Physics Instability Caused by 32 bit DLLs
n7275 opened this issue · comments
This issue is most noticeable when taking off from Mars in some of the default Delta Glider or Shuttle A scenarios. Reference: Piraxus/OrbiterSkyboltClient#8
I have noted similar issues randomly taking off from KSC, where the earth appears to slowly fall away from the vessel. Occasionally, semi-major axis will change as though there is a force being applied when no thrust is active.
Video: https://youtu.be/B3S6ZECeomk
I am not sure what the cause could be here, and I don't want draw the wrong conclusion.
Observations:
-Later MJDs seem to be better (or it might be a coincidence in what I observed).
-The "jumping" effect seems to be present only on Mars
-Sometimes it appears as though a phantom force is being applied to the vessel or planet (apparent acceleration).
-Reloading a scenario in Mars orbit, sometimes results in a drastically different Orbit.
Anything I can help test to make it more clear what the root cause is, let me know.
Are you able to replicate this?
You could try doing a 32-bit build. Some of the Ephemeris modules won't work in x64 including Phobos which seems to be spiraling towards center of Mars. Maybe that will feed NaN's to the system.
I can confirm, this issue does not occur in 32 bit builds.
Are most developers targeting x86 at the moment in their builds?
Is there a reason why not every Ephemeris module is x64 ?
Here's a list (created with sysinternals sigcheck)
| Path | Machine Type |
|---|---|
| Modules\Celbody\Ariel.dll | 32-bit |
| Modules\Celbody\Callisto.dll | 64-bit |
| Modules\Celbody\Deimos.dll | 32-bit |
| Modules\Celbody\Dione.dll | 64-bit |
| Modules\Celbody\Earth.dll | 64-bit |
| Modules\Celbody\Enceladus.dll | 64-bit |
| Modules\Celbody\Europa.dll | 64-bit |
| Modules\Celbody\Ganymede.dll | 64-bit |
| Modules\Celbody\Hyperion.dll | 64-bit |
| Modules\Celbody\Iapetus.dll | 64-bit |
| Modules\Celbody\Io.dll | 64-bit |
| Modules\Celbody\Jupiter.dll | 64-bit |
| Modules\Celbody\Mars.dll | 64-bit |
| Modules\Celbody\Mercury.dll | 64-bit |
| Modules\Celbody\Mimas.dll | 64-bit |
| Modules\Celbody\Miranda.dll | 32-bit |
| Modules\Celbody\Moon.dll | 64-bit |
| Modules\Celbody\Neptune.dll | 64-bit |
| Modules\Celbody\Oberon.dll | 32-bit |
| Modules\Celbody\Phobos.dll | 32-bit |
| Modules\Celbody\Rhea.dll | 64-bit |
| Modules\Celbody\Saturn.dll | 64-bit |
| Modules\Celbody\Sun.dll | 64-bit |
| Modules\Celbody\Tethys.dll | 64-bit |
| Modules\Celbody\Titan.dll | 64-bit |
| Modules\Celbody\Titania.dll | 32-bit |
| Modules\Celbody\Triton.dll | 32-bit |
| Modules\Celbody\Umbriel.dll | 32-bit |
| Modules\Celbody\Uranus.dll | 64-bit |
| Modules\Celbody\Venus.dll | 64-bit |
Because not every module gets built: https://github.com/orbitersim/orbiter/tree/0326e4d077c5a4f880ae821e2d0c7d82dc10469c/Src/Celbody/Deimos
I don't believe we have the source code for these DLLs. They will need to be rewritten so that can be built during the x64 build process.
as far as I understand it
Thanks for the info! I found out myself after posting the list (oops).
So we have to wait until Martin (?!) can provide some source code for the 8 DLLs.
We don't have to wait, but someone will need to write them. I don't think for most of these, a simple cfg file would work. Would need ephemerides and a celbody module.
Not sure I have the time right now to be able to volunteer but it is very tempting...