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diff --git a/doc/images/bsdf_roughdiffuse_0.jpg b/doc/images/bsdf_roughdiffuse_0.jpg
new file mode 100644
index 00000000..46d303ee
Binary files /dev/null and b/doc/images/bsdf_roughdiffuse_0.jpg differ
diff --git a/doc/images/bsdf_roughdiffuse_0_7.jpg b/doc/images/bsdf_roughdiffuse_0_7.jpg
new file mode 100644
index 00000000..2c2ab3b0
Binary files /dev/null and b/doc/images/bsdf_roughdiffuse_0_7.jpg differ
diff --git a/doc/macros.sty b/doc/macros.sty
index f8408cc0..e4d215cc 100644
--- a/doc/macros.sty
+++ b/doc/macros.sty
@@ -37,9 +37,7 @@
%\toprule
\\[-2.2ex]
\textbf{Parameter}&\textbf{Type}&\textbf{Description}\\
- \otoprule
#1
- %\bottomrule
\end{tabular}}
\end{figure}
\setlength\fboxrule\fboxrulebackup
@@ -60,12 +58,8 @@
\newcommand{\smallrendering}[2]{ \subfigure[#1]{\fbox{\includegraphics[width=0.2\textwidth]{images/#2}}}\hfill}
\newcommand{\parameter}[3]{
- \small\texttt{#1} & \small #2 & \small #3\\
\otoprule
+ \small\texttt{#1} & \small #2 & \small #3 \\
}
-\newcommand{\lastparameter}[3]{
- \small\texttt{#1} & \small #2 & \small #3\\
- }
-
\newcommand{\default}[1]{ (Default: #1)}
diff --git a/doc/section_bsdf.tex b/doc/section_bsdf.tex
index dccf24b2..7120baa9 100644
--- a/doc/section_bsdf.tex
+++ b/doc/section_bsdf.tex
@@ -1,4 +1,16 @@
\subsection{Surface scattering models}
+\begin{figure}[h!]
+\centering
+\includegraphics[width=15.5cm]{images/bsdf_overview.pdf}
+\caption{
+ Schematic overview of the surface scattering models that ship with
+ Mitsuba. The arrows indicate possible outcomes of an
+ interaction with a surface that has the respective model applied to it.
+ \vspace{4mm}
+}
+\end{figure}
+
+
\label{sec:bsdfs}
Surface scattering models describe the manner in which light interacts
with surfaces in the scene. They conveniently summarize the mesoscopic
@@ -11,53 +23,11 @@ please refer to Sections~\ref{sec:media} and \ref{sec:subsurface}.
This section presents an overview of all surface scattering models that are
supported, along with their parameters.
-\subsubsection*{Correctness considerations}
-\begin{figure}[b!]
-\centering
-\vspace{-5mm}
-\includegraphics[width=15cm]{images/glass_explanation.pdf}
-\vspace{-5mm}
-\caption{
- \label{fig:glass-explanation}
- Some of the scattering models in Mitsuba need to know
- the indices of refraction on the exterior and interior-facing
- side of a surface.
- It is therefore important to decompose the mesh into meaningful
- separate surfaces corresponding to each index of refraction change.
- The example here shows such a decomposition for a water-filled Glass.
-}
-\end{figure}
-
-
-A vital consideration when modeling a scene in a physically-based rendering
-system is that the used materials do not violate physical properties, and
-that their arrangement is meaningful. For instance, imagine having designed
-an architectural interior scene that looks good except for a white desk that
-seems a bit too dark. A closer inspection reveals that it uses a Lambertian
-material with a diffuse reflectance of $0.9$.
-
-In many rendering systems, it would be feasible to increase the
-reflectance value above $1.0$ in such a situation. But in Mitsuba, even a
-small surface that reflects a little more light than it receives will
-likely break the available rendering algorithms, or cause them to produce otherwise
-unpredictable results. In fact, we should rather change the lighting setup and
-then \emph{reduce} the material's reflectance, since it is quite unlikely that
-we could find a real-world desk with a reflectance as high as $0.9$.
-
-As an example of the necessity for a meaningful material arrangement, consider
-the glass model illustrated in \figref{glass-explanation}. Here, careful thinking
-is needed to decompose the object into boundaries that mark index of
-refraction-changes. If this is done incorrectly and a beam of light can
-potentially pass through a sequence of incompatible index of refraction changes (e.g. $1.00\to 1.33$
-followed by $1.50\to1.33$), the output is undefined and will quite likely
-even contain inaccuracies in parts of the scene that are some distance
-away from the glass.
-
\subsubsection*{BSDFs}
To achieve realistic results, Mitsuba comes with a library of both
general-purpose surface scattering models (smooth or rough glass, metal,
plastic, etc.) and specializations to particular materials (woven cloth,
-masks, etc.). Some model plugins fit neither category and could be described
+masks, etc.). Some model plugins fit neither category and can best be described
as \emph{modifiers} that are applied on top of one or more scattering models.
Throughout the documentation and within the scene description
@@ -95,4 +65,45 @@ The following fragment shows an example of both kinds of usages:
It is generally more economical to use named BSDFs when they
are used in several places, since this reduces Mitsuba's internal
memory usage.
+\subsubsection*{Correctness considerations}
+\begin{figure}[b!]
