Voodoo 5 5500 AGP review
Posted by Thomas
McGuire on September 13, 2000 - Page 2/5
Interactive Product: Voodoo
5 5500 AGP
things to note are;
= 16-bit colour depth, Alpha Blending & 3D
Filter Quality set to Automatic.
= 16-bit colour depth, Alpha Blending set to Sharper
& 3D Filter Quality set to High.
= 32-bit colour depth, Alpha Blending & 3D
Filter Quality are ignored.
- 16 bit
- 22 bit
As you can see banding in the sky is nigh on perfectly
removed with the 22-bit image quality capable with the
Voodoo 5. 32-bit still looks better in this respect
obviously & 16-bit remains quite banded as per normal.
The post filters allow for a much nicer image than 16-bit
& most importantly without the performance drop
associated with using 32-bit colour.
filter isn’t used at 32-bit colour depth (obviously) &
neither is it used when X4 FSAA is used (regardless
of colour depth). The reason for the post filter disabling
at X4 FSAA is as follows (Thanks to Dave Barron of Beyond3D
using 4x FSAA 3dfx no longer uses the post filter. Instead,
when they combine the 4 sub-pixels they actually get an
improved result, but a similar one. The basic concept of the
post filter is to take a 4 pixel matrix & using an
adaptive blur, sort of fill in the blanks (areas that were
dithered out to bring it to 16-bit). However, with 4
complete pixels you are actually averaging the values so you
get an improved result.
I rarely play using 32-bit colour depth for the simple
reason that in most cases I could run the game at a higher
resolution with 22-bit colour instead, e.g. 800*600*32 or
3dfx’s own open-source Texture compression scheme. This
offers compression rates of 8:1 at highest compression
levels. 4 different compression schemes are used with the
best one selected to achieve the highest quality results.
The compression algorithms used being – CC_MIXED, CC_HIGH,
CC_CHROMA & CC_ALPHA. S3TC in comparison
offers only 1 algorithm for use.
you want to read more about FXT1 then check out the 3dfx
whitepaper on it.
VSA-100 supports FXT1, DXTC & Narrow Channel texture
compression in hardware. In OpenGL FXT1 can essentially
emulate S3TC. Although it’s not a perfect emulation (For
example, Soldier of Fortune supports S3TC, but FXT1
currently can’t be used), although Quake 3 engine games
support it just fine.
texture compression has 2 effects – 1 is that it can
improve performance, particularly on levels/games with a
high amount of textures, the 2nd effect is that
it will cause some loss in graphical data. To be fair, the
loss isn’t readily apparent, certain textures in a game
may appear a bit weird & this is a result of it. Still,
in Quake 3 the sky doesn’t get pixelated, at least not to
the extent many GeForce owners have complained about when
they have texture compression enabled.
2 Quake 3 shots showing both Texture Compression Enabled
you can see the only real difference appears with the sky.
With texture compression enabled banding is more
apparent than with texture compression disabled. No
other discernible “loss” in image quality is noticeable
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