Comments on: Box2D + Processing

By: Nick Inzucchi

Nick Inzucchi — Tue, 07 Feb 2012 03:11:00 +0000

Hi Daniel! Thanks for the great wrapper. Any way to set a body’s angle directly? Looks like body.setTransform(Vec2 position, float angle) is not implemented?

By: Dekamayro

Dekamayro — Fri, 27 Jan 2012 01:56:00 +0000

All right, thank you.

By: Anonymous

Anonymous — Thu, 26 Jan 2012 17:12:00 +0000

Sadly, my answer to this again is if you wait for the next version of the library it won’t have this limitation! Working on it now to release in the next few weeks. (you can go and use JBox2D directly if you don’t want to wait: http://code.google.com/p/jbox2d/)

By: Dekamayro

Dekamayro — Thu, 26 Jan 2012 05:54:00 +0000

Hi (it’s me again)! Do you have any suggestions as to how to make a box2d world sidescroll? I’ve been trying to make a room bigger than one screen (my size is (800, 600)) and only display things a certain distance from a character, but that doesn’t work. Also, when I try to make a wall way out of the size – like at 1990, 300 – I get an assertion error. Does that have to do with PBox2D’s reliance on the size(float x, float y) to determine the size of its world?

Thanks.

By: Siarfnopmop

Siarfnopmop — Sun, 22 Jan 2012 15:17:00 +0000

youhouh ty so much i’m waiting for the final version
thx again! ?

By: Anonymous

Anonymous — Thu, 19 Jan 2012 21:17:00 +0000

If you store a reference to the Shape object you can reset its density and then update its mass accordingly. The forum post is for Box2D 2.0 (my library still uses the old Box2D). I’ll be updating it very soon!

By: Siarfnopmop

Siarfnopmop — Thu, 19 Jan 2012 09:19:00 +0000

Hi!

Sorry programming is a brand new thing for me, I know processing since a few month only and I would like to do something with box2d

I have a specific question, is it possible to edit the density of an object the fly with pbox2d ?

I found this thread http://www.box2d.org/forum/viewtopic.php?f=19&t=6089
but actually i’m totally lost uhuh

sorry for my dumb question

By: Anonymous

Anonymous — Mon, 09 Jan 2012 02:40:00 +0000

Thanks for the tip!

By: Ignivome

Ignivome — Sat, 07 Jan 2012 23:40:00 +0000

Thanks a lot Shiffman to always make everything easier

FYI
I notice a small bug on your CollisionsAndControl lib example.
Particle class/ done method: you wrote
// Is it off the bottom of the screen?
if (pos.y > height+r*2) {,

instead, i’d write
if (body.isFrozen())

because, if the particle goes outsite by the left, top or right side, killBody() wont be called and arrayList will keep unused particles.
Little memory leak there

thanks again

By: Dstavy

Dstavy — Tue, 27 Dec 2011 13:41:00 +0000

i have got an assertion error when trying to add few hundred of falling circles
any idea?
Exception in thread “Animation Thread” java.lang.AssertionError at org.jbox2d.collision.BroadPhase.createProxy(BroadPhase.java:226) at org.jbox2d.collision.shapes.Shape.createProxy(Shape.java:337) at org.jbox2d.dynamics.Body.createShape(Body.java:308) at critical_mass$Particle.makeBody(critical_mass.java:615) at critical_mass$Particle.(critical_mass.java:562) at critical_mass.draw(critical_mass.java:257) at processing.core.PApplet.handleDraw(Unknown Source) at processing.core.PApplet.run(Unknown Source) at java.lang.Thread.run(Thread.java:722)