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Diffstat (limited to 'intern/cycles/kernel/osl/bsdf_ward.cpp')
| -rw-r--r-- | intern/cycles/kernel/osl/bsdf_ward.cpp | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/intern/cycles/kernel/osl/bsdf_ward.cpp b/intern/cycles/kernel/osl/bsdf_ward.cpp new file mode 100644 index 00000000000..a7742a04d13 --- /dev/null +++ b/intern/cycles/kernel/osl/bsdf_ward.cpp @@ -0,0 +1,222 @@ +/* + * 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. + */ + +#include <OpenImageIO/fmath.h> + +#include <OSL/genclosure.h> + +#include "osl_closures.h" + +#include "util_math.h" + +CCL_NAMESPACE_BEGIN + +using namespace OSL; + +// anisotropic ward - leaks energy at grazing angles +// see http://www.graphics.cornell.edu/~bjw/wardnotes.pdf +class WardClosure : public BSDFClosure { +public: + Vec3 m_N; + Vec3 m_T; + float m_ax, m_ay; + WardClosure() : BSDFClosure(Labels::GLOSSY) { } + + void setup() + { + m_ax = clamp(m_ax, 1e-5f, 1.0f); + m_ay = clamp(m_ay, 1e-5f, 1.0f); + } + + bool mergeable (const ClosurePrimitive *other) const { + const WardClosure *comp = (const WardClosure *)other; + return m_N == comp->m_N && m_T == comp->m_T && + m_ax == comp->m_ax && m_ay == comp->m_ay && + BSDFClosure::mergeable(other); + } + + size_t memsize () const { return sizeof(*this); } + + const char *name () const { return "ward"; } + + void print_on (std::ostream &out) const { + out << name() << " (("; + out << m_N[0] << ", " << m_N[1] << ", " << m_N[2] << "), ("; + out << m_T[0] << ", " << m_T[1] << ", " << m_T[2] << "), "; + out << m_ax << ", " << m_ay << ")"; + } + + float albedo (const Vec3 &omega_out) const + { + return 1.0f; + } + + Color3 eval_reflect (const Vec3 &omega_out, const Vec3 &omega_in, float& pdf) const + { + float cosNO = m_N.dot(omega_out); + float cosNI = m_N.dot(omega_in); + if (cosNI > 0 && cosNO > 0) { + // get half vector and get x,y basis on the surface for anisotropy + Vec3 H = omega_in + omega_out; + H.normalize(); // normalize needed for pdf + Vec3 X, Y; + make_orthonormals(m_N, m_T, X, Y); + // eq. 4 + float dotx = H.dot(X) / m_ax; + float doty = H.dot(Y) / m_ay; + float dotn = H.dot(m_N); + float exp_arg = (dotx * dotx + doty * doty) / (dotn * dotn); + float denom = (4 * (float) M_PI * m_ax * m_ay * sqrtf(cosNO * cosNI)); + float exp_val = expf(-exp_arg); + float out = cosNI * exp_val / denom; + float oh = H.dot(omega_out); + denom = 4 * (float) M_PI * m_ax * m_ay * oh * dotn * dotn * dotn; + pdf = exp_val / denom; + return Color3 (out, out, out); + } + return Color3 (0, 0, 0); + } + + Color3 eval_transmit (const Vec3 &omega_out, const Vec3 &omega_in, float& pdf) const + { + return Color3 (0, 0, 0); + } + + ustring sample (const Vec3 &Ng, + const Vec3 &omega_out, const Vec3 &domega_out_dx, const Vec3 &domega_out_dy, + float randu, float randv, + Vec3 &omega_in, Vec3 &domega_in_dx, Vec3 &domega_in_dy, + float &pdf, Color3 &eval) const + { + float cosNO = m_N.dot(omega_out); + if (cosNO > 0) { + // get x,y basis on the surface for anisotropy + Vec3 X, Y; + make_orthonormals(m_N, m_T, X, Y); + // generate random angles for the half vector + // eq. 7 (taking care around discontinuities to keep + // output angle in the right quadrant) + // we take advantage of cos(atan(x)) == 1/sqrt(1+x^2) + // and sin(atan(x)) == x/sqrt(1+x^2) + float alphaRatio = m_ay / m_ax; + float cosPhi, sinPhi; + if (randu < 0.25f) { + float val = 4 * randu; + float tanPhi = alphaRatio * tanf((float) M_PI_2 * val); + cosPhi = 1 / sqrtf(1 + tanPhi * tanPhi); + sinPhi = tanPhi * cosPhi; + } else if (randu < 0.5) { + float val = 1 - 4 * (0.5f - randu); + float tanPhi = alphaRatio * tanf((float) M_PI_2 * val); + // phi = (float) M_PI - 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((float) M_PI_2 * val); + //phi = (float) M_PI + phi; + cosPhi = -1 / sqrtf(1 + tanPhi * tanPhi); + sinPhi = tanPhi * cosPhi; + } else { + float val = 1 - 4 * (1 - randu); + float tanPhi = alphaRatio * tanf((float) M_PI_2 * val); + // phi = 2 * (float) M_PI - phi; + cosPhi = 1 / sqrtf(1 + tanPhi * tanPhi); + sinPhi = -tanPhi * cosPhi; + } + // eq. 6 + // we take advantage of cos(atan(x)) == 1/sqrt(1+x^2) + // and sin(atan(x)) == x/sqrt(1+x^2) + float thetaDenom = (cosPhi * cosPhi) / (m_ax * m_ax) + (sinPhi * sinPhi) / (m_ay * m_ay); + float tanTheta2 = -logf(1 - randv) / thetaDenom; + float cosTheta = 1 / sqrtf(1 + tanTheta2); + float sinTheta = cosTheta * sqrtf(tanTheta2); + + Vec3 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 / m_ax; + float doty = h.y / 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 = h.dot(omega_out); + omega_in.x = 2 * oh * h.x - omega_out.x; + omega_in.y = 2 * oh * h.y - omega_out.y; + omega_in.z = 2 * oh * h.z - omega_out.z; + if (Ng.dot(omega_in) > 0) { + float cosNI = m_N.dot(omega_in); + if (cosNI > 0) { + // eq. 9 + float exp_arg = (dotx * dotx + doty * doty) / (dotn * dotn); + float denom = 4 * (float) M_PI * m_ax * m_ay * oh * dotn * dotn * dotn; + pdf = expf(-exp_arg) / denom; + // compiler will reuse expressions already computed + denom = (4 * (float) M_PI * m_ax * m_ay * sqrtf(cosNO * cosNI)); + float power = cosNI * expf(-exp_arg) / denom; + eval.setValue(power, power, power); + domega_in_dx = (2 * m_N.dot(domega_out_dx)) * m_N - domega_out_dx; + domega_in_dy = (2 * m_N.dot(domega_out_dy)) * m_N - domega_out_dy; + + /* disabled for now - gives texture filtering problems */ +#if 0 + // 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 Labels::REFLECT; + } +}; + + + +ClosureParam bsdf_ward_params[] = { + CLOSURE_VECTOR_PARAM(WardClosure, m_N), + CLOSURE_VECTOR_PARAM(WardClosure, m_T), + CLOSURE_FLOAT_PARAM (WardClosure, m_ax), + CLOSURE_FLOAT_PARAM (WardClosure, m_ay), + CLOSURE_STRING_KEYPARAM("label"), + CLOSURE_FINISH_PARAM(WardClosure) }; + +CLOSURE_PREPARE(bsdf_ward_prepare, WardClosure) + +CCL_NAMESPACE_END + |