upstream-man-pages/man4/xhtml/glReadBuffer.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd">
   3 <!-- saved from url=(0013)about:internet -->
   4 <?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><link rel="stylesheet" type="text/css" href="opengl-man.css" /><title>glReadBuffer - OpenGL 4 Reference Pages</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glReadBuffer"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glReadBuffer — select a color buffer source for pixels</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><p><code class="funcdef">void <b class="fsfunc">glReadBuffer</b>(</code>GLenum <var class="pdparam">mode</var><code>)</code>;</p></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>mode</code></em></span></dt><dd><p>
   5                     Specifies a color buffer.
   6                     Accepted values are
   7                     <code class="constant">GL_FRONT_LEFT</code>,
   8                     <code class="constant">GL_FRONT_RIGHT</code>,
   9                     <code class="constant">GL_BACK_LEFT</code>,
  10                     <code class="constant">GL_BACK_RIGHT</code>,
  11                     <code class="constant">GL_FRONT</code>,
  12                     <code class="constant">GL_BACK</code>,
  13                     <code class="constant">GL_LEFT</code>,
  14                     <code class="constant">GL_RIGHT</code>, and the constants
  15                     <code class="constant">GL_COLOR_ATTACHMENT<span class="emphasis"><em>i</em></span></code>.
  16                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  17             <code class="function">glReadBuffer</code> specifies a color buffer as the source for subsequent
  18             <a href="glReadPixels.xml"><span class="citerefentry"><span class="refentrytitle">glReadPixels</span></span></a>, <a href="glCopyTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage1D</span></span></a>, <a href="glCopyTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage2D</span></span></a>,
  19             <a href="glCopyTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage1D</span></span></a>, <a href="glCopyTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage2D</span></span></a>, and
  20             <a href="glCopyTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage3D</span></span></a> commands.
  21             <em class="parameter"><code>mode</code></em> accepts one of twelve or more predefined values.
  22             In a fully configured system,
  23             <code class="constant">GL_FRONT</code>,
  24             <code class="constant">GL_LEFT</code>, and
  25             <code class="constant">GL_FRONT_LEFT</code> all name the front left buffer,
  26             <code class="constant">GL_FRONT_RIGHT</code> and
  27             <code class="constant">GL_RIGHT</code> name the front right buffer, and
  28             <code class="constant">GL_BACK_LEFT</code> and
  29             <code class="constant">GL_BACK</code> name the back left buffer.
  30             Further more, the constants <code class="constant">GL_COLOR_ATTACHMENT<span class="emphasis"><em>i</em></span></code> may be used to indicate the
  31             <span class="emphasis"><em>i</em></span><sup>th</sup> color attachment where <span class="emphasis"><em>i</em></span> ranges from zero to the
  32             value of <code class="constant">GL_MAX_COLOR_ATTACHMENTS</code> minus one.
  33         </p><p>
  34             Nonstereo double-buffered configurations have only a front left and a
  35             back left buffer.
  36             Single-buffered configurations have a front left and a front right
  37             buffer if stereo, and only a front left buffer if nonstereo.
  38             It is an error to specify a nonexistent buffer to <code class="function">glReadBuffer</code>.
  39         </p><p>
  40             <em class="parameter"><code>mode</code></em> is initially <code class="constant">GL_FRONT</code> in single-buffered configurations
  41             and <code class="constant">GL_BACK</code> in double-buffered configurations.
  42         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
  43             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>mode</code></em> is not one of the twelve
  44             (or more) accepted values.
  45         </p><p>
  46             <code class="constant">GL_INVALID_OPERATION</code> is generated if <em class="parameter"><code>mode</code></em> specifies a buffer
  47             that does not exist.
  48         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
  49             <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_READ_BUFFER</code>
  50         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
  51             <a href="glCopyTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage1D</span></span></a>,
  52             <a href="glCopyTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage2D</span></span></a>,
  53             <a href="glCopyTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage1D</span></span></a>,
  54             <a href="glCopyTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage2D</span></span></a>,
  55             <a href="glCopyTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage3D</span></span></a>,
  56             <a href="glDrawBuffer.xml"><span class="citerefentry"><span class="refentrytitle">glDrawBuffer</span></span></a>,
  57             <a href="glReadPixels.xml"><span class="citerefentry"><span class="refentrytitle">glReadPixels</span></span></a>
  58         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
  59             Copyright <span class="trademark"></span>© 1991-2006 Silicon Graphics, Inc.
  60             Copyright <span class="trademark"></span>© 2011 Khronos Group.
  61             This document is licensed under the SGI
  62             Free Software B License. For details, see
  63             <a href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
  64         </p></div></div></body></html>