documentation updates, allow to specify the configuration file

SConstruct

@@ -5,12 +5,17 @@ import os
 import fnmatch
 import multiprocessing
 
-if not os.path.exists('config.py'):
+AddOption("--configfile", dest="configfile", type="string", nargs=1, action='store', help='Manually specify a configuration file')
+configFile = GetOption('configfile')
+if configFile == None:
+	configFile = "config.py"
+
+if not os.path.exists(configFile):
 	print 'A configuration file must be selected! Have a look at \"README\"'
 	Exit(1)
 
 # Parse configuration options
-vars = Variables('config.py');
+vars = Variables(configFile);
 vars.Add('CXX',           'C++ compiler')
 vars.Add('CC',            'C compiler')
 vars.Add('CXXFLAGS',      'C++ flags')

doc/compiling.tex

@@ -159,7 +159,50 @@ In the case that you have multiple processors, you might want to parallelize the
 If all goes well, the build process will finish successfully after a few
 minutes. In comparison to the other platforms, you don't have to run the \code{setpath.sh} script at this point. 
 All binaries are now located in the \code{dist} directory, and they should be executed directly from there.
+\subsubsection{Integration with the Visual Studio interface}
+If you plan to modify Mitsuba and you enjoy working within the Visual
+Studio interface, the following steps should help you integrate the two
+(thanks to Marios Papas for this description!). The instructions are for Visual Studio 2008,
+hence some changes may be necessary on other versions. Also, they assume
+that you followed all of the previous steps.
 
+\begin{enumerate}
+\item Create a copy of \code{config.py} in the Mitsuba root directory and
+name it \code{config\_debug.py}. This will later be used to support debug
+builds. Open the file and make the following changes:
+\begin{enumerate}
+\item In \code{CXXFLAGS}, replace \code{/Ox} by \code{/Od} (this disables
+optimizations, which is necessary to see variable contents in the debugger)
+\item In \code{CXXFLAGS}, add an entry \code{'/Z7'}.
+\item In \code{LINKFLAGS}, add an entry \code{'/DEBUG'}.
+\end{enumerate}
+\item Now, start a fresh instance of Visual Studio and click on 
+the \emph{File$\to$New$\to$Project From Existing Code} menu entry.
+\item Choose \emph{Visual C++} from the drop-down menu and press \emph{Next}
+\item Specify the Mitsuba root directory at the top and enter \emph{mitsuba}
+as the project name. Uncheck \emph{Show all files in Solution explorer} and
+press \emph{Next}.
+\item Choose \emph{Use external build systen} and press \emph{Next}.
+\item In the following, feel free to replace any occurrence of
+\code{scons} by \code{scons -jX}, where \code{X} is the number of
+cores in your machine (this will provide faster build times). 
+Fill in the following values:
+
+\begin{tabular}{ll}i
+\emph{Build command line}:&\code{scons}\\
+\emph{Rebuild command line}:&\code{scons -c \&\& scons}\\
+\emph{Clean command line}:&\code{scons -c}\\
+\emph{Output}:&\code{dist\textbackslash mtsgui.exe}\\
+\emph{Include search paths}:&\code{C:\textbackslash Qt\textbackslash
+include} (your Qt path may be different)
+\end{tabular}
+\item On the next page, uncheck \emph{Same as Debug configuration}.
+Afterwards, enter exactly the same values as before except replacing
+every occurrence of \code{scons} by \code{scons {-}-cfg=config\_debug.py}.
+\item Click \emph{Finish} and wait for IntelliSense to finish (this might take
+a while).
+\item Switch to the Release configuration.
+\end{enumerate}
 \subsection{Building on Mac OS X}
 On Mac OS X, you will need to install both scons (\code{www.scons.org}) and 
 a recent release of XCode. You will also need to get Qt 4.7.0 or a newer version

include/mitsuba/render/sampler.h

@@ -38,12 +38,13 @@ MTS_NAMESPACE_BEGIN
  *
  * The general interaction between a sampler and a rendering algorithm is as 
  * follows: Before beginning to render a pixel, the rendering algorithm calls 
- * \ref generate(). The first pixel sample is generated, after which \ref
+ * \ref generate(). The first pixel sample can now be computed, after which
- * advance() needs to be invoked, and so on. Note that any implementations need
+ * \ref advance() needs to be invoked. This repeats until all pixel samples have
- * to be configured for a certain number of pixel samples, and exceeding these
+ * been generated. Note that some implementations need to be configured for a 
- * will lead to an exception being thrown. While computing a pixel sample, the
+ * certain number of pixel samples, and exceeding these will lead to an 
- * rendering algorithm usually requests batches of (pseudo-) random numbers 
+ * exception being thrown. While computing a pixel sample, the rendering 
- * using the \ref next1D(), \ref next2D(), \ref next1DArray() and 
+ * algorithm usually requests batches of (pseudo-) random numbers using 
+ * the \ref next1D(), \ref next2D(), \ref next1DArray() and 
  * \ref next2DArray() functions.
  *
  */