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1 | <?xml version="1.0" encoding="UTF-8"?> |
2 | <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN" | |
3 | "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd"> | |
4 | <refentry id="glXMakeCurrent"> | |
5 | <refmeta> | |
6 | <refmetainfo> | |
7 | <copyright> | |
8 | <year>1991-2006</year> | |
9 | <holder>Silicon Graphics, Inc.</holder> | |
10 | </copyright> | |
11 | </refmetainfo> | |
12 | <refentrytitle>glXMakeCurrent</refentrytitle> | |
13 | <manvolnum>3G</manvolnum> | |
14 | </refmeta> | |
15 | <refnamediv> | |
16 | <refname>glXMakeCurrent</refname> | |
17 | <refpurpose>attach a GLX context to a window or a GLX pixmap</refpurpose> | |
18 | </refnamediv> | |
19 | <refsynopsisdiv><title>C Specification</title> | |
20 | <funcsynopsis> | |
21 | <funcprototype> | |
22 | <funcdef>Bool <function>glXMakeCurrent</function></funcdef> | |
23 | <paramdef>Display * <parameter>dpy</parameter></paramdef> | |
24 | <paramdef>GLXDrawable <parameter>drawable</parameter></paramdef> | |
25 | <paramdef>GLXContext <parameter>ctx</parameter></paramdef> | |
26 | </funcprototype> | |
27 | </funcsynopsis> | |
28 | </refsynopsisdiv> | |
29 | <!-- eqn: ignoring delim $$ --> | |
30 | <refsect1 id="parameters"><title>Parameters</title> | |
31 | <variablelist> | |
32 | <varlistentry> | |
33 | <term><parameter>dpy</parameter></term> | |
34 | <listitem> | |
35 | <para> | |
36 | Specifies the connection to the X server. | |
37 | </para> | |
38 | </listitem> | |
39 | </varlistentry> | |
40 | <varlistentry> | |
41 | <term><parameter>drawable</parameter></term> | |
42 | <listitem> | |
43 | <para> | |
44 | Specifies a GLX drawable. | |
45 | Must be either an X window ID or a GLX pixmap ID. | |
46 | </para> | |
47 | </listitem> | |
48 | </varlistentry> | |
49 | <varlistentry> | |
50 | <term><parameter>ctx</parameter></term> | |
51 | <listitem> | |
52 | <para> | |
53 | Specifies a GLX rendering context that is to be attached to <parameter>drawable</parameter>. | |
54 | </para> | |
55 | </listitem> | |
56 | </varlistentry> | |
57 | </variablelist> | |
58 | </refsect1> | |
59 | <refsect1 id="description"><title>Description</title> | |
60 | <para> | |
61 | <function>glXMakeCurrent</function> does two things: | |
62 | It makes <parameter>ctx</parameter> the current GLX rendering context of the calling thread, | |
63 | replacing the previously current context if there was one, | |
64 | and it attaches <parameter>ctx</parameter> to a GLX drawable, | |
65 | either a window or a GLX pixmap. | |
66 | As a result of these two actions, | |
67 | subsequent GL rendering calls | |
68 | use rendering context <parameter>ctx</parameter> to modify GLX drawable <parameter>drawable</parameter> (for | |
69 | reading and writing). | |
70 | Because <function>glXMakeCurrent</function> always replaces the current rendering context with <parameter>ctx</parameter>, | |
71 | there can be only one current context per thread. | |
72 | </para> | |
73 | <para> | |
74 | Pending commands to the | |
75 | previous context, if any, are flushed before it is released. | |
76 | </para> | |
77 | <para> | |
78 | The first time <parameter>ctx</parameter> is made current to any thread, | |
79 | its viewport is set to the full size of <parameter>drawable</parameter>. | |
80 | Subsequent calls by any thread to <function>glXMakeCurrent</function> with <parameter>ctx</parameter> | |
81 | have no effect on its viewport. | |
82 | </para> | |
83 | <para> | |
84 | To release the current context without assigning a new one, | |
85 | call <function>glXMakeCurrent</function> with <parameter>drawable</parameter> set to <constant>None</constant> and <parameter>ctx</parameter> | |
86 | set to <constant>NULL</constant>. | |
87 | </para> | |
88 | <para> | |
89 | <function>glXMakeCurrent</function> returns <constant>True</constant> if it is successful, | |
90 | <constant>False</constant> otherwise. | |
91 | If <constant>False</constant> is returned, the previously current rendering context | |
