upstream-man-pages/man2/xhtml/glXMakeCurrent.xml

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   3 <?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" /><title>glXMakeCurrent</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glXMakeCurrent"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glXMakeCurrent — attach a GLX context to a window or a GLX pixmap</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">Bool <b class="fsfunc">glXMakeCurrent</b>(</code></td><td>Display *  </td><td><var class="pdparam">dpy</var>, </td></tr><tr><td> </td><td>GLXDrawable  </td><td><var class="pdparam">drawable</var>, </td></tr><tr><td> </td><td>GLXContext  </td><td><var class="pdparam">ctx</var><code>)</code>;</td></tr></table></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>dpy</code></em></span></dt><dd><p>
   4                     Specifies the connection to the X server.
   5                 </p></dd><dt><span class="term"><em class="parameter"><code>drawable</code></em></span></dt><dd><p>
   6                     Specifies a GLX drawable.
   7                     Must be either an X window ID or a GLX pixmap ID.
   8                 </p></dd><dt><span class="term"><em class="parameter"><code>ctx</code></em></span></dt><dd><p>
   9                     Specifies a GLX rendering context that is to be attached to <em class="parameter"><code>drawable</code></em>.
  10                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  11             <code class="function">glXMakeCurrent</code> does two things:
  12             It makes <em class="parameter"><code>ctx</code></em> the current GLX rendering context of the calling thread,
  13             replacing the previously current context if there was one,
  14             and it attaches <em class="parameter"><code>ctx</code></em> to a GLX drawable,
  15             either a window or a GLX pixmap.
  16             As a result of these two actions,
  17             subsequent GL rendering calls
  18             use rendering context <em class="parameter"><code>ctx</code></em> to modify GLX drawable <em class="parameter"><code>drawable</code></em> (for
  19             reading and writing).
  20             Because <code class="function">glXMakeCurrent</code> always replaces the current rendering context with <em class="parameter"><code>ctx</code></em>,
  21             there can be only one current context per thread.
  22         </p><p>
  23             Pending commands to the
  24             previous context, if any, are flushed before it is released.
  25         </p><p>
  26             The first time <em class="parameter"><code>ctx</code></em> is made current to any thread,
  27             its viewport is set to the full size of <em class="parameter"><code>drawable</code></em>.
  28             Subsequent calls by any thread to <code class="function">glXMakeCurrent</code> with <em class="parameter"><code>ctx</code></em>
  29             have no effect on its viewport.
  30         </p><p>
  31             To release the current context without assigning a new one,
  32             call <code class="function">glXMakeCurrent</code> with <em class="parameter"><code>drawable</code></em> set to <code class="constant">None</code> and <em class="parameter"><code>ctx</code></em>
  33             set to <code class="constant">NULL</code>.
  34         </p><p>
  35             <code class="function">glXMakeCurrent</code> returns <code class="constant">True</code> if it is successful,
  36             <code class="constant">False</code> otherwise.
  37             If <code class="constant">False</code> is returned, the previously current rendering context
  38             and drawable (if any) remain unchanged.
  39         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
  40             A <span class="emphasis"><em>process</em></span> is a single-execution environment,
  41             implemented in a single address space,
  42             consisting of one or more threads.
  43         </p><p>
  44             A <span class="emphasis"><em>thread</em></span> is one of a set of subprocesses that share
  45             a single address space,
  46             but maintain separate program counters,
  47             stack spaces,
  48             and other related global data.
  49             A <span class="emphasis"><em>thread</em></span> that is the only member of its subprocess group
  50             is equivalent to a <span class="emphasis"><em>process</em></span>.
  51         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
  52             <code class="constant">BadMatch</code> is generated if <em class="parameter"><code>drawable</code></em> was not
  53             created with the same X screen and visual as <em class="parameter"><code>ctx</code></em>.
  54             It is also generated if <em class="parameter"><code>drawable</code></em> is <code class="constant">None</code> and <em class="parameter"><code>ctx</code></em> is not
  55             <code class="constant">NULL</code>.
  56         </p><p>
  57             <code class="constant">BadAccess</code> is generated if <em class="parameter"><code>ctx</code></em> was current to another thread
  58             at the time <code class="function">glXMakeCurrent</code> was called.
  59         </p><p>
  60             <code class="constant">GLXBadDrawable</code> is generated if <em class="parameter"><code>drawable</code></em> is not a valid GLX drawable.
  61         </p><p>
  62             <code class="constant">GLXBadContext</code> is generated if <em class="parameter"><code>ctx</code></em> is not a valid GLX context.
  63         </p><p>
  64             <code class="constant">GLXBadContextState</code> is generated if <code class="function">glXMakeCurrent</code> is executed between
  65             the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> and the corresponding execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
  66         </p><p>
  67             <code class="constant">GLXBadContextState</code> is also generated if the rendering context current
  68             to the calling thread has GL renderer state <code class="constant">GLX_FEEDBACK</code> or
  69             <code class="constant">GLX_SELECT</code>.
  70         </p><p>
  71             <code class="constant">GLXBadCurrentWindow</code> is generated if there are pending GL
  72             commands for the previous context and the current drawable is
  73             a window that is no longer valid.
  74         </p><p>
  75             <code class="constant">BadAlloc</code> may be generated if the server has delayed allocation
  76             of ancillary buffers until <code class="function">glXMakeCurrent</code> is called, only to find that it has
  77             insufficient resources to complete the allocation.
  78         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
  79             <a class="citerefentry" href="glXCreateContext.xml"><span class="citerefentry"><span class="refentrytitle">glXCreateContext</span></span></a>,
  80             <a class="citerefentry" href="glXCreateGLXPixmap.xml"><span class="citerefentry"><span class="refentrytitle">glXCreateGLXPixmap</span></span></a>
  81             <a class="citerefentry" href="glXGetCurrentContext.xml"><span class="citerefentry"><span class="refentrytitle">glXGetCurrentContext</span></span></a>,
  82             <a class="citerefentry" href="glXGetCurrentDisplay.xml"><span class="citerefentry"><span class="refentrytitle">glXGetCurrentDisplay</span></span></a>,
  83             <a class="citerefentry" href="glXGetCurrentDrawable.xml"><span class="citerefentry"><span class="refentrytitle">glXGetCurrentDrawable</span></span></a>,
  84             <a class="citerefentry" href="glXGetCurrentReadDrawable.xml"><span class="citerefentry"><span class="refentrytitle">glXGetCurrentReadDrawable</span></span></a>,
  85             <a class="citerefentry" href="glXMakeContextCurrent.xml"><span class="citerefentry"><span class="refentrytitle">glXMakeContextCurrent</span></span></a>
  86         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
  87             Copyright <span class="trademark"></span>© 1991-2006
  88             Silicon Graphics, Inc. This document is licensed under the SGI
  89             Free Software B License. For details, see
  90             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
  91         </p></div></div></body></html>