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<?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>glXMakeContextCurrent</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glXMakeContextCurrent"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glXMakeContextCurrent — attach a GLX context to a GLX drawable</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">glXMakeContextCurrent</b>(</code></td><td>Display *  </td><td><var class="pdparam">display</var>, </td></tr><tr><td> </td><td>GLXDrawable  </td><td><var class="pdparam">draw</var>, </td></tr><tr><td> </td><td>GLXDrawable  </td><td><var class="pdparam">read</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>display</code></em></span></dt><dd><p>
                    Specifies the connection to the X server.
                </p></dd><dt><span class="term"><em class="parameter"><code>draw</code></em></span></dt><dd><p>
                    Specifies a GLX drawable to render into.
                    Must be an XID representing a GLXWindow, GLXPixmap, or GLXPbuffer.
                </p></dd><dt><span class="term"><em class="parameter"><code>read</code></em></span></dt><dd><p>
                    Specifies a GLX drawable to read from.
                    Must be an XID representing a GLXWindow, GLXPixmap, or GLXPbuffer.
                </p></dd><dt><span class="term"><em class="parameter"><code>ctx</code></em></span></dt><dd><p>
                    Specifies the GLX context to be bound to <em class="parameter"><code>read</code></em> and <em class="parameter"><code>ctx</code></em>.
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
            <code class="function">glXMakeContextCurrent</code> binds <em class="parameter"><code>ctx</code></em> to the current rendering thread and to the <em class="parameter"><code>draw</code></em>
            and <em class="parameter"><code>read</code></em> GLX drawables. <em class="parameter"><code>draw</code></em> and <em class="parameter"><code>read</code></em> may be the same.
        </p><p>
            <em class="parameter"><code>draw</code></em> is used for all OpenGL operations except:
        </p><p>
            Any pixel data that are read based on the value of <code class="constant">GLX_READ_BUFFER</code>.
            Note that accumulation operations use the value of <code class="constant">GLX_READ_BUFFER</code>,
            but are not allowed unless <em class="parameter"><code>draw</code></em> is identical to <em class="parameter"><code>read</code></em>.
        </p><p>
            Any depth values that are retrieved by <a class="citerefentry" href="glReadPixels.xml"><span class="citerefentry"><span class="refentrytitle">glReadPixels</span></span></a> or <a class="citerefentry" href="glCopyPixels.xml"><span class="citerefentry"><span class="refentrytitle">glCopyPixels</span></span></a>.
        </p><p>
            Any stencil values that are retrieved by <a class="citerefentry" href="glReadPixels.xml"><span class="citerefentry"><span class="refentrytitle">glReadPixels</span></span></a> or
            <a class="citerefentry" href="glCopyPixels.xml"><span class="citerefentry"><span class="refentrytitle">glCopyPixels</span></span></a>.
        </p><p>
            Frame buffer values are taken from <em class="parameter"><code>draw</code></em>.
        </p><p>
            If the current rendering thread has a current rendering context, that
            context is flushed and replaced by <em class="parameter"><code>ctx</code></em>.
        </p><p>
            The first time that <em class="parameter"><code>ctx</code></em> is made current, the viewport and scissor
            dimensions are set to the size of the <em class="parameter"><code>draw</code></em> drawable.  The viewport
            and scissor are not modified when <em class="parameter"><code>ctx</code></em> is subsequently made current.
        </p><p>
            To release the current context without assigning a new one,
            call <code class="function">glXMakeContextCurrent</code> with <em class="parameter"><code>draw</code></em> and <em class="parameter"><code>read</code></em> set to <code class="constant">None</code> and <em class="parameter"><code>ctx</code></em>
            set to <code class="constant">NULL</code>.
        </p><p>
            <code class="function">glXMakeContextCurrent</code> returns <code class="constant">True</code> if it is successful,
            <code class="constant">False</code> otherwise.
            If <code class="constant">False</code> is returned, the previously current rendering context
            and drawable (if any) remain unchanged.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
            <code class="function">glXMakeContextCurrent</code> is available only if the GLX version is 1.3 or greater.
        </p><p>
            If the GLX version is 1.1 or 1.0, the GL version must be 1.0.
            If the GLX version is 1.2, then the GL version must be 1.1.
