Originally Posted by

**mireazma**
Hello there.

I've read about different compression formats out of which I came to prefer s3tc and etc (maybe astc but it's a bit slower at real-time decompression). Now I wonder for each of them how unused space in a texture is more compressed and how different sized empty space is compressed: to a constant size, linear, logarithmic etc. For ex: if 25% of empty space => 1 byte and 75% => 3 bytes, then it's linear; if both compress into 5 bytes, then it's constant, you get the point.

Does anyone know or could give me a link?

Second question is somehow related. About mipmapping I've read on Wikipedia that a set only occupies 33% more space than the original texture alone and it's shown with a 3 channel texture, which it makes sense. But what about 1, 2 or 4 channels? Does the "discount" apply?