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Finish clean up Swizzling text

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Jesse Talavera-Greenberg 2015-12-03 13:43:20 -05:00
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doc/glm.tex
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@ -199,9 +199,9 @@ GLM does not depend on external libraries or external headers such as \verb|gl.h
\newpage{}
\section{Swizzle Operators}
\section{Swizzling}
Shader languages like GLSL often feature so-called swizzle operators, which may be used to freely select and arrange a vector's components. For example, \verb|variable.x|, \verb|variable.xzy| and \verb|variable.zxyy| respectively form a scalar, a 3D vector and a 4D vector. The result of a swizzle expression in GLSL can be either an R-value or an L-value. Swizzle expressions can be written with characters from exactly one of \verb|xyzw| (usually for positions), \verb|rgba| (usually for colors), or \verb|stpq| (usually for texture coordinates).
Shader languages like GLSL often feature so-called swizzle expression, which may be used to freely select and arrange a vector's components. For example, \verb|variable.x|, \verb|variable.xzy| and \verb|variable.zxyy| respectively form a scalar, a 3D vector and a 4D vector. The result of a swizzle expression in GLSL can be either an R-value or an L-value. Swizzle expressions can be written with characters from exactly one of \verb|xyzw| (usually for positions), \verb|rgba| (usually for colors), or \verb|stpq| (usually for texture coordinates).
\begin{glslcode}
vec4 A;
@ -213,13 +213,13 @@ vec3 C = A.bgr;
vec3 D = B.rsz; // Invalid, won't compile
\end{glslcode}
GLM optionally supports some of this functionality, through the methods described in the following sections. Swizzle operators can be enabled by defining \verb|GLM_SWIZZLE| before including any GLM header files, or as part of your project's build process.
GLM optionally supports some of this functionality via the methods described in the following sections. Swizzling can be enabled by defining \verb|GLM_SWIZZLE| before including any GLM header files, or as part of your project's build process.
\emph{Note that enabling swizzle operators will massively increase the size of your binaries and the time it takes to compile them!}
\emph{Note that enabling swizzle expressions will massively increase the size of your binaries and the time it takes to compile them!}
\subsection{Default C++98 Implementation}
When compiling GLM as C++98, R-value swizzle operators are simulated through member functions of each vector type.
When compiling GLM as C++98, R-value swizzle expressions are simulated through member functions of each vector type.
\begin{cppcode}
#define GLM_SWIZZLE // Or define when building (e.g. -DGLM_SWIZZLE)
@ -257,7 +257,7 @@ void foo()
\subsection{Anonymous Union Member Implementation}
Visual C++ supports, as a \emph{non-standard language extension}, anonymous \verb|struct|s in \verb|union|s. This enables a very powerful implementation of swizzle operators on Windows, which both allows L-value swizzle operators and makes the syntax for it closer to GLSL's. This implementation of the swizzle operators is only enabled when the language extension is enabled and \verb|GLM_SWIZZLE| is defined.
Visual C++ supports, as a \emph{non-standard language extension}, anonymous \verb|struct|s in \verb|union|s. This enables a very powerful implementation of swizzle expressions on Windows, which both allows L-value swizzle operators and makes the syntax for it closer to GLSL's. You must enable this language extension in a supported compiler and define \verb|GLM_SWIZZLE| to use this implementation of swizzling.
\begin{cppcode}
#define GLM_SWIZZLE
@ -280,7 +280,7 @@ void foo()
}
\end{cppcode}
This versions returns implementation-specific objects that \emph{implicitly convert} to their respective vector types. Unfortunately, these extra types can't be directly used by GLM functions; the programmer must instead convert a swizzle-made \say{vector} to a conventional vector type or call the swizzle object's \verb|operator()|.
This versions returns implementation-specific objects that \emph{implicitly convert} to their respective vector types. Unfortunately, these extra types can't be directly used by GLM functions; you must instead convert a swizzle-made \say{vector} to a conventional vector type or call the swizzle object's \verb|operator()|.
\begin{cppcode}
#define GLM_SWIZZLE