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documentation updates, added a smooth plastic material

metadata
Wenzel Jakob 2011-07-08 04:04:52 +02:00
parent 4b95e7ba64
commit 2b140885e8
11 changed files with 312 additions and 241 deletions
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9
data/tests/test_bsdf.xml
View File

@ -2,7 +2,10 @@
to be tested for consistency. This is done
using the testcase 'test_chisquare' -->
<scene>
<!-- Test the diffuse model -->
<!-- Test the smooth plastic model -->
<bsdf type="plastic"/>
<!-- Test the smooth diffuse model -->
<bsdf type="diffuse"/>
<!-- Test the diffuse transmission model -->
@ -21,10 +24,10 @@
</bsdf>
</bsdf>
<!-- Test the conductor model -->
<!-- Test the smooth conductor model -->
<bsdf type="conductor"/>
<!-- Test the dielectric model -->
<!-- Test the smooth dielectric model -->
<bsdf type="dielectric">
<string name="intIOR" value="water"/>
<string name="extIOR" value="air"/>

6
src/bsdfs/SConscript
View File

@ -1,14 +1,14 @@
Import('env', 'plugins')
# Basic materials (smooth & rough versions of each)
plugins += env.SharedLibrary('diffuse', ['diffuse.cpp'])
plugins += env.SharedLibrary('dielectric', ['dielectric.cpp'])
plugins += env.SharedLibrary('conductor', ['conductor.cpp'])
plugins += env.SharedLibrary('diffuse', ['diffuse.cpp'])
#plugins += env.SharedLibrary('plastic', ['plastic.cpp'])
plugins += env.SharedLibrary('plastic', ['plastic.cpp'])
#plugins += env.SharedLibrary('roughdiffuse', ['roughdiffuse.cpp'])
plugins += env.SharedLibrary('roughdielectric', ['roughdielectric.cpp'])
plugins += env.SharedLibrary('roughconductor', ['roughconductor.cpp'])
#plugins += env.SharedLibrary('roughdiffuse', ['roughdiffuse.cpp'])
#plugins += env.SharedLibrary('roughplastic', ['roughplastic.cpp'])
# Other

36
src/bsdfs/conductor.cpp
View File

@ -26,13 +26,13 @@ MTS_NAMESPACE_BEGIN
/*!\plugin{conductor}{Smooth conductor}
* \order{5}
* \parameters{
* \parameter{preset}{\String}{Name of a material preset, see
* \parameter{material}{\String}{Name of a material preset, see
* \tblref{conductor-iors}.\!\default{\texttt{Cu} / copper}}
* \parameter{eta}{\Spectrum}{Real part of the material's index
* of refraction \default{based on the value of \texttt{preset}}}
* of refraction \default{based on the value of \texttt{material}}}
* \parameter{k}{\Spectrum}{Imaginary part of the material's index of
* refraction, also known as absorption coefficient.
* \default{based on the value of \texttt{preset}}}
* \default{based on the value of \texttt{material}}}
* \lastparameter{specular\showbreak Reflectance}{\Spectrum\Or\Texture}{
* Optional factor used to modulate the reflectance component
* \default{1.0}}
@ -54,7 +54,7 @@ MTS_NAMESPACE_BEGIN
* considerable changes throughout the visible color spectrum.
*
* To faciliate the tedious task of specifying spectrally-varying index of
* refraction information, Mitsuba ships with a set of measured data for a
* refraction information, Mitsuba ships with a set of measured data for
* several materials, where visible-spectrum information was publicly
* available\footnote{
* These index of refraction values are identical to the data distributed
@ -74,14 +74,17 @@ MTS_NAMESPACE_BEGIN
* refraction (named ``ordinary'' and ``extraordinary ray'').
*
* When using this plugin, you should ideally compile Mitsuba with support for
* spectral renderings to get the most accurate results. While it also works
* spectral rendering to get the most accurate results. While it also works
* in RGB mode, the computations will be much more approximate in this case.
* Also note that this material is one-sided---that is, observed from the
* back side, it will be completely black. If this is undesirable,
* consider using the \pluginref{twosided} BRDF adapter plugin.\vspace{4mm}
*
* \begin{xml}[caption=Material configuration for a smooth conductor with
* \begin{xml}[caption=A material configuration for a smooth conductor with
* measured gold data, label=lst:conductor-gold]
* <shape type="...">
* <bsdf type="conductor">
* <string name="preset" value="Au"/>
* <string name="material" value="Au"/>
* </bsdf>
* <shape>
* \end{xml}
@ -149,15 +152,15 @@ public:
m_specularReflectance = new ConstantSpectrumTexture(
props.getSpectrum("specularReflectance", Spectrum(1.0f)));
std::string preset = props.getString("preset", "Cu");
Spectrum presetEta, presetK;
presetEta.fromContinuousSpectrum(InterpolatedSpectrum(
fResolver->resolve("data/ior/" + preset + ".eta.spd")));
presetK.fromContinuousSpectrum(InterpolatedSpectrum(
fResolver->resolve("data/ior/" + preset + ".k.spd")));
std::string material = props.getString("material", "Cu");
Spectrum materialEta, materialK;
materialEta.fromContinuousSpectrum(InterpolatedSpectrum(
fResolver->resolve("data/ior/" + material + ".eta.spd")));
materialK.fromContinuousSpectrum(InterpolatedSpectrum(
fResolver->resolve("data/ior/" + material + ".k.spd")));
m_eta = props.getSpectrum("eta", presetEta);
m_k = props.getSpectrum("k", presetK);
m_eta = props.getSpectrum("eta", materialEta);
m_k = props.getSpectrum("k", materialK);
m_components.push_back(EDeltaReflection | EFrontSide);
m_usesRayDifferentials = false;
@ -193,7 +196,8 @@ public:
void configure() {
BSDF::configure();
/* Verify the input parameter and fix them if necessary */
/* Verify the input parameters and fix them if necessary */
m_specularReflectance = ensureEnergyConservation(
m_specularReflectance, "specularReflectance", 1.0f);
}

