blender/intern/cycles/kernel/osl/bsdf_phong.cpp
Thomas Dinges 3f7b4916e9 OSL Backend:
* 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]
2012-09-05 23:22:36 +00:00

278 lines
10 KiB
C++

/*
* Adapted from Open Shading Language with this license:
*
* Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
* All Rights Reserved.
*
* Modifications Copyright 2012, 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;
// vanilla phong - leaks energy at grazing angles
// see Global Illumination Compendium entry (66)
class PhongClosure : public BSDFClosure {
public:
Vec3 m_N;
float m_exponent;
PhongClosure() : BSDFClosure(Labels::GLOSSY) { }
void setup() {};
bool mergeable (const ClosurePrimitive *other) const {
const PhongClosure *comp = (const PhongClosure *)other;
return m_N == comp->m_N && m_exponent == comp->m_exponent &&
BSDFClosure::mergeable(other);
}
size_t memsize () const { return sizeof(*this); }
const char *name () const { return "phong"; }
void print_on (std::ostream &out) const {
out << name() << " ((";
out << m_N[0] << ", " << m_N[1] << ", " << m_N[2] << "), ";
out << m_exponent << ")";
}
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 cosNI = m_N.dot(omega_in);
float cosNO = m_N.dot(omega_out);
if (cosNI > 0 && cosNO > 0) {
// reflect the view vector
Vec3 R = (2 * cosNO) * m_N - omega_out;
float cosRI = R.dot(omega_in);
if (cosRI > 0) {
float common = 0.5f * (float) M_1_PI * powf(cosRI, m_exponent);
float out = cosNI * (m_exponent + 2) * common;
pdf = (m_exponent + 1) * common;
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) {
// reflect the view vector
Vec3 R = (2 * cosNO) * m_N - omega_out;
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;
Vec3 T, B;
make_orthonormals (R, T, B);
float phi = 2 * (float) M_PI * randu;
float cosTheta = powf(randv, 1 / (m_exponent + 1));
float sinTheta2 = 1 - cosTheta * cosTheta;
float sinTheta = sinTheta2 > 0 ? sqrtf(sinTheta2) : 0;
omega_in = (cosf(phi) * sinTheta) * T +
(sinf(phi) * sinTheta) * B +
( cosTheta) * R;
if (Ng.dot(omega_in) > 0)
{
// common terms for pdf and eval
float cosNI = m_N.dot(omega_in);
// make sure the direction we chose is still in the right hemisphere
if (cosNI > 0)
{
float common = 0.5f * (float) M_1_PI * powf(cosTheta, m_exponent);
pdf = (m_exponent + 1) * common;
float out = cosNI * (m_exponent + 2) * common;
eval.setValue(out, out, out);
// Since there is some blur to this reflection, make the
// derivatives a bit bigger. In theory this varies with the
// exponent but the exact relationship is complex and
// requires more ops than are practical.
domega_in_dx *= 10;
domega_in_dy *= 10;
}
}
}
return Labels::REFLECT;
}
};
class PhongRampClosure : public BSDFClosure {
public:
static const int MAXCOLORS = 8;
Vec3 m_N;
float m_exponent;
Color3 m_colors[MAXCOLORS];
PhongRampClosure() : BSDFClosure(Labels::GLOSSY) { }
void setup() {};
bool mergeable (const ClosurePrimitive *other) const {
const PhongRampClosure *comp = (const PhongRampClosure *)other;
if (! (m_N == comp->m_N && m_exponent == comp->m_exponent &&
BSDFClosure::mergeable(other)))
return false;
for (int i = 0; i < MAXCOLORS; ++i)
if (m_colors[i] != comp->m_colors[i])
return false;
return true;
}
size_t memsize () const { return sizeof(*this); }
const char *name () const { return "phong_ramp"; }
void print_on (std::ostream &out) const {
out << name() << " ((";
out << m_N[0] << ", " << m_N[1] << ", " << m_N[2] << "), ";
out << m_exponent << ")";
}
Color3 get_color (float pos) const
{
float npos = pos * (float)(MAXCOLORS - 1);
int ipos = (int)npos;
if (ipos >= (MAXCOLORS - 1))
return m_colors[MAXCOLORS - 1];
float offset = npos - (float)ipos;
return m_colors[ipos] * (1.0f - offset) + m_colors[ipos+1] * offset;
}
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 cosNI = m_N.dot(omega_in);
float cosNO = m_N.dot(omega_out);
if (cosNI > 0 && cosNO > 0) {
// reflect the view vector
Vec3 R = (2 * cosNO) * m_N - omega_out;
float cosRI = R.dot(omega_in);
if (cosRI > 0) {
float cosp = powf(cosRI, m_exponent);
float common = 0.5f * (float) M_1_PI * cosp;
float out = cosNI * (m_exponent + 2) * common;
pdf = (m_exponent + 1) * common;
return get_color(cosp) * 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) {
// reflect the view vector
Vec3 R = (2 * cosNO) * m_N - omega_out;
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;
Vec3 T, B;
make_orthonormals (R, T, B);
float phi = 2 * (float) M_PI * randu;
float cosTheta = powf(randv, 1 / (m_exponent + 1));
float sinTheta2 = 1 - cosTheta * cosTheta;
float sinTheta = sinTheta2 > 0 ? sqrtf(sinTheta2) : 0;
omega_in = (cosf(phi) * sinTheta) * T +
(sinf(phi) * sinTheta) * B +
( cosTheta) * R;
if (Ng.dot(omega_in) > 0)
{
// common terms for pdf and eval
float cosNI = m_N.dot(omega_in);
// make sure the direction we chose is still in the right hemisphere
if (cosNI > 0)
{
float cosp = powf(cosTheta, m_exponent);
float common = 0.5f * (float) M_1_PI * cosp;
pdf = (m_exponent + 1) * common;
float out = cosNI * (m_exponent + 2) * common;
eval = get_color(cosp) * out;
// Since there is some blur to this reflection, make the
// derivatives a bit bigger. In theory this varies with the
// exponent but the exact relationship is complex and
// requires more ops than are practical.
domega_in_dx *= 10;
domega_in_dy *= 10;
}
}
}
return Labels::REFLECT;
}
};
ClosureParam bsdf_phong_params[] = {
CLOSURE_VECTOR_PARAM(PhongClosure, m_N),
CLOSURE_FLOAT_PARAM (PhongClosure, m_exponent),
CLOSURE_STRING_KEYPARAM("label"),
CLOSURE_FINISH_PARAM(PhongClosure) };
ClosureParam bsdf_phong_ramp_params[] = {
CLOSURE_VECTOR_PARAM (PhongRampClosure, m_N),
CLOSURE_FLOAT_PARAM (PhongRampClosure, m_exponent),
CLOSURE_COLOR_ARRAY_PARAM(PhongRampClosure, m_colors, PhongRampClosure::MAXCOLORS),
CLOSURE_STRING_KEYPARAM("label"),
CLOSURE_FINISH_PARAM (PhongRampClosure) };
CLOSURE_PREPARE(bsdf_phong_prepare, PhongClosure)
CLOSURE_PREPARE(bsdf_phong_ramp_prepare, PhongRampClosure)
CCL_NAMESPACE_END