I remember randomly reading about this in the Hugi demoscene diskmag as a young teen, and it completely blew my mind (notably the reverse transform, apparently not covered in OP's article): https://hugi.scene.org/online/coding/hugi%2013%20-%20cobwt.h...
The author later wrote many now-famous articles, including A Trip Through the Graphics Pipeline.
Oh wow, I clicked that link without reading the last section of your comment, and was like “Fabian Giesen!”, an absolute HN favourite: https://hn.algolia.com/?q=fgiesen
The author later wrote many now-famous articles, including A Trip Through the Graphics Pipeline.