Displaying 2K textures on a res lower than 2K?

[Prenihility]

Pretty much as the title says. I was very curious about this once i first saw 2K texture mods for Skyrim.

 

If 2K is a higher res than 1920 x 1080, for example... and it it being displayed on a 1920 x 1080 display, does that affect the visual quality of the 2K textures? I don't see why it would even make sense to display the textures on a res lower than 2K.

 

MY logic = The displayed surface on the textures is very small, so it will be scaled down. Therefore you are able to see 2K assets very well on a res lower than 2K. That's my answer.

 

If anyone can help further explain, it would be greatly appreciated. How can 2K assets be displayed and look correct visually, on resolutions lower than 2K. I just don't get it.

 

 

[Twizzler77]

Prenihility,

 

You are essentially correct. This is where texture compression in the form of mipmapping and texture filtering (bilinear, trilinear, and anisotropic) come into play.

 

- Mipmaps are smaller versions of a texture file. For example, 512x512 texture will have additional mipmaps at 256x256, 128x128, 64x64, etc. As the object gets smaller on-screen, the GPU will automagically and (hopefully) seamlessly blend between the different mipmap levels. This helps prevent the GPU from having to render 512x512's worth of pixels at lower resolution. However, this doesn't solve for assets being rotated in such a way that the viewing angle becomes very oblique (nearly parallel) to the viewer.

- Bilinear/Trilinear filtering are different methods (although not exclusive) of swapping between the mip levels of a texture. Both of them can introduce a variety of graphics artifacts. This is where anisotropic filtering comes. While this is a fairly bandwidth intensive method, it does solve for the artifacts brought about with bi/trilinear filtering.

 

If you have ever played a game where you think you see a definite line where the texture is being blurred based on your view or movement, that is an artifact of bilinear/trilnear filtering. Essentially, the GPU is trying to accommodate for a texture whose resolution is either too low OR too high for the screen resolution to properly display. The blurring works both ways! So, by using a higher res texture on a lower resolution screen, you could actually be increasing the chance for graphical artifacts. Ideally, you want as close to 1:1 ratio as possible.

 

Hope that makes sense! It makes perfect sense in my head, sometimes not so much in text. :smile:

Edited June 4, 2013 by Twizzler77