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Ca3DE doesn't start? Check "Extention Limit" driver setting!

Posted: 2008-06-24, 19:12
by Carsten
Hi all,

I would like to let you know about a bunch of similar reports that I recently got:
Under Windows Vista (and XP?), the newer NVidia 3D graphics drivers have an option "Extension Limit" in the advanced settings of their control panels.

Please note that this setting should ALWAYS be turned OFF. :idea:

When switched on, Ca3DE initialization can fail entirely, and it doesn't even start.
Thus, if you have problems with running Ca3DE, please check the "Extension Limit" setting first, and make sure that it is OFF. (Some people reported that it was ON even though they never consciously turned it on.)

Please note that this issue is not Ca3DE's fault, but that of the NVidia driver. Turning "Extension Limit" on limits the list of extensions that are enumerated by a call to glGetString(GL_EXTENSIONS), among those the very basic and important GL_ARB_multitexture extension. As there is no technical reason to limit the list of extensions (and thus drop the GL_ARB_multitexture), this has likely been implemented in order to work-around problems with certain broken applications or games. However, activating this setting breaks all the correct programs that are able to parse the extensions list properly and rely on basic extensions like GL_ARB_multitexture (besides Ca3DE, also games like Doom3, Quake4, Prey etc. are affected).
In summary, the correct action had been for the vendors to fix their broken programs that crash due to an unexpectedly long list of extensions, not introduce a driver hot-fix that breaks 99% of all other (and correct) programs.