Search found 12 matches

by FrancescoITA
Mon Jun 13, 2011 7:52 pm
Forum: Java
Topic: Can JBox2d be deterministic?
Replies: 22
Views: 7599

Re: Can JBox2d be deterministic?

Ok sorry everybody, we eventually achieved determinism, we were setting up the test wrong!

Wish there was a simpler method to render JBox2D deterministic, without having to modify its classes manually.
Anyway, this characteristic should definitively be much more advertised.
by FrancescoITA
Sun Jun 12, 2011 6:48 pm
Forum: Java
Topic: Can JBox2d be deterministic?
Replies: 22
Views: 7599

Re: Can JBox2d be deterministic?

Hi all. Me and my friend are developing a network game, and are very interested in this topic. So we made some tests. By initializing only the random number generator or by only adding strictfp to every class, isn't enough to supply determinism. But by using both, we achieved consistent results on t...
by FrancescoITA
Mon May 02, 2011 11:22 am
Forum: Java
Topic: Newbie Questions by any other name...
Replies: 6
Views: 2810

Re: Newbie Questions by any other name...

Hi, I can only answer your first question: JBox2D doesn't support force fields, which I think is the thing you are after, but it implements a general body.applyForce which can be used to create one. The implementation, though, is up to you. I would also like a precise answer to the second and third ...
by FrancescoITA
Fri Apr 29, 2011 6:00 am
Forum: Java
Topic: How to use ProcessingDebugDraw correctly
Replies: 3
Views: 1158

Re: How to use ProcessingDebugDraw correctly

I think you need to apply a transform to those vertices before drawing them (the position of those vertices is not global but local).
by FrancescoITA
Thu Apr 28, 2011 1:33 am
Forum: Java
Topic: Raycast trouble
Replies: 4
Views: 1403

Re: Raycast trouble

Glad to help! :) I would suggest that you use the stable version of jbox for anything that isn't testing or debugging though.
Cheers!
by FrancescoITA
Wed Apr 27, 2011 2:36 pm
Forum: Java
Topic: Raycast trouble
Replies: 4
Views: 1403

Re: Raycast trouble

Hi, in AABB class in the collision package, change public final void getExtentsToOut(final Vec2 out) { out.x = (upperBound.x - lowerBound.x) * .5f; out.x = (upperBound.y - lowerBound.y) * .5f; } to public final void getExtentsToOut(final Vec2 out) { out.x = (upperBound.x - lowerBound.x) * .5f; out.y...
by FrancescoITA
Wed Apr 27, 2011 3:30 am
Forum: Java
Topic: Jbox2D and OpenCL
Replies: 0
Views: 965

Jbox2D and OpenCL

Hi to all. I know this topic has been brought up over and over again (and this is the second time I bring it up :P), and that jbox2d philosophy is to optimize a single threaded execution, but is there any chance that there is some part of the code that could be cheaply executed in parallel (maybe in...
by FrancescoITA
Thu Apr 01, 2010 7:30 am
Forum: General Discussion
Topic: Frictionless circle contact
Replies: 0
Views: 911

Frictionless circle contact

Hi, I am using the Java port of box2d. I noticed that when two circles with no friction collide, they actually start slightly rotating. Is this effect noticeable in the original c version of box2d? Are there any workarounds? (It's not really very important, since the resultant angular velocity is re...
by FrancescoITA
Wed Mar 31, 2010 2:28 pm
Forum: Java
Topic: FastMath sqrt
Replies: 1
Views: 1341

FastMath sqrt

I noticed that with FastMath enabled, the fast integration of the sqrt returns a very little number (10^-20 or something like that) when the input is 0. I know the invsqrt is an approximation, but wouldn't it be better to set a control for the zero case? One problem i get, for example, is the calula...
by FrancescoITA
Mon Jan 11, 2010 3:47 pm
Forum: Java
Topic: Parallel computing?
Replies: 2
Views: 2289

Parallel computing?

I was wondering how much box2d would benefit from parallel computing, especially after I ran into this http://code.google.com/p/javacl/. (click on the Particle Test Demo to see a web applet manage 1Million particles. You need a fairly new GPU). :shock:
Just wondering...

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