92 | and drawable (if any) remain unchanged. | |
93 | </para> | |
94 | </refsect1> | |
95 | <refsect1 id="notes"><title>Notes</title> | |
96 | <para> | |
97 | A <emphasis>process</emphasis> is a single-execution environment, | |
98 | implemented in a single address space, | |
99 | consisting of one or more threads. | |
100 | </para> | |
101 | <para> | |
102 | A <emphasis>thread</emphasis> is one of a set of subprocesses that share | |
103 | a single address space, | |
104 | but maintain separate program counters, | |
105 | stack spaces, | |
106 | and other related global data. | |
107 | A <emphasis>thread</emphasis> that is the only member of its subprocess group | |
108 | is equivalent to a <emphasis>process</emphasis>. | |
109 | </para> | |
110 | </refsect1> | |
111 | <refsect1 id="errors"><title>Errors</title> | |
112 | <para> | |
113 | <constant>BadMatch</constant> is generated if <parameter>drawable</parameter> was not | |
114 | created with the same X screen and visual as <parameter>ctx</parameter>. | |
115 | It is also generated if <parameter>drawable</parameter> is <constant>None</constant> and <parameter>ctx</parameter> is not | |
116 | <constant>NULL</constant>. | |
117 | </para> | |
118 | <para> | |
119 | <constant>BadAccess</constant> is generated if <parameter>ctx</parameter> was current to another thread | |
120 | at the time <function>glXMakeCurrent</function> was called. | |
121 | </para> | |
122 | <para> | |
123 | <constant>GLXBadDrawable</constant> is generated if <parameter>drawable</parameter> is not a valid GLX drawable. | |
124 | </para> | |
125 | <para> | |
126 | <constant>GLXBadContext</constant> is generated if <parameter>ctx</parameter> is not a valid GLX context. | |
127 | </para> | |
128 | <para> | |
129 | <constant>GLXBadContextState</constant> is generated if <function>glXMakeCurrent</function> is executed between | |
130 | the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>. | |
131 | </para> | |
132 | <para> | |
133 | <constant>GLXBadContextState</constant> is also generated if the rendering context current | |
134 | to the calling thread has GL renderer state <constant>GLX_FEEDBACK</constant> or | |
135 | <constant>GLX_SELECT</constant>. | |
136 | </para> | |
137 | <para> | |
138 | <constant>GLXBadCurrentWindow</constant> is generated if there are pending GL | |
139 | commands for the previous context and the current drawable is | |
140 | a window that is no longer valid. | |
141 | </para> | |
142 | <para> | |
143 | <constant>BadAlloc</constant> may be generated if the server has delayed allocation | |
144 | of ancillary buffers until <function>glXMakeCurrent</function> is called, only to find that it has | |
145 | insufficient resources to complete the allocation. | |
146 | </para> | |
147 | </refsect1> | |
148 | <refsect1 id="seealso"><title>See Also</title> | |
149 | <para> | |
150 | <citerefentry><refentrytitle>glXCreateContext</refentrytitle></citerefentry>, | |
151 | <citerefentry><refentrytitle>glXCreateGLXPixmap</refentrytitle></citerefentry> | |
152 | <citerefentry><refentrytitle>glXGetCurrentContext</refentrytitle></citerefentry>, | |
153 | <citerefentry><refentrytitle>glXGetCurrentDisplay</refentrytitle></citerefentry>, | |
154 | <citerefentry><refentrytitle>glXGetCurrentDrawable</refentrytitle></citerefentry>, | |
155 | <citerefentry><refentrytitle>glXGetCurrentReadDrawable</refentrytitle></citerefentry>, | |
156 | <citerefentry><refentrytitle>glXMakeContextCurrent</refentrytitle></citerefentry> | |
157 | </para> | |
158 | </refsect1> | |
159 | <refsect1 id="Copyright"><title>Copyright</title> | |
160 | <para> | |
161 | Copyright <trademark class="copyright"></trademark> 1991-2006 | |
162 | Silicon Graphics, Inc. This document is licensed under the SGI | |
163 | Free Software B License. For details, see | |
164 | <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>. | |
165 | </para> | |
166 | </refsect1> | |
167 | </refentry> |