I'm quite interested as well. On Wed, Apr 1, 2009 at 3:04 PM, mscwd01 <mscw...@gmail.com> wrote: > > Thanks for the demo Anton, > > It certainly runs much smoother than the Phys2D and JBox2D engines I > have tried and you have more objects being simulated - so you must > have done something right ;) > > I would expect it to run 2-3 times faster on an actual device too from > what I have read. > > Once you have finished off the improvements do you have any plans to > release it? > > Thanks > > On Apr 1, 7:44 am, Anton <socialhac...@gmail.com> wrote: >> OK, for anyone interested in my simple physics demo, check out: >> >> http://www.antonstoys.com/android/BallPit.apk >> >> It's pretty basic, but it shows that you can do some amount of >> physics on the G-phone at a reasonable rate. And as always, there are >> many improvements to be made. :) >> >> -Anton >> >> On Mar 31, 2:12 pm, Anton <socialhac...@gmail.com> wrote: >> >> > I'll definitely post the app tonight for you guys to check out (at >> > work now). I am an embedded systems programmer by trade. But I do >> > physics toys for fun and am just getting into Java/Android >> > optimizations. I will point out that optimizing for Java and >> > optimizing for Android are very different. As people have pointed out >> > before, the key things to be careful with on Android are memory >> > allocation and floating point math. I've removed both of these from >> > my physics loop. I also found that function call overhead was quite >> > large and had to manually inline all of my fixed point math code. I >> > think that with the correct spatial data structures I can get a couple >> > hundred objects interacting. I have a 2D rigid body physics engine >> > that is currently all C++ (no exceptions or templates or RTTI or >> > multiple inheritance) that I may port over as well. >> >> > However, having said all of that, I think it may be the case that >> > we will just have to wait until a native SDK is available to really >> > write a top notch physics engine. It's sort of the perfect example of >> > a piece of code that doesn't need anything more than libc and JNI >> > bindings. And since you only call it a couple times per frame the JNI >> > overhead would be well amortized. >> >> > Anton >> >> > On Mar 31, 9:17 am, mscwd01 <mscw...@gmail.com> wrote: >> >> > > Thanks for your feedback Shaun, I too unfortunately think a bespoke >> > > engine will need to be written for Android, which is a real pity as >> > > the iPhone has several physics engines which can easily handle >> > > hundreds of objects. >> >> > > Having said that Anton (2nd reply) has said he has an engine running, >> > > it would be nice to see a demo of this if that'd be possible? >> >> > > Clark, i'd definately host any .apk's on my own site, I wouldn't put >> > > it on the marketplace if it wasn't a "finished" app - do people >> > > actually do that?! >> >> > > I think i'll stay away from developing games with physics for the time >> > > being and concentrate on something else, I cant see it being feasible >> > > to include it any time soon which is a real pity. >> >> > > On Mar 31, 3:28 pm, shaun <shashepp...@gmail.com> wrote: >> >> > > > I am the author of simpull. >> >> > > > Sorry guys for the demo being out of whack for Simpull to the Core. >> > > > The version of PulpCore that I integrated simpull with did not support >> > > > Chrome, but you should be able to see it in IE, FF Safari. It is nice >> > > > to take a look at that demo to get a feel for what the engine is >> > > > capable of, but the performance does not translate over to the fixed >> > > > point branch/version of simpull when running on Android. >> >> > > > I ran tests on both the emulator and the actual device and there was a >> > > > significant increase in performance because of the fixed point >> > > > implementation, but I got very frustrated that it still did not >> > > > support the amount of objects in a scene that I considered good for a >> > > > physics-based game. It seemed to handle ~10 objects moving and >> > > > colliding OK. It has been a while since I was playing with it, so I >> > > > do not really remember the exact number of objects or the frame rate. >> > > > I mostly remember being upset with it. >> >> > > > I am leaving the physics ideas for games out of the picture when >> > > > thinking Android for now. Someone would have to write a ground up >> > > > engine with all the performance and memory concerns of Android in >> > > > mind, which was not the case with Simpull.....I created it for >> > > > applets, then thought to port over to fixed-point for Android. It >> > > > works well with small scenes, but certainly not the staple engine to >> > > > use in my opinion. >> >> > > > Also, Phys2D will not run worth a damn on Android. I tried it and I >> > > > even went through some heavy performance tuning. Garbage collection >> > > > is the major issue even after all I did. I seriously doubt JBox2D >> > > > will run well either. I'll stick to what I said earlier, a ground-up >> > > > solution by someone smarter than me is probably required. >> >> > > > On Mar 31, 9:49 am, "admin.androidsl...