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Diffstat (limited to 'intern/cycles/kernel/closure/bsdf_ashikhmin_velvet.h')
| -rw-r--r-- | intern/cycles/kernel/closure/bsdf_ashikhmin_velvet.h | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/intern/cycles/kernel/closure/bsdf_ashikhmin_velvet.h b/intern/cycles/kernel/closure/bsdf_ashikhmin_velvet.h new file mode 100644 index 00000000000..016fd73204e --- /dev/null +++ b/intern/cycles/kernel/closure/bsdf_ashikhmin_velvet.h @@ -0,0 +1,153 @@ +/* + * 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_ASHIKHMIN_VELVET_H__ +#define __BSDF_ASHIKHMIN_VELVET_H__ + +CCL_NAMESPACE_BEGIN + +__device int bsdf_ashikhmin_velvet_setup(ShaderClosure *sc) +{ + float sigma = sc->data0; + sigma = fmaxf(sigma, 0.01f); + + float m_invsigma2 = 1.0f/(sigma * sigma); + + sc->type = CLOSURE_BSDF_ASHIKHMIN_VELVET_ID; + sc->data0 = m_invsigma2; + + return SD_BSDF|SD_BSDF_HAS_EVAL; +} + +__device void bsdf_ashikhmin_velvet_blur(ShaderClosure *sc, float roughness) +{ +} + +__device float3 bsdf_ashikhmin_velvet_eval_reflect(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf) +{ + float m_invsigma2 = sc->data0; + float3 N = sc->N; + + float cosNO = dot(N, I); + float cosNI = dot(N, omega_in); + if(cosNO > 0 && cosNI > 0) { + float3 H = normalize(omega_in + I); + + float cosNH = dot(N, H); + float cosHO = fabsf(dot(I, H)); + + if(!(fabsf(cosNH) < 1.0f-1e-5f && cosHO > 1e-5f)) + return make_float3(0, 0, 0); + + float cosNHdivHO = cosNH / cosHO; + cosNHdivHO = fmaxf(cosNHdivHO, 1e-5f); + + float fac1 = 2 * fabsf(cosNHdivHO * cosNO); + float fac2 = 2 * fabsf(cosNHdivHO * cosNI); + + float sinNH2 = 1 - cosNH * cosNH; + float sinNH4 = sinNH2 * sinNH2; + float cotangent2 = (cosNH * cosNH) / sinNH2; + + float D = expf(-cotangent2 * m_invsigma2) * m_invsigma2 * M_1_PI_F / sinNH4; + float G = min(1.0f, min(fac1, fac2)); // TODO: derive G from D analytically + + float out = 0.25f * (D * G) / cosNO; + + *pdf = 0.5f * M_1_PI_F; + return make_float3(out, out, out); + } + + return make_float3(0, 0, 0); +} + +__device float3 bsdf_ashikhmin_velvet_eval_transmit(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf) +{ + return make_float3(0.0f, 0.0f, 0.0f); +} + +__device int bsdf_ashikhmin_velvet_sample(const ShaderClosure *sc, float3 Ng, float3 I, float3 dIdx, float3 dIdy, float randu, float randv, float3 *eval, float3 *omega_in, float3 *domega_in_dx, float3 *domega_in_dy, float *pdf) +{ + float m_invsigma2 = sc->data0; + float3 N = sc->N; + + // we are viewing the surface from above - send a ray out with uniform + // distribution over the hemisphere + sample_uniform_hemisphere(N, randu, randv, omega_in, pdf); + + if(dot(Ng, *omega_in) > 0) { + float3 H = normalize(*omega_in + I); + + float cosNI = dot(N, *omega_in); + float cosNO = dot(N, I); + float cosNH = dot(N, H); + float cosHO = fabsf(dot(I, H)); + + if(fabsf(cosNO) > 1e-5f && fabsf(cosNH) < 1.0f-1e-5f && cosHO > 1e-5f) { + float cosNHdivHO = cosNH / cosHO; + cosNHdivHO = fmaxf(cosNHdivHO, 1e-5f); + + float fac1 = 2 * fabsf(cosNHdivHO * cosNO); + float fac2 = 2 * fabsf(cosNHdivHO * cosNI); + + float sinNH2 = 1 - cosNH * cosNH; + float sinNH4 = sinNH2 * sinNH2; + float cotangent2 = (cosNH * cosNH) / sinNH2; + + float D = expf(-cotangent2 * m_invsigma2) * m_invsigma2 * M_1_PI_F / sinNH4; + float G = min(1.0f, min(fac1, fac2)); // TODO: derive G from D analytically + + float power = 0.25f * (D * G) / cosNO; + + *eval = make_float3(power, power, power); + +#ifdef __RAY_DIFFERENTIALS__ + // TODO: find a better approximation for the retroreflective bounce + *domega_in_dx = (2 * dot(N, dIdx)) * N - dIdx; + *domega_in_dy = (2 * dot(N, dIdy)) * N - dIdy; + *domega_in_dx *= 125.0f; + *domega_in_dy *= 125.0f; +#endif + } + else + *pdf = 0.0f; + } + else + *pdf = 0.0f; + + return LABEL_REFLECT|LABEL_DIFFUSE; +} + +CCL_NAMESPACE_END + +#endif /* __BSDF_ASHIKHMIN_VELVET_H__ */ + |