+\centering
+\vspace{-5mm}
+\includegraphics[width=15cm]{images/glass_explanation.pdf}
+\vspace{-5mm}
+\caption{
+ \label{fig:glass-explanation}
+ Some of the scattering models in Mitsuba need to know
+ the indices of refraction on the exterior and interior-facing
+ side of a surface.
+ It is therefore important to decompose the mesh into meaningful
+ separate surfaces corresponding to each index of refraction change.
+ The example here shows such a decomposition for a water-filled Glass.
+}
+\end{figure}
+
+A vital consideration when modeling a scene in a physically-based rendering
+system is that the used materials do not violate physical properties, and
+that their arrangement is meaningful. For instance, imagine having designed
+an architectural interior scene that looks good except for a white desk that
+seems a bit too dark. A closer inspection reveals that it uses a Lambertian
+material with a diffuse reflectance of $0.9$.
+
+In many rendering systems, it would be feasible to increase the
+reflectance value above $1.0$ in such a situation. But in Mitsuba, even a
+small surface that reflects a little more light than it receives will
+likely break the available rendering algorithms, or cause them to produce otherwise
+unpredictable results. In fact, we should rather change the lighting setup and
+then \emph{reduce} the material's reflectance, since it is quite unlikely that
+we could find a real-world desk with a reflectance as high as $0.9$.
+
+As an example of the necessity for a meaningful material arrangement, consider
+the glass model illustrated in \figref{glass-explanation}. Here, careful thinking
+is needed to decompose the object into boundaries that mark index of
+refraction-changes. If this is done incorrectly and a beam of light can
+potentially pass through a sequence of incompatible index of refraction changes (e.g. $1.00\to 1.33$
+followed by $1.50\to1.33$), the output is undefined and will quite likely
+even contain inaccuracies in parts of the scene that are some distance
+away from the glass.
+
diff --git a/include/mitsuba/core/frame.h b/include/mitsuba/core/frame.h
index 24f099f8..ebd2b89b 100644
--- a/include/mitsuba/core/frame.h
+++ b/include/mitsuba/core/frame.h
@@ -112,6 +112,38 @@ struct Frame {
return 1.0f - v.z * v.z;
}
+ /** \brief Assuming that the given direction is in the local coordinate
+ * system, return the sine of the phi parameter in spherical coordinates */
+ inline static Float sinPhi(const Vector &v) {
+ Float sinTheta = Frame::sinTheta(v);
+ if (sinTheta == 0.0f)
+ return 1.0f;
+ return clamp(v.y / sinTheta, -1.0f, 1.0f);
+ }
+
+ /** \brief Assuming that the given direction is in the local coordinate
+ * system, return the cosine of the phi parameter in spherical coordinates */
+ inline static Float cosPhi(const Vector &v) {
+ Float sinTheta = Frame::sinTheta(v);
+ if (sinTheta == 0.0f)
+ return 1.0f;
+ return clamp(v.x / sinTheta, -1.0f, 1.0f);
+ }
+
+ /** \brief Assuming that the given direction is in the local coordinate
+ * system, return the squared sine of the phi parameter in spherical
+ * coordinates */
+ inline static Float sinPhiSquared(const Vector &v) {
+ return clamp(v.y * v.y / sinTheta2(v), 0.0f, 1.0f);
+ }
+
+ /** \brief Assuming that the given direction is in the local coordinate
+ * system, return the squared cosine of the phi parameter in spherical
+ * coordinates */
+ inline static Float cosPhiSquared(const Vector &v) {
+ return clamp(v.x * v.x / sinTheta2(v), 0.0f, 1.0f);
+ }
+
/// Return a string representation of this frame
inline std::string toString() const {
std::ostringstream oss;
diff --git a/src/bsdfs/conductor.cpp b/src/bsdfs/conductor.cpp
index b5632f58..baa33e10 100644
--- a/src/bsdfs/conductor.cpp
+++ b/src/bsdfs/conductor.cpp
@@ -32,7 +32,7 @@ MTS_NAMESPACE_BEGIN
* \parameter{k}{\Spectrum}{Imaginary part of the material's index of
* refraction, also known as absorption coefficient.