            If the GLX version is 1.3, then the GL version must be 1.2.
        </p><p>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
            <code class="constant">BadMatch</code> is generated if <em class="parameter"><code>draw</code></em> and <em class="parameter"><code>read</code></em> are not compatible.
        </p><p>
            <code class="constant">BadAccess</code> is generated if <em class="parameter"><code>ctx</code></em> is current to some other
            thread.
        </p><p>
            <code class="constant">GLXContextState</code> is generated if there is a current rendering
            context and its render mode is either <code class="constant">GLX_FEEDBACK</code> or
            <code class="constant">GLX_SELECT</code>.
        </p><p>
            <code class="constant">GLXBadContext</code> is generated if <em class="parameter"><code>ctx</code></em> is not a valid GLX
            rendering context.
        </p><p>
            <code class="constant">GLXBadDrawable</code> is generated if <em class="parameter"><code>draw</code></em> or <em class="parameter"><code>read</code></em> is not a valid 
            GLX drawable.
        </p><p>
            <code class="constant">GLXBadWindow</code> is generated if the underlying X window for either
            <em class="parameter"><code>draw</code></em> or <em class="parameter"><code>read</code></em> is no longer valid.
        </p><p>
            <code class="constant">GLXBadCurrentDrawable</code> is generated if the previous context of
            the calling thread has unflushed commands and the previous drawable is
            no longer valid.
        </p><p>
            <code class="constant">BadAlloc</code> is generated if the X server does not have enough
            resources to allocate the buffers.
        </p><p>
            <code class="constant">BadMatch</code> is generated if:
        </p><p>
            <em class="parameter"><code>draw</code></em> and <em class="parameter"><code>read</code></em> cannot fit into frame buffer memory simultaneously.
        </p><p>
            <em class="parameter"><code>draw</code></em> or <em class="parameter"><code>read</code></em> is a GLXPixmap and <em class="parameter"><code>ctx</code></em> is a direct-rendering
            context.
        </p><p>
            <em class="parameter"><code>draw</code></em> or <em class="parameter"><code>read</code></em> is a GLXPixmap and <em class="parameter"><code>ctx</code></em> was previously bound to a
            GLXWindow or GLXPbuffer.
        </p><p>
            <em class="parameter"><code>draw</code></em> or <em class="parameter"><code>read</code></em> is a GLXWindow or GLXPbuffer and <em class="parameter"><code>ctx</code></em> was
            previously bound to a GLXPixmap.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
            <a class="citerefentry" href="glXCreateNewContext.xml"><span class="citerefentry"><span class="refentrytitle">glXCreateNewContext</span></span></a>,
            <a class="citerefentry" href="glXCreateWindow.xml"><span class="citerefentry"><span class="refentrytitle">glXCreateWindow</span></span></a>,
            <a class="citerefentry" href="glXCreatePixmap.xml"><span class="citerefentry"><span class="refentrytitle">glXCreatePixmap</span></span></a>,
            <a class="citerefentry" href="glXCreatePbuffer.xml"><span class="citerefentry"><span class="refentrytitle">glXCreatePbuffer</span></span></a>,
            <a class="citerefentry" href="glXDestroyContext.xml"><span class="citerefentry"><span class="refentrytitle">glXDestroyContext</span></span></a>,
            <a class="citerefentry" href="glXGetCurrentContext.xml"><span class="citerefentry"><span class="refentrytitle">glXGetCurrentContext</span></span></a>,
            <a class="citerefentry" href="glXGetCurrentDisplay.xml"><span class="citerefentry"><span class="refentrytitle">glXGetCurrentDisplay</span></span></a>,
            <a class="citerefentry" href="glXGetCurrentDrawable.xml"><span class="citerefentry"><span class="refentrytitle">glXGetCurrentDrawable</span></span></a>,
            <a class="citerefentry" href="glXGetCurrentReadDrawable.xml"><span class="citerefentry"><span class="refentrytitle">glXGetCurrentReadDrawable</span></span></a>,
            <a class="citerefentry" href="glXMakeCurrent.xml"><span class="citerefentry"><span class="refentrytitle">glXMakeCurrent</span></span></a>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
        </p></div></div></body></html>
