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TestUFO Anti aliasing visibility test question

PostPosted: 02 Sep 2019, 12:05
by Strobe
That AA test on testufo.com website, you can turn the anti aliasing of that white line on and off. My question is, what type of anti aliasing was is used when its set to "on"?

There is many different types of anti aliasing with many different settings, I have no idea what specific type of anti aliasing of what specific strenght is used when its set to ON setting.

For example, is it 4x AA or 16x?? 8bit color depth requires alot more than even 16x AA for maximum aliasing suppression, the higher the dynamic range (bit depth), the higher the anti aliasing needs to be to avoid banding.

Re: TestUFO Anti aliasing visibility test question

PostPosted: 02 Sep 2019, 21:05
by Chief Blur Buster
Strobe wrote:That AA test on testufo.com website, you can turn the anti aliasing of that white line on and off. My question is, what type of anti aliasing was is used when its set to "on"?

Browser default AA, provided by Javascript. I'm not sure what AA algorithm is in use, but probably simple linear AA used for line drawing that was available since the pre-GPU days.

Strobe wrote:the higher the anti aliasing needs to be to avoid banding.

Banding from a far distance is often more linked to gamma used in the AA blending -- rather than the AA algorithm. This is because of the average brightness of an analog pin prick at any arbitrary point along the grid, is not always constant along the axis, and can even be noticed when pixels are smaller than human resolution. There are some articles and papers that covers this sort of thing.

Strobe wrote:For example, is it 4x AA or 16x??

AA for line-drawing does not have a multiplier value.
It is frequently done using the Wus Algorithm but there are a lot of other AA algorithms used during line-drawing. However, the specifics of the AA algorithm used by the default JavaScript line drawing function, is a black box to the software developer.