* \default{based on the value of \texttt{material}}}
- * \lastparameter{specular\showbreak Reflectance}{\Spectrum\Or\Texture}{
+ * \parameter{specular\showbreak Reflectance}{\Spectrum\Or\Texture}{
* Optional factor used to modulate the reflectance component
* \default{1.0}}
* }
diff --git a/src/bsdfs/dielectric.cpp b/src/bsdfs/dielectric.cpp
index 40d86b3b..78eb3a04 100644
--- a/src/bsdfs/dielectric.cpp
+++ b/src/bsdfs/dielectric.cpp
@@ -31,7 +31,7 @@ MTS_NAMESPACE_BEGIN
* 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 reflectance component\default{1.0}}
- * \lastparameter{specular\showbreak Transmittance}{\Spectrum\Or\Texture}{Optional
+ * \parameter{specular\showbreak Transmittance}{\Spectrum\Or\Texture}{Optional
* factor used to modulate the transmittance component\default{1.0}}
* }
*
diff --git a/src/bsdfs/difftrans.cpp b/src/bsdfs/difftrans.cpp
index 6267f15a..a8761a12 100644
--- a/src/bsdfs/difftrans.cpp
+++ b/src/bsdfs/difftrans.cpp
@@ -25,7 +25,7 @@ MTS_NAMESPACE_BEGIN
/*! \plugin{difftrans}{Diffuse transmitter}
*
* \parameters{
- * \lastparameter{transmittance}{\Spectrum\Or\Texture}{
+ * \parameter{transmittance}{\Spectrum\Or\Texture}{
* Specifies the diffuse transmittance of the material
* \default{0.5}
* }
diff --git a/src/bsdfs/diffuse.cpp b/src/bsdfs/diffuse.cpp
index f7c169d1..ce4fb005 100644
--- a/src/bsdfs/diffuse.cpp
+++ b/src/bsdfs/diffuse.cpp
@@ -25,17 +25,20 @@ MTS_NAMESPACE_BEGIN
/*!\plugin{diffuse}{Smooth diffuse material}
* \order{1}
* \parameters{
- * \lastparameter{reflectance}{\Spectrum\Or\Texture}{
- * Specifies the diffuse reflectance / albedo of the material \linebreak(Default: 0.5)
+ * \parameter{reflectance}{\Spectrum\Or\Texture}{
+ * Specifies the diffuse albedo of the
+ * material \default{0.5}
* }
* }
*
* \renderings{
- * \rendering{Homogeneous reflectance, see \lstref{diffuse-uniform}}{bsdf_diffuse_plain}
- * \rendering{Textured reflectance, see \lstref{diffuse-textured}}{bsdf_diffuse_textured}
+ * \rendering{Homogeneous reflectance, see \lstref{diffuse-uniform}}
+ * {bsdf_diffuse_plain}
+ * \rendering{Textured reflectance, see \lstref{diffuse-textured}}
+ * {bsdf_diffuse_textured}
* }
*
- * The smooth diffuse material (sometimes referred to as ``Lambertian'')
+ * The smooth diffuse material (also referred to as ``Lambertian'')
* represents an ideally diffuse material with a user-specified amount of
* reflectance. Any received illumination is scattered so that the surface
* looks the same independently of the direction of observation.
@@ -51,13 +54,15 @@ MTS_NAMESPACE_BEGIN
* consider using the \pluginref{twosided} BRDF adapter plugin.
* \vspace{4mm}
*
- * \begin{xml}[caption={A diffuse material, whose reflectance is specified as an sRGB color}, label=lst:diffuse-uniform]
+ * \begin{xml}[caption={A diffuse material, whose reflectance is specified
+ * as an sRGB color}, label=lst:diffuse-uniform]
*
*
*
* \end{xml}
*
- * \begin{xml}[caption=A diffuse material with a texture map, label=lst:diffuse-textured]
+ * \begin{xml}[caption=A diffuse material with a texture map,
+ * label=lst:diffuse-textured]
*
*
*
diff --git a/src/bsdfs/plastic.cpp b/src/bsdfs/plastic.cpp
index 9b162bdf..862566ed 100644
--- a/src/bsdfs/plastic.cpp
+++ b/src/bsdfs/plastic.cpp
@@ -31,7 +31,7 @@ MTS_NAMESPACE_BEGIN
* 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 component\default{1.0}}
- * \lastparameter{diffuse\showbreak Reflectance}{\Spectrum\Or\Texture}{Optional
+ * \parameter{diffuse\showbreak Reflectance}{\Spectrum\Or\Texture}{Optional
* factor used to modulate the diffuse component\default{0.5}}
* }
*
diff --git a/src/bsdfs/roughconductor.cpp b/src/bsdfs/roughconductor.cpp
index e22cf0b2..1ef66372 100644
--- a/src/bsdfs/roughconductor.cpp
+++ b/src/bsdfs/roughconductor.cpp
@@ -62,7 +62,7 @@ MTS_NAMESPACE_BEGIN
* \default{0.1}.
* }
* \parameter{alphaU, alphaV}{\Float\Or\Texture}{
- * Specifies the anisotropic rougness values along the tangent and
+ * Specifies the anisotropic roughness values along the tangent and
* bitangent directions. These parameter are only valid when
* \texttt{distribution=as}. \default{0.1}.
* }
@@ -73,7 +73,7 @@ MTS_NAMESPACE_BEGIN
* \parameter{k}{\Spectrum}{Imaginary part of the material's index of
* refraction, also known as absorption coefficient.
* \default{based on the value of \texttt{material}}}
- * \lastparameter{specular\showbreak Reflectance}{\Spectrum\Or\Texture}{Optional
+ * \parameter{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
@@ -117,7 +117,7 @@ MTS_NAMESPACE_BEGIN
* 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
+ * and $\alpha=0.3-0.7$ is \emph{extremely} rough (e.g. an etched or ground
* finish).
* \vspace{-2mm}
* \subsubsection*{Techical details}\vspace{-2mm}
diff --git a/src/bsdfs/roughdielectric.cpp b/src/bsdfs/roughdielectric.cpp
index ff4e5510..8a0082ac 100644
--- a/src/bsdfs/roughdielectric.cpp
+++ b/src/bsdfs/roughdielectric.cpp
@@ -59,7 +59,7 @@ MTS_NAMESPACE_BEGIN
* \default{0.1}.
* }
* \parameter{alphaU, alphaV}{\Float\Or\Texture}{
- * Specifies the anisotropic rougness values along the tangent and
+ * Specifies the anisotropic roughness values along the tangent and
* bitangent directions. These parameter are only valid when
* \texttt{distribution=as}. \default{0.1}.
