17ec681f3SmrgApplication Issues 27ec681f3Smrg================== 37ec681f3Smrg 47ec681f3SmrgThis page documents known issues with some OpenGL applications. 57ec681f3Smrg 67ec681f3SmrgTopogun 77ec681f3Smrg------- 87ec681f3Smrg 97ec681f3Smrg`Topogun <http://www.topogun.com/>`__ for Linux (version 2, at least) 107ec681f3Smrgcreates a GLX visual without requesting a depth buffer. This causes bad 117ec681f3Smrgrendering if the OpenGL driver happens to choose a visual without a 127ec681f3Smrgdepth buffer. 137ec681f3Smrg 147ec681f3SmrgMesa 9.1.2 and later (will) support a DRI configuration option to work 157ec681f3Smrgaround this issue. Using the 167ec681f3Smrg`driconf <https://dri.freedesktop.org/wiki/DriConf>`__ tool, set the 177ec681f3Smrg"Create all visuals with a depth buffer" option before running Topogun. 187ec681f3SmrgThen, all GLX visuals will be created with a depth buffer. 197ec681f3Smrg 207ec681f3SmrgOld OpenGL games 217ec681f3Smrg---------------- 227ec681f3Smrg 237ec681f3SmrgSome old OpenGL games (approx. ten years or older) may crash during 247ec681f3Smrgstart-up because of an extension string buffer-overflow problem. 257ec681f3Smrg 267ec681f3SmrgThe problem is a modern OpenGL driver will return a very long string for 277ec681f3Smrgthe ``glGetString(GL_EXTENSIONS)`` query and if the application naively 287ec681f3Smrgcopies the string into a fixed-size buffer it can overflow the buffer 297ec681f3Smrgand crash the application. 307ec681f3Smrg 317ec681f3SmrgThe work-around is to set the ``MESA_EXTENSION_MAX_YEAR`` environment 327ec681f3Smrgvariable to the approximate release year of the game. This will cause 337ec681f3Smrgthe ``glGetString(GL_EXTENSIONS)`` query to only report extensions older 347ec681f3Smrgthan the given year. 357ec681f3Smrg 367ec681f3SmrgFor example, if the game was released in 2001, do 377ec681f3Smrg 387ec681f3Smrg.. code-block:: console 397ec681f3Smrg 407ec681f3Smrg export MESA_EXTENSION_MAX_YEAR=2001 417ec681f3Smrg 427ec681f3Smrgbefore running the game. 437ec681f3Smrg 447ec681f3SmrgViewperf 457ec681f3Smrg-------- 467ec681f3Smrg 477ec681f3SmrgSee the :doc:`Viewperf issues <viewperf>` page for a detailed list of 487ec681f3SmrgViewperf issues. 49