I'm curious too! :)
On Apr 1, 9:25 pm, mscwd01 <mscw...@gmail.com> wrote:
> I have some good news too, I have successfully ported APE
> (http://www.cove.org/ape/) to Android and have a simulation of 50 objects
> running extremely smoothly.
>
> Considering I have only spent an hour or so converting everything to
> Android and making minimal optimisations this is really good news
> indeed. One thing I have noticed with APE is how lightweight it is;
> compared to the other engines I have tested this is 5-10 times smaller
> at least.
>
> I'll have a demo for you guys within a day or two, if your interested.
>
> On Apr 2, 2:12 am, Streets Of Boston <flyingdutc...@gmail.com> wrote:
>
>
>
> > About open-sourcing it:
>
> > Thanks! That would be great and i'll be happy to do some work on it to
> > make it even better (if i *can* do this; you already did a great job).
>
> > Let us know when your api is ready to be put on open-source. :-)
>
> > On Apr 1, 8:48 pm, Anton <socialhac...@gmail.com> wrote:
>
> > > I've done some more profile based hand optimization and I now have
> > > it running superfast. :) I've put the new version in the same
> > > location as the previous one. I still had some floating point code
> > > that was slowing me down. The difference between floating point and
> > > fixed point is not to be underestimated is what I'm taking away from
> > > that work. It reminds me of writing optimized 3D graphics for the
> > > 486. :) I loved that.
>
> > > Daniel, you're right about the ghosting. I hadn't really noticed
> > > it until you pointed it out, and now it's really obvious. :) The
> > > green balls were just a quick rendering with my raytracer. I'll
> > > definitely change them out for something better. :)
>
> > > Mscwd, I think I will open source the resulting engine. Though
> > > It'll be a little while before it's actually useful. Right now it's
> > > more of a proof of abilities. Something to show that with enough
> > > optimization, you can do decent physics on Android.
>
> > > Thanks all,
> > > Anton
>
> > > On Apr 1, 6:55 am, Streets Of Boston <flyingdutc...@gmail.com> wrote:
>
> > > > 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- Hide
> > > > > > > > > > > > > quoted text -
>
> - Show quoted text -...
>
> read more »
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