* }
@@ -69,7 +69,7 @@ MTS_NAMESPACE_BEGIN
* 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 reflectance component\default{1.0}}
- * \lastparameter{specular\showbreak Transmittance}{\Spectrum\Or\Texture}{Optional
+ * \parameter{specular\showbreak Transmittance}{\Spectrum\Or\Texture}{Optional
* factor used to modulate the transmittance component\default{1.0}}
* }\vspace{4mm}
*
@@ -111,7 +111,7 @@ MTS_NAMESPACE_BEGIN
* 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
+ * and $\alpha=0.3-0.7$ is \emph{extremely} rough (e.g. an etched or ground
* finish).
*
* Please note that when using this plugin, it is crucial that the scene contains
@@ -142,7 +142,7 @@ MTS_NAMESPACE_BEGIN
* \renderings{
* \rendering{Ground glass (GGX, $\alpha$=0.304,
* \lstref{roughdielectric-roughglass})}{bsdf_roughdielectric_ggx_0_304.jpg}
- * \rendering{Textured rougness (\lstref{roughdielectric-textured})}
+ * \rendering{Textured roughness (\lstref{roughdielectric-textured})}
* {bsdf_roughdielectric_textured.jpg}
* }
*
@@ -467,7 +467,7 @@ public:
1. Take the Fresnel term with respect to the surface
normal to be a good approximation to the microsurface
Fresnel term -- this will be less true for higher
- rougness values. To be safe, clamp it to some
+ roughness values. To be safe, clamp it to some
reasonable range.
2. Use this approximate term and a random number to
choose between reflection and refraction component.
@@ -595,7 +595,7 @@ public:
1. Take the Fresnel term with respect to the surface
normal to be a good approximation to the microsurface
Fresnel term -- this will be less true for higher
- rougness values. To be safe, clamp it to some
+ roughness values. To be safe, clamp it to some
reasonable range.
2. Use this approximate term and a random number to
choose between reflection and refraction component.
diff --git a/src/bsdfs/roughdiffuse.cpp b/src/bsdfs/roughdiffuse.cpp
index 1a30e27e..5465c298 100644
--- a/src/bsdfs/roughdiffuse.cpp
+++ b/src/bsdfs/roughdiffuse.cpp
@@ -21,60 +21,65 @@
MTS_NAMESPACE_BEGIN
-/*!\plugin{diffuse}{Rough diffuse material}
+/*!\plugin{roughdiffuse}{Rough diffuse material}
* \order{2}
* \parameters{
* \parameter{reflectance}{\Spectrum\Or\Texture}{
- * Specifies the reflectance / albedo of the material \linebreak(Default: 0.5)
+ * Specifies the diffuse albedo of the
+ * material. \default{0.5}
* }
- * \lastparameter{alpha}{\Spectrum\Or\Texture}{
- * Specifies the roughness of the unresolved surface microgeometry.
- * This parameter is approximately equal to the \emph{root mean square}
- * (RMS) slope of the microfacets.\default{0.1}
+ * \parameter{alpha}{\Spectrum\Or\Texture}{
+ * Specifies the roughness of the unresolved surface microgeometry
+ * using the \emph{root mean square} (RMS) slope of the
+ * microfacets. \default{0.2}
+ * }
+ * \parameter{useFastApprox}{\Boolean}{
+ * This parameter selects between the full version of the model
+ * or a fast approximation that still retains most qualitative features.
+ * \default{\texttt{false}, i.e. use the high-quality version}
* }
* }
*
* \renderings{
- * \rendering{Homogeneous reflectance, see \lstref{diffuse-uniform}}{bsdf_diffuse_plain}
- * \rendering{Textured reflectance, see \lstref{diffuse-textured}}{bsdf_diffuse_textured}
+ * \rendering{Smooth diffuse surface ($\alpha=0$)}
+ * {bsdf_roughdiffuse_0}
+ * \rendering{Very rough diffuse surface ($\alpha=0.7$)}
+ * {bsdf_roughdiffuse_0_7}
+ * \vspace{-3mm}
+ * \caption{The effect of switching from smooth to rough diffuse scattering
+ * is fairly subtle on this model---generally, there will be higher
+ * reflectance at grazing angles, as well as an overall reduced contrast.}\vspace{3mm}
* }
*
- * This reflectance model describes scattering from a rough diffuse material,
- * such as plaster, sand, clay, or concrete.
+ * This reflectance model describes the interaction of light with a rough
+ * diffuse material, such as plaster, sand, clay, or concrete.
* The underlying theory was developed by Oren and Nayar
* \cite{Oren1994Generalization}, who model the microscopic surface structure as
* unresolved planar facets arranged in V-shaped grooves, where each facet
* is an ideal diffuse reflector. The model takes into account shadowing,
* masking, as well as interreflections between the facets.
*
- * Since the original publication in 1994, this approach has been shown to
+ * Since the original publication, this approach has been shown to
* be a good match for many real-world materials, particularly compared
* to Lambertian scattering, which does not take surface roughness into account.
*
* The implementation in Mitsuba uses a surface roughness parameter $\alpha$ that
- * is slighly different from the slope-area variance in the original paper.
+ * is slighly different from the slope-area variance in the original 1994 paper.
* The reason for this change is to make the parameter $\alpha$ portable
- * across different models (i.e. \pluginref{roughglass},
+ * across different models (i.e. \pluginref{roughglass}, \pluginref{roughplastic},
* \pluginref{roughconductor}).
