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| ID | Project | Category | View Status | Date Submitted | Last Update | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0002050 | OpenClonk | Objects | public | 2018-12-28 08:50 | 2019-01-20 19:09 | ||||||||
| Reporter | Marky | ||||||||||||
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| Priority | normal | Severity | minor | Reproducibility | always | ||||||||
| Status | new | Resolution | open | ||||||||||
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| Target Version | Fixed in Version | ||||||||||||
| Summary | 0002050: Behaviour of smoke with non-standard gravity | ||||||||||||
| Description | I think that my commit yesterday does actually NOT produce 'correct' smoke behaviour: https://github.com/openclonk/openclonk/commit/94e200f201596ab09b8642a6bea863bfddaa44d0 Correct is: F_up = <density of atmosphere> * <volume of smoke> * <gravity acceleration> Also, particles have no downward force by default, which means that we have to factor in F_down = <density of smoke> * <volume of smoke> * <gravity acceleration> So F_total = F_down - F_up = <gravity acceleration> * <volume of smoke> (<density of smoke> - <density of atmosphere)> which means that the original implementation was closer to correct than I thought? | ||||||||||||
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Zapper (developer) 2019-01-14 14:44 |
Your commit says you are now using a "starting value". The documentation says that the second parameter is a constant summand. Is that what you intended? Before it was <gravity> * (-100 + heavy*90) + 0 and now it's <gravity> * (100 + heavy*90) - 10. Did you test your commit? It looks like a big change and really odd. And what is the problem with non-standard gravity? I can't tell from your bug report, maybe explain what you intend and I can help :) Also I can't tell what "correct" means in this context |
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Marky (developer) 2019-01-20 19:09 |
I tested the commit, an it behaves as I want to, but we had a discussion in #openclonk-dev what is physically correct. Back to the original implementation and my problem with it: When gravity is 50% of default gravity, then smoke used to go about 50% as high, but I'd expect it to fly higher actually (from non-physically thinking intuition). Analogous, if gravity is 200% and everything falls down faster, smoke flies double as high. However, it seems that the original implementation is actually correct, and my implementation is incorrect. |
| Notes |
| Issue History |
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| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2018-12-28 08:50 | Marky | New Issue | |
| 2019-01-14 14:44 | Zapper | Note Added: 0006199 | |
| 2019-01-20 19:09 | Marky | Note Added: 0006200 | |
| Issue History |