21
src/bsdfs/dielectric.cpp
View File

@ -98,19 +98,19 @@ MTS_NAMESPACE_BEGIN
* \rmfamily \textbf{Name} & \multicolumn{2}{l}{\textbf{Value}}\\
* \cmidrule{1-3} \cmidrule{5-7}
* vacuum & 1 & 0 & &
* silicone oil & 1 & 52045\\
* helium & 1 & 00004 & &
* bromine & 1 & 661\\
* helium & 1 & 00004 & &
* water ice & 1 & 31\\
* hydrogen & 1 & 00013& &
* water ice & 1 & 31\\[-.8mm]
* fused quartz & 1 & 458\\[-.8mm]
* \cmidrule{5-7}\\[-5.5mm]
* air & 1 & 00028& &
* fused quartz & 1 & 458\\
* pyrex & 1 & 470\\
* carbon dioxide & 1 & 00045& &
* pyrex & 1 & 470\\[-.8mm]
* acrylic glass & 1 & 49\\[-.8mm]
* \cmidrule{1-3}\\[-5.5mm]
* water & 1 & 3330& &
* acrylic glass & 1 & 490\\
* polypropylene & 1 & 49\\
* acetone & 1 & 36 & &
* bk7 & 1 & 5046\\
* ethanol & 1 & 361& &
@ -121,6 +121,7 @@ MTS_NAMESPACE_BEGIN
* pet & 1 & 575\\
* benzene & 1 & 501& &
* diamond & 2 & 419\\
* silicone oil & 1 & 52045\\
* \bottomrule
* \end{tabular}
* \caption{
@ -192,7 +193,8 @@ public:
void configure() {
BSDF::configure();
/* Verify the input parameter and fix them if necessary */
/* Verify the input parameters and fix them if necessary */
m_specularReflectance = ensureEnergyConservation(
m_specularReflectance, "specularReflectance", 1.0f);
m_specularTransmittance = ensureEnergyConservation(
@ -344,9 +346,8 @@ public:
cosThetaT = -cosThetaT;
}
/* Calculate the refracted/reflected vectors+coefficients */
if (sampleTransmission && sampleReflection) {
/* Importance sample according to the reflectance/transmittance */
/* Importance sample wrt. the Fresnel reflectance */
if (sample.x <= Fr) {
bRec.sampledComponent = 0;
bRec.sampledType = EDeltaReflection;
@ -426,9 +427,7 @@ public:
cosThetaT = -cosThetaT;
}
/* Calculate the refracted/reflected vectors+coefficients */
if (sampleTransmission && sampleReflection) {
/* Importance sample according to the reflectance/transmittance */
if (sample.x <= Fr) {
bRec.sampledComponent = 0;
bRec.sampledType = EDeltaReflection;

3
src/bsdfs/difftrans.cpp
View File

@ -65,7 +65,8 @@ public:
void configure() {
BSDF::configure();
/* Verify the input parameter and fix them if necessary */
/* Verify the input parameters and fix them if necessary */
m_transmittance = ensureEnergyConservation(m_transmittance, "transmittance", 1.0f);
}

1
src/bsdfs/diffuse.cpp
View File

@ -89,6 +89,7 @@ public:
void configure() {
BSDF::configure();
/* Verify the input parameter and fix them if necessary */
m_reflectance = ensureEnergyConservation(m_reflectance, "reflectance", 1.0f);
}

3
src/bsdfs/ior.h
View File

@ -55,7 +55,8 @@ static IOREntry iorData[] = {
{ "water ice", 1.31f },
{ "fused quartz", 1.458f },
{ "pyrex", 1.470f },
{ "acrylic glass", 1.490f },
{ "acrylic glass", 1.49f },
{ "polypropylene", 1.49f },
{ "bk7", 1.5046f },
{ "sodium chloride", 1.544f },
{ "amber", 1.55f },

