From: tunny@INFERENCE.COM (Jim Tunnicliffe)
Newsgroups: bit.listserv.win3-l
Subject: Re: gifs
Date: 6 Oct 92 16:07:23 GMT
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU

> How is a GIF made? From what I can tell, GIF images are more like a photograph
> than other images, thus more life like. Are there problems in using GIF images
> in games? I don't think I have seen any games with GIF's in them.

George,

GIF (Graphics Interchange Format, pioneered by Compuserve) is simply a
specification for compressing graphics images (really, the basic compression
scheme would work for any data, but there is header information in a GIF file
that is specific to graphics, like image size, number of colors, palette
information, etc.)  There is nothing that makes a GIF file inherently "more
like a photograph" than images in other formats.  It's just that most 256-color
images (the relatively large number of colors being what gives them that
"photographic" quality) are stored as GIF's, because that compression scheme
allows them to be stored quite efficiently.  There are various other formats
that you will sometimes see, and the thing to remember is that it is the number
of colors (and to a lesser degree, the resolution) that determines how "photo-
realistic" an image potentially is.  Some hardware and software support images
with over 32000 colors, or even 16.7 million colors (24-bit, or "True Color"),
though you won't find many files with this many colors on many BBS's or ftp
sites, because most folks can't display them with their mainstream hardware.

Now, the reason you don't see many 256-color images in games (yet!) is that
most games opt for higher resolution modes (more pixels on the screen, hence
more detailed graphics), rather than color depth.  A standard VGA card can
typically display in a 640x480 pixel mode in 16 colors, but only 320x200 pixels
at 256 colors.  Some games DO have pretty photo-realistic screens (see Links!,
a very nice golf game, as one example), but most arcade-type games have no
use for more than 16 colors, so they go for the higher resolution.  Sometimes
you'll see a title screen in 256 colors, then the program will switch to hi-res
16-color mode for the game, since you have to be in one mode or the other at a
given time.

Now, with high-end video cards and monitors becoming affordable that offer 256
colors in resolutions up to (and beyond) 1024x768, hopefully the game makers
and other software designers will respond to this growing market segment with
programs that take full advantage of the capabilities of the hardware and
software.  I've seen a couple of "Super VGA" enhancements advertised for a
couple of games already...

Hope this helps clear things up a bit.

	- tunny
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James A. Tunnicliffe        |                                           \\
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Views expressed are my own and do not necessarily reflect those of my employer
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU