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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="glXMakeContextCurrent"> | |
5 | <refmeta> | |
6 | <refmetainfo> | |
7 | <copyright> | |
8 | <year>1991-2006</year> | |
9 | <holder>Silicon Graphics, Inc.</holder> | |
10 | </copyright> | |
11 | </refmetainfo> | |
12 | <refentrytitle>glXMakeContextCurrent</refentrytitle> | |
13 | <manvolnum>3G</manvolnum> | |
14 | </refmeta> | |
15 | <refnamediv> | |
16 | <refname>glXMakeContextCurrent</refname> | |
17 | <refpurpose>attach a GLX context to a GLX drawable</refpurpose> | |
18 | </refnamediv> | |
19 | <refsynopsisdiv><title>C Specification</title> | |
20 | <funcsynopsis> | |
21 | <funcprototype> | |
22 | <funcdef>Bool <function>glXMakeContextCurrent</function></funcdef> | |
23 | <paramdef>Display * <parameter>display</parameter></paramdef> | |
24 | <paramdef>GLXDrawable <parameter>draw</parameter></paramdef> | |
25 | <paramdef>GLXDrawable <parameter>read</parameter></paramdef> | |
26 | <paramdef>GLXContext <parameter>ctx</parameter></paramdef> | |
27 | </funcprototype> | |
28 | </funcsynopsis> | |
29 | </refsynopsisdiv> | |
30 | <!-- eqn: ignoring delim $$ --> | |
31 | <refsect1 id="parameters"><title>Parameters</title> | |
32 | <variablelist> | |
33 | <varlistentry> | |
34 | <term><parameter>display</parameter></term> | |
35 | <listitem> | |
36 | <para> | |
37 | Specifies the connection to the X server. | |
38 | </para> | |
39 | </listitem> | |
40 | </varlistentry> | |
41 | <varlistentry> | |
42 | <term><parameter>draw</parameter></term> | |
43 | <listitem> | |
44 | <para> | |
45 | Specifies a GLX drawable to render into. | |
46 | Must be an XID representing a GLXWindow, GLXPixmap, or GLXPbuffer. | |
47 | </para> | |
48 | </listitem> | |
49 | </varlistentry> | |
50 | <varlistentry> | |
51 | <term><parameter>read</parameter></term> | |
52 | <listitem> | |
53 | <para> | |
54 | Specifies a GLX drawable to read from. | |
55 | Must be an XID representing a GLXWindow, GLXPixmap, or GLXPbuffer. | |
56 | </para> | |
57 | </listitem> | |
58 | </varlistentry> | |
59 | <varlistentry> | |
60 | <term><parameter>ctx</parameter></term> | |
61 | <listitem> | |
62 | <para> | |
63 | Specifies the GLX context to be bound to <parameter>read</parameter> and <parameter>ctx</parameter>. | |
64 | </para> | |
65 | </listitem> | |
66 | </varlistentry> | |
67 | </variablelist> | |
68 | </refsect1> | |
69 | <refsect1 id="description"><title>Description</title> | |
70 | <para> | |
71 | <function>glXMakeContextCurrent</function> binds <parameter>ctx</parameter> to the current rendering thread and to the <parameter>draw</parameter> | |
72 | and <parameter>read</parameter> GLX drawables. <parameter>draw</parameter> and <parameter>read</parameter> may be the same. | |
73 | </para> | |
74 | <para> | |
75 | <parameter>draw</parameter> is used for all OpenGL operations except: | |
76 | </para> | |
77 | <para> | |
78 | Any pixel data that are read based on the value of <constant>GLX_READ_BUFFER</constant>. | |
79 | Note that accumulation operations use the value of <constant>GLX_READ_BUFFER</constant>, | |
80 | but are not allowed unless <parameter>draw</parameter> is identical to <parameter>read</parameter>. | |
81 | </para> | |
82 | <para> | |
83 | Any depth values that are retrieved by <citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry> or <citerefentry><refentrytitle>glCopyPixels</refentrytitle></citerefentry>. | |
84 | </para> | |
85 | <para> | |
86 | Any stencil values that are retrieved by <citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry> or | |
87 | <citerefentry><refentrytitle>glCopyPixels</refentrytitle></citerefentry>. | |
88 | </para> | |
89 | <para> | |
90 | Frame buffer values are taken from <parameter>draw</parameter>. | |
91 | </para> | |
92 | <para> | |
93 | If the current rendering thread has a current rendering context, that | |
94 | context is flushed and replaced by <parameter>ctx</parameter>. | |
95 | </para> | |
96 | <para> | |
97 | The first time that <parameter>ctx</parameter> is made current, the viewport and scissor | |
98 | dimensions are set to the size of the <parameter>draw</parameter> drawable. The viewport | |
99 | and scissor are not modified when <parameter>ctx</parameter> is subsequently made current. | |
100 | </para> | |
101 | <para> | |
102 | To release the current context without assigning a new one, | |
103 | call <function>glXMakeContextCurrent</function> with <parameter>draw</parameter> and <parameter>read</parameter> set to <constant>None</constant> and <parameter>ctx</parameter> | |
104 | set to <constant>NULL</constant>. | |
105 | </para> | |
106 | <para> | |
