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1 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd"> |
2 | <!-- saved from url=(0013)about:internet --> | |
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>glXCreateContext</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glXCreateContext"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glXCreateContext — create a new GLX rendering context</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">GLXContext <b class="fsfunc">glXCreateContext</b>(</code></td><td>Display * </td><td><var class="pdparam">dpy</var>, </td></tr><tr><td> </td><td>XVisualInfo * </td><td><var class="pdparam">vis</var>, </td></tr><tr><td> </td><td>GLXContext </td><td><var class="pdparam">shareList</var>, </td></tr><tr><td> </td><td>Bool </td><td><var class="pdparam">direct</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>vis</code></em></span></dt><dd><p> | |
6 | Specifies the visual that defines the frame buffer resources available to | |
7 | the rendering context. | |
8 | It is a pointer to an <code class="constant">XVisualInfo</code> structure, | |
9 | not a visual ID or a pointer to a <code class="constant">Visual</code>. | |
10 | </p></dd><dt><span class="term"><em class="parameter"><code>shareList</code></em></span></dt><dd><p> | |
11 | Specifies the context with which to share display lists. | |
12 | <code class="constant">NULL</code> indicates that no sharing is to take place. | |
13 | </p></dd><dt><span class="term"><em class="parameter"><code>direct</code></em></span></dt><dd><p> | |
14 | Specifies whether rendering is to be done with a direct connection | |
15 | to the graphics system if possible (<code class="constant">True</code>) | |
16 | or through the X server (<code class="constant">False</code>). | |
17 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p> | |
18 | <code class="function">glXCreateContext</code> creates a GLX rendering context and returns its handle. | |
19 | This context can be used to render into both windows and GLX pixmaps. | |
20 | If <code class="function">glXCreateContext</code> fails to create a rendering context, | |
21 | <code class="constant">NULL</code> is returned. | |
22 | </p><p> | |
23 | If <em class="parameter"><code>direct</code></em> is <code class="constant">True</code>, | |
24 | then a direct rendering context is created if the | |
25 | implementation supports direct rendering, if the connection is to an X | |
26 | server that is local, and if a direct rendering context is available. (An implementation may return an indirect context when <em class="parameter"><code>direct</code></em> is <code class="constant">True</code>.) | |
27 | If <em class="parameter"><code>direct</code></em> is <code class="constant">False</code>, | |
28 | then a rendering context that renders through the X server is always created. | |
29 | Direct rendering provides a performance advantage in some implementations. | |
30 | However, direct rendering contexts cannot be shared outside a single process, | |
31 | and they may be unable to render to GLX pixmaps. | |
32 | </p><p> | |
33 | If <em class="parameter"><code>shareList</code></em> is not <code class="constant">NULL</code>, | |
34 | then all display-list indexes and definitions are shared by | |
35 | context <em class="parameter"><code>shareList</code></em> and by the newly created context. | |
36 | An arbitrary number of contexts can share a single display-list space. | |
37 | However, | |
38 | all rendering contexts that share a single display-list space must | |
39 | themselves exist in the same address space. | |
40 | Two rendering contexts share an address space if both are nondirect | |
41 | using the same server, | |
42 | or if both are direct and owned by a single process. | |
43 | Note that in the nondirect case, it is not necessary for the calling | |
44 | threads to share an address space, | |
45 | only for their related rendering contexts to share an address space. | |
46 | </p><p> | |
47 | If the GL version is 1.1 or greater, | |
48 | then all texture objects except object 0 | |
49 | are shared by any contexts that share display lists. | |
50 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p> | |
51 | <code class="constant">XVisualInfo</code> is defined in <span class="emphasis"><em>Xutil.h.</em></span> | |
52 | It is a structure that includes <span class="emphasis"><em>visual</em></span>, <span class="emphasis"><em>visualID</em></span>, <span class="emphasis"><em>screen</em></span>, and | |
53 | <span class="emphasis"><em>depth</em></span> elements. | |
54 | </p><p> | |
55 | A <span class="emphasis"><em>process</em></span> is a single execution environment, | |
56 | implemented in a single address space, | |
57 | consisting of one or more threads. | |
58 | </p><p> | |
59 | A <span class="emphasis"><em>thread</em></span> is one of a set of subprocesses that share | |
60 | a single address space, | |
61 | but maintain separate program counters, | |
62 | stack spaces, | |
63 | and other related global data. | |
64 | A <span class="emphasis"><em>thread</em></span> that is the only member of its subprocess group | |
65 | is equivalent to a <span class="emphasis"><em>process</em></span>. | |
66 | </p><p> | |
67 | It may not be possible to render to a GLX pixmap with a direct rendering | |
68 | context. | |
69 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p> | |
70 | <code class="constant">NULL</code> is returned if execution fails on the client side. | |
71 | </p><p> | |
72 | <code class="constant">BadMatch</code> is generated if the context to be created would not | |
73 | share the address space or the screen of the context specified by <em class="parameter"><code>shareList</code></em>. | |
74 | </p><p> | |
75 | <code class="constant">BadValue</code> is generated if <em class="parameter"><code>vis</code></em> is not a valid visual (for | |
76 | example, if a particular GLX implementation does not support it). | |
77 | </p><p> | |
78 | <code class="constant">GLXBadContext</code> is generated if <em class="parameter"><code>shareList</code></em> is not a GLX context | |
79 | and is not <code class="constant">NULL</code>. | |
80 | </p><p> | |
81 | <code class="constant">BadAlloc</code> is generated if the server does not have enough | |
82 | resources to allocate the new context. | |
83 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p> | |
84 | <a class="citerefentry" href="glXDestroyContext.xml"><span class="citerefentry"><span class="refentrytitle">glXDestroyContext</span></span></a>, | |
85 | <a class="citerefentry" href="glXGetConfig.xml"><span class="citerefentry"><span class="refentrytitle">glXGetConfig</span></span></a>, | |
86 | <a class="citerefentry" href="glXIsDirect.xml"><span class="citerefentry"><span class="refentrytitle">glXIsDirect</span></span></a>, | |
87 | <a class="citerefentry" href="glXMakeCurrent.xml"><span class="citerefentry"><span class="refentrytitle">glXMakeCurrent</span></span></a> | |
88 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> | |
89 | Copyright <span class="trademark"></span>© 1991-2006 | |
90 | Silicon Graphics, Inc. This document is licensed under the SGI | |
91 | Free Software B License. For details, see | |
92 | <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>. | |
93 | </p></div></div></body></html> |