*
* To get an intuition about the effect of the
* 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 (for such small
- * values, the model will behave almost identically to \pluginref{diffuse}), $\alpha=0.1$
- * is relatively rough, and $\alpha=0.3-0.5$ is \emph{extremely} rough
+ * values, the model will behave identically to \pluginref{diffuse}), $\alpha=0.1$
+ * is relatively rough, and $\alpha=0.3-0.7$ is \emph{extremely} rough
* (e.g. an etched or ground surface).
*
* 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={A diffuse material, whose reflectance is specified as an sRGB color}, label=lst:diffuse-uniform]
- *
- *
- *
- * \end{xml}
*/
class RoughDiffuse : public BSDF {
public:
@@ -84,9 +89,11 @@ public:
'reflectance' and 'diffuseReflectance' as parameter names */
m_reflectance = new ConstantSpectrumTexture(props.getSpectrum(
props.hasProperty("reflectance") ? "reflectance"
- : "diffuseReflectance", Spectrum(.5f)));
+ : "diffuseReflectance", Spectrum(0.5f)));
- m_alpha = new ConstantFloatTexture(props.getFloat("alpha", 0.1f));
+ m_useFastApprox = props.getBoolean("useFastApprox", false);
+
+ m_alpha = new ConstantFloatTexture(props.getFloat("alpha", 0.2f));
m_components.push_back(EGlossyReflection | EFrontSide);
m_usesRayDifferentials = false;
}
@@ -95,6 +102,7 @@ public:
: BSDF(stream, manager) {
m_reflectance = static_cast(manager->getInstance(stream));
m_alpha = static_cast(manager->getInstance(stream));
+ m_useFastApprox = stream->readBool();
m_components.push_back(EGlossyReflection | EFrontSide);
m_usesRayDifferentials = m_reflectance->usesRayDifferentials();
}
@@ -110,7 +118,7 @@ public:
Spectrum eval(const BSDFQueryRecord &bRec, EMeasure measure) const {
if (!(bRec.typeMask & EGlossyReflection) || measure != ESolidAngle
- || Frame::cosTheta(bRec.wi) <= 0
+ || Frame::cosTheta(bRec.wi) <= 0
|| Frame::cosTheta(bRec.wo) <= 0)
return Spectrum(0.0f);
@@ -124,12 +132,80 @@ public:
Float sigma = m_alpha->getValue(bRec.its).average()
* conversionFactor;
- Float sigma2 = sigma*sigma;
- Float A = 10.f - (sigma2 / (2.0f * (sigma2 + 0.33f)));
- Float B = 0.45f * sigma2 / (sigma2 + 0.09f);
+ const Float sigma2 = sigma*sigma;
- return m_reflectance->getValue(bRec.its)
- * (INV_PI * Frame::cosTheta(bRec.wo));
+ Float sinThetaI = Frame::sinTheta(bRec.wi),
+ sinThetaO = Frame::sinTheta(bRec.wo);
+
+ Float cosPhiDiff = 0;
+ if (sinThetaI > Epsilon && sinThetaO > Epsilon) {
+ /* Compute cos(phiO-phiI) using the half-angle formulae */
+ Float sinPhiI = Frame::sinPhi(bRec.wi),
+ cosPhiI = Frame::cosPhi(bRec.wi),
+ sinPhiO = Frame::sinPhi(bRec.wo),
+ cosPhiO = Frame::cosPhi(bRec.wo);
+ cosPhiDiff = cosPhiI * cosPhiO + sinPhiI * sinPhiO;
+ }
+
+ if (m_useFastApprox) {
+ Float A = 1.0f - 0.5f * sigma2 / (sigma2 + 0.33f),
+ B = 0.45f * sigma2 / (sigma2 + 0.09f),
+ sinAlpha, tanBeta;
+
+ if (Frame::cosTheta(bRec.wi) > Frame::cosTheta(bRec.wo)) {
+ sinAlpha = sinThetaO;
+ tanBeta = sinThetaI / Frame::cosTheta(bRec.wi);
+ } else {
+ sinAlpha = sinThetaI;
+ tanBeta = sinThetaO / Frame::cosTheta(bRec.wo);
+ }
+
+ return m_reflectance->getValue(bRec.its)
+ * (INV_PI * Frame::cosTheta(bRec.wo) * (A + B
+ * std::max(cosPhiDiff, (Float) 0.0f) * sinAlpha * tanBeta));
+ } else {
+ Float sinThetaI = Frame::sinTheta(bRec.wi),
+ sinThetaO = Frame::sinTheta(bRec.wo),
+ thetaI = std::acos(Frame::cosTheta(bRec.wi)),
+ thetaO = std::acos(Frame::cosTheta(bRec.wo)),
+ alpha = std::max(thetaI, thetaO),
+ beta = std::min(thetaI, thetaO);
+
+ Float sinAlpha, sinBeta, tanBeta;
+ if (Frame::cosTheta(bRec.wi) > Frame::cosTheta(bRec.wo)) {
+ sinAlpha = sinThetaO; sinBeta = sinThetaI;
+ tanBeta = sinThetaI / Frame::cosTheta(bRec.wi);
+ } else {
+ sinAlpha = sinThetaI; sinBeta = sinThetaO;
+ tanBeta = sinThetaO / Frame::cosTheta(bRec.wo);
+ }
+
+ Float tmp = sigma2 / (sigma2 + 0.09f),
+ tmp2 = (4*INV_PI*INV_PI) * alpha * beta,
+ tmp3 = 2*beta*INV_PI;
+
+ Float C1 = 1.0f - 0.5f * sigma2 / (sigma2 + 0.33f),
