Which are the lowest end Ati and Nvidia cards that have GLSL support ?
Radeon 9500
GeForce FX 5200
Ok. I asked because i’m developing a flight simulator and recently i added shaders to the graphic engine. I was thinking to give users the possibility to enable or disable shaders, but since the low-end graphic cards that support them are relatively “obsolete” than i could just go for a shader-only version.
Depending on your average user, I think keeping a legacy path could be a good thing. I would’nt spend much time on it (eg I wouldn’t go into NV reg combiners or ATI_fs for older cards), but a simple multitexturing path that can run anywhere would be nice. At least the app starts and runs properly, that’s better than a message box at startup that says “buy an new card” and exit.
Also, don’t expect good performance on FX 5200. Depending on the complexity of your shaders, it might become practically un-usable. In this case, the option to choose between shader and “old-school” version is a big plus.
This is also true to a certain extent on older ATI cards (speaking of Radeon 9500 up to 9800 here). These cards have significant restrictions regarding instruction count and such. If your shaders are too complex, they won’t run in hardware.
All this to say : beware of what “GLSL support” means. For simple shaders, there should be no problems, but for complex ones, the hardware limitations of each generation appear again.