Vertical pixel blur

[silikone]

Why do some games appear to blend pixels together in the vertical dimension? It seems like most games have this effect, with San Andreas among the exceptions. Looking at the frame buffer dumps, it's clearly not anti-aliasing. I thought it was likely be a deinterlacing artifact, although I saw something like this even in a 480p game. Perhaps it's just a deliberate effect unrelated to PCSX2, so then the question is what for?

[refraction]

do you have a screenshot to show what you mean?

[silikone]

Smoothed horizontal edges on the buildings, but jaggies nonetheless.

Sharp in both directions.

[refraction]

its quite hard to see with the size of the picture, can you full screen it and do a print screen (with the first picture)

[silikone]

[refraction]

it looks like anti-aliasing. You are using software mode yes? as the PS2 has a very limited anti-aliasing method which software mode supports known as AAx1, so there is only 1 sample, so it's very possible the only pixel filled in is a vertical one, most likely because there are more pixels horizontally than there are vertically in most/all resolutions

[silikone]

Wouldn't anti-aliasing create an alternating pattern, depending on the amount? From what I have seen, this blending is uniform from top to bottom, so it must be a really terrible form of AA.

[refraction]

Ooh it is, I'm not even sure it's a similar algorithm to aa, but it's what the ps2 does lol

[Dreadmoth]

The same effect occurs in Tribes: Aerial Assault

It occurs in both software and hardware modes, and scales with resolution (at Native resolution there will be a 1 pixel "double image" above and below a line, at 4x Native there will be 4 pixels worth)

Software


4x Native


Affects everything in the scene.

It doesn't seem to be affected by skipdraw, aggressive CRC or the Edge Anti-aliasing (AA1) setting in GSDX.

Wouldn't anti-aliasing create an alternating pattern, depending on the amount? From what I have seen, this blending is uniform from top to bottom, so it must be a really terrible form of AA.

I guess at native resolution (looking at it from far away) it sort of looks like a very low quality implementation of 1x2 SSAA or 2xMSAA...

[refraction]

It probably is some sort of cheap in game antialiasing which looks fine on a CRT monitor (FFX did a similar thing) but looks terrible when on an LCD or upscaled.