forked from bartvdbraak/blender
3f7b4916e9
* Added the Phong BRDF from the inbuilt OSL shader library. This can be used in OSL shaders only for now: * phong(normal N, float exponent) * phong_ramp(normal N, float exponent, color colors[8]
278 lines
10 KiB
C++
278 lines
10 KiB
C++
/*
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* Adapted from Open Shading Language with this license:
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*
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* Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
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* All Rights Reserved.
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*
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* Modifications Copyright 2012, Blender Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Sony Pictures Imageworks nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <OpenImageIO/fmath.h>
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#include <OSL/genclosure.h>
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#include "osl_closures.h"
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#include "util_math.h"
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CCL_NAMESPACE_BEGIN
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using namespace OSL;
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// vanilla phong - leaks energy at grazing angles
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// see Global Illumination Compendium entry (66)
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class PhongClosure : public BSDFClosure {
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public:
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Vec3 m_N;
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float m_exponent;
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PhongClosure() : BSDFClosure(Labels::GLOSSY) { }
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void setup() {};
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bool mergeable (const ClosurePrimitive *other) const {
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const PhongClosure *comp = (const PhongClosure *)other;
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return m_N == comp->m_N && m_exponent == comp->m_exponent &&
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BSDFClosure::mergeable(other);
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}
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size_t memsize () const { return sizeof(*this); }
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const char *name () const { return "phong"; }
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void print_on (std::ostream &out) const {
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out << name() << " ((";
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out << m_N[0] << ", " << m_N[1] << ", " << m_N[2] << "), ";
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out << m_exponent << ")";
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}
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float albedo (const Vec3 &omega_out) const
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{
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return 1.0f;
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}
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Color3 eval_reflect (const Vec3 &omega_out, const Vec3 &omega_in, float& pdf) const
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{
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float cosNI = m_N.dot(omega_in);
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float cosNO = m_N.dot(omega_out);
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if (cosNI > 0 && cosNO > 0) {
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// reflect the view vector
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Vec3 R = (2 * cosNO) * m_N - omega_out;
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float cosRI = R.dot(omega_in);
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if (cosRI > 0) {
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float common = 0.5f * (float) M_1_PI * powf(cosRI, m_exponent);
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float out = cosNI * (m_exponent + 2) * common;
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pdf = (m_exponent + 1) * common;
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return Color3 (out, out, out);
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}
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}
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return Color3 (0, 0, 0);
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}
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Color3 eval_transmit (const Vec3 &omega_out, const Vec3 &omega_in, float& pdf) const
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{
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return Color3 (0, 0, 0);
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}
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ustring sample (const Vec3 &Ng,
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const Vec3 &omega_out, const Vec3 &domega_out_dx, const Vec3 &domega_out_dy,
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float randu, float randv,
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Vec3 &omega_in, Vec3 &domega_in_dx, Vec3 &domega_in_dy,
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float &pdf, Color3 &eval) const
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{
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float cosNO = m_N.dot(omega_out);
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if (cosNO > 0) {
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// reflect the view vector
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Vec3 R = (2 * cosNO) * m_N - omega_out;
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domega_in_dx = (2 * m_N.dot(domega_out_dx)) * m_N - domega_out_dx;
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domega_in_dy = (2 * m_N.dot(domega_out_dy)) * m_N - domega_out_dy;
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Vec3 T, B;
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make_orthonormals (R, T, B);
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float phi = 2 * (float) M_PI * randu;
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float cosTheta = powf(randv, 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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omega_in = (cosf(phi) * sinTheta) * T +
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(sinf(phi) * sinTheta) * B +
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( cosTheta) * R;
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if (Ng.dot(omega_in) > 0)
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{
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// common terms for pdf and eval
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float cosNI = m_N.dot(omega_in);
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// make sure the direction we chose is still in the right hemisphere
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if (cosNI > 0)
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{
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float common = 0.5f * (float) M_1_PI * powf(cosTheta, m_exponent);
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pdf = (m_exponent + 1) * common;
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float out = cosNI * (m_exponent + 2) * common;
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eval.setValue(out, out, out);
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// Since there is some blur to this reflection, make the
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// derivatives a bit bigger. In theory this varies with the
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// exponent but the exact relationship is complex and
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// requires more ops than are practical.
