Search found 10 matches
- Sat May 05, 2018 1:24 pm
- Forum: General
- Topic: Deterministic fixed-point port, open source
- Replies: 28
- Views: 107714
Re: Deterministic fixed-point port, open source
From what I hear from Norbo, there's not much hope of getting V2 to be deterministic. Its highly optimized to use SIMD instructions, which don't really translate to integer math at all.
- Fri May 04, 2018 3:30 pm
- Forum: General
- Topic: Deterministic fixed-point port, open source
- Replies: 28
- Views: 107714
Re: Deterministic fixed-point port, open source
Hey, thanks for forking!
Where exactly did you notice jitter? Running the BEPUphysics demo scenes I didn't really notice any jitter, so maybe there's a bug I missed?
Where exactly did you notice jitter? Running the BEPUphysics demo scenes I didn't really notice any jitter, so maybe there's a bug I missed?
- Wed Feb 28, 2018 12:42 pm
- Forum: General
- Topic: Deterministic fixed-point port, open source
- Replies: 28
- Views: 107714
Re: Deterministic fixed-point port, open source
I am of course measuring the results with a benchmark. I am using four of the BEPUphysics demos and running them for 1000 steps each and measuring the full runtime: Old version (inlined without ref): DiscreteVsContinuousBenchmark... 0.21s InverseKinematicsBenchmark... 17.31s PathFollowingBenchmark.....
- Wed Feb 28, 2018 7:48 am
- Forum: General
- Topic: Deterministic fixed-point port, open source
- Replies: 28
- Views: 107714
Re: Deterministic fixed-point port, open source
Thank you both so much for your help with this, I very much appreciate it! @test44x: I did see your inlining comment, but I think there's more going on: (a.M11.rawVal * b.M11.rawVal) >> Fast64.Q This should more or less turn into a single mul machine instruction and a shift, but aren't you losing ha...
- Tue Feb 27, 2018 11:23 am
- Forum: General
- Topic: Deterministic fixed-point port, open source
- Replies: 28
- Views: 107714
Re: Deterministic fixed-point port, open source
Thank you for the hints! The disassembly in particular looks interesting, if a bit overwhelming at first. I think one relative low hanging fruit should be the fixed point multiplication: var xl = x.RawValue; var yl = y.RawValue; var xlo = (ulong)(xl & 0x00000000FFFFFFFF); var xhi = xl >> FRACTIO...
- Mon Feb 26, 2018 9:16 am
- Forum: General
- Topic: Deterministic fixed-point port, open source
- Replies: 28
- Views: 107714
[RELEASED] Deterministic fixed-point port, open source
I have released the current state of the fork: https://github.com/sam-vdp/bepuphysics1int All existing BEPUphysics demos work as expected. However, the performance is still quite bad, about 4 times slower than the float version. I am getting quite different profiler results when using sampling or in...
- Mon Feb 26, 2018 9:13 am
- Forum: Questions and Help
- Topic: Deterministic Lock-step in Unity3D(iOS/Android)
- Replies: 17
- Views: 22000
Re: Deterministic Lock-step in Unity3D(iOS/Android)
I am currently working on a deterministic fixed-point port of BEPUphysics v1. The current state of the project is available at https://github.com/sam-vdp/bepuphysics1int . All existing BEPUphysics demos work, but the fork is about 4 times slower than the float version. PR, bug reports and performanc...
- Thu Feb 15, 2018 11:31 am
- Forum: General
- Topic: Deterministic fixed-point port, open source
- Replies: 28
- Views: 107714
Re: Deterministic fixed-point port, open source
EDIT: Problems solved (for now), just posting for general info. As always, thank you for your brilliant help! However, I would be surprised if the jitteriness is actually caused by a lack of precision; I would assume the problem is elsewhere. Spot on. FixedMath uses a pretty rough approximation for...
- Tue Feb 13, 2018 7:38 am
- Forum: General
- Topic: Deterministic fixed-point port, open source
- Replies: 28
- Views: 107714
Re: Deterministic fixed-point port, open source
Thank you for your help! I managed to get the Pow-function implemented, but now I've hit some more issues. Most of the demos work as expected, if a bit slower, but two behave weirdly: 1. The moving object in the PathFollowingDemo is a bit jittery, I guess that's just a lack of precision converting f...
- Sun Feb 11, 2018 12:24 pm
- Forum: General
- Topic: Deterministic fixed-point port, open source
- Replies: 28
- Views: 107714
Deterministic fixed-point port, open source
EDIT: Source code is now available at https://github.com/sam-vdp/bepuphysics1int Hi everyone, like test44x I was looking for a deterministic fixed-point physics engine and have started porting BEPUv1 to use integer math. I followed the instructions from the previous thread quite closely and the port...