Subj : Re: Lemmings game for DOS
To   : hollowone
From : Bob Worm
Date : Wed Nov 01 2023 23:17:24

  Re: Re: Lemmings game for DOS
  By: hollowone to Bob Worm on Wed Nov 01 2023 10:29:19

Hi, hollowone.

 >  BW> I know in the 320x200 16 colour modes you were stuck with a fixed
 >  BW> palette (on EGA at least, some kind of CGA compatibility thing) but I
 >  BW> thought VGA 640x480 had configurable palettes?
 >
 > Not in VGA card. SVGA offered that for the first time with video modes
 > starting from 100h in the int 10h VGA interrupt list (assembly level
 > explanation). Core VGA card offered that only in low res (MCGA or ModeX)
 >
 > Check wikipedia entry on VGA, it explains it all:
 >
 > https://en.wikipedia.org/wiki/video_graphics_array

That article says:

"The 640 x 480 16-color and 320 x 200 256-color modes had fully redefinable palettes, with each entry selected from an 18-bit (262,144-color) gamut"

Standard VGA 640 x 480 16 colour is mode 12h, apparently the palette calls are the same as 13h even if the display memory works differently.

BobW
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