+ C2 = 0.45f * tmp,
+ C3 = 0.125f * tmp * tmp2 * tmp2,
+ C4 = 0.17f * sigma2 / (sigma2 + 0.13f);
+
+ if (cosPhiDiff > 0)
+ C2 *= sinAlpha;
+ else
+ C2 *= sinAlpha - tmp3*tmp3*tmp3;
+
+ /* Compute tan(0.5 * (alpha+beta)) using the half-angle formulae */
+ Float tanHalf = (sinAlpha + sinBeta) / (
+ std::sqrt(std::max((Float) 0.0f, 1.0f - sinAlpha * sinAlpha)) +
+ std::sqrt(std::max((Float) 0.0f, 1.0f - sinBeta * sinBeta)));
+
+ Spectrum rho = m_reflectance->getValue(bRec.its),
+ snglScat = rho * (C1 + cosPhiDiff * C2 * tanBeta +
+ (1.0f - std::abs(cosPhiDiff)) * C3 * tanHalf),
+ dblScat = rho * rho * (C4 * (1.0f - cosPhiDiff*tmp3*tmp3));
+
+ return (snglScat + dblScat) * (INV_PI * Frame::cosTheta(bRec.wo));
+ }
}
Float pdf(const BSDFQueryRecord &bRec, EMeasure measure) const {
@@ -148,7 +224,8 @@ public:
bRec.wo = squareToHemispherePSA(sample);
bRec.sampledComponent = 0;
bRec.sampledType = EGlossyReflection;
- return m_reflectance->getValue(bRec.its);
+ return eval(bRec, ESolidAngle) /
+ (Frame::cosTheta(bRec.wo) * INV_PI);
}
Spectrum sample(BSDFQueryRecord &bRec, Float &pdf, const Point2 &sample) const {
@@ -159,8 +236,7 @@ public:
bRec.sampledComponent = 0;
bRec.sampledType = EGlossyReflection;
pdf = Frame::cosTheta(bRec.wo) * INV_PI;
- return m_reflectance->getValue(bRec.its)
- * (INV_PI * Frame::cosTheta(bRec.wo));
+ return eval(bRec, ESolidAngle);
}
void addChild(const std::string &name, ConfigurableObject *child) {
@@ -182,6 +258,7 @@ public:
manager->serialize(stream, m_reflectance.get());
manager->serialize(stream, m_alpha.get());
+ stream->writeBool(m_useFastApprox);
}
std::string toString() const {
@@ -189,7 +266,8 @@ public:
oss << "RoughDiffuse[" << endl
<< " name = \"" << getName() << "\"," << endl
<< " reflectance = " << indent(m_reflectance->toString()) << "," << endl
- << " alpha = " << indent(m_alpha->toString()) << endl
+ << " alpha = " << indent(m_alpha->toString()) << "," << endl
+ << " useFastApprox = " << m_useFastApprox << endl
<< "]";
return oss.str();
}
@@ -200,6 +278,7 @@ public:
private:
ref m_reflectance;
ref m_alpha;
+ bool m_useFastApprox;
};
// ================ Hardware shader implementation ================
@@ -233,11 +312,27 @@ public:
oss << "vec3 " << evalName << "(vec2 uv, vec3 wi, vec3 wo) {" << endl
<< " if (cosTheta(wi) < 0.0 || cosTheta(wo) < 0.0)" << endl
<< " return vec3(0.0);" << endl
- << " return " << depNames[0] << "(uv) * 0.31831 * cosTheta(wo);" << endl
+ << " float sigma = " << depNames[1] << "(uv)[0] * 0.70711;" << endl
+ << " float sigma2 = sigma * sigma;" << endl
+ << " float A = 1.0 - 0.5 * sigma2 / (sigma2 + 0.33);" << endl
+ << " float B = 0.45 * sigma2 / (sigma2 + 0.09);" << endl
+ << " float maxCos = max(0.0, cosPhi(wi)*cosPhi(wo)+sinPhi(wi)*sinPhi(wo));" << endl
+ << " float sinAlpha, tanBeta;" << endl
+ << " if (cosTheta(wi) > cosTheta(wo)) {" << endl
+ << " sinAlpha = sinTheta(wo);" << endl
+ << " tanBeta = sinTheta(wi) / cosTheta(wi);" << endl
+ << " } else {" << endl
+ << " sinAlpha = sinTheta(wi);" << endl
+ << " tanBeta = sinTheta(wo) / cosTheta(wo);" << endl
+ << " }" << endl
+ << " float value = A + B * maxCos * sinAlpha * tanBeta;" << endl
+ << " return " << depNames[0] << "(uv) * 0.31831 * cosTheta(wo) * value;" << endl
<< "}" << endl
<< endl
<< "vec3 " << evalName << "_diffuse(vec2 uv, vec3 wi, vec3 wo) {" << endl
- << " return " << evalName << "(uv, wi, wo);" << endl
+ << " if (cosTheta(wi) < 0.0 || cosTheta(wo) < 0.0)" << endl
+ << " return vec3(0.0);" << endl
+ << " return " << depNames[0] << "(uv) * 0.31831 * cosTheta(wo);" << endl
<< "}" << endl;
}
diff --git a/src/converter/collada.cpp b/src/converter/collada.cpp
index 95b8b87b..1f761be2 100644
--- a/src/converter/collada.cpp
+++ b/src/converter/collada.cpp
@@ -1103,7 +1103,7 @@ void loadCamera(ColladaContext &ctx, Transform transform, domCamera &camera) {
int xres=768;
// Cameras in Mitsuba point along the positive Z axis (COLLADA: neg. Z)
