Particles interpolate during time freeze

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Major Cooke
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Particles interpolate during time freeze

Post by Major Cooke »

I haven't been able to check yet but this should be easy to replicate. Fire a rocket with the particle trails on and freeze the game, then let the game continue. You'll notice jittering of the particles due to continuous interpolation.

One could say this is a non-issue, until you play D4D where you have the option to have particles act like bullets. That's a problem, because there is an upgrade with the megasphere which allows time to be frozen upon picking one up, and it looks awful.
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Graf Zahl
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Re: Particles interpolate during time freeze

Post by Graf Zahl »

I already suspected some problems when I saw how the interpolation was implemented, but since so far nothing showed I let it stand.
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Rachael
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Re: Particles interpolate during time freeze

Post by Rachael »

It uses pretty much the same 'freeze' checks as the model interpolation code. If the particle interpolation is broken, it's likely that model interpolation is as well.
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Graf Zahl
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Re: Particles interpolate during time freeze

Post by Graf Zahl »

If I read the code properly it doesn't actually do interpolation but extrapolation, i.e. it projects the particle based on velocity instead of using a value between 2 known positions - and I don't think that actually works as intended.
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Re: Particles interpolate during time freeze

Post by Rachael »

Yes, that is correct. I did not know that's what it was called, though.
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Re: Particles interpolate during time freeze

Post by Rachael »

The original issue is addressed here.

However, I did not yet address the interpolate-by-last-frame issue.
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