forked from bartvdbraak/blender
107 lines
3.1 KiB
C
107 lines
3.1 KiB
C
/*
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* Copyright 2011, Blender Foundation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#ifndef __BSDF_OREN_NAYAR_H__
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#define __BSDF_OREN_NAYAR_H__
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CCL_NAMESPACE_BEGIN
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typedef struct BsdfOrenNayarClosure {
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float m_a;
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float m_b;
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} BsdfOrenNayarClosure;
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__device float3 bsdf_oren_nayar_get_intensity(const ShaderClosure *sc, float3 n, float3 v, float3 l)
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{
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float nl = max(dot(n, l), 0.0f);
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float nv = max(dot(n, v), 0.0f);
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float t = dot(l, v) - nl * nv;
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if (t > 0.0f)
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t /= max(nl, nv) + FLT_MIN;
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float is = nl * (sc->data0 + sc->data1 * t);
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return make_float3(is, is, is);
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}
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__device void bsdf_oren_nayar_setup(ShaderData *sd, ShaderClosure *sc, float sigma)
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{
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sc->type = CLOSURE_BSDF_OREN_NAYAR_ID;
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sd->flag |= SD_BSDF | SD_BSDF_HAS_EVAL;
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sigma = clamp(sigma, 0.0f, 1.0f);
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float div = 1.0f / (M_PI_F + ((3.0f * M_PI_F - 4.0f) / 6.0f) * sigma);
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sc->data0 = 1.0f * div;
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sc->data1 = sigma * div;
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}
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__device void bsdf_oren_nayar_blur(ShaderClosure *sc, float roughness)
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{
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}
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__device float3 bsdf_oren_nayar_eval_reflect(const ShaderData *sd, const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
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{
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if (dot(sd->N, omega_in) > 0.0f) {
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*pdf = 0.5f * M_1_PI_F;
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return bsdf_oren_nayar_get_intensity(sc, sd->N, I, omega_in);
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}
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else {
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*pdf = 0.0f;
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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}
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__device float3 bsdf_oren_nayar_eval_transmit(const ShaderData *sd, const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
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{
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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__device float bsdf_oren_nayar_albedo(const ShaderData *sd, const ShaderClosure *sc, const float3 I)
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{
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return 1.0f;
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}
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__device int bsdf_oren_nayar_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)
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{
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sample_uniform_hemisphere(sd->N, randu, randv, omega_in, pdf);
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if (dot(sd->Ng, *omega_in) > 0.0f) {
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*eval = bsdf_oren_nayar_get_intensity(sc, sd->N, sd->I, *omega_in);
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#ifdef __RAY_DIFFERENTIALS__
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// TODO: find a better approximation for the bounce
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*domega_in_dx = (2.0f * dot(sd->N, sd->dI.dx)) * sd->N - sd->dI.dx;
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*domega_in_dy = (2.0f * dot(sd->N, sd->dI.dy)) * sd->N - sd->dI.dy;
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*domega_in_dx *= 125.0f;
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*domega_in_dy *= 125.0f;
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#endif
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}
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else {
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*pdf = 0.0f;
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*eval = make_float3(0.0f, 0.0f, 0.0f);
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}
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return LABEL_REFLECT | LABEL_DIFFUSE;
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}
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CCL_NAMESPACE_END
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#endif /* __BSDF_OREN_NAYAR_H__ */
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