docs/opengles.rst

   1 OpenGL ES
   2 =========
   3
   4 Mesa implements OpenGL ES 1.1 and OpenGL ES 2.0. More information about
   5 OpenGL ES can be found at https://www.khronos.org/opengles/.
   6
   7 OpenGL ES depends on a working EGL implementation. Please refer to
   8 :doc:`Mesa EGL <egl>` for more information about EGL.
   9
  10 Build the Libraries
  11 -------------------
  12
  13 #. Run ``meson configure`` with ``-D gles1=true -D gles2=true`` and
  14    enable the Gallium driver for your hardware.
  15 #. Build and install Mesa as usual.
  16
  17 Alternatively, if XCB-DRI2 is installed on the system, one can use
  18 ``egl_dri2`` EGL driver with OpenGL|ES-enabled DRI drivers
  19
  20 #. Run ``meson configure`` with ``-D gles1=true -D gles2=true``.
  21 #. Build and install Mesa as usual.
  22
  23 Both methods will install libGLESv1_CM, libGLESv2, libEGL, and one or
  24 more EGL drivers for your hardware.
  25
  26 Run the Demos
  27 -------------
  28
  29 There are some demos in ``mesa/demos`` repository.
  30
  31 Developers
  32 ----------
  33
  34 Dispatch Table
  35 ~~~~~~~~~~~~~~
  36
  37 OpenGL ES has an additional indirection when dispatching functions
  38
  39 ::
  40
  41      Mesa:       glFoo() --> _mesa_Foo()
  42      OpenGL ES:  glFoo() --> _es_Foo() --> _mesa_Foo()
  43
  44 The indirection serves several purposes
  45
  46 -  When a function is in Mesa and the type matches, it checks the
  47    arguments and calls the Mesa function.
  48 -  When a function is in Mesa but the type mismatches, it checks and
  49    converts the arguments before calling the Mesa function.
  50 -  When a function is not available in Mesa, or accepts arguments that
  51    are not available in OpenGL, it provides its own implementation.
  52
  53 Other than the last case, OpenGL ES uses ``APIspec.xml`` to generate
  54 functions to check and/or converts the arguments.