Quote:Original post by snake5
That could never be a kind of filtering. Notice the triange pattern! Inverted bilinear filtering would give quads.

Wrong. There are many different ways to do bilinear filtering. Doing it on a planar quad is only one possibility. It is perfectly possible to do it on a triangle using barycentric coordinates, or even on a planar hexagon if you really wanted. Especially back in the times of software rendering, people used all kinds of weird tricks to get instruction count a little down.

Hard to say whether the triangles are an actually planned effect, or just an artifact of some optimization algorithm that turned out to look OK. They are certainly not fractals. They aren't recursive but regular grid-like. The colour shifts are definitely blending quantization artifacts.

For the triangles, my bet is on either banding artifacts or an attempt to combine dithering with some interesting looking patterns.