392
src/bsdfs/plastic.cpp
View File

@ -17,40 +17,48 @@
*/
#include <mitsuba/render/bsdf.h>
#include <mitsuba/render/consttexture.h>
#include <mitsuba/render/texture.h>
#include "ior.h"
MTS_NAMESPACE_BEGIN
/*! \plugin{plastic}{Smooth plastic material}
*
/*!\plugin{plastic}{Smooth plastic material}
* \order{7}
* \parameters{
* \parameter{intIOR}{\Float}{Interior index of refraction \default{1.5046}}
* \parameter{extIOR}{\Float}{Exterior index of refraction \default{1.0}}
* \parameter{diffuse\showbreak Reflectance}{\Spectrum\Or\Texture}{Optional
* factor used to modulate the diffuse reflectance component\default{1.0}}
* \parameter{intIOR}{\Float\Or\String}{Interior index of refraction specified
* numerically or using a known material name. \default{\texttt{polypropylene} / 1.49}}
* \parameter{extIOR}{\Float\Or\String}{Exterior index of refraction specified
* numerically or using a known material name. \default{\texttt{air} / 1.000277}}
* \parameter{specular\showbreak Reflectance}{\Spectrum\Or\Texture}{Optional
* factor used to modulate the specular reflectance component\default{1.0}}
* factor used to modulate the specular component\default{1.0}}
* \lastparameter{specular\showbreak Transmittance}{\Spectrum\Or\Texture}{Optional
* factor used to modulate the diffuse component\default{0.5}}
* }
*
* \renderings{
* \medrendering{Air$\leftrightarrow$Water (IOR: 1.33) interface.
* See \lstref{dielectric-water}.}{bsdf_dielectric_water}
* \medrendering{Air$\leftrightarrow$Diamond (IOR: 2.419)}{bsdf_dielectric_diamond}
* \medrendering{Air$\leftrightarrow$Glass (IOR: 1.504) interface and absorption within.
* See \lstref{dielectric-glass}.}{bsdf_dielectric_glass}
* }
*/
class SmoothPlastic : public BSDF {
public:
SmoothPlastic(const Properties &props)
: BSDF(props) {
SmoothPlastic(const Properties &props) : BSDF(props) {
/* Specifies the internal index of refraction at the interface */
m_intIOR = props.getFloat("intIOR", 1.5046f);
/* Specifies the external index of refraction at the interface */
m_extIOR = props.getFloat("extIOR", 1);
m_intIOR = lookupIOR(props, "intIOR", "polypropylene");
/* Specifies the external index of refraction at the interface */
m_extIOR = lookupIOR(props, "extIOR", "air");
m_diffuseReflectance = new ConstantSpectrumTexture(
props.getSpectrum("diffuseReflectance", Spectrum(0.5f)));
m_specularReflectance = new ConstantSpectrumTexture(
props.getSpectrum("specularReflectance", Spectrum(1.0f)));
m_diffuseReflectance = new ConstantSpectrumTexture(
props.getSpectrum("diffuseReflectance", Spectrum(0.5f)));
m_componentCount = 2;
m_type = new unsigned int[m_componentCount];
m_type[0] = EDiffuseReflection | EFrontSide;
m_type[1] = EDeltaTransmission | EFrontSide;
m_combinedType = m_type[0] | m_type[1];
m_components.push_back(EDeltaReflection | EFrontSide);
m_components.push_back(EDiffuseReflection | EFrontSide);
m_usesRayDifferentials = false;
}
@ -58,241 +66,225 @@ public:
: BSDF(stream, manager) {
m_intIOR = stream->readFloat();
m_extIOR = stream->readFloat();
m_diffuseReflectance = static_cast<Texture *>(manager->getInstance(stream));
m_specularReflectance = static_cast<Texture *>(manager->getInstance(stream));
m_componentCount = 2;
m_type = new unsigned int[m_componentCount];
m_type[0] = EDiffuseReflection | EFrontSide;
m_type[1] = EDeltaTransmission | EFrontSide;
m_combinedType = m_type[0] | m_type[1];
m_diffuseReflectance = static_cast<Texture *>(manager->getInstance(stream));
m_components.push_back(EDeltaReflection | EFrontSide);
m_components.push_back(EDiffuseReflection | EFrontSide);
m_usesRayDifferentials =
m_diffuseReflectance->usesRayDifferentials() ||
m_specularReflectance->usesRayDifferentials();
m_specularReflectance->usesRayDifferentials() ||
m_diffuseReflectance->usesRayDifferentials();
}
virtual ~SmoothPlastic() {
delete[] m_type;
}
virtual ~SmoothPlastic() { }
void serialize(Stream *stream, InstanceManager *manager) const {
BSDF::serialize(stream, manager);
stream->writeFloat(m_intIOR);
stream->writeFloat(m_extIOR);
manager->serialize(stream, m_diffuseReflectance.get());