107 | <function>glXMakeContextCurrent</function> returns <constant>True</constant> if it is successful, | |
108 | <constant>False</constant> otherwise. | |
109 | If <constant>False</constant> is returned, the previously current rendering context | |
110 | and drawable (if any) remain unchanged. | |
111 | </para> | |
112 | </refsect1> | |
113 | <refsect1 id="notes"><title>Notes</title> | |
114 | <para> | |
115 | <function>glXMakeContextCurrent</function> is available only if the GLX version is 1.3 or greater. | |
116 | </para> | |
117 | <para> | |
118 | If the GLX version is 1.1 or 1.0, the GL version must be 1.0. | |
119 | If the GLX version is 1.2, then the GL version must be 1.1. | |
120 | If the GLX version is 1.3, then the GL version must be 1.2. | |
121 | </para> | |
122 | <para> | |
123 | </para> | |
124 | </refsect1> | |
125 | <refsect1 id="errors"><title>Errors</title> | |
126 | <para> | |
127 | <constant>BadMatch</constant> is generated if <parameter>draw</parameter> and <parameter>read</parameter> are not compatible. | |
128 | </para> | |
129 | <para> | |
130 | <constant>BadAccess</constant> is generated if <parameter>ctx</parameter> is current to some other | |
131 | thread. | |
132 | </para> | |
133 | <para> | |
134 | <constant>GLXContextState</constant> is generated if there is a current rendering | |
135 | context and its render mode is either <constant>GLX_FEEDBACK</constant> or | |
136 | <constant>GLX_SELECT</constant>. | |
137 | </para> | |
138 | <para> | |
139 | <constant>GLXBadContext</constant> is generated if <parameter>ctx</parameter> is not a valid GLX | |
140 | rendering context. | |
141 | </para> | |
142 | <para> | |
143 | <constant>GLXBadDrawable</constant> is generated if <parameter>draw</parameter> or <parameter>read</parameter> is not a valid | |
144 | GLX drawable. | |
145 | </para> | |
146 | <para> | |
147 | <constant>GLXBadWindow</constant> is generated if the underlying X window for either | |
148 | <parameter>draw</parameter> or <parameter>read</parameter> is no longer valid. | |
149 | </para> | |
150 | <para> | |
151 | <constant>GLXBadCurrentDrawable</constant> is generated if the previous context of | |
152 | the calling thread has unflushed commands and the previous drawable is | |
153 | no longer valid. | |
154 | </para> | |
155 | <para> | |
156 | <constant>BadAlloc</constant> is generated if the X server does not have enough | |
157 | resources to allocate the buffers. | |
158 | </para> | |
159 | <para> | |
160 | <constant>BadMatch</constant> is generated if: | |
161 | </para> | |
162 | <para> | |
163 | <parameter>draw</parameter> and <parameter>read</parameter> cannot fit into frame buffer memory simultaneously. | |
164 | </para> | |
165 | <para> | |
166 | <parameter>draw</parameter> or <parameter>read</parameter> is a GLXPixmap and <parameter>ctx</parameter> is a direct-rendering | |
167 | context. | |
168 | </para> | |
169 | <para> | |
170 | <parameter>draw</parameter> or <parameter>read</parameter> is a GLXPixmap and <parameter>ctx</parameter> was previously bound to a | |
171 | GLXWindow or GLXPbuffer. | |
172 | </para> | |
173 | <para> | |
174 | <parameter>draw</parameter> or <parameter>read</parameter> is a GLXWindow or GLXPbuffer and <parameter>ctx</parameter> was | |
175 | previously bound to a GLXPixmap. | |
176 | </para> | |
177 | </refsect1> | |
178 | <refsect1 id="seealso"><title>See Also</title> | |
179 | <para> | |
180 | <citerefentry><refentrytitle>glXCreateNewContext</refentrytitle></citerefentry>, | |
181 | <citerefentry><refentrytitle>glXCreateWindow</refentrytitle></citerefentry>, | |
182 | <citerefentry><refentrytitle>glXCreatePixmap</refentrytitle></citerefentry>, | |
183 | <citerefentry><refentrytitle>glXCreatePbuffer</refentrytitle></citerefentry>, | |
184 | <citerefentry><refentrytitle>glXDestroyContext</refentrytitle></citerefentry>, | |
185 | <citerefentry><refentrytitle>glXGetCurrentContext</refentrytitle></citerefentry>, | |
186 | <citerefentry><refentrytitle>glXGetCurrentDisplay</refentrytitle></citerefentry>, | |
187 | <citerefentry><refentrytitle>glXGetCurrentDrawable</refentrytitle></citerefentry>, | |
188 | <citerefentry><refentrytitle>glXGetCurrentReadDrawable</refentrytitle></citerefentry>, | |
189 | <citerefentry><refentrytitle>glXMakeCurrent</refentrytitle></citerefentry> | |
190 | </para> | |
191 | </refsect1> | |
192 | <refsect1 id="Copyright"><title>Copyright</title> | |
193 | <para> | |
194 | Copyright <trademark class="copyright"></trademark> 1991-2006 | |
195 | Silicon Graphics, Inc. This document is licensed under the SGI | |
196 | Free Software B License. For details, see | |
197 | <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>. | |
198 | </para> | |
199 | </refsect1> | |
200 | </refentry> |