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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<head>
<title xmlns:xlink="http://www.w3.org/1999/xlink">eglCreateContext - EGL Reference Pages</title>
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<body>
<header/>
<div class="refentry" id="eglCreateContext">
<div class="titlepage"/>
<div class="refnamediv">
<h2>Name</h2>
<p>eglCreateContext —
create a new <abbr class="acronym">EGL</abbr> rendering context
</p>
</div>
<div class="refsynopsisdiv">
<h2>C Specification</h2>
<div class="funcsynopsis">
<table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">
<tr>
<td>
<code class="funcdef">EGLContext <strong class="fsfunc">eglCreateContext</strong>(</code>
</td>
<td>EGLDisplay <var class="pdparam">display</var>, </td>
</tr>
<tr>
<td> </td>
<td>EGLConfig <var class="pdparam">config</var>, </td>
</tr>
<tr>
<td> </td>
<td>EGLContext <var class="pdparam">share_context</var>, </td>
</tr>
<tr>
<td> </td>
<td>EGLint const * <var class="pdparam">attrib_list</var><code>)</code>;</td>
</tr>
</table>
<div class="funcprototype-spacer"> </div>
</div>
</div>
<div class="refsect1" id="parameters">
<h2>Parameters</h2>
<div class="variablelist">
<dl class="variablelist">
<dt>
<span class="term">
<em class="parameter">
<code>display</code>
</em>
</span>
</dt>
<dd>
<p>
Specifies the
<abbr class="acronym">EGL</abbr>
display connection.
</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>config</code>
</em>
</span>
</dt>
<dd>
<p>Specifies the EGL frame buffer configuration that
defines the frame buffer resource available to the rendering context.
</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>share_context</code>
</em>
</span>
</dt>
<dd>
<p>
Specifies another
<abbr class="acronym">EGL</abbr>
rendering context with which to share data, as
defined by the client API corresponding to the
contexts. Data is also shared with all other
contexts with which
<em class="parameter"><code>share_context</code></em> shares data.
<code class="constant">EGL_NO_CONTEXT</code> indicates that
no sharing is to take place.
</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>attrib_list</code>
</em>
</span>
</dt>
<dd>
<p>
Specifies attributes and attribute values for the
context being created. Only the attribute
<code class="constant">EGL_CONTEXT_CLIENT_VERSION</code> may
be specified.
</p>
</dd>
</dl>
</div>
</div>
<div class="refsect1" id="description">
<h2>Description</h2>
<p>
<code class="function">eglCreateContext</code> creates an EGL
rendering context for the current rendering API (as set with
<code class="function">eglBindAPI</code>) and returns a handle to the
context. The context can then be used to render into an EGL
drawing surface. If <code class="function">eglCreateContext</code>
fails to create a rendering context,
<code class="constant">EGL_NO_CONTEXT</code> is returned.
</p>
<p>
If <em class="parameter"><code>share_context</code></em> is not
<code class="constant">EGL_NO_CONTEXT</code>, then all shareable data
in the context (as defined by the client API specification
for the current rendering API) are shared by context
<em class="parameter"><code>share_context</code></em>, all other contexts
<em class="parameter"><code>share_context</code></em> already shares with,
and the newly created context. An arbitrary number of
rendering contexts can share data. However, all rendering
contexts that share data must themselves exist in the same
address space. Two rendering contexts share an address space
if both are owned by a single process.
</p>
<p>
<em class="parameter"><code>attrib_list</code></em> specifies a list of
attributes for the context. The list has the same structure
as described for <code class="function">eglChooseConfig</code>. The
attributes and attribute values which may be specified are
as follows:
</p>
<div class="variablelist">
<dl class="variablelist">
<dt>
<span class="term">
<code class="constant">EGL_CONTEXT_MAJOR_VERSION</code>
</span>
</dt>
<dd>
<p>
Must be followed by an integer specifying the requested
major version of an OpenGL or OpenGL ES context. The
default value is 1. This attribute is an alias of the
older <code class="constant">EGL_CONTEXT_CLIENT_VERSION</code>,
and the tokens may be used interchangeably.