manager->serialize(stream, m_specularReflectance.get());
manager->serialize(stream, m_diffuseReflectance.get());
}
void addChild(const std::string &name, ConfigurableObject *child) {
if (child->getClass()->derivesFrom(MTS_CLASS(Texture)) && name == "diffuseReflectance") {
m_diffuseReflectance = static_cast<Texture *>(child);
m_usesRayDifferentials |= m_diffuseReflectance->usesRayDifferentials();
} else if (child->getClass()->derivesFrom(MTS_CLASS(Texture)) && name == "specularReflectance") {
if (child->getClass()->derivesFrom(MTS_CLASS(Texture)) && name == "specularReflectance") {
m_specularReflectance = static_cast<Texture *>(child);
m_usesRayDifferentials |= m_specularReflectance->usesRayDifferentials();
} else if (child->getClass()->derivesFrom(MTS_CLASS(Texture)) && name == "diffuseReflectance") {
m_diffuseReflectance = static_cast<Texture *>(child);
m_usesRayDifferentials |= m_diffuseReflectance->usesRayDifferentials();
} else {
BSDF::addChild(name, child);
}
}
void configure() {
BSDF::configure();
/* Verify the input parameters and fix them if necessary */
m_specularReflectance = ensureEnergyConservation(
m_specularReflectance, "specularReflectance", 1.0f);
m_diffuseReflectance = ensureEnergyConservation(
m_diffuseReflectance, "diffuseReflectance", 1.0f);
}
/// Reflection in local coordinates
inline Vector reflect(const Vector &wi) const {
return Vector(-wi.x, -wi.y, wi.z);
}
Spectrum f(const BSDFQueryRecord &bRec) const {
bool sampleDiffuse = (bRec.typeMask & EDiffuseReflection)
Spectrum eval(const BSDFQueryRecord &bRec, EMeasure measure) const {
bool sampleSpecular = (bRec.typeMask & EDeltaReflection)
&& (bRec.component == -1 || bRec.component == 0);
bool sampleDiffuse = (bRec.typeMask & EDiffuseReflection)
&& (bRec.component == -1 || bRec.component == 1);
if (Frame::cosTheta(bRec.wi) <= 0 ||
Frame::cosTheta(bRec.wo) <= 0 || !sampleDiffuse)
if (Frame::cosTheta(bRec.wo) <= 0 || Frame::cosTheta(bRec.wi) <= 0)
return Spectrum(0.0f);
return m_diffuseReflectance->getValue(bRec.its) * INV_PI *
(1 - fresnel(Frame::cosTheta(bRec.wi), m_extIOR, m_intIOR));
}
Float Fr = fresnel(Frame::cosTheta(bRec.wi), m_extIOR, m_intIOR);
Spectrum fDelta(const BSDFQueryRecord &bRec) const {
bool sampleSpecular = (bRec.typeMask & EDeltaReflection)
&& (bRec.component == -1 || bRec.component == 1);
if (Frame::cosTheta(bRec.wi) <= 0 ||
Frame::cosTheta(bRec.wo) <= 0 || !sampleSpecular)
return Spectrum(0.0f);
return m_specularReflectance->getValue(bRec.its) *
fresnel(Frame::cosTheta(bRec.wi), m_extIOR, m_intIOR);
}
Float pdf(const BSDFQueryRecord &bRec) const {
bool sampleDiffuse = (bRec.typeMask & EDiffuseReflection)
&& (bRec.component == -1 || bRec.component == 0);
if (Frame::cosTheta(bRec.wi) <= 0 ||
Frame::cosTheta(bRec.wo) <= 0 || !sampleDiffuse)
return 0.0f;
bool sampleSpecular = (bRec.typeMask & EDeltaReflection)
&& (bRec.component == -1 || bRec.component == 1);
Float pdf = Frame::cosTheta(bRec.wo) * INV_PI;
if (sampleSpecular)
pdf *= 1 - fresnel(Frame::cosTheta(bRec.wi),
m_extIOR, m_intIOR);
return pdf;
}
Float pdfDelta(const BSDFQueryRecord &bRec) const {
bool sampleSpecular = (bRec.typeMask & EDeltaReflection)
&& (bRec.component == -1 || bRec.component == 1);
if (Frame::cosTheta(bRec.wi) <= 0 ||
Frame::cosTheta(bRec.wo) <= 0 || !sampleSpecular)
return 0.0f;
bool sampleDiffuse = (bRec.typeMask & EDiffuseReflection)
&& (bRec.component == -1 || bRec.component == 0);
Float pdf = std::abs(Frame::cosTheta(bRec.wo));
if (measure == EDiscrete && sampleSpecular) {
/* Check if the provided direction pair matches an ideal
specular reflection; tolerate some roundoff errors */
bool reflection = std::abs(1 - dot(reflect(bRec.wi), bRec.wo)) < Epsilon;
if (reflection)
return m_specularReflectance->getValue(bRec.its) * Fr;
} else if (measure == ESolidAngle && sampleDiffuse) {
if (sampleDiffuse)
pdf *= fresnel(Frame::cosTheta(bRec.wi), m_extIOR, m_intIOR);
return pdf;
}
Spectrum sample(BSDFQueryRecord &bRec, Float &pdf, const Point2 &_sample) const {
bool sampleDiffuse = (bRec.typeMask & EDiffuseReflection)
&& (bRec.component == -1 || bRec.component == 0);
