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Unity vs. Floating Point

55 points by ibobev

by corysama

2 subcomments

Only tangentially related. But, I still have not forgiven Unity for the floating point footgun in https://docs.unity3d.com/6000.4/Documentation/ScriptReferenc...
> The operation is finished when the progress float reaches 1.0 and isDone is called. If you set allowSceneActivation to false, progress is halted at 0.9 until it is set to true.
So, I needed to have my UI do other stuff until both this and something else was ready. Obvious thing to do would be to check this for "AsyncOperation.progress >= 0.9" and also check the other thing. Right?
Except AsyncOperation.progress is a float, 0.9 is a double and 0.9f < 0.9. Progress is not halted at 0.9. It never reaches 0.9. It's halted at 0.9f! Just a few million ulps short!

by Zarathruster

2 subcomments

Interesting. When I first got started with Unity I found really buggy behavior if you do any kind of physics calculations near world origin (0, 0, 0). It has a weird gravity well effect if you get too near it. I never found a satisfactory explanation for it but maybe this is it.

by garaetjjte

1 subcomments

>Official Mono releases have switched to do that since then, but (I think) for backwards compatibility reasons Unity never enabled that functionality and kept everything at double precision so far.
Probably because Unity uses ancient Mono fork. And that apparently started because they didn't renew their non-copyleft license with Xamarin.

by koolala

3 subcomments

I wish JavaScript or any open-source Array Language could do Single-precision Floats. It's awesome they were able to show the assembly breakdown.