Why transparencies change as camera turns around?

[pspeed]

Alpha/Transparency Sorting, Your Z-buffer, and You

Since this comes up every three or four days, I decided to put together some visual aids. There is often a lot of confusion with how pixels get processed in relation to the z-buffer and why sorting is important. Most importantly it can be mind-warping trying to wrap one’s head around how to ‘fix’ the cases where proper sorting isn’t possible. Hopefully these diagrams help show the futility of it all… I mean the trade offs one has to make to get transparency looking its best in the general cas…

The back to front sorting for the cubes will be different as you turn around.

@Gussak

how can I fix that?

Short answer: you can’t, really. It’s just the nature of transparency.

You could control the sort order but then it will be wrong in other directions.

You could turn off depth testing but then it will interact poorly with other things.

At some point, transparent objects are not going to play well together so it’s best to not put too many of them together.