167 lines
8.1 KiB
XML
167 lines
8.1 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
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"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
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<refentry id="glXMakeCurrent">
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<refmeta>
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<refmetainfo>
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<copyright>
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<year>1991-2006</year>
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<holder>Silicon Graphics, Inc.</holder>
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</copyright>
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</refmetainfo>
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<refentrytitle>glXMakeCurrent</refentrytitle>
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<manvolnum>3G</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>glXMakeCurrent</refname>
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<refpurpose>attach a GLX context to a window or a GLX pixmap</refpurpose>
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</refnamediv>
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<refsynopsisdiv><title>C Specification</title>
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<funcsynopsis>
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<funcprototype>
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<funcdef>Bool <function>glXMakeCurrent</function></funcdef>
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<paramdef>Display * <parameter>dpy</parameter></paramdef>
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<paramdef>GLXDrawable <parameter>drawable</parameter></paramdef>
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<paramdef>GLXContext <parameter>ctx</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<!-- eqn: ignoring delim $$ -->
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<refsect1 id="parameters"><title>Parameters</title>
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<variablelist>
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<varlistentry>
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<term><parameter>dpy</parameter></term>
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<listitem>
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<para>
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Specifies the connection to the X server.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>drawable</parameter></term>
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<listitem>
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<para>
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Specifies a GLX drawable.
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Must be either an X window ID or a GLX pixmap ID.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>ctx</parameter></term>
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<listitem>
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<para>
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Specifies a GLX rendering context that is to be attached to <parameter>drawable</parameter>.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1 id="description"><title>Description</title>
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<para>
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<function>glXMakeCurrent</function> does two things:
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It makes <parameter>ctx</parameter> the current GLX rendering context of the calling thread,
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replacing the previously current context if there was one,
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and it attaches <parameter>ctx</parameter> to a GLX drawable,
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either a window or a GLX pixmap.
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As a result of these two actions,
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subsequent GL rendering calls
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use rendering context <parameter>ctx</parameter> to modify GLX drawable <parameter>drawable</parameter> (for
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reading and writing).
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Because <function>glXMakeCurrent</function> always replaces the current rendering context with <parameter>ctx</parameter>,
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there can be only one current context per thread.
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</para>
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<para>
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Pending commands to the
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previous context, if any, are flushed before it is released.
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</para>
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<para>
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The first time <parameter>ctx</parameter> is made current to any thread,
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its viewport is set to the full size of <parameter>drawable</parameter>.
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Subsequent calls by any thread to <function>glXMakeCurrent</function> with <parameter>ctx</parameter>
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have no effect on its viewport.
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</para>
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<para>
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To release the current context without assigning a new one,
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call <function>glXMakeCurrent</function> with <parameter>drawable</parameter> set to <constant>None</constant> and <parameter>ctx</parameter>
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set to <constant>NULL</constant>.
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</para>
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<para>
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<function>glXMakeCurrent</function> returns <constant>True</constant> if it is successful,
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<constant>False</constant> otherwise.
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If <constant>False</constant> is returned, the previously current rendering context
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and drawable (if any) remain unchanged.
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</para>
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</refsect1>
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<refsect1 id="notes"><title>Notes</title>
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<para>
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A <emphasis>process</emphasis> is a single-execution environment,
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implemented in a single address space,
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consisting of one or more threads.
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</para>
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<para>
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A <emphasis>thread</emphasis> is one of a set of subprocesses that share
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a single address space,
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but maintain separate program counters,
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stack spaces,
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and other related global data.
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A <emphasis>thread</emphasis> that is the only member of its subprocess group
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is equivalent to a <emphasis>process</emphasis>.
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</para>
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</refsect1>
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<refsect1 id="errors"><title>Errors</title>
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<para>
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<constant>BadMatch</constant> is generated if <parameter>drawable</parameter> was not
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created with the same X screen and visual as <parameter>ctx</parameter>.
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It is also generated if <parameter>drawable</parameter> is <constant>None</constant> and <parameter>ctx</parameter> is not
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<constant>NULL</constant>.
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</para>
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<para>
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<constant>BadAccess</constant> is generated if <parameter>ctx</parameter> was current to another thread
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at the time <function>glXMakeCurrent</function> was called.
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</para>
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<para>
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<constant>GLXBadDrawable</constant> is generated if <parameter>drawable</parameter> is not a valid GLX drawable.
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</para>
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<para>
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<constant>GLXBadContext</constant> is generated if <parameter>ctx</parameter> is not a valid GLX context.
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</para>
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<para>
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<constant>GLXBadContextState</constant> is generated if <function>glXMakeCurrent</function> is executed between
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the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
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</para>
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<para>
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<constant>GLXBadContextState</constant> is also generated if the rendering context current
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to the calling thread has GL renderer state <constant>GLX_FEEDBACK</constant> or
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<constant>GLX_SELECT</constant>.
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</para>
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<para>
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<constant>GLXBadCurrentWindow</constant> is generated if there are pending GL
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commands for the previous context and the current drawable is
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a window that is no longer valid.
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</para>
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<para>
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<constant>BadAlloc</constant> may be generated if the server has delayed allocation
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of ancillary buffers until <function>glXMakeCurrent</function> is called, only to find that it has
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insufficient resources to complete the allocation.
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</para>
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</refsect1>
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<refsect1 id="seealso"><title>See Also</title>
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<para>
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<citerefentry><refentrytitle>glXCreateContext</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>glXCreateGLXPixmap</refentrytitle></citerefentry>
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<citerefentry><refentrytitle>glXGetCurrentContext</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>glXGetCurrentDisplay</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>glXGetCurrentDrawable</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>glXGetCurrentReadDrawable</refentrytitle></citerefentry>,
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<citerefentry><refentrytitle>glXMakeContextCurrent</refentrytitle></citerefentry>
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</para>
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</refsect1>
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<refsect1 id="Copyright"><title>Copyright</title>
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<para>
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Copyright <trademark class="copyright"></trademark> 1991-2006
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Silicon Graphics, Inc. This document is licensed under the SGI
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Free Software B License. For details, see
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<ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
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</para>
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</refsect1>
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</refentry>
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