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domega_in_dx *= 10;
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domega_in_dy *= 10;
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}
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}
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}
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return Labels::REFLECT;
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}
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};
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class PhongRampClosure : public BSDFClosure {
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public:
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static const int MAXCOLORS = 8;
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Vec3 m_N;
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float m_exponent;
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Color3 m_colors[MAXCOLORS];
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PhongRampClosure() : BSDFClosure(Labels::GLOSSY) { }
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void setup() {};
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bool mergeable (const ClosurePrimitive *other) const {
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const PhongRampClosure *comp = (const PhongRampClosure *)other;
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if (! (m_N == comp->m_N && m_exponent == comp->m_exponent &&
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BSDFClosure::mergeable(other)))
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return false;
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for (int i = 0; i < MAXCOLORS; ++i)
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if (m_colors[i] != comp->m_colors[i])
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return false;
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return true;
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}
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size_t memsize () const { return sizeof(*this); }
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const char *name () const { return "phong_ramp"; }
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void print_on (std::ostream &out) const {
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out << name() << " ((";
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out << m_N[0] << ", " << m_N[1] << ", " << m_N[2] << "), ";
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out << m_exponent << ")";
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}
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Color3 get_color (float pos) const
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{
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float npos = pos * (float)(MAXCOLORS - 1);
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int ipos = (int)npos;
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if (ipos >= (MAXCOLORS - 1))
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return m_colors[MAXCOLORS - 1];
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float offset = npos - (float)ipos;
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return m_colors[ipos] * (1.0f - offset) + m_colors[ipos+1] * offset;
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}
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float albedo (const Vec3 &omega_out) const
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{
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return 1.0f;
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}
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Color3 eval_reflect (const Vec3 &omega_out, const Vec3 &omega_in, float& pdf) const
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{
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float cosNI = m_N.dot(omega_in);
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float cosNO = m_N.dot(omega_out);
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if (cosNI > 0 && cosNO > 0) {
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// reflect the view vector
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Vec3 R = (2 * cosNO) * m_N - omega_out;
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float cosRI = R.dot(omega_in);
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if (cosRI > 0) {
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float cosp = powf(cosRI, m_exponent);
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float common = 0.5f * (float) M_1_PI * cosp;
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float out = cosNI * (m_exponent + 2) * common;
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pdf = (m_exponent + 1) * common;
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return get_color(cosp) * out;
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}
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}
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return Color3 (0, 0, 0);
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}
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Color3 eval_transmit (const Vec3 &omega_out, const Vec3 &omega_in, float& pdf) const
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{
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return Color3 (0, 0, 0);
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}
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ustring sample (const Vec3 &Ng,
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const Vec3 &omega_out, const Vec3 &domega_out_dx, const Vec3 &domega_out_dy,
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float randu, float randv,
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Vec3 &omega_in, Vec3 &domega_in_dx, Vec3 &domega_in_dy,
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float &pdf, Color3 &eval) const
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{
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float cosNO = m_N.dot(omega_out);
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if (cosNO > 0) {
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// reflect the view vector
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Vec3 R = (2 * cosNO) * m_N - omega_out;
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domega_in_dx = (2 * m_N.dot(domega_out_dx)) * m_N - domega_out_dx;
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domega_in_dy = (2 * m_N.dot(domega_out_dy)) * m_N - domega_out_dy;
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Vec3 T, B;
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make_orthonormals (R, T, B);
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float phi = 2 * (float) M_PI * randu;
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float cosTheta = powf(randv, 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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omega_in = (cosf(phi) * sinTheta) * T +
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(sinf(phi) * sinTheta) * B +
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( cosTheta) * R;
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if (Ng.dot(omega_in) > 0)
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{
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// common terms for pdf and eval
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float cosNI = m_N.dot(omega_in);
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// make sure the direction we chose is still in the right hemisphere
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if (cosNI > 0)
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{
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float cosp = powf(cosTheta, m_exponent);
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float common = 0.5f * (float) M_1_PI * cosp;
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pdf = (m_exponent + 1) * common;
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float out = cosNI * (m_exponent + 2) * common;
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eval = get_color(cosp) * out;
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// Since there is some blur to this reflection, make the
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// derivatives a bit bigger. In theory this varies with the
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// exponent but the exact relationship is complex and
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// requires more ops than are practical.
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domega_in_dx *= 10;
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domega_in_dy *= 10;
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}
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}
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}
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return Labels::REFLECT;
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}
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};
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ClosureParam bsdf_phong_params[] = {
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CLOSURE_VECTOR_PARAM(PhongClosure, m_N),
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CLOSURE_FLOAT_PARAM (PhongClosure, m_exponent),
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CLOSURE_STRING_KEYPARAM("label"),
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CLOSURE_FINISH_PARAM(PhongClosure) };
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ClosureParam bsdf_phong_ramp_params[] = {
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CLOSURE_VECTOR_PARAM (PhongRampClosure, m_N),
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CLOSURE_FLOAT_PARAM (PhongRampClosure, m_exponent),
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CLOSURE_COLOR_ARRAY_PARAM(PhongRampClosure, m_colors, PhongRampClosure::MAXCOLORS),
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CLOSURE_STRING_KEYPARAM("label"),
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CLOSURE_FINISH_PARAM (PhongRampClosure) };
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CLOSURE_PREPARE(bsdf_phong_prepare, PhongClosure)
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CLOSURE_PREPARE(bsdf_phong_ramp_prepare, PhongRampClosure)
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CCL_NAMESPACE_END
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