bool sampleSpecular = (bRec.typeMask & EDeltaReflection)
&& (bRec.component == -1 || bRec.component == 1);
if ((!sampleDiffuse && !sampleSpecular) || Frame::cosTheta(bRec.wi) <= 0)
return Spectrum(0.0f);
Float Fr = fresnel(Frame::cosTheta(bRec.wi), m_extIOR, m_intIOR);
Point2 sample(_sample);
if (sampleDiffuse && sampleSpecular) {
if (sample.x > Fr) {
sample.x = (sample.x - Fr) / (1 - Fr);
bRec.wo = squareToHemispherePSA(sample);
bRec.sampledComponent = 0;
bRec.sampledType = EDiffuseReflection;
pdf = Frame::cosTheta(bRec.wo) * INV_PI * (1-Fr);
return m_diffuseReflectance->getValue(bRec.its) * INV_PI * (1-Fr);
} else {
bRec.sampledComponent = 1;
bRec.sampledType = EDeltaReflection;
bRec.wo = reflect(bRec.wi);
pdf = std::abs(Frame::cosTheta(bRec.wo)) * Fr;
return m_specularReflectance->getValue(bRec.its) * Fr;
}
} else if (sampleDiffuse) {
bRec.wo = squareToHemispherePSA(sample);
bRec.sampledComponent = 0;
bRec.sampledType = EDiffuseReflection;
pdf = Frame::cosTheta(bRec.wo) * INV_PI;
return m_diffuseReflectance->getValue(bRec.its) * INV_PI * (1-Fr);
} else {
bRec.sampledComponent = 1;
bRec.sampledType = EDeltaReflection;
bRec.wo = reflect(bRec.wi);
pdf = std::abs(Frame::cosTheta(bRec.wo));
return m_specularReflectance->getValue(bRec.its) * Fr;
}
}
Spectrum sample(BSDFQueryRecord &bRec, const Point2 &_sample) const {
bool sampleDiffuse = (bRec.typeMask & EDiffuseReflection)
&& (bRec.component == -1 || bRec.component == 0);
bool sampleSpecular = (bRec.typeMask & EDeltaReflection)
&& (bRec.component == -1 || bRec.component == 1);
if ((!sampleDiffuse && !sampleSpecular) || Frame::cosTheta(bRec.wi) <= 0)
return Spectrum(0.0f);
Float Fr = fresnel(Frame::cosTheta(bRec.wi), m_extIOR, m_intIOR);
Point2 sample(_sample);
if (sampleDiffuse && sampleSpecular) {
if (sample.x > Fr) {
sample.x = (sample.x - Fr) / (1 - Fr);
bRec.wo = squareToHemispherePSA(sample);
bRec.sampledComponent = 0;
bRec.sampledType = EDiffuseReflection;
return m_diffuseReflectance->getValue(bRec.its)
/ Frame::cosTheta(bRec.wo);
} else {
bRec.sampledComponent = 1;
bRec.sampledType = EDeltaReflection;
bRec.wo = reflect(bRec.wi);
return m_specularReflectance->getValue(bRec.its)
/ std::abs(Frame::cosTheta(bRec.wo));
* (INV_PI * Frame::cosTheta(bRec.wo) * (1-Fr));
}
} else if (sampleDiffuse) {
bRec.wo = squareToHemispherePSA(sample);
return Spectrum(0.0f);
}
Float pdf(const BSDFQueryRecord &bRec, EMeasure measure) const {
bool sampleSpecular = (bRec.typeMask & EDeltaReflection)
&& (bRec.component == -1 || bRec.component == 0);
bool sampleDiffuse = (bRec.typeMask & EDiffuseReflection)
&& (bRec.component == -1 || bRec.component == 1);
if (Frame::cosTheta(bRec.wo) <= 0 || Frame::cosTheta(bRec.wi) <= 0)
return 0.0f;
if (measure == EDiscrete && sampleSpecular) {
/* Check if the provided direction pair matches an ideal
specular reflection; tolerate some roundoff errors */
bool reflection = std::abs(1 - dot(reflect(bRec.wi), bRec.wo)) < Epsilon;
if (reflection)
return sampleDiffuse ?
fresnel(Frame::cosTheta(bRec.wi), m_extIOR, m_intIOR) : 1.0f;
} else if (measure == ESolidAngle && sampleDiffuse) {
return Frame::cosTheta(bRec.wo) * INV_PI *
sampleSpecular ? (1 - fresnel(Frame::cosTheta(bRec.wi),
m_extIOR, m_intIOR)) : 1.0f;
}
return 0.0f;
}
Spectrum sample(BSDFQueryRecord &bRec, const Point2 &sample) const {
bool sampleSpecular = (bRec.typeMask & EDeltaReflection)
&& (bRec.component == -1 || bRec.component == 0);
bool sampleDiffuse = (bRec.typeMask & EDiffuseReflection)
&& (bRec.component == -1 || bRec.component == 1);
if ((!sampleDiffuse && !sampleSpecular) || Frame::cosTheta(bRec.wi) < 0)
return Spectrum(0.0f);
Float Fr = fresnel(Frame::cosTheta(bRec.wi), m_extIOR, m_intIOR);
if (sampleDiffuse && sampleSpecular) {
/* Importance sample wrt. the Fresnel reflectance */
if (sample.x <= Fr) {
bRec.sampledComponent = 0;
bRec.sampledType = EDiffuseReflection;
return m_diffuseReflectance->getValue(bRec.its) * (1-Fr)
/ Frame::cosTheta(bRec.wo);
} else {
bRec.sampledComponent = 1;
bRec.sampledType = EDeltaReflection;
bRec.wo = reflect(bRec.wi);
return m_specularReflectance->getValue(bRec.its) * Fr
