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

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How to create Whirlpool/Vortex effect?

Im trying to make a Vortex effect on a Circle Body that is a Sensor. I've been looking for this and all examples i look for are in C++ or Objective C and i dont seem to translate them well. when my ...
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1answer
173 views

Dynamic Hills like Contre Jour in Cocos2d

I'm interested in maps/environments which are flexible and change at runtime, such as those in Contre Jour. I have looked for a long time to find out how to make this effect, but I couldn't find an ...
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106 views

Physics don't apply on a unique body AndEngine

I am developing a game in AndEngine. So far I managed to create everything I wanted for my sprite that was connected to a BoxBody. I was rotating it, moving it, everything was great. I wanted my ...
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1answer
58 views

Only render/calculate the chunks in frustum!

I have a 2D world in form of a Block[][]-Array that holds all the blocks of the world. Every block has it's own Box2D Body (I want a "minecraft"-like 2D world for this project). Naturally I don't want ...
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83 views

How do I handle rope physics with fixed ends and a sliding weight?

I've been interested in rope physics recently—I've successfully implemented a simple Verlet rope with moveable ends. Now I am trying something a little different: I want to start by recreating the ...
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1answer
678 views

AndEngine; Box2D - high speed body overlapping, prismatic joints

I'm trying to make good suspension for my car game, but I'm getting nervous of some problems with it. At the beginning, I've tried to make it out of one prismatic joint/revolute joint per one wheel ...
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1answer
15 views

Get speed from vector using box2d and javascript

I need to find the speed of an object in a game. The game is made in HTML5 with jquery and jquery.box2d. For this I can use these methods: GetLinearVelocity().x; GetLinearVelocity().y; I'm then ...
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22 views

libGDX fixed object and camera do movement

I develop game to andorid and there is moving object with arrows - simple movement like in RPG games. I did: camera.position.x = PIXELS_PER_METER*man.body.getPosition().x; camera.position.y = ...
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39 views

Creating a Player object in a physics engine

I have a working physics environment using Farseer - but how do I create a player object that can walk around? My current attempt involves applying forces to a rectangular body whenever keys are ...
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1answer
86 views

What units is Box2d-AndEngine's velocity measured in?

I'm developing a game on AndEngine (with Box2d) and on iOS Sprite Kit simultaneously. I want the game's physics to be identical on both platforms. Sprite Kit uses Box2d internally for physics ...
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15 views

Box2D - create object with different physic parts

I have object with physic: BodyDef bodyDef = new BodyDef(); bodyDef.type = BodyDef.BodyType.DynamicBody; bodyDef.position.set(position); bodyDef.angle = angle; ...
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63 views

Box2D object wont move until tons of force is used

Im making a game for android im using LibGDX and Jbox2D it is a space flying exploration game controlled with the accelerometer. so I have set the world to no have no gravity. the objects in Box2D ...
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9 views

Destroying fixtures in Box2D/AndEngine

In my game I need to break of parts of a body when the body crashes into something too violently. Currently I do that by by getting all the normal impulses of the ContactImpulse and if the max value ...
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1answer
147 views

Change the shape of body dynamically

I have a problem where i have a ballon which i need to continuously inflate and defalte in update method, I have tried to used setScaleCenter but it is not giving desired result. Below is a code i am ...
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24 views

Intersection issue with box2d in iOS

I'm trying to use the code here http://www.iforce2d.net/b2dtut/raycasting So I can know whether a line cross a box2d object or not. It half works, in that when the line crosses the object it does ...
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1answer
22 views

Is there a Box2d b2World::ShiftOrigin function in Libgdx?

Is there an equivalent Box2d b2World::ShiftOrigin function in Libgdx? I can't seem to find it.
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1answer
13 views

box2D and libgdx: Attach ParticleEffect to Body

Hello I am a newbie with libgdx, my question is: how could I add a Particleeffect to a Body that is moving? I searched about the matter and I didnt find anything related to it. I have the following ...
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1answer
69 views

Box2D—how make character tilt

I have got a floating character, which should be a robot like thing, floating over the ground, whereby I am using the »hovercar« effect described here. Zhe Image below outlines the basic setup of the ...
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2answers
366 views

Running multiple box2D world objects on a server

I'm creating a multiplayer game using LibGdx (with Box2d) and Kryonet. Since this is the first time I work on multiplayer games, I read a bit about server - client implementations, and it turns out ...
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1answer
29 views

How can I create a character design that maintains a fixed rotation body, while allowing the body's “arm” to rotate 180 degrees?

I am attempting to create a 2d shooter in Farseer Physics on the Xbox360. I have a player body which has a fixed rotation, as I do not want the body to rotate at all during gameplay. I am now looking ...
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1answer
112 views

Box2d pathfinding using raytracing / predicted collisions

I have a Box2d/Cocos2d iOS game with enemies that attempt to follow the player (to attack). I'm working on improving the pathfinding logic so that the enemies won't crash into objects in the world. ...
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1answer
466 views

Communication between Box2D and libGDX Stage (Scene2D) running in separate threads

I'm making a physics based 2D game using libGDX and Box2D. I want to move the execution of the simulation out of render thread. I use immutable messages and the BlockingQueue to pass the information ...
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82 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 ...
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83 views

Box2D platformer: Why does horizontal movement stop jumping?

I'm writing my sBox2D game character's movement code, but my implementation of jumping is failing: When I press the Jump key, the character jumps OK. However, when I press jump and another key (like ...
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1answer
884 views

Drawing Shape in DebugView (Farseer)

As the title says, I need to draw a shape/polygon in Farseer using debugview. I have this piece of code which converts a Texture to polygon: //load texture that will represent the tray ...
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1answer
159 views

Box2d - Attaching a fired arrow to a moving enemy

I am firing an arrow from the player to moving enemies. When the arrow hits the enemy, I want it to attach exactly where it hit and cause the enemy (a square) to tumble to the ground. Excluding the ...
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1answer
263 views

Letting the user draw a Polygon Body and Image

In my game, I want to provide the user with a drawing feature. By free hand drawing, the user creates a polygon shape. Then, in my game implementation, I have to create a body for the found vertices ...
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45 views

Client-server architecture with box2d

I am running a client-server architecture with an authoritative server running box2d and the client running box2d as well. If gravity is set to 0, is there any point to linear interpolation and ...
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3answers
73 views

Box2d bodies that are really close together, are getting “stuck”

I'm using a tiled tmx map, and I created a class that adds bodies to each tile within a certain layer. This has been working great so far except for when a character or an enemy moves around on the ...
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1answer
55 views

Set Position of multiple bodies

I have a character composed of five bodies which are tied together by a lot of joints. On of them is the overall chassis, to which all forces and impulses are applied to move the whole Character. All ...
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26 views

LibGDX Box2D TileGame Efficiency

I am trying to implement Box2D into my top down tile game in LibGDX. Each world consists of a set of chunks, and each chunk is 16 tiles wide/long. The maximum/minimum chunks loaded at one time is 9 (a ...
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2answers
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Box2D `ApplyLinearImpulse` is not working whereas `SetLinearVelocity` works

I need to mimic jumping behavior for the player in my game. Player consists of two fixtures with circle and rectangle shapