docs/application-issues.rst

   1 Application Issues
   2 ==================
   3
   4 This page documents known issues with some OpenGL applications.
   5
   6 Topogun
   7 -------
   8
   9 `Topogun <http://www.topogun.com/>`__ for Linux (version 2, at least)
  10 creates a GLX visual without requesting a depth buffer. This causes bad
  11 rendering if the OpenGL driver happens to choose a visual without a
  12 depth buffer.
  13
  14 Mesa 9.1.2 and later (will) support a DRI configuration option to work
  15 around this issue. Using the
  16 `driconf <https://dri.freedesktop.org/wiki/DriConf>`__ tool, set the
  17 "Create all visuals with a depth buffer" option before running Topogun.
  18 Then, all GLX visuals will be created with a depth buffer.
  19
  20 Old OpenGL games
  21 ----------------
  22
  23 Some old OpenGL games (approx. ten years or older) may crash during
  24 start-up because of an extension string buffer-overflow problem.
  25
  26 The problem is a modern OpenGL driver will return a very long string for
  27 the ``glGetString(GL_EXTENSIONS)`` query and if the application naively
  28 copies the string into a fixed-size buffer it can overflow the buffer
  29 and crash the application.
  30
  31 The work-around is to set the ``MESA_EXTENSION_MAX_YEAR`` environment
  32 variable to the approximate release year of the game. This will cause
  33 the ``glGetString(GL_EXTENSIONS)`` query to only report extensions older
  34 than the given year.
  35
  36 For example, if the game was released in 2001, do
  37
  38 .. code-block:: console
  39
  40    export MESA_EXTENSION_MAX_YEAR=2001
  41
  42 before running the game.
  43
  44 Viewperf
  45 --------
  46
  47 See the :doc:`Viewperf issues <viewperf>` page for a detailed list of
  48 Viewperf issues.