box2d

I'm using AndEngine with the PhysicsBox2DExtension to make a game. My game keeps crashing and I get this in the unfiltered LogCat: 07-06 13:25:27.266: I/DEBUG(19582): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** 07-06 13:25:27.266: I/DEBUG(19582): Build fingerprint: 'TMOUS/SGH-T959V/SGH-T959V/SGH-T959V:2.2.1/FROYO/VUVKD1:user/release-keys' 07-06 13:25:27.274: I/DEBUG(19582): pid: 22238, tid: 22263 >>> com.prattia.webs.testgfx5 <<< 07-06 13:25:27.274: I/DEBUG(19582): signal 11 (SIGSEGV), fault addr deadbaad 07-06 13:25:27.286: I/DEBUG(19582): r0 00000000 r1 afd14921 r2

I want to simulate Newton's law of universal gravitation using Box2D. I went through the manual but couldn't find a way to do this. Basically what I want to do is place several objects in space (zero gravity) and simulate the movement. Any tips? It's pretty easy to implement: for ( int i = 0; i < numBodies; i++ ) { b2Body* bi = bodies[i]; b2Vec2 pi = bi->GetWorldCenter(); float mi = bi->GetMass(); for ( int k = i; k < numBodies; k++ ) { b2Body* bk = bodies[k]; b2Vec2 pk = bk->GetWorldCenter(); float mk = bk->GetMass(); b2Vec2 delta = pk - pi; float r = delta.Length(); float force = G * mi * mk

This post is related to an earlier post of wanting to learn how to properly render in between LIBGDX and Box2D. I had to understand viewport well before I could proceed. After much code/post readings, I felt the meaning of "viewport" was "the rectangle opening of a lens of the camera that views LIBGDX's Game world, where I can move it about the world to view what I want". But, after more reading, I seemed to be nowhere near the actual meaning. I've read the LIBGDX wiki, and read in the OpenGL documentation, which seem to explain viewport as being two different things. LIBGDX Wiki: "The

I have two bodies, both dynamic, one of them I have turned off the gravity and only want to turn it on when it is hit by my other body. I know I can set my own contact listener but I want to specify an action only if two specific bodies touch. Any one have any guidance? U can set the userdata of the body and use it like that public class GameColiision implements ContactListener { public GameColiision() { } @Override public void beginContact(Contact contact) { // TODO Auto-generated method stub Body a=contact.getFixtureA().getBody(); Body b=contact.getFixtureB().getBody(); a.getUserData(); if(a

Compiling the Box2d Tesbed is supposed to be simple: from iforce2d : Download the Box2D source code archive from here. If you want to use the terminal all the way, you could also do this (if wget is not available, use yum to install it): wget http://box2d.googlecode.com/files/Box2D_v2.1.2.zip Use the following commands to unzip and build it. [...] unzip Box2D_v2.1.2.zip cd Box2D_v2.1.2/Box2D/Build cmake .. make ( These instructions are pretty old, I did get my source with git clone https://github.com/erincatto/Box2D.git ) Running cmake .. from Box2D/Build in the freshly cloned directory causes

This was asked earlier , but the original asker didn't need to change the dynamic property so he answered his own question by unasking it. I'm using Sprite Kit in iOS7 and I'd like to be able to change an SKPhysicsBody's dynamic property at runtime. Originally I was changing that in my touchesBegan: method. Someone in the Apple Dev forum suggested moving the change to the didSimulatePhysics: method but that didn't help either. This code causes the error: -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { if (!heyWereSwappingDynamismHere) { heyWereSwappingDynamismHere = YES;