- transform = transform * Transform::scale(Vector(1,1,-1));
+ transform = transform * Transform::scale(Vector(1, 1, -1));
std::ostringstream matrix;
for (int i=0; i<4; ++i)
@@ -1130,14 +1130,8 @@ void loadCamera(ColladaContext &ctx, Transform transform, domCamera &camera) {
xres = ctx.cvt->m_xres;
aspect = (Float) ctx.cvt->m_xres / (Float) ctx.cvt->m_yres;
} else {
- if (persp->getAspect_ratio().cast() != 0) {
+ if (persp->getAspect_ratio().cast() != 0)
aspect = (Float) persp->getAspect_ratio()->getValue();
- if (std::abs(aspect-0.1) < Epsilon) {
- SLog(EWarn, "Found the suspicious aspect ratio \"0.1\", which is likely due to a bug in Blender 2.5"
- " - setting to 1.0. Please use the \"-r\" parameter to override the resolution.");
- aspect = 1.0f;
- }
- }
}
ctx.os << "\t" << endl;
if (persp->getXfov().cast()) {
diff --git a/src/libcore/transform.cpp b/src/libcore/transform.cpp
index b6b5b79f..23501184 100644
--- a/src/libcore/transform.cpp
+++ b/src/libcore/transform.cpp
@@ -174,16 +174,16 @@ Transform Transform::glOrthographic(Float clipNear, Float clipFar) {
Transform Transform::lookAt(const Point &p, const Point &t, const Vector &up) {
Matrix4x4 result;
- Vector dirct = normalize(t-p);
- Vector right = normalize(cross(dirct, up));
+ Vector dir = normalize(t-p);
+ Vector left = normalize(cross(normalize(up), dir));
/* Generate a new, orthogonalized up vector */
- Vector newUp = cross(right, dirct);
+ Vector newUp = cross(dir, left);
/* Store as columns */
- result.m[0][0] = right.x; result.m[1][0] = right.y; result.m[2][0] = right.z; result.m[3][0] = 0;
+ result.m[0][0] = left.x; result.m[1][0] = left.y; result.m[2][0] = left.z; result.m[3][0] = 0;
result.m[0][1] = newUp.x; result.m[1][1] = newUp.y; result.m[2][1] = newUp.z; result.m[3][1] = 0;
- result.m[0][2] = dirct.x; result.m[1][2] = dirct.y; result.m[2][2] = dirct.z; result.m[3][2] = 0;
+ result.m[0][2] = dir.x; result.m[1][2] = dir.y; result.m[2][2] = dir.z; result.m[3][2] = 0;
result.m[0][3] = p.x; result.m[1][3] = p.y; result.m[2][3] = p.z; result.m[3][3] = 1;
return Transform(result);
diff --git a/src/libhw/vpl.cpp b/src/libhw/vpl.cpp
index d3832f01..f6729376 100644
--- a/src/libhw/vpl.cpp
+++ b/src/libhw/vpl.cpp
@@ -308,6 +308,7 @@ void VPLShaderManager::setVPL(const VPL &vpl) {
case 4: lightViewTrafo = Transform::lookAt(p, p + Vector(0, 0, 1), Vector(0, 1, 0)).inverse(); break;
case 5: lightViewTrafo = Transform::lookAt(p, p + Vector(0, 0, -1), Vector(0, 1, 0)).inverse(); break;
}
+ lightViewTrafo = Transform::scale(Vector(-1, 1, 1)) * lightViewTrafo;
const Matrix4x4 &viewMatrix = lightViewTrafo.getMatrix();
m_shadowProgram->setParameter(m_shadowProgramParam_cubeMapTransform[i], lightProjTrafo * lightViewTrafo);
m_shadowProgram->setParameter(m_shadowProgramParam_depthVec[i], Vector4(
@@ -331,6 +332,7 @@ void VPLShaderManager::setVPL(const VPL &vpl) {
case 4: lightViewTrafo = Transform::lookAt(p, p + Vector(0, 0, 1), Vector(0, 1, 0)).inverse(); break;
case 5: lightViewTrafo = Transform::lookAt(p, p + Vector(0, 0, -1), Vector(0, 1, 0)).inverse(); break;
}
+ lightViewTrafo = Transform::scale(Vector(-1, 1, 1)) * lightViewTrafo;
const Matrix4x4 &viewMatrix = lightViewTrafo.getMatrix();
m_altShadowProgram->setParameter(m_altShadowProgramParam_cubeMapTransform, lightProjTrafo * lightViewTrafo);
@@ -368,13 +370,6 @@ void VPLShaderManager::configure(const VPL &vpl, const BSDF *bsdf,
return;
}
-#if 0
- if (bsdfShader->getFlags() & Shader::ETransparent) {
- m_renderer->setColor(Spectrum(1.0f), 0.3f);
- return;
- }
-#endif
-
bool anisotropic = bsdf->getType() & BSDF::EAnisotropic;
m_targetConfig = VPLProgramConfiguration(vplShader, bsdfShader,
@@ -495,6 +490,8 @@ void VPLShaderManager::configure(const VPL &vpl, const BSDF *bsdf,
<< "float sinTheta2(vec3 v) { return 1.0-v.z*v.z; }" << endl
<< "float sinTheta(vec3 v) { float st2 = sinTheta2(v); if (st2 <= 0) return 0.0; else return sqrt(sinTheta2(v)); }" << endl