/ std::abs(Frame::cosTheta(bRec.wo));
return m_specularReflectance->getValue(bRec.its);
} else {
bRec.sampledComponent = 1;
bRec.sampledType = EDiffuseReflection;
bRec.wo = squareToHemispherePSA(Point2(
(sample.x - Fr) / (1 - Fr),
sample.y
));
return m_diffuseReflectance->getValue(bRec.its);
}
} else if (sampleSpecular) {
bRec.sampledComponent = 0;
bRec.sampledType = EDeltaReflection;
bRec.wo = reflect(bRec.wi);
return m_specularReflectance->getValue(bRec.its) * Fr;
} else {
bRec.sampledComponent = 1;
bRec.sampledType = EDiffuseReflection;
if (Fr == 1.0f) /* Total internal reflection */
return Spectrum(0.0f);
bRec.wo = squareToSphere(sample);
return m_diffuseReflectance->getValue(bRec.its) * (1-Fr);
}
}
Spectrum sample(BSDFQueryRecord &bRec, Float &pdf, const Point2 &sample) const {
bool sampleSpecular = (bRec.typeMask & EDeltaReflection)
&& (bRec.component == -1 || bRec.component == 0);
bool sampleDiffuse = (bRec.typeMask & EDiffuseReflection)
&& (bRec.component == -1 || bRec.component == 1);
if ((!sampleDiffuse && !sampleSpecular) || Frame::cosTheta(bRec.wi) < 0)
return Spectrum(0.0f);
Float Fr = fresnel(Frame::cosTheta(bRec.wi), m_extIOR, m_intIOR);
if (sampleDiffuse && sampleSpecular) {
/* Importance sample wrt. the Fresnel reflectance */
if (sample.x <= Fr) {
bRec.sampledComponent = 0;
bRec.sampledType = EDeltaReflection;
bRec.wo = reflect(bRec.wi);
pdf = Fr;
return m_specularReflectance->getValue(bRec.its) * Fr;
} else {
bRec.sampledComponent = 1;
bRec.sampledType = EDiffuseReflection;
bRec.wo = squareToHemispherePSA(Point2(
(sample.x - Fr) / (1 - Fr),
sample.y
));
pdf = (1-Fr) * Frame::cosTheta(bRec.wo) * INV_PI;
return m_diffuseReflectance->getValue(bRec.its)
* (INV_PI * Frame::cosTheta(bRec.wo) * (1-Fr));
}
} else if (sampleSpecular) {
bRec.sampledComponent = 0;
bRec.sampledType = EDeltaReflection;
bRec.wo = reflect(bRec.wi);
pdf = 1;
return m_specularReflectance->getValue(bRec.its) * Fr;
} else {
bRec.sampledComponent = 1;
bRec.sampledType = EDiffuseReflection;
if (Fr == 1.0f) /* Total internal reflection */
return Spectrum(0.0f);
bRec.wo = squareToSphere(sample);
pdf = Frame::cosTheta(bRec.wo) * INV_PI;
return m_diffuseReflectance->getValue(bRec.its)
* (INV_PI * Frame::cosTheta(bRec.wo) * (1-Fr));
}
}
std::string toString() const {
std::ostringstream oss;
oss << "SmoothPlastic[" << endl
<< " name = \"" << getName() << "\"," << endl
<< " intIOR = " << m_intIOR << "," << endl
<< " extIOR = " << m_extIOR << "," << endl
<< " diffuseReflectance = " << indent(m_diffuseReflectance->toString()) << "," << endl
<< " specularReflectance = " << indent(m_specularReflectance->toString()) << endl
<< " specularReflectance = " << indent(m_specularReflectance->toString()) << "," << endl
<< " diffuseReflectance = " << indent(m_diffuseReflectance->toString()) << endl
<< "]";
return oss.str();
}
Shader *createShader(Renderer *renderer) const;
MTS_DECLARE_CLASS()
private:
Float m_intIOR, m_extIOR;
ref<Texture> m_specularReflectance;
ref<Texture> m_diffuseReflectance;
ref<Texture> m_specularReflectance;
};
/* Fake glass shader -- it is really hopeless to visualize
this material in the VPL renderer, so let's try to do at least
something that suggests the presence of a transparent boundary */
class SmoothPlasticShader : public Shader {
public:
SmoothPlasticShader(Renderer *renderer) :
Shader(renderer, EBSDFShader) {
m_flags = ETransparent;
}
void generateCode(std::ostringstream &oss,
const std::string &evalName,
const std::vector<std::string> &depNames) const {
oss << "vec3 " << evalName << "(vec2 uv, vec3 wi, vec3 wo) {" << endl
<< " return vec3(0.08);" << endl
<< "}" << endl;
oss << "vec3 " << evalName << "_diffuse(vec2 uv, vec3 wi, vec3 wo) {" << endl
<< " return vec3(0.08);" << endl
<< "}" << endl;
}
MTS_DECLARE_CLASS()
};
Shader *SmoothPlastic::createShader(Renderer *renderer) const {
return new SmoothPlasticShader(renderer);
}
MTS_IMPLEMENT_CLASS(SmoothPlasticShader, false, Shader)
MTS_IMPLEMENT_CLASS_S(SmoothPlastic, false, BSDF)
MTS_EXPORT_PLUGIN(SmoothPlastic, "Smooth plastic BSDF");
MTS_NAMESPACE_END

