I noticed that with the latest Geforce drivers (version 182.08) alpha-to-coverage results into much more transparent surfaces, and the dithering pattern has changed.
There was a bug before 182.08 (I’m not sure which exact version, but a recent one) that caused incorrect rasterization on triangle edges between connected alpha blended (non-multisampled) polygons (e.g. full screen quad) in front of the area of the geometry using alpha-to-coverage. I guess that was a flaw of the old alpha-to-coverage method and they replaced it, hence the different ‘look’.
But the new dither pattern isn’t as nice. :-/ It looks closer to the DirectX pattern now, and is more pronounced.
Anyway, I’m wondering, is the new rasterization correct (that is, more correct than the old)? I guess the ‘amount’ of transparency should compare to regular alpha blending as closely as possible?
Is there anything in place that gives me control over this pattern? I see some new extensions.