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updated the documentation

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ikits 2004-02-19 06:17:47 +00:00
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@ -35,6 +35,9 @@ GLEW: The OpenGL Extension Wrangler Library
<tr><td align=center>
<a href="#Namespace"><small>Separate Namespace</small></a>
</td></tr>
<tr><td align=center>
<a href="#Context"><small>Multiple Rendering Contexts (GLEW MX)</small></a>
</td></tr>
<tr><td align=center><a href="#Issues"><small>Known Issues</small></a></td></tr>
<tr><td align=center><a href="#Credits"><small>Credits, Copyright</small></a></td></tr>
<tr><td align=center><a href="#Log"><small>Change Log</small></a></td></tr>
@ -49,14 +52,15 @@ GLEW: The OpenGL Extension Wrangler Library
<td bgcolor="#ffffff">
<center><a name="Introduction"><h2>Introduction</h2></a></center>
<p>
The goal of the OpenGL Extension Wrangler Library (GLEW) is to assist
C/C++ OpenGL developers with two tedious tasks: initializing and
using extensions and writing portable applications. GLEW provides
an efficient run-time mechanism to determine whether a certain
extension is supported by the driver or not. OpenGL core and
extension functionality is exposed via a single header file. GLEW
currently supports SGI systems and PCs with commodity graphics cards
on three operating systems: Windows, Linux, and IRIX.
C/C++ OpenGL developers with two tedious tasks: initializing and using
extensions and writing portable applications. GLEW provides an
efficient run-time mechanism to determine whether a certain extension
is supported by the driver or not. OpenGL core and extension
functionality is exposed via a single header file. GLEW currently
supports a variety of platforms and operating systems, including
Windows, Linux, Darwin, Irix, and Solaris.
<p>
</td>
</tr>
@ -385,9 +389,20 @@ href="wglinfo.txt">here</a>. For additional usage information, type
<tt>glewinfo</tt> allows you to verify the entry points for the
extensions supported on your platform. It uses GLEW to find out which
extensions and entry points are available. On Windows it reports the
results to a text file called <tt>glewinfo.txt</tt>, on Linux and IRIX
it prints them to <tt>stdout</tt>.
results to a text file called <tt>glewinfo.txt</tt>, on Unix it prints
them to <tt>stdout</tt>. <p>
Windows Usage: <blockquote><pre>glewinfo [-pf &lt;id&gt;]</pre></blockquote>
where <tt>&lt;id&gt;</tt> is the pixelformat id for which the
capabilities are displayed.
<p>
Unix Usage:
<blockquote><pre>glewinfo [-display &lt;dpy&gt;] [-visual &lt;id&gt;]</pre></blockquote>
where <tt>&lt;dpy&gt;</tt> is the X11 display and <tt>&lt;id&gt;</tt> is
the visual id for which the capabilities are displayed.
<p>
</td>
</tr>
@ -401,7 +416,7 @@ it prints them to <tt>stdout</tt>.
<center><a name="Auto"><h2>Automatic Code Generation</h2></a></center>
<p>
Starting from release 1.1.0, the source code and parts of the
Starting with release 1.1.0, the source code and parts of the
documentation are automatically generated from the extension
specifications via a two-step process. In the first step,
specification files from the OpenGL registry are parsed and skeleton
@ -440,6 +455,50 @@ effect token and function pointer definitions.
</tr>
<tr><td bgcolor="#fff0d0" align="center"></td></tr>
<tr>
<td bgcolor="#ffffff">
<center><a name="Context"><h2>Multiple Rendering
Contexts (GLEW MX)</h2></a></center>
<p>
Starting with release 1.2.0, thread-safe support for multiple
rendering contexts (possibly with different capabilities) is
available. Since this is not required by most users, it is not added
to the binary releases to maintain compatibility between different
versions. To include multi-context support, you have to do the
following:
<ol>
<li>Compile and use GLEW with the <tt>GLEW_MX</tt> preprocessor token defined.</li>
<li>Replace the global <tt>glewInit()</tt> call with <tt>glewContextInit(GLEWContext* ctx)</tt>. Note, that <tt>ctx</tt> has to reside in global or thread-local memory.</li>
<li>Define the <tt>glewGetContext()</tt> macro or function that retrieves the GLEW context for the thread from which the OpenGL/WGL/GLX call is issued. This dispatch mechanism is primitive, but generic.</li>
</ol>
<p> Note that according to <a
href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/ntopnglr_6yer.asp">WGL
documentation</a>, you have to initialize the entry points for every
rendering context you create using pixel formats with different
capabilities (for example the pixel formats provided by the generic
software OpenGL implementation by Microsoft vs. the hardware
accelerated pixel formats). <b>GLEW by default ignores this
requirement, and does not define per-context entry points (you can
however do this using the steps described above).</b> Assuming a
global namespace for the entry points works in most situations,
because typically all hardware accelerated pixel formats provide the
same entry points and capabilities (and why would anyone want to use
the software renderer when hardware acceleration is available?). This
means that unless you use the multi-context version of GLEW, you need
to call <tt>glewInit()</tt> only once in your program, or more
precisely, once per process.
<p>
</td>
</tr>
<tr><td bgcolor="#fff0d0" align="center"></td></tr>
<tr>
@ -448,17 +507,9 @@ effect token and function pointer definitions.
<center><a name="Issues"><h2>Known Issues</h2></a></center>
<p>
GLEW requires GLX 1.2 to assure compatibility with GLUT. In addition,
GLEW requires GLX 1.2 to assure compatibility with GLUT. Also,
the SGI GLX video extensions are currently not supported.
<p>
Note that according to <a
href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/opengl/ntopnglr_6yer.asp">WGL documentation</a> you have to initialize the entry points
for every rendering context you create. <b>GLEW ignores this
requirement, and does not define per-context entry points.</b> This means
that you need to call <tt>glewInit()</tt> only once in your program,
or more precisely, once per process. We have not noticed any problems
so far from ignoring the specification.
<p>
</td>
</tr>
@ -482,8 +533,7 @@ Wimmer.
<p>
<p>
GLEW is originally derived from the <a
href="http://www.levp.de/3d/">EXTGL</a> project by Lev Povalahev. The
GLEW is originally derived from the EXTGL project by Lev Povalahev. The
source code is licensed under the modified BSD license, the <a
href="sgi.txt">SGI Free Software License B</a>, and the <a
href="glx.txt">GLX Public License</a>. The automatic code
@ -502,6 +552,16 @@ generation scripts are released under the <a href="gpl.txt">GPL</a>.
<p>
<ul class="none">
<li><b>1.2.0</b> [02-19-04]
<ul>
<li> Added full OpenGL 1.5 support
<li> Added support for multiple rendering contexts with different capabilities
<li> Added command line flags to <tt>glewinfo</tt> for selecting displays and visuals
<li> Added GLX_SGIS_multisample, GLX_SUN_video_resize, and GL_SUN_read_video_pixels
<li> Added MinGW/MSYS support
<li> Bug fixes in GL_ARB_shader_objects and the OS X build
</ul>
<p>
<li><b>1.1.4</b> [12-15-03]
<ul>
<li> Added GL_APPLE_float_pixels, GL_APPLE_texture_range,
@ -603,7 +663,7 @@ GL_ARB_vertex_shader
<table border="0" cellspacing="0" cellpadding="0" width="100%">
<tr>
<td align="right">
<i>Last update: 12-15-03</i></td>
<i>Last update: 02-19-04</i></td>
</tr>
</table>
</td>