</p>
</dd>
<dt>
<span class="term">
<code class="constant">EGL_CONTEXT_MINOR_VERSION</code>
</span>
</dt>
<dd>
<p>
Must be followed by an integer specifying the requested
minor version of an OpenGL or OpenGL ES context. The
default value is 0.
</p>
</dd>
<dt>
<span class="term">
<code class="constant">EGL_CONTEXT_OPENGL_PROFILE_MASK</code>
</span>
</dt>
<dd>
<p>
Must be followed by an integer bitmask specifying the
<em class="firstterm">profile</em> of an OpenGL context.
Bits which may be set include
<code class="constant">EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT</code>
for a core profile and
<code class="constant">EGL_CONTEXT_OPENGL_COMPATIBILITY_PROFILE_BIT</code>
for a compatibility profile. The default value is
<code class="constant">EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT</code>.
All OpenGL 3.2 and later implementations are required to
implement the core profile, but implementation of the
compatibility profile is optional.
</p>
</dd>
<dt>
<span class="term">
<code class="constant">EGL_CONTEXT_OPENGL_DEBUG</code>
</span>
</dt>
<dd>
<p>
Must be followed by <code class="constant">EGL_TRUE</code>,
specifying that an OpenGL or OpenGL ES <em class="firstterm">debug
context</em> should be created, or
<code class="constant">EGL_FALSE</code>, if a non-debug context
should be created. The default value is
<code class="constant">EGL_FALSE</code>.
</p>
</dd>
<dt>
<span class="term">
<code class="constant">EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE</code>
</span>
</dt>
<dd>
<p>
Must be followed by <code class="constant">EGL_TRUE</code>,
specifying that a
<em class="firstterm">forward-compatible</em> OpenGL context
should be created, or <code class="constant">EGL_FALSE</code>, if
a non-forward-compatible context should be created. The
default value is <code class="constant">EGL_FALSE</code>.
</p>
</dd>
<dt>
<span class="term">
<code class="constant">EGL_CONTEXT_OPENGL_ROBUST_ACCESS</code>
</span>
</dt>
<dd>
<p>
Must be followed by <code class="constant">EGL_TRUE</code>,
specifying that an OpenGL or OpenGL ES context
supporting <em class="firstterm">robust buffer access</em>
should be created, or <code class="constant">EGL_FALSE</code>, if
a non-robust context should be created. The default
value is <code class="constant">EGL_FALSE</code>.
</p>
</dd>
<dt>
<span class="term">
<code class="constant">EGL_CONTEXT_OPENGL_RESET_NOTIFICATION_STRATEGY</code>
</span>
</dt>
<dd>
<p>
Must be followed by
<code class="constant">EGL_LOSE_CONTEXT_ON_RESET</code>,
specifying that an OpenGL or OpenGL ES context with
reset notification behavior
<code class="constant">GL_LOSE_CONTEXT_ON_RESET_ARB</code> should
be created, or
<code class="constant">EGL_NO_RESET_NOTIFICATION</code>,
specifying that an OpenGL or OpenGL ES context with
reset notification behavior
<code class="constant">GL_NO_RESET_NOTIFICATION_ARB</code> should
be created, as described by the
<code class="constant">GL_ARB_robustness</code> extension.
</p>
<p>
If the
<code class="constant">EGL_CONTEXT_OPENGL_ROBUST_ACCESS</code>
attribute is not set to <code class="constant">EGL_TRUE</code>,
context creation will not fail, but the resulting
context may not support robust buffer access, and
therefore may not support the requested reset
notification strategy The default value for
<code class="constant">EGL_CONTEXT_OPENGL_RESET_NOTIFICATION_STRATEGY</code>
is <code class="constant">EGL_NO_RESET_NOTIFICATION</code> .
</p>
</dd>
</dl>
</div>
<p>
There are many possible interactions between requested OpenGL
and OpenGL ES context creation attributes, depending on the API
versions and extensions supported by the implementation. These
interactions are described in detail in the EGL 1.5
Specification, but are not listed here for compactness. The
requested attributes may not be able to be satisfied, but
context creation may still succeed. Applications should ensure
that the OpenGL or OpenGL ES contexts supports needed features
before using them, by determining the actual context version,
supported extensions, and supported context flags using runtime
queries.
</p>
</div>
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