<< "float tanTheta(vec3 v) { return sinTheta(v)/cosTheta(v); }" << endl
+ << "float sinPhi(vec3 v) { return v.y/sinTheta(v); }" << endl
+ << "float cosPhi(vec3 v) { return v.x/sinTheta(v); }" << endl
<< endl;
std::string vplEvalName, bsdfEvalName, lumEvalName;
diff --git a/src/librender/scene.cpp b/src/librender/scene.cpp
index a52e8e3d..f45146e0 100644
--- a/src/librender/scene.cpp
+++ b/src/librender/scene.cpp
@@ -237,14 +237,17 @@ void Scene::configure() {
Float maxExtents = std::max(extents.x, extents.y);
Float distance = maxExtents/(2.0f * std::tan(45 * .5f * M_PI/180));
- props.setTransform("toWorld", Transform::translate(Vector(center.x, center.y, aabb.min.z - distance)));
+ props.setTransform("toWorld", Transform::translate(Vector(center.x,
+ center.y, aabb.min.z - distance)));
props.setFloat("fov", 45.0f);
- m_camera = static_cast (PluginManager::getInstance()->createObject(MTS_CLASS(Camera), props));
+ m_camera = static_cast (PluginManager::getInstance()->
+ createObject(MTS_CLASS(Camera), props));
m_camera->configure();
m_sampler = m_camera->getSampler();
} else {
- Log(EWarn, "Unable to set up a default camera -- does the scene contain anything at all?");
+ Log(EWarn, "Unable to set up a default camera -- does the scene "
+ "contain anything at all?");
}
}
diff --git a/src/qtgui/glwidget.cpp b/src/qtgui/glwidget.cpp
index 940919c3..e6e7a7b8 100644
--- a/src/qtgui/glwidget.cpp
+++ b/src/qtgui/glwidget.cpp
@@ -675,7 +675,7 @@ void GLWidget::mouseMoveEvent(QMouseEvent *event) {
if (coords.x < 0 || coords.x > M_PI)
m_context->up *= -1;
- if (camera->getViewTransform().det3x3() < 0)
+ if (camera->getViewTransform().det3x3() > 0)
camera->setInverseViewTransform(Transform::lookAt(p, target, m_context->up));
else
camera->setInverseViewTransform(
@@ -693,7 +693,7 @@ void GLWidget::mouseMoveEvent(QMouseEvent *event) {
* camera->getViewTransform();
d = trafo.inverse()(Vector(0,0,1));
- if (camera->getViewTransform().det3x3() < 0)
+ if (camera->getViewTransform().det3x3() > 0)
camera->setInverseViewTransform(Transform::lookAt(p, p+d, up));
else
camera->setInverseViewTransform(
@@ -713,7 +713,7 @@ void GLWidget::mouseMoveEvent(QMouseEvent *event) {
Float roll = rel.x() * m_mouseSensitivity * .02f;
Float fovChange = rel.y() * m_mouseSensitivity * .03f;
- if (camera->getViewTransform().det3x3() < 0) {
+ if (camera->getViewTransform().det3x3() > 0) {
m_context->up = Transform::rotate(d, roll)(up);
camera->setInverseViewTransform(Transform::lookAt(p, p+d, m_context->up));
} else {
@@ -743,7 +743,7 @@ void GLWidget::mouseMoveEvent(QMouseEvent *event) {
Vector d = Vector(camera->getImagePlaneNormal());
p = p + (oldFocusDepth - focusDepth) * d;
- if (camera->getViewTransform().det3x3() < 0)
+ if (camera->getViewTransform().det3x3() > 0)
camera->setInverseViewTransform(Transform::lookAt(p, p+d, up));
else
camera->setInverseViewTransform(
@@ -809,8 +809,13 @@ void GLWidget::wheelEvent(QWheelEvent *event) {
Vector d = Vector(camera->getImagePlaneNormal());
Point o = camera->getPosition() + (oldFocusDepth - focusDepth) * d;
- camera->setInverseViewTransform(
- Transform::lookAt(o, o+d, up));
+ if (camera->getViewTransform().det3x3() > 0)
+ camera->setInverseViewTransform(Transform::lookAt(o, o+d, up));
+ else
+ camera->setInverseViewTransform(
+ Transform::lookAt(o, o+d, up) *
+ Transform::scale(Vector(-1,1,1))
+ );
m_wheelTimer->reset();
if (!m_movementTimer->isActive())
diff --git a/src/qtgui/save.cpp b/src/qtgui/save.cpp
index c8f190fe..86c8b8d4 100644
--- a/src/qtgui/save.cpp
+++ b/src/qtgui/save.cpp
@@ -165,7 +165,7 @@ void saveScene(QWidget *parent, SceneContext *ctx, const QString &targetFile) {
u = ctx->up;
Point t, p = sceneCamera->getInverseViewTransform()(Point(0,0,0));
- if (sceneCamera->getViewTransform().det3x3() > 0) {
+ if (sceneCamera->getViewTransform().det3x3() < 0) {
QDomElement scale = doc.createElement("scale");
scale.setAttribute("x", "-1");
cameraTransform.insertBefore(scale, lookAt);