Reply 420 of 611, by Ozzuneoj
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Joseph_Joestar wrote on 2022-12-07, 08:56:Quake 2 doesn't require this feature to render skyboxes. What happens is that if you have "8-bit textures" set to "yes", then th […]
Ozzuneoj wrote on 2022-12-07, 08:05:If that's the case, it seems odd that the sky boxes in Quake 2 would require this feature because the 8bit files are simply a PCX file, just like all of the other 8bit textures in the game that work fine. Or is it a matter of the "8bit textures" option using "GL_EXT_paletted_texture" to convert the smoother looking .tga textures to 8bit (with a full 256 color palette) so that they look better, where as all of the cards that don't support that feature are just stuck with the nasty looking .pcx versions?
Quake 2 doesn't require this feature to render skyboxes. What happens is that if you have "8-bit textures" set to "yes", then the game will use the hardware support for paletted textures of the graphics card to improve performance. This comes at the cost of reduced visual quality, as stated by the game's manual, which is why skyboxes look worse in that case.
As I've said before, setting "8-bit textures" to "yes" in Quake 2 makes the engine use GL_EXT_shared_texture_palette which, in term, calls GL_EXT_paletted_texture. This can be easily verified by pulling down the console and checking the output on a graphics card which supports paletted textures in hardware.
Is there also a Direct3D equivalent feature that isn't supported on these cards?
There is, but it isn't documented as well as the OpenGL extension. It is known that games like Driver and Final Fantasy 8 use paletted textures in Direct3D. This is evident from their documentation and/or config files. See screenshot below.
Also, it appears that Microsoft's dxview.exe sees the capability of graphics cards to support paletted textures in hardware as 8bit RBG PAL8.
Thanks for the explanation.
So, this has me thinking now... maybe the really really bad looking 8bit .pcx versions of the skybox files are only used when the game is in software mode, since the full 24bit skybox may be a bit too resource heavy and there would be no hardware available to perform the equivalent function of the GL extension to reduce it down.