-<html>
-
-<title>Mesa EGL</title>
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html lang="en">
+<head>
+ <meta http-equiv="content-type" content="text/html; charset=utf-8">
+ <title>Mesa EGL</title>
+ <link rel="stylesheet" type="text/css" href="mesa.css">
+</head>
+<body>
-<head><link rel="stylesheet" type="text/css" href="mesa.css"></head>
+<div class="header">
+ <h1>The Mesa 3D Graphics Library</h1>
+</div>
-<body>
+<iframe src="contents.html"></iframe>
+<div class="content">
<h1>Mesa EGL</h1>
<p>The current version of EGL in Mesa implements EGL 1.4. More information
about EGL can be found at
-<a href="http://www.khronos.org/egl/" target="_parent">
+<a href="http://www.khronos.org/egl/">
http://www.khronos.org/egl/</a>.</p>
<p>The Mesa's implementation of EGL uses a driver architecture. The main
dynamically loaded by the main library and most of the EGL API calls are
directly dispatched to the drivers.</p>
-<p>The driver in use decides the window system to support. For drivers that
-support hardware rendering, there are usually multiple drivers supporting the
-same window system. Each one of of them supports a certain range of graphics
-cards.</p>
+<p>The driver in use decides the window system to support.</p>
<h2>Build EGL</h2>
<ol>
<li>
-<p>Run <code>configure</code> with the desired state trackers and enable
-the Gallium driver for your hardware. For example</p>
+<p>Run <code>configure</code> with the desired client APIs and enable
+the driver for your hardware. For example</p>
<pre>
- $ ./configure --enable-gles-overlay --enable-openvg --enable-gallium-intel
+ $ ./configure --enable-gles1 --enable-gles2 \
+ --with-dri-drivers=... \
+ --with-gallium-drivers=...
</pre>
-<p>The main library and OpenGL is enabled by default. The first option enables
-<a href="opengles.html">OpenGL ES 1.x and 2.x</a>. The second option enables
-<a href="openvg.html">OpenVG</a>.
-</p>
+<p>The main library and OpenGL is enabled by default. The first two options
+above enables <a href="opengles.html">OpenGL ES 1.x and 2.x</a>. The last two
+options enables the listed classic and and Gallium drivers respectively.</p>
</li>
</ol>
<p>In the given example, it will build and install <code>libEGL</code>,
-<code>libGL</code>, <code>libGLESv1_CM</code>, <code>libGLESv2</code>,
-<code>libOpenVG</code>, and one or more EGL drivers.</p>
+<code>libGL</code>, <code>libGLESv1_CM</code>, <code>libGLESv2</code>, and one
+or more EGL drivers.</p>
<h3>Configure Options</h3>
<p>There are several options that control the build of EGL at configuration
time</p>
-<ul>
-<li><code>--enable-egl</code>
+<dl>
+<dt><code>--enable-egl</code></dt>
+<dd>
<p>By default, EGL is enabled. When disabled, the main library and the drivers
will not be built.</p>
-</li>
+</dd>
-<li><code>--with-egl-driver-dir</code>
+<dt><code>--with-egl-driver-dir</code></dt>
+<dd>
<p>The directory EGL drivers should be installed to. If not specified, EGL
drivers will be installed to <code>${libdir}/egl</code>.</p>
-</li>
+</dd>
-<li><code>--with-egl-platforms</code>
+<dt><code>--enable-gallium-egl</code></dt>
+<dd>
+
+<p>Enable the optional <code>egl_gallium</code> driver.</p>
+
+</dd>
+
+<dt><code>--with-egl-platforms</code></dt>
+<dd>
<p>List the platforms (window systems) to support. Its argument is a comma
seprated string such as <code>--with-egl-platforms=x11,drm</code>. It decides
<p>The available platforms are <code>x11</code>, <code>drm</code>,
<code>fbdev</code>, and <code>gdi</code>. The <code>gdi</code> platform can
-only be built with SCons.</p>
+only be built with SCons. Unless for special needs, the build system should
+select the right platforms automatically.</p>
-</li>
+</dd>
-<li><code>--enable-gles-overlay</code>
+<dt><code>--enable-gles1</code></dt>
+<dt><code>--enable-gles2</code></dt>
+<dd>
-<p>OpenGL is built by default. To build OpenGL ES, this option must be
-explicitly given.</p>
+<p>These options enable OpenGL ES support in OpenGL. The result is one big
+internal library that supports multiple APIs.</p>
-</li>
+</dd>
-<li><code>--enable-gles1</code> and <code>--enable-gles2</code>
+<dt><code>--enable-shared-glapi</code></dt>
+<dd>
-<p>Unlike <code>--enable-gles-overlay</code>, which builds one library for each
-rendering API, these options enable OpenGL ES support in OpenGL. The result is
-one big library that supports multiple APIs.</p>
+<p>By default, <code>libGL</code> has its own copy of <code>libglapi</code>.
