Box2D is an open-source rigid-body 2D physics simulation library for games, written in C++, with ports in various languages

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Ledge climb animation and movement (2d platformer)

Struggling to make a decision on the implementation of a ledge climb mechanic for a physics driven 2d platformer. What is the best way to go about this without it getting overly complex? So far I ...
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Get a body from TiledMap via MapBodyBuilder and draw a sprite on it in LibGDX?

I use a various of MapBodyBuilder in my Libgdx project. I created a body from map.tmx via my MapBodyBuilder and in my SpriteBuilder buildSprite method i created its sprite: sprite = new ...
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Rotating kinematic object around a moving point Box2D

I'm new at Box2D and I am making a simple game where you control the rotation of the maze and the gravity leads the ball to the exit. The game looks like: The problem: I want to rotate the maze, ...
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balloon ligher than air with libgdx, impementation of FixtureDef.density, gravityScale, linearDamping?

I use libGdx/box2d's physic. My intention is to create a balloon filled with helium (a body, what hovers above a surface, if we apply a little force to it - it moves fast but not far, if we push ...
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139 views

generate box2d bodies from isometric tiled map

I followed the tutorial here to generate box2d bodies from a tiled map and that worked fine.... for orthogonal tiled maps. Unfortunately isometric maps use their own coordinate system where (0, 0) is ...
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beginContact triggered more than once on some objects

Short version: It looks like beginContact is detecting continuous collisions. I'd like to avoid that. Long version : I use Box2Dweb to write a 2D platformer. It's my first game using this lib, and, ...
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changing body type without change of center of mass

I have an box2d project with some bodies in it, which move around without any user interaction. But if the user selects one of the bodies, he should be able to move it around just like he wants to. ...
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Movement for Box2D Bodies

I'm having trouble wrapping my head around something that should be relatively simple. I'm making a breakout clone using LibGDX and Box2D. I'm also using the Ashley ECS. For movement with bodies, I ...
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35 views

Moving box2D body with texture?

I was following the solution from this http://stackoverflow.com/questions/20180063/box2d-body-with-texture. I ended up getting this working for static bodies. But when trying to get the PolygonSprite ...
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Should I compute impact damage with energy or momentum?

My game uses physics (Box2D in particular). Just about every object in the game can be destroyed, and the primary method of combat is by slamming objects into one another at high speed. It makes ...
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Multiple bodies or multiple fixtures for a wall in Box2D?

I am making a game with a sort of "playfield" where the game takes place, acting as boundaries on a top-down shooter. I am using Box2D for physics, and I am questioning which of the following would be ...
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LibGDX: Box2d hovering, rotating body

Hello I am working on a hovering triangle (equilateral triangle). The triangle should allways rotate at a constant speed and hover over the ground. The problem is if I setAngularVelocity it does rise ...
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How to disable static friction in Box2D?

I'm making a 2D platformer. One of the issues is that when the character hits the ground, there's an initial pause and then the character finally slows down to a halt. I believe the initial pause is ...
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41 views

Sizing a Box2D ground object

I am developing a platformer game using SDL2 for graphics and Box2D for physics. I am currently designing my levels and would like to know if it is better to make the static part of each level (ie: ...
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59 views

Calculate the rest length of a box2d distance joint

Given the length of a distance joint along with its frequency and the mass of the bodies involved, is it possible to determine the final rest length? I'm only interested in the vertical axis if that ...
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Using Box2D in LibGDX, is there a reason a fixture set to be a sensor would only -sometimes- detect a collision?

I am working on a 2D game in LibGDX. Currently, I am testing interactions between a player's weapon and enemies - in particular, a sword and an enemy monster. The player has a hurtbox and the sword ...
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86 views

Farseer: Friend/Foe Collision - cannot push foes but friends

we are using Farseer in our project and I try to find a setup to achieve the following quite complicated collision behavior: Friendly Units can push each other aside. However, the push should be a ...
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89 views

Mouse click coordinates not mapping to Box2d world

I'm using Box2d in Java with OpenGL, trying to detect if a mouse has clicked on a Body. But having trouble mapping mouse coordinates to Box2d world. I have a Body positioned at 20.0f, 30.0f in the ...
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Libgdx/Box2D PolygonShape has no position… well, what now?

As my prototype works perfectly fine I want to advance to more fun areas of the project and add a more complex player-character body. So for Box2D I figured I'd need multiple fixtures, like one for ...
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How to tell if a fixture is being squeezed by two other fixtures in Box2D?

Let's say I had a ground fixture, a player box, and a kinematic block moving up and down. If the player stands under the block, weird things happen. I want to simply play an event where the player ...
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109 views

Box2D random crash when adding joints

I'm currently working on a project which uses Box2D, when the player uses a certain key it should anchor to the ground. For that I use a weld joint, but when I add the joint the game will sometimes ...
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unity4.3 rigidbody2d unexpected force behaviour

So guys ive edited the question and here is what my problem is i have a player which has a rigidbody2d attached to it.my player is able to doublejump in the air nicely and stick to walls when ...
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Need to join 2 bodies via weld joint but not on center of mass

I have successfully join 2 bodies via weld joint , but my problem is I want to join corners of bodies not on centre of mass. Is there any way to achieve this? Above image consist 3 polygon body that ...
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212 views

Box2D Qt wrong collisions

I am working on a simple Box2D game (with Qt), but my objects don't collide correctly: As you can see on the picture, objects try to go through each other and slide over. My b2World: b2Vec2 ...
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352 views

Image Texture Tracing Algorithm - Cocos2D Box2D

Context: I am working on a 2D Destructible Terrain engine for Cocos2D with Box2D. All images, when a level loads, have their border's traced and cached for the purposes of forming Box2D b2EdgeShape ...
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Why do restitution values less than one still cause infinite bouncing in Box2D?

