RE: [GD-Consoles] Textures vs. Polygons

[Tom F. <to...@mu...>]

DX/OGL vertex shaders have limits as well, and in some cases they're
possibly lower than the VU ones. So yeah, splitting meshes up like this is
something people have to do.

I don't know of any magic stuff that wil help. There's detail textures - but
that just adds some "noise" to things - it's good for gravel and grass and
other landscape stuff, but probably not very useful for people until you get
horrendously close (cloth weave, fingerprints, pores, etc). If you're aiming
for ultimate realism, they will be useful, but my impression is that you're
having trouble well before then.

Having different bits of the body at different sizes on thetexture can work
well. We always have faces take up about four times the texture area (i.e.
twice as big in each direction) as equivalently-sized body parts, because
people look at faces much more closely, so you notice pixellisation much
quicker there than elsewhere. They're still on the same texture as the rest
of the body though.

For really high detail there's not much that cn beat just using a big
texture. Obviously you can compress them with the S3TC/DXtn stuff for space
advantages. Another compression trick I've been thinking about is to take a
huge texture made by the artist, then extract the luminance as a separate
texture. Then quantise it to 4 bits. Then remove that influence from the
original texture, downsample the texture quite a bit down to more sensible
sizes, and compress using S3TC/DXTn.

Then we can render the combo using multitexture hardware. The colour and
subtle gradient info is encoded in the (relatively) low-res RGB texture, and
the high-frequency luminance info is in the high-res monochrome texture
(some hardware may not understand A4 texture, so it might need expanding to
A8 unfortunatelky).

It's the same trick as used by television of course, and I believe there's a
Sony sample using this method too.

Tom Forsyth - Muckyfoot bloke.

What's he up to now (and can I have a go)?
http://www.eidosinteractive.com/downloads/search.html?gmid=86

> -----Original Message-----
> From: Jamie Fowlston [mailto:ja...@qu...]
> Sent: 20 November 2001 11:26
> To: gam...@li...
> Subject: RE: [GD-Consoles] Textures vs. Polygons
> 
> 
> I had a half insane idea for character rendering on PS2. I'm 
> probably not
> the only one who's had it, but I'll share it anyway :)
> 
> One of the limitations on PS2 is the number of matrices you 
> can fit on VU
> for skinning (don't worry, this will get relevant to your 
> problem). So to
> counteract this, you could split the character geometry 
> according to which
> matrices it uses. This way you'd never _need_ more than 3 * M 
> matrices on VU
> at any one time (where M is the maximum number of matrices applied per
> vertex). You may, of course, choose to lump in a few more matrices.
> 
> From a texturing point of view, this should fairly naturally split the
> geometry into chunks which are skinned, so you can then use 
> textures more
> efficiently, and use several per character effectively.
> 
> Disclaimer: I haven't actually done this :)
> 
> Jamie
> 
> 
> -----Original Message-----
> From: gam...@li...
> [mailto:gam...@li...]On 
> Behalf Of R
> & D (GameBrains)
> Sent: 20 November 2001 06:19
> To: gam...@li...
> Subject: [GD-Consoles] Textures vs. Polygons
> 
> 
> List has been quiet of late and I have a semi-OT question....
> 
> Technology has come far enough in close-up character 
> rendering that the
> skins for characters seem to take up too much precious space 
> for the quality
> they show on screen and I was wondering if there are 
> solutions around this.
> For example, when you see a character up close that has been 
> skinned, even
> with a hi-res texture you can see pixelation around the 
> places like the neck
> etc. and the pixel filtering makes it look really not natural 
> when compared
> to the individually textured environments in the background.  
> The "easy"
> solution is to not use skins, but to individually texture 
> each part of the
> character, but then the subtle detail of clothing seams and 
> shadows is gone.
> To get around this we could use shadow maps, decaled textures, vertex
> coloring, etc.
> 
> 1.  How have others solved this problem, especially on 
> consoles such as the
> PS2 where texture cache is limited?
> 2.  For those using skins, what has been a good resolution 
> for the skin for
> consoles?  For PC?
> 3.  Can multi-texturing and other solutions actually solve 
> this problem?
> 
> Any advice that those have to offer would be welcome:)  Most 
> of our previous
> games have used rigid body objects rather than organic 
> characters, so we are
> new to the problems that are likely old-hat to everyone else...
> 
> Thanks!
> Brett
> 
> 
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