Two thumbs up! It's fast, not superfast, but there are quite a number of balls in the pit. I'm impressed. If this code could get into the native system, into the firmware...
On Apr 1, 2:44 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 -- Hide quoted text - > > - Show quoted text - --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. 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