125 lines
4.0 KiB
C
125 lines
4.0 KiB
C
/* SPDX-FileCopyrightText: 2009-2010 Sony Pictures Imageworks Inc., et al. All Rights Reserved.
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* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Adapted code from Open Shading Language. */
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#pragma once
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#include "kernel/util/color.h"
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CCL_NAMESPACE_BEGIN
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#ifdef __OSL__
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typedef struct PhongRampBsdf {
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SHADER_CLOSURE_BASE;
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float exponent;
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ccl_private float3 *colors;
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} PhongRampBsdf;
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static_assert(sizeof(ShaderClosure) >= sizeof(PhongRampBsdf), "PhongRampBsdf is too large!");
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ccl_device float3 bsdf_phong_ramp_get_color(const float3 colors[8], float pos)
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{
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int MAXCOLORS = 8;
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float npos = pos * (float)(MAXCOLORS - 1);
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int ipos = float_to_int(npos);
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if (ipos < 0)
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return colors[0];
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if (ipos >= (MAXCOLORS - 1))
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return colors[MAXCOLORS - 1];
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float offset = npos - (float)ipos;
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return colors[ipos] * (1.0f - offset) + colors[ipos + 1] * offset;
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}
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ccl_device int bsdf_phong_ramp_setup(ccl_private PhongRampBsdf *bsdf)
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{
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bsdf->type = CLOSURE_BSDF_PHONG_RAMP_ID;
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bsdf->exponent = max(bsdf->exponent, 0.0f);
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return SD_BSDF | SD_BSDF_HAS_EVAL;
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}
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ccl_device Spectrum bsdf_phong_ramp_eval(ccl_private const ShaderClosure *sc,
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const float3 wi,
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const float3 wo,
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ccl_private float *pdf)
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{
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ccl_private const PhongRampBsdf *bsdf = (ccl_private const PhongRampBsdf *)sc;
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float m_exponent = bsdf->exponent;
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float cosNI = dot(bsdf->N, wi);
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float cosNO = dot(bsdf->N, wo);
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if (cosNI > 0 && cosNO > 0) {
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// reflect the view vector
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float3 R = (2 * cosNI) * bsdf->N - wi;
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float cosRO = dot(R, wo);
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if (cosRO > 0) {
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float cosp = powf(cosRO, m_exponent);
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float common = 0.5f * M_1_PI_F * cosp;
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float out = cosNO * (m_exponent + 2) * common;
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*pdf = (m_exponent + 1) * common;
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return rgb_to_spectrum(bsdf_phong_ramp_get_color(bsdf->colors, cosp) * out);
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}
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}
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*pdf = 0.0f;
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return zero_spectrum();
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}
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ccl_device_inline float phong_ramp_exponent_to_roughness(float exponent)
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{
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return sqrt(1.0f / ((exponent + 2.0f) / 2.0f));
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}
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ccl_device int bsdf_phong_ramp_sample(ccl_private const ShaderClosure *sc,
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float3 Ng,
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float3 wi,
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const float2 rand,
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ccl_private Spectrum *eval,
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ccl_private float3 *wo,
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ccl_private float *pdf,
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ccl_private float2 *sampled_roughness)
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{
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ccl_private const PhongRampBsdf *bsdf = (ccl_private const PhongRampBsdf *)sc;
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float cosNI = dot(bsdf->N, wi);
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float m_exponent = bsdf->exponent;
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const float m_roughness = phong_ramp_exponent_to_roughness(m_exponent);
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*sampled_roughness = make_float2(m_roughness, m_roughness);
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if (cosNI > 0) {
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// reflect the view vector
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float3 R = (2 * cosNI) * bsdf->N - wi;
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float3 T, B;
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make_orthonormals(R, &T, &B);
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float phi = M_2PI_F * rand.x;
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float cosTheta = powf(rand.y, 1 / (m_exponent + 1));
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float sinTheta2 = 1 - cosTheta * cosTheta;
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float sinTheta = sinTheta2 > 0 ? sqrtf(sinTheta2) : 0;
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*wo = (cosf(phi) * sinTheta) * T + (sinf(phi) * sinTheta) * B + (cosTheta)*R;
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if (dot(Ng, *wo) > 0.0f) {
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// common terms for pdf and eval
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float cosNO = dot(bsdf->N, *wo);
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// make sure the direction we chose is still in the right hemisphere
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if (cosNO > 0) {
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float cosp = powf(cosTheta, m_exponent);
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float common = 0.5f * M_1_PI_F * cosp;
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*pdf = (m_exponent + 1) * common;
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float out = cosNO * (m_exponent + 2) * common;
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*eval = rgb_to_spectrum(bsdf_phong_ramp_get_color(bsdf->colors, cosp) * out);
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}
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}
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}
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else {
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*eval = zero_spectrum();
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*pdf = 0.0f;
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}
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return LABEL_REFLECT | LABEL_GLOSSY;
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}
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#endif /* __OSL__ */
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CCL_NAMESPACE_END
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