[sldev] P2P/Squid Web Textures: Enabling Greater Quality Images - draft 2

dale at daleglass.net dale at daleglass.net
Sat Jul 7 08:33:24 PDT 2007


On Sat, Jul 07, 2007 at 08:05:50AM -0700, Dzonatas wrote:
> dale at daleglass.net wrote:
> >But scuplties use really tiny textures. You could simply get LL to make
> >an exception for 64x64 textures. At 16 bit color, uncompressed, that's
> >just 8K. You could not compress it at all.
> >  
> Internally (in the viewer), all images are converted to 32 bit.  
> Uncompressed, that would be at least 130k. Sculpties use the full 8 bit 
> RGB values, and there is discussion on how to use the alpha channel as well.
Huh? That's some bad math there.

A 64x64 image has 64 * 64 = 4096 pixels.

16 bit color is 2 bytes per pixel, in 555 or 565 format (doesn't matter
which), so 8K.

32 bit color is 4 bytes per pixel, 8 bits for each of R, G, B, A. That's
16K.

ATM, I think textures as small as 16K wouldn't amount to much bandwidth
at all. Most textures I see around are a lot larger.

 
> There are artist that have asked for lossless detail on their images. It 
> sounds as if that is how they want to do their business. It is beyond 
> just scuplties.
Fair enough, but in that case I'd like to see comparison images. 

First we see what it looks like, and based on that we could see what
could be done. Other possiblities include tweaking compression quality,
or allowing uncompressed uploads but charging more for them.

 
> Nevertheless, there is the overhead to transfer images (even at 8k) 
> through the sim network with UDP or TCP. All of that can be moved 
> externally to reduce server lag. More images added to the sim network 
> mean more chances of lag. Consider that another continent is now under 
> way, there will be more textures on the network even if they are just 
> 64x64 sculpties. We can reduce this traffic.
IMO, if you want to reduce bandwidth usage that's a very good goal to
have, but the logical thing would be to start from the BIG things, not
from the tiny ones.

For example, how about *reducing* quality? Make the price dependent on
texture size and compression quality. This would give the people an
incentive to avoid upload things that are larger than necessary.

 
> There is no magic to distinguish a sculptie image from another texture 
> image, as it doesn't exist. While we could just enable lossless uploads 
> right now with a flick of a switch, that would mean there is no 
> immediate way to stop people from uploading lossless 1024x1024 images. I 
> rather not have this implementation be the cause as for why everybody's 
> tier rate would increase. Even though it is possible right now directly 
> with the sim, a cache that is external to the sim is more practical.
Sure there is: image size.

There's no reason why you couldn't accept uncompressed images only up to
64x64.

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