+This options makes <code>libGL</code> use the shared <code>libglapi</code>. This
+is required if applications mix OpenGL and OpenGL ES.</p>
-</li>
+</dd>
-<li><code>--enable-openvg</code>
+<dt><code>--enable-openvg</code></dt>
+<dd>
<p>OpenVG must be explicitly enabled by this option.</p>
-</li>
+</dd>
-</ul>
+</dl>
<h2>Use EGL</h2>
<p>There are several environment variables that control the behavior of EGL at
runtime</p>
-<ul>
-<li><code>EGL_DRIVERS_PATH</code>
+<dl>
+<dt><code>EGL_DRIVERS_PATH</code></dt>
+<dd>
<p>By default, the main library will look for drivers in the directory where
the drivers are installed to. This variable specifies a list of
addition to the default directory. This variable is ignored for setuid/setgid
binaries.</p>
-</li>
+<p>This variable is usually set to test an uninstalled build. For example, one
+may set</p>
-<li><code>EGL_DRIVER</code>
+<pre>
+ $ export LD_LIBRARY_PATH=$mesa/lib
+ $ export EGL_DRIVERS_PATH=$mesa/lib/egl
+</pre>
-<p>This variable specifies a full path to an EGL driver and it forces the
-specified EGL driver to be loaded. It comes in handy when one wants to test a
-specific driver. This variable is ignored for setuid/setgid binaries.</p>
+<p>to test a build without installation</p>
-<p><code>egl_gallium</code> dynamically loads hardware drivers and client API
-modules found in <code>EGL_DRIVERS_PATH</code>. Thus, specifying this variable
-alone is not sufficient for <code>egl_gallium</code> for an uninstalled
-build.</p>
+</dd>
-</li>
+<dt><code>EGL_DRIVER</code></dt>
+<dd>
+
+<p>This variable specifies a full path to or the name of an EGL driver. It
+forces the specified EGL driver to be loaded. It comes in handy when one wants
+to test a specific driver. This variable is ignored for setuid/setgid
+binaries.</p>
+
+</dd>
-<li><code>EGL_PLATFORM</code>
+<dt><code>EGL_PLATFORM</code></dt>
+<dd>
<p>This variable specifies the native platform. The valid values are the same
as those for <code>--with-egl-platforms</code>. When the variable is not set,
the main library uses the first platform listed in
-<code>--with-egl-platforms</code> as the native platform</p>
+<code>--with-egl-platforms</code> as the native platform.</p>
-</li>
+<p>Extensions like <code>EGL_MESA_drm_display</code> define new functions to
+create displays for non-native platforms. These extensions are usually used by
+applications that support non-native platforms. Setting this variable is
+probably required only for some of the demos found in mesa/demo repository.</p>
-<li><code>EGL_LOG_LEVEL</code>
+</dd>
+
+<dt><code>EGL_LOG_LEVEL</code></dt>
+<dd>
<p>This changes the log level of the main library and the drivers. The valid
values are: <code>debug</code>, <code>info</code>, <code>warning</code>, and
<code>fatal</code>.</p>
-</li>
+</dd>
-<li><code>EGL_SOFTWARE</code>
+<dt><code>EGL_SOFTWARE</code></dt>
+<dd>
<p>For drivers that support both hardware and software rendering, setting this
variable to true forces the use of software rendering.</p>
-</li>
-</ul>
+</dd>
+</dl>
<h2>EGL Drivers</h2>
-<ul>
-<li><code>egl_gallium</code>
+<dl>
+<dt><code>egl_dri2</code></dt>
+<dd>
+
+<p>This driver supports both <code>x11</code> and <code>drm</code> platforms.
+It functions as a DRI driver loader. For <code>x11</code> support, it talks to
+the X server directly using (XCB-)DRI2 protocol.</p>
+
+<p>This driver can share DRI drivers with <code>libGL</code>.</p>
+
+</dd>
+
+<dt><code>egl_gallium</code></dt>
+<dd>
<p>This driver is based on Gallium3D. It supports all rendering APIs and
hardwares supported by Gallium3D. It is the only driver that supports OpenVG.
The supported platforms are X11, DRM, FBDEV, and GDI.</p>
-</li>
+<p>This driver comes with its own hardware drivers
+(<code>pipe_<hw></code>) and client API modules
+(<code>st_<api></code>).</p>
-<li><code>egl_glx</code>
+</dd>
+
+<dt><code>egl_glx</code></dt>
+<dd>
<p>This driver provides a wrapper to GLX. It uses exclusively GLX to implement
the EGL API. It supports both direct and indirect rendering when the GLX does.
It is accelerated when the GLX is. As such, it cannot provide functions that
is not available in GLX or GLX extensions.</p>
-</li>
+</dd>
+</dl>
-<li><code>egl_dri2</code>
+<h2>Packaging</h2>
-<p>This driver supports the X Window System as its window system. It functions
-as a DRI2 driver loader. Unlike <code>egl_glx</code>, it has no dependency on
-<code>libGL</code>. It talks to the X server directly using (XCB-)DRI2
-protocol.</p>
+<p>The ABI between the main library and its drivers are not stable. Nor is
+there a plan to stabilize it at the moment. Of the EGL drivers,
+<code>egl_gallium</code> has its own hardware drivers and client API modules.
+They are considered internal to <code>egl_gallium</code> and there is also no
+stable ABI between them. These should be kept in mind when packaging for
+distribution.</p>
-</li>
-</ul>
+<p>Generally, <code>egl_dri2</code> is preferred over <code>egl_gallium</code>
+when the system already has DRI drivers. As <code>egl_gallium</code> is loaded
+before <code>egl_dri2</code> when both are available, <code>egl_gallium</code>
+is disabled by default.</p>
<h2>Developers</h2>
to an <code>EGLDisplay</code> without going through the EGL APIs, the driver
should as well lock the display before using it.
-<h3>TODOs</h3>
-
-<ul>
-<li>Pass the conformance tests</li>
-<li>Mixed use of OpenGL, OpenGL ES 1.1, and OpenGL ES 2.0 is supported. But
-which one of <code>libGL.so</code>, <code>libGLESv1_CM.so</code>, and
-<code>libGLESv2.so</code> should an application link to? Bad things may happen
-when, say, an application is linked to <code>libGLESv2.so</code> and
-<code>libcairo</code>, which is linked to <code>libGL.so</code> instead.</li>
-
-</ul>
-
+</div>
</body>
</html>
OSDN Git Service