I'm currently trying to implement basketball bouncing into my game using Box2d (jBox2d technically), but I'm a bit confused about restitution. While trying to create the ball in the testbed first, ...
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How to properly add texture to multi-fixture/shape b2Body

Hello to everyone this is my first poste here I hope that will be not fail start. At start I must say I make part 1 in Ray's Tutorial "How To Make A Game Like Fruit Ninja With Box2D and Cocos2D". But ...
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37 views

How to dynamically draw a filled polygon with a given array of vertices?

Say I have a simple array of vertices (or floats with every odd index being the X of a vertex and every even being the Y), how could I paint all the area between the vertices? As in, I have maybe ...
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23 views

Get entity at supplied world position LIBGDX

So I'm making a simple 2D rpg. What I need is to be able to interact with the entity that the player is looking at. I need to be able to look at E.g another player in the world and press 'E' and have ...
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32 views

LibGDX Box2DLights - Global Illumination

I'm using LibGDX + Box2D to create dynamic lights in my game, but I'm currently stuck. I'm trying to light up every game object in the game with its own shadow, kinda like global illumination. Do you ...
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22 views

Libgdx Box2D - Object not showing up

I am trying to put a sprite into my b2d-world. But for some reason, it is not showing up. I've already checked the camera settings, they are defenetly correct. Then I came to the point to check the ...
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Rendering BOX2D shapes with LIBGDX

I have been creating a game on my own and I need a little help to begin with graphics. I haven' t found much in the internet about this topic, so I came here. Right now I've got a chainshape that i'm ...
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Touch and Collisions not working together in AndEngine when i set a custom Physics Handler

I have a set of custom sprites which implement a custom physics handler. The aim is to allow the user to move them by touch, then upon release they should act like a spring is connecting them to the ...
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Box2D revolute joint positioning

I'm trying to auto test some basic assumptions about how bodies tied together with a revolute joint should be positioned: void tst_GameController::physicsJointInitialPosition() { ...
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19 views

DynamicBody diving into StaticBody

In my game I want a DynamicBody to dive down into a StaticBody. I set up both bodies. At the moment they are colliding. How can I get my DynamicBody to dive down? Is it going to work with this ...
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Box2D collision between dynamic body

I'm implementing Box2D for my 2d top down LIBGDX game and i have some struggle with two dynamic body. Currently, my two bodies are created that way : BodyDef bodyDef = new BodyDef(); ...
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boost/geometry replacement in Java/for the JVM (Destructable Box2D terrain)

I'd like to reimplement https://github.com/seemk/DestructibleBox2D in Java. The main problem is finding an adequate replacement for the boost/geometry library. Any ideas?
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Raycast trouble

i'm having some trouble with the RayCast. I'm raycasting from the player position and my mouse position. I have this situation : http://i.imgur.com/h7iplnY.png (the white line is a representation of ...
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Which Box2D-like physics engine parameters need pixel conversion?

The official guide does not have any useful details on the matter: http://www.box2d.org/manual.html Position is an obvious one. What about velocity? Density? Anything else? Update: the context is ...
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Use libgdx box2d for dynamically generated top down map

So, I've already found some information on how to use box2d and tiledmap together. Since I want to generate my top down map (100 by 100 tiles), I thought about only using box2d. The tiles would be ...
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LibGDX , Box2D body Mass Center

I am creating complex bodies using this editor. But the mass center of the body is not in the right place , when I apply force to it it begins rotating . So I am confused why is the masscenter in the ...
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Adapting qml-box2d to work with QGraphicsScene: transform origin is incorrect

I'm taking the convenient QObject wrappers from the Box2D QML Plugin and using them with a QGraphicsScene-based game. My motivation is to save time writing them myself, as I need to expose stuff to ...
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Why does physics interpolation give me periodic jumps/flickers?

I have seen this question but it didn't solve the problem. I have followed the same steps as in this article. What I notice in my Android game is that my interpolation alpha (or fraction or ...
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Setting Up the PTM_Ratio for Different Devices

I want to set the the physics for my Game and I have used Box2d for the Physics Simulation. And to do that I have set the PTM_Ratio to 32.0f.But When I run my Game on Different Android or iOS Devices ...
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Box2d c++ can't see b2PolygonShape

i try to follow this tutorial and convert it to c++ http://www.emanueleferonato.com/2009/04/06/two-ways-to-make-box2d-cars/ the second part of the tutorial Now im facing very strange Behaviorno ...
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Can't perform normal jump after applying revolute joint

I have encountered the following problem: I have two PolygonShapes which I had connected with a RevoluteJoint. The first body is called square the second is called weapon, before connecting the two ...
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Box2D replace Fixture not working as expected

I am using box2D to develop a simple game, and I am using the Physics body editor by Aurelien Ribon to load the fixtures into bodies. I have written the following method which should scale my ...
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179 views

Preferred way to integrate box2d with SFML

I'm trying to integrate Box2D with sfml. My current solution is to have overloaded functions creating sfml shapes from box2d fixtureDef shapes. I store created sfml shapes under the name 'visual' in a ...
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Box2D shape/fixture position vs. body position

I load my rectangular shapes from a simple Tiled level into libGDX and want to create a physics world out of it via Box2D and attach sprite assets for rendering. I get the tiled object layer and ...
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280 views

How can I make a swinging rope?

Base question: How can I make a swinging rope in box2d? Context: The idea is to have a rope where the player can grab it, swing a little bit to get more "momentum" and reach the next platform. Like ...