@googlemail.com" >> >> > > > <admin.androidsl...@googlemail.com> wrote: >> > > > > Not tried but if you can provide us with some example source code or >> > > > > put something on the market, I'm sure we could take a look. >> >> > > > > G1 performance is significantly faster than emulator, but there are >> > > > > limitations. >> >> > > > > Particularly with garbage collection and memory allocation on code >> > > > > that gets run continuously in loops, so I don't know how optimised >> > > > > these physics engines are for this purpose. >> >> > > > > Would be interesting to find out though. >> >> > > > > On Mar 31, 12:52 pm, mscwd01 <mscw...@gmail.com> wrote: >> >> > > > > > Oh I forgot to re-ask... >> >> > > > > > "Has anyone tested Phys2D or JBox2D on an actual device to see if >> > > > > > they >> > > > > > run better than on the emulator? >> >> > > > > > I have a feeling the performance will better on a G1 than the >> > > > > > emulator >> > > > > > for some reason! >> >> > > > > > On Mar 31, 12:51 pm, mscwd01 <mscw...@gmail.com> wrote: >> >> > > > > > > I did take a look at Simpull, however the demo application >> > > > > > > failed to >> > > > > > > run as it relied on some library which wasn't supplied or >> > > > > > > referenced >> > > > > > > to - I just got annoyed after spending two days failing to get >> > > > > > > Phys2D >> > > > > > > and JBox2D to work in Android and didn't bother trying to work >> > > > > > > out the >> > > > > > > problems! >> >> > > > > > > I might give it another look though... >> >> > > > > > > On Mar 30, 10:41 pm, Streets Of Boston <flyingdutc...@gmail.com> >> > > > > > > wrote: >> >> > > > > > > > I wonder how well this one works on Android: >> >> > > > > > > > http://code.google.com/p/simpull/ >> >> > > > > > > > -- Anton Spaans >> >> > > > > > > > On Mar 30, 4:58 pm, Anton <socialhac...@gmail.com> wrote: >> >> > > > > > > > > I have a simple 2D physics engine written and running. >> > > > > > > > > It uses >> > > > > > > > > the now famous Jacobson physics tricks (Verlet integration >> > > > > > > > > and hard >> > > > > > > > > constraints). I can manage 40 balls on the screen, with >> > > > > > > > > fill n^2 >> > > > > > > > > interaction between balls. I am working on spatial data >> > > > > > > > > structure >> > > > > > > > > optimizations now to improve the computational complexity of >> > > > > > > > > the >> > > > > > > > > collision detection code. I run the constraint update loop >> > > > > > > > > five times >> > > > > > > > > per frame and get 30 frames per second. Once the engine is >> > > > > > > > > up and >> > > > > > > > > running there are no memory allocations done in my program. >> > > > > > > > > And once >> > > > > > > > > the system settles down from the app launch there are very >> > > > > > > > > few GC >> > > > > > > > > events from other programs. Though they do still happen. >> > > > > > > > > Viewing >> > > > > > > > > LogCat I see a GC every 10 or 20 seconds because of some >> > > > > > > > > background >> > > > > > > > > application. But between those events I get a consistent >> > > > > > > > > frame rate. >> > > > > > > > > I am using OpenGL for my rendering. >> >> > > > > > > > > -Anton >> >> > > > > > > > > On Mar 30, 1:14 pm, mscwd01 <mscw...@gmail.com> wrote: >> >> > > > > > > > > > Does anyone know of, or have implemented, a physics engine >> > > > > > > > > > which runs >> > > > > > > > > > smoothly in Android? >> >> > > > > > > > > > I have spent the last couple of days trying Phys2D and >> > > > > > > > > > JBox2D, however >> > > > > > > > > > both perform very poorly - I am struggling to get even a >> > > > > > > > > > few objects >> > > > > > > > > > to simulate smoothly as frequent garbage collection spoils >> > > > > > > > > > it. >> >> > > > > > > > > > One question I do have is will these run smoother on an >> > > > > > > > > > actual G1 >> > > > > > > > > > device or is the performance of the emulator accurate? >> >> > > > > > > > > > Thanks- Hide quoted text - >> >> > > > > > > > > - Show quoted text - > > >
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