96
src/bsdfs/roughconductor.cpp
View File

@ -67,24 +67,92 @@ MTS_NAMESPACE_BEGIN
* bitangent directions. These parameter are only valid when
* \texttt{distribution=as}. \default{0.1}.
* }
* \parameter{preset}{\String}{Name of a material preset, see
* \parameter{material}{\String}{Name of a material preset, see
* \tblref{conductor-iors}.\!\default{\texttt{Cu} / copper}}
* \parameter{eta}{\Spectrum}{Real part of the material's index
* of refraction \default{based on the value of \texttt{preset}}}
* of refraction \default{based on the value of \texttt{material}}}
* \parameter{k}{\Spectrum}{Imaginary part of the material's index of
* refraction, also known as absorption coefficient.
* \default{based on the value of \texttt{preset}}}
* \default{based on the value of \texttt{material}}}
* \lastparameter{specular\showbreak Reflectance}{\Spectrum\Or\Texture}{Optional
* factor used to modulate the reflectance component\default{1.0}}
* }
* This plugin implements a realistic microfacet scattering model for rendering
* rough conducting materials, such as metals. Microfacet theory describes rough
* surfaces as an arrangement of unresolved and ideally specular facets, whose
* normal directions are given by a specially chosen \emph{microfacet distribution}.
* By accounting for shadowing and masking effects between these facets, it is
* possible to reproduce the important off-specular reflections peaks observed
* in real-world measurements of such materials.
* \renderings{
* \rendering{Rough copper (Beckmann, $\alpha=0.1$)}
* {bsdf_roughconductor_copper.jpg}
* \rendering{Vertically brushed aluminium (Ashikhmin-Shirley,
* $\alpha_u=0.05,\
* \alpha_v=0.3$)}{bsdf_roughconductor_anisotropic_aluminium.jpg}
* $\alpha_u=0.05,\ \alpha_v=0.3$), see
* \lstref{roughconductor-aluminium}}
* {bsdf_roughconductor_anisotropic_aluminium.jpg}
* \vspace{-7mm}
* }
*
* This plugin is essentially the ``roughened'' equivalent of the (smooth) plugin
* \pluginref{conductor}. For very low values of $\alpha$, the two will
* be very similar, though scenes using this plugin will take longer to render
* due to the additional computational burden of tracking surface roughness.
*
* The implementation is based on the paper ``Microfacet Models
* for Refraction through Rough Surfaces'' by Walter et al.
* \cite{Walter07Microfacet}. It supports several different types of microfacet
* distributions and has a texturable roughness parameter.
* To faciliate the tedious task of specifying spectrally-varying index of
* refraction information, this plugin can access a set of measured materials
* for which visible-spectrum information was publicly available
* (see \tblref{conductor-iors} for the full list).
*
* When no parameters are given, the plugin activates the default settings,
* which describe copper with a light amount of roughness modeled using a
* Beckmann distribution.
*
* To get an intuition about the effect of the surface roughness
* parameter $\alpha$, consider the following approximate differentiation:
* a value of $\alpha=0.001-0.01$ corresponds to a material
* with slight imperfections on an
* otherwise smooth surface finish, $\alpha=0.1$ is relatively rough,
* and $\alpha=0.3-0.5$ is \emph{extremely} rough (e.g. an etched or ground
* finish).
* \vspace{-2mm}
* \subsubsection*{Techical details}\vspace{-2mm}
* When rendering with the Ashikhmin-Shirley or Phong microfacet
* distributions, a conversion is used to turn the specified
* $\alpha$ roughness value into the exponents of these distributions.
* This is done in a way, such that the different
* distributions all produce a similar appearance for the same value of
