Because blog posts do not write themselves :) Once upon a time someone posted this demo called “zoom blur” to wonderfl that did radial blur by averaging discrete number of samples along radius vector. This approach causes noticeable ghosting with small number of samples. At the time I had no idea how to improve that, but recently I came across its spin-off and there I remembered this:
It was a side effect of sub-optimal zoom filter implementation I did two years ago. Basically, source image gets radially compressed and then decompressed back, and corresponding data loss looks like a blur. So today I decided to give it another try – this time with stage3d/agal. Unfortunately my GPU renders it like this:
The ghosting is gone – enter the aliasing :( After some head scratching, I must admit I have no idea where does it come from. So if anyone reading this has any idea how to fight it and why there is no aliasing issue in pixel bender – please leave a comment or fork the code, thanks.