Celestia Forums

With a 64Mo video card, it works perfectly !!

Can anybody explain me the difference between DDS texture and "classic" ones, like jpg or png, because there is no comparison possible : DDS is much more performant !!

As I understand it, DDS textures use the DXT compressed file format, which is 'hardware native', meaning the graphics card doesn't have to decompress it in order to load it into memory. Formats like JPG and PNG must be decompressed into a bitmap for the graphics card to load them. This means a DDS texture will only take up as little as 1/8th the video card memory as a JPG or PNG (even though they are smaller files on disk). Chris can probably give you a more accurate answer, he does this sort of stuff for a living..

Not necessary, your response is perfectly clear.
Thank you !

Well, even with JPG and PNG (or whatever) you can let the driver compress the images on the fly and upload the compressed one to video card memory. Once the texture has been upload there's no diff in performance between the native DDS image and the "compressed on-the-fly" one.

The BIG difference is loading time. A 16kX8x image takes 384MB uncompressed so when you are using JPG you must first uncompress the image to main memory (assuming you have 384MB free), recompress it and finally upload to video card. As you can imagine this is a very time/resource consuming process.