Compression and Normal Maps

FYI - I found this an interesting read - from Robert Duffy’s plan .

Thought it might give someone some ideas/info when doing Normal maps and texture compression.

Didn’t read it, but isn’t this just the DXT5 trick, right?

Yeah, looks like they swap red and alpha, very clever.

For anyone interested, here’s a link that provides an brief explanation and demo of this technique, among other things. It’s in HLSL, but I found it interesting anyway.

http://66.102.7.104/search?q=cache:HGlaZ…XT5+trick&hl=en