QUOTE(dvsone @ Aug 27 2007, 04:30 AM)
Your talking about scaling. Someone correct me if I'm wrong but I'm pretty sure most textures are made in the native resolution of the game. If a game is native 1080p, most of the textures (if not all) will be in 1080p. And a 1080p texture is 3 times larger than a 720p texture.
it has nothing to do with scaling.
Texture resolution is completely independent of the final target render resolution.
Here's a good run down of understanding texture resolutions:http://www.thegnomonworkshop.com/tutorials...exture_res.html
Basically if you have a 100x100 texture stretched across a wall in the game it has nothing to do what what resolution the game is rendering to... that texture is still the same size and is still stretched across the same amount of wall space.
The textures on every object in the game can be a completely different resolutions... it's a matter of developer choice in terms of how much memory they have to work with and what needs more detail and what doesn't.
Obviously if you're dumping out to a display at a higher rendered output resolution you'll be able to see more detail (or lack of detail) in the textures than you would at a lower resolution. So if a game will never go beyond 480p there is a point of diminishing returns in terms of the resolution of the textures.... However, just because they render to 1080p doesn't mean they're going to use higher textures resolutions...
If you're still not getting this let me put it in an example...
Lets say you painted a texture on a piece of paper... the texture is made up of tiny squares like pixels... if you're standing at 10ft you might not notice any of the squares and the picture looks natural, but if you're up really close you can easily see all of the squares that make up the texture.
Now lets hang it on a wall... If your picture is 20 squares by 40 squares... that is it's resolution... Now lets take a picture with a digital camera at a resolution of 1280x720... just because the picture is 720p doesn't mean the texture is any better or any worse.
If you take that 720p picture at 10ft it will probably look good even though it's low resolution, if you take the picture at 1ft then it will probably look like crap...
Now if I use a 1080p camera does it change the quality of my texture? No of course not... except since the 1080p camera show more detail anything closer than 20ft and I can start to see the limited quality of my texture.
Now from a developer standpoint I want to use the best textures I can so that they look good at any distance even in higher resolutions. But I might only have limited resources to work with... so I trade off... some of my textures will be low resolutions like rock faces dirt and grass... while other textures will be high resolution like character faces and weapons. This will give me detail where it matters and reduce the detail where it doesn't matter so I can save some space.
This is also why going to 1080p sometimes give yous WORSE LOOKING results... basically you're allowing you're self to see all the flaws in the graphics where lower resolutions would provide a natural blending of the textures hiding their flaws.
Other techniques are used to soften textures like Alpha Filtering (first used on the N64 IIRC) which is like Anti Aliasing for textures and prevents you from seeing jaggies in the textures when viewed up close
this is why when you walk up to a wall in an FPS the image on the wall is a blurry mess, even though it looks decent from a reasonable distance.