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 12 OpenGL ES can be found at <a href="http://www.khronos.org/opengles/" 13 target="_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 24 Alternatively, 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 33 EGL 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 38 your 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
