diff options
Diffstat (limited to 'intern/cycles/kernel/svm/bsdf_ward.h')
| -rw-r--r-- | intern/cycles/kernel/svm/bsdf_ward.h | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/intern/cycles/kernel/svm/bsdf_ward.h b/intern/cycles/kernel/svm/bsdf_ward.h new file mode 100644 index 00000000000..bf591acc9fa --- /dev/null +++ b/intern/cycles/kernel/svm/bsdf_ward.h @@ -0,0 +1,202 @@ +/* + * 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_WARD_H__ +#define __BSDF_WARD_H__ + +CCL_NAMESPACE_BEGIN + +/* WARD */ + +typedef struct BsdfWardClosure { + //float3 m_N; + //float3 m_T; + float m_ax; + float m_ay; +} BsdfWardClosure; + +__device void bsdf_ward_setup(ShaderData *sd, float3 N, float3 T, float ax, float ay) +{ + BsdfWardClosure *self = (BsdfWardClosure*)sd->svm_closure_data; + + //self->m_N = N; + //self->m_T = T; + self->m_ax = clamp(ax, 1e-5f, 1.0f); + self->m_ay = clamp(ay, 1e-5f, 1.0f); + + sd->svm_closure = CLOSURE_BSDF_WARD_ID; + sd->flag |= SD_BSDF_HAS_EVAL|SD_BSDF_GLOSSY; +} + +__device void bsdf_ward_blur(ShaderData *sd, float roughness) +{ + BsdfWardClosure *self = (BsdfWardClosure*)sd->svm_closure_data; + + self->m_ax = fmaxf(roughness, self->m_ax); + self->m_ay = fmaxf(roughness, self->m_ay); +} + +__device float3 bsdf_ward_eval_reflect(const ShaderData *sd, const float3 I, const float3 omega_in, float *pdf) +{ + const BsdfWardClosure *self = (const BsdfWardClosure*)sd->svm_closure_data; + float3 m_N = sd->N; + float3 m_T = normalize(sd->dPdu); + + float cosNO = dot(m_N, I); + float cosNI = dot(m_N, omega_in); + if(cosNI > 0 && cosNO > 0) { + // get half vector and get x,y basis on the surface for anisotropy + float3 H = normalize(omega_in + I); // normalize needed for pdf + float3 X, Y; + make_orthonormals_tangent(m_N, m_T, &X, &Y); + // eq. 4 + float dotx = dot(H, X) / self->m_ax; + float doty = dot(H, Y) / self->m_ay; + float dotn = dot(H, m_N); + float exp_arg = (dotx * dotx + doty * doty) / (dotn * dotn); + float denom = (4 * M_PI_F * self->m_ax * self->m_ay * sqrtf(cosNO * cosNI)); + float exp_val = expf(-exp_arg); + float out = cosNI * exp_val / denom; + float oh = dot(H, I); + denom = 4 * M_PI_F * self->m_ax * self->m_ay * oh * dotn * dotn * dotn; + *pdf = exp_val / denom; + return make_float3 (out, out, out); + } + return make_float3 (0, 0, 0); +} + +__device float3 bsdf_ward_eval_transmit(const ShaderData *sd, const float3 I, const float3 omega_in, float *pdf) +{ + return make_float3(0.0f, 0.0f, 0.0f); +} + +__device float bsdf_ward_albedo(const ShaderData *sd, const float3 I) +{ + return 1.0f; +} + +__device int bsdf_ward_sample(const ShaderData *sd, float randu, float randv, float3 *eval, float3 *omega_in, float3 *domega_in_dx, float3 *domega_in_dy, float *pdf) +{ + const BsdfWardClosure *self = (const BsdfWardClosure*)sd->svm_closure_data; + float3 m_N = sd->N; + float3 m_T = normalize(sd->dPdu); + + float cosNO = dot(m_N, sd->I); + if(cosNO > 0) { + // get x,y basis on the surface for anisotropy + float3 X, Y; + make_orthonormals_tangent(m_N, m_T, &X, &Y); + // generate