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gerrit-public.fairphone.software / fp2-dev / platform / external / mesa3d / bc73a6289f5e28636d579e17e8a8d70a2d8d7500 / . / docs / opengles.html
blob: 63cc1146a2edfe91420269e51be105daf70bd7ac [file] [log] [blame]
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]1<html>
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Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]3<title>OpenGL ES</title>
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]4
5<head><link rel="stylesheet" type="text/css" href="mesa.css"></head>
6
7<body>
8
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]9<h1>OpenGL ES</h1>
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]10
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]11<p>Mesa implements OpenGL ES 1.1 and OpenGL ES 2.0. More informations about
12OpenGL ES can be found at <a href="http://www.khronos.org/opengles/"
13target="_parent"> http://www.khronos.org/opengles/</a>.</p>
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]14
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]15<p>OpenGL ES depends on a working EGL implementation. Please refer to
16<a href="egl.html">Mesa EGL</a> for more information about EGL.</p>
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]17
18<h2>Build the Libraries</h2>
19<ol>
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]20<li>Run <code>configure</code> with <code>--enable-gles-overlay</code> and enable the Gallium driver for your hardware.</li>
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]21<li>Build and install Mesa as usual.</li>
22</ol>
23
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]24Alternatively, if XCB-DRI2 is installed on the system, one can use
25<code>egl_dri2</code> EGL driver with OpenGL|ES-enabled DRI drivers
26
27<ol>
28<li>Run <code>configure</code> with <code>--enable-gles1 --enable-gles2</code>.</li>
29<li>Build and install Mesa as usual.</li>
30</ol>
31
32<p>Both methods will install libGLESv1_CM, libGLESv2, libEGL, and one or more
33EGL drivers for your hardware.</p>
34
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]35<h2>Run the Demos</h2>
36
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]37<p>There are some demos in <code>progs/egl/</code>. You can use them to test
38your build. For example,</p>
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]39
40<pre>
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]41 $ cd progs/egl/eglut
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]42 $ make
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]43 $ cd ../opengles1
44 $ make
45 $ ./torus_x11
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]46</pre>
47
48<h2>Developers</h2>
49
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]50<h3>Internal Libraries</h3>
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]51
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]52<table border="1" style="text-align: center;">
53 <tr><td>Library Name</td><td>Used By</td><td>Enabled</td><td>OpenGL</td><td>OpenGL ES 1.x</td><td>OpenGL ES 2.x</td></tr>
Chia-I Wu87cc2da2010-05-12 14:17:17 +0800[diff] [blame]54 <tr><td><code>libmesa.a</td><td>Classic DRI drivers</td><td>y</td><td>y</td><td>--enable-gles1</td><td>--enable-gles2</td></tr>
55 <tr><td><code>libmesagallium.a</td><td>Gallium EGL and DRI drivers</td><td>y</td><td>y</td><td>--enable-gles1</td><td>--enable-gles2</td></tr>
56 <tr><td><code>libes1gallium.a</td><td>Gallium EGL drivers</td><td>--enable-gles-overlay</td><td>n</td><td>y</td><td>n</td></tr>
57 <tr><td><code>libes2gallium.a</td><td>Gallium EGL drivers</td><td>--enable-gles-overlay</td><td>n</td><td>n</td><td>y</td></tr>
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]58</table>
59
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]60<h3>Dispatch Table</h3>
61
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]62<p>OpenGL ES has an additional indirection when dispatching fucntions</p>
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]63
64<pre>
65 Mesa: glFoo() --&gt; _mesa_Foo()
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]66 OpenGL ES: glFoo() --&gt; _es_Foo() --&gt; _mesa_Foo()
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]67</pre>
68
69<p>The indirection serves several purposes</p>
70
71<ul>
72<li>When a function is in Mesa and the type matches, it checks the arguments and calls the Mesa function.</li>
73<li>When a function is in Mesa but the type mismatches, it checks and converts the arguments before calling the Mesa function.</li>
74<li>When a function is not available in Mesa, or accepts arguments that are not available in OpenGL, it provides its own implementation.</li>
75</ul>
76
Chia-I Wu2e3c4e42010-05-07 14:13:08 +0800[diff] [blame]77<p>Other than the last case, OpenGL ES uses <code>APIspec.xml</code> to generate functions to check and/or converts the arguments.</p>
Chia-I Wud8299af2010-01-11 18:25:03 +0800[diff] [blame]78
79</body>
80</html>