<html> <title>OpenGL ES</title> <head><link rel="stylesheet" type="text/css" href="mesa.css"></head> <body> <h1>OpenGL ES</h1> <p>Mesa implements OpenGL ES 1.1 and OpenGL ES 2.0. More informations about OpenGL ES can be found at <a href="http://www.khronos.org/opengles/" target="_parent"> http://www.khronos.org/opengles/</a>.</p> <p>OpenGL ES depends on a working EGL implementation. Please refer to <a href="egl.html">Mesa EGL</a> for more information about EGL.</p> <h2>Build the Libraries</h2> <ol> <li>Run <code>configure</code> with <code>--enable-gles1 --enable-gles2</code> and enable the Gallium driver for your hardware.</li> <li>Build and install Mesa as usual.</li> </ol> Alternatively, if XCB-DRI2 is installed on the system, one can use <code>egl_dri2</code> EGL driver with OpenGL|ES-enabled DRI drivers <ol> <li>Run <code>configure</code> with <code>--enable-gles1 --enable-gles2</code>.</li> <li>Build and install Mesa as usual.</li> </ol> <p>Both methods will install libGLESv1_CM, libGLESv2, libEGL, and one or more EGL drivers for your hardware.</p> <h2>Run the Demos</h2> <p>There are some demos in <code>progs/egl/</code>. You can use them to test your build. For example,</p> <pre> $ cd progs/egl/eglut $ make $ cd ../opengles1 $ make $ ./torus_x11 </pre> <h2>Developers</h2> <h3>Internal Libraries</h3> <table border="1" style="text-align: center;"> <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> <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> <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> </table> <h3>Dispatch Table</h3> <p>OpenGL ES has an additional indirection when dispatching fucntions</p> <pre> Mesa: glFoo() --> _mesa_Foo() OpenGL ES: glFoo() --> _es_Foo() --> _mesa_Foo() </pre> <p>The indirection serves several purposes</p> <ul> <li>When a function is in Mesa and the type matches, it checks the arguments and calls the Mesa function.</li> <li>When a function is in Mesa but the type mismatches, it checks and converts the arguments before calling the Mesa function.</li> <li>When a function is not available in Mesa, or accepts arguments that are not available in OpenGL, it provides its own implementation.</li> </ul> <p>Other than the last case, OpenGL ES uses <code>APIspec.xml</code> to generate functions to check and/or converts the arguments.</p> </body> </html>