf)
{
const DiffuseRampBsdf *bsdf = (const DiffuseRampBsdf *)sc;
float3 N = bsdf->N;
float cos_pi = fmaxf(dot(N, omega_in), 0.0f);
*pdf = cos_pi * M_1_PI_F;
return rgb_to_spectrum(bsdf_diffuse_ramp_get_color(bsdf->colors, cos_pi) * M_1_PI_F);
}
ccl_device Spectrum bsdf_diffuse_ramp_eval_transmit(ccl_private const ShaderClosure *sc,
const float3 I,
const float3 omega_in,
ccl_private float *pdf)
{
return zero_spectrum();
}
ccl_device int bsdf_diffuse_ramp_sample(ccl_private const ShaderClosure *sc,
float3 Ng,
float3 I,
float randu,
float randv,
ccl_private Spectrum *eval,
ccl_private float3 *omega_in,
ccl_private float *pdf)
{
const DiffuseRampBsdf *bsdf = (const DiffuseRampBsdf *)sc;
float3 N = bsdf->N;
// distribution over the hemisphere
sample_cos_hemisphere(N, randu, randv, omega_in, pdf);
if (dot(Ng, *omega_in) > 0.0f) {
*eval = rgb_to_spectrum(bsdf_diffuse_ramp_get_color(bsdf->colors, *pdf * M_PI_F) * M_1_PI_F);
}
else {
*pdf = 0.0f;
*eval = zero_spectrum();
}
return LABEL_REFLECT | LABEL_DIFFUSE;
}
#endif /* __OSL__ */
CCL_NAMESPACE_END
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