44 lines
1.8 KiB
TeX
44 lines
1.8 KiB
TeX
\newpage
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\subsection{Sensors}
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\label{sec:sensors}
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In Mitsuba, \emph{sensors}, along with a \emph{film}, are responsible for recording radiance
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measurements in some usable format. This includes default choices such as perspective
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or orthographic cameras, as well as more specialized sensors that measure the radiance
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into a given direction or the irradiance received by a certain surface. This subsection
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lists the available choices.
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\subsubsection*{Syntax}
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In the XML scene description language, a sensor declaration looks as follows
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\begin{xml}
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<scene version=$\MtsVer$>
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<!-- ... scene contents ... -->
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<sensor type="... sensor type ...">
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<!-- ... sensor parameters ... -->
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<sampler type=" ... sampler type ... ">
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<!-- ... sampler parameters ... -->
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</sampler>
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<film type=" ... film type ... ">
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<!-- ... film parameters ... -->
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</film>
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</sensor>
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</scene>
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\end{xml}
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In other words, the \code{<sensor>} declaration is a child element of the \code{<scene>} (the particular
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position in the scene file does not play a role). Nested within the sensor declaration is a
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sampler instance (described in \secref{samplers}) and a film instance (described in
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\secref{films}).
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\subsubsection*{Handedness convention}
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Sensors in Mitsuba are \emph{right-handed}.
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Any number of rotations and translations can be applied to them
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without changing this property. By default they are located at the
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origin and oriented in such a way that in the rendered image, $+X$ points left,
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$+Y$ points upwards, and $+Z$ points along the viewing direction.
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Left-handed sensors are also supported. To switch the handedness,
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flip any one of the axes, e.g. by passing a scale transformation like
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\code{<scale x="-1"/>} to the sensor's \code{toWorld} parameter.
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