Box2d Revisited

http://j15r.com/blog/2013/04/25/Box2d_Revisited

by mmastrac • 13 years ago

67 41 13 years ago

j15r.com

CmonNoReg• 13 years ago

Not too useful as does not include one of the very popular ports and an additional major platform:

http://farseerphysics.codeplex.com/

joelgwebber7• 13 years ago

I must admit to being unfamiliar with Farseer, but if you feel like submitting a pull request, I'll figure out a way to run it on my Mac (I presume the "platform" you're referring to is .NET, or perhaps WinMo).

seanmcdirmid2• 13 years ago

It doesn't make sense to test farseer on anything but Windows. I would be curious to see how .NET stands these days with relation to Java and native.

dukoid• 13 years ago

I don't get this comment. This is about performance in browsers, not different physics engines...?!

joelgwebber7• 13 years ago

It looks like Farseer is based on Box2D, but extended, so it makes a kind of sense. I suspect the .NET VM performance will be somewhere around what the JVM gets, so it shouldn't be too much of a surprise.

mambodog• 13 years ago

It's perfectly useful as comparison of browser-based Box2d ports, and how they perform relative to the original C library.

Stranger20133• 13 years ago

Farseer can run in browser using Silverlight.

Stranger20133• 13 years ago

Is NaCl even cross-browser?

nezza-_-• 13 years ago

I can't zoom on this page with my phone and, due to that, can't read it at all except with the "Reader" function.

joelgwebber7• 13 years ago

What phone browser are you using? It seems ok on my Nexus 4 and mobile Safari, but I may need to fix the viewport or some such thing.

neeee• 13 years ago

Something strange happens on the default android browser.

http://goput.it/p1l.png

nitrogen• 13 years ago

That enormous position:fixed header makes it difficult to read even on a desktop.

evmar2• 13 years ago

I'm curious whether the performance varies if you used a C compiler from the last five years -- GCC 4.2.1 was released in July 2007. (I'm not claimed the author of the post is unfairly biasing the results, I'm just honestly curious.)

evmar2• 13 years ago

To answer my own question, I got:

  gcc 4.6.3: 3.554688 +/- 4.786550
  clang trunk: 3.593750 +/- 4.798172  
  Chrome: 41.03515625 +/- 9.331709130062185

Which puts Chrome at about 11x these native compilers, consistent with the blog post.

joelgwebber7• 13 years ago

FWIW, I just ran it through Clang 4.1 (the standard on XCode these days), and got roughly identical performance. I'm still compiling gcc 4.8 just to be sure, but it seems unlikely to make much of a difference.

joelgwebber7• 13 years ago

Ditto for gcc-4.8. Roughly the same (ever so slightly worse) performance.

dmm2• 13 years ago

    gcc 4.8.0: 1.640625 +/- 3.703323
    clang 3.2: 1.718750 +/- 3.772718
    chrome   : 23.28515625 +/- 3.636932727324763

So chrome is about ~14x the native compilers.

Changing gcc to use -O2 instead of -O3 gets: 1.562500 +/- 3.630922.

mrmiller• 13 years ago

Interesting how JS still doesn't live up to AS3. Everyone always discredits Flash... but if you're trying to make a Physics-based browser game, it still seems appropriate!

cpleppert• 13 years ago

You could get even better performance if you directly coded against the alchemy VM instructions or used alchemy directly. This would be comparable to asm.js or coding Java against the unsafe memory operators.

azakai2• 13 years ago

Well, the asm.js version of the benchmark is JS, and it outperformed AS3. Although as cpleppert said, perhaps an alchemy version for Flash would be faster than AS3, that would be interesting to see.

But, I'm not aware of an alchemy version of Box2D for Flash that is convenient to use from normal Flash (what presumably the rest of the game is written in), while for asm.js there is such a version (that is easily usable from normal JS), here's a demo

http://kripken.github.io/box2d.js/webgl_demo/box2d.html

So comparing currently usable versions of Box2D, the fastest JS one (the asm.js one) is faster than the fastest Flash one.

furyofantares2• 13 years ago

I'd love to see the numbers for the asm.js version running in Safari and Chrome

azakai2• 13 years ago

You can grab his repo and try it yourself, but as I commented on the blogpost, on my machine I see firefox without asm.js optimizations and chrome as being about the same speed, both of them are half the speed of firefox with asm.js optimizations. (I don't have a machine with safari to test on.)

Which means the asm.js version is faster than other JS versions, even without specific asm.js optimizations.

furyofantares2• 13 years ago

Thanks. I didn't do it myself because I wasn't able to find the asm.js version version, I must be blind.

niggler2• 13 years ago

Interesting that NaCl is far closer to native performance than asm.js. Can that performance gap be closed?

jlongster• 13 years ago

I'm not sure I'd call that "far" different, but asm.js is certainly in early stages so it probably will get faster.

niggler2• 13 years ago

    C (gcc 4.2.1)	2.62 +/- 0.24	1.0x
    NaCl (x86-32)	3.39 +/- 0.25	1.3x
    asm.js (Firefox Nightly)	5.12 +/- 0.59	1.9x

NaCl is 30% slower, asm.js is 90% slower.

ne0phyte2• 13 years ago

Please revisit your web design.

http://imgur.com/fBZZXYY.png

joelgwebber7• 13 years ago

I might be able to do that more effectively if you'd point out what browser you're running.

ne0phyte2• 13 years ago

That was the Hacker News app which uses the Android browser. I am running Android 4.2.2.

Box2d Revisited

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