* $\alpha$.
*
* The Ashikhmin-Shirley microfacet distribution allows the specification
* of two distinct roughness values along the tangent and bitangent
* directions. This can be used to provide a material with a ``brushed''
* appearance. The alignment of the anisotropy will follow the UV
* parameterization of the underlying mesh in this case. This means that
* such an anisotropic material cannot be applied to triangle meshes that
* are missing texture coordinates.
*
* When using this plugin, you should ideally compile Mitsuba with support for
* spectral rendering to get the most accurate results. While it also works
* in RGB mode, the computations will be much more approximate in this case.
* Also note that this material is one-sided---that is, observed from the
* back side, it will be completely black. If this is undesirable,
* consider using the \pluginref{twosided} BRDF adapter plugin.
*
* \begin{xml}[caption={A material definition for brushed aluminium}, label=lst:roughconductor-aluminium]
* <bsdf type="roughconductor">
* <string name="material" value="Cu"/>
* <string name="distribution" value="as"/>
* <float name="alphaU" value="0.05"/>
* <float name="alphaV" value="0.3"/>
* </bsdf>
* \end{xml}
*
*/
class RoughConductor : public BSDF {
public:
@ -94,15 +162,15 @@ public:
m_specularReflectance = new ConstantSpectrumTexture(
props.getSpectrum("specularReflectance", Spectrum(1.0f)));
std::string preset = props.getString("preset", "Cu");
Spectrum presetEta, presetK;
presetEta.fromContinuousSpectrum(InterpolatedSpectrum(
fResolver->resolve("data/ior/" + preset + ".eta.spd")));
presetK.fromContinuousSpectrum(InterpolatedSpectrum(
fResolver->resolve("data/ior/" + preset + ".k.spd")));
std::string material = props.getString("material", "Cu");
Spectrum materialEta, materialK;
materialEta.fromContinuousSpectrum(InterpolatedSpectrum(
fResolver->resolve("data/ior/" + material + ".eta.spd")));
materialK.fromContinuousSpectrum(InterpolatedSpectrum(
fResolver->resolve("data/ior/" + material + ".k.spd")));
m_eta = props.getSpectrum("eta", presetEta);
m_k = props.getSpectrum("k", presetK);
m_eta = props.getSpectrum("eta", materialEta);
m_k = props.getSpectrum("k", materialK);
m_distribution = MicrofacetDistribution(
props.getString("distribution", "beckmann")
@ -156,7 +224,7 @@ public:
m_components.push_back(
EGlossyReflection | EFrontSide | extraFlags);
/* Verify the input parameter and fix them if necessary */
/* Verify the input parameters and fix them if necessary */
m_specularReflectance = ensureEnergyConservation(
m_specularReflectance, "specularReflectance", 1.0f);

2
src/bsdfs/roughdielectric.cpp
View File

@ -241,7 +241,7 @@ public:
m_components.push_back(
EGlossyTransmission | EFrontSide | EBackSide | ECanUseSampler | extraFlags);
/* Verify the input parameter and fix them if necessary */
/* Verify the input parameters and fix them if necessary */
m_specularReflectance = ensureEnergyConservation(
m_specularReflectance, "specularReflectance", 1.0f);
m_specularTransmittance = ensureEnergyConservation(

6
src/tests/test_chisquare.cpp
View File

@ -173,9 +173,11 @@ public:
mismatch = true;
}
if (mismatch)
Log(EWarn, "Potential inconsistency (3): f/pdf=%s (method 1), f/pdf=%s (methdod 2), sampled f/pdf=%s",
if (mismatch) {
Log(EWarn, "Potential inconsistency (3): f/pdf=%s (method 1), f/pdf=%s (method 2), sampled f/pdf=%s",
sampled2.toString().c_str(), evaluated.toString().c_str(), sampled.toString().c_str());
Log(EWarn, " f=%s, f2=%s, pdf=%f, pdf2=%f", f.toString().c_str(), f.toString().c_str(), pdfVal, pdfVal2);
}
#if defined(MTS_DEBUG_FP)
disableFPExceptions();