random angles for the half vector + // eq. 7 (taking care around discontinuities to keep + //ttoutput angle in the right quadrant) + // we take advantage of cos(atan(x)) == 1/sqrt(1+x^2) + //tttt and sin(atan(x)) == x/sqrt(1+x^2) + float alphaRatio = self->m_ay / self->m_ax; + float cosPhi, sinPhi; + if(randu < 0.25f) { + float val = 4 * randu; + float tanPhi = alphaRatio * tanf(M_PI_2_F * val); + cosPhi = 1 / sqrtf(1 + tanPhi * tanPhi); + sinPhi = tanPhi * cosPhi; + } else if(randu < 0.5f) { + float val = 1 - 4 * (0.5f - randu); + float tanPhi = alphaRatio * tanf(M_PI_2_F * val); + // phi = M_PI_F - phi; + cosPhi = -1 / sqrtf(1 + tanPhi * tanPhi); + sinPhi = -tanPhi * cosPhi; + } else if(randu < 0.75f) { + float val = 4 * (randu - 0.5f); + float tanPhi = alphaRatio * tanf(M_PI_2_F * val); + //phi = M_PI_F + phi; + cosPhi = -1 / sqrtf(1 + tanPhi * tanPhi); + sinPhi = tanPhi * cosPhi; + } else { + float val = 1 - 4 * (1 - randu); + float tanPhi = alphaRatio * tanf(M_PI_2_F * val); + // phi = 2 * M_PI_F - phi; + cosPhi = 1 / sqrtf(1 + tanPhi * tanPhi); + sinPhi = -tanPhi * cosPhi; + } + // eq. 6 + // we take advantage of cos(atan(x)) == 1/sqrt(1+x^2) + //tttt and sin(atan(x)) == x/sqrt(1+x^2) + float thetaDenom = (cosPhi * cosPhi) / (self->m_ax * self->m_ax) + (sinPhi * sinPhi) / (self->m_ay * self->m_ay); + float tanTheta2 = -logf(1 - randv) / thetaDenom; + float cosTheta = 1 / sqrtf(1 + tanTheta2); + float sinTheta = cosTheta * sqrtf(tanTheta2); + + float3 h; // already normalized becaused expressed from spherical coordinates + h.x = sinTheta * cosPhi; + h.y = sinTheta * sinPhi; + h.z = cosTheta; + // compute terms that are easier in local space + float dotx = h.x / self->m_ax; + float doty = h.y / self->m_ay; + float dotn = h.z; + // transform to world space + h = h.x * X + h.y * Y + h.z * m_N; + // generate the final sample + float oh = dot(h, sd->I); + omega_in->x = 2 * oh * h.x - sd->I.x; + omega_in->y = 2 * oh * h.y - sd->I.y; + omega_in->z = 2 * oh * h.z - sd->I.z; + if(dot(sd->Ng, *omega_in) > 0) { + float cosNI = dot(m_N, *omega_in); + if(cosNI > 0) { + // eq. 9 + float exp_arg = (dotx * dotx + doty * doty) / (dotn * dotn); + float denom = 4 * M_PI_F * self->m_ax * self->m_ay * oh * dotn * dotn * dotn; + *pdf = expf(-exp_arg) / denom; + // compiler will reuse expressions already computed + denom = (4 * M_PI_F * self->m_ax * self->m_ay * sqrtf(cosNO * cosNI)); + float power = cosNI * expf(-exp_arg) / denom; + *eval = make_float3(power, power, power); +#ifdef __RAY_DIFFERENTIALS__ + *domega_in_dx = (2 * dot(m_N, sd->dI.dx)) * m_N - sd->dI.dx; + *domega_in_dy = (2 * dot(m_N, sd->dI.dy)) * m_N - sd->dI.dy; + // Since there is some blur to this reflection, make the + // derivatives a bit bigger. In theory this varies with the + // roughness but the exact relationship is complex and + // requires more ops than are practical. + *domega_in_dx *= 10; + *domega_in_dy *= 10; +#endif + } + } + } + return LABEL_REFLECT|LABEL_GLOSSY; +} + +CCL_NAMESPACE_END + +#endif /* __BSDF_WARD_H__ */ + |