1<html> 2 3<title>OpenGL ES</title> 4 5<head><link rel="stylesheet" type="text/css" href="mesa.css"></head> 6 7<body> 8 9<h1>OpenGL ES</h1> 10 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> 14 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> 17 18<h2>Build the Libraries</h2> 19<ol> 20<li>Run <code>configure</code> with <code>--enable-gles-overlay</code> and enable the Gallium driver for your hardware.</li> 21<li>Build and install Mesa as usual.</li> 22</ol> 23 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 35<h2>Run the Demos</h2> 36 37<p>There are some demos in <code>progs/egl/</code>. You can use them to test 38your build. For example,</p> 39 40<pre> 41 $ cd progs/egl/eglut 42 $ make 43 $ cd ../opengles1 44 $ make 45 $ ./torus_x11 46</pre> 47 48<h2>Developers</h2> 49 50<h3>Internal Libraries</h3> 51 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> 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> 58</table> 59 60<h3>Dispatch Table</h3> 61 62<p>OpenGL ES has an additional indirection when dispatching fucntions</p> 63 64<pre> 65 Mesa: glFoo() --> _mesa_Foo() 66 OpenGL ES: glFoo() --> _es_Foo() --> _mesa_Foo() 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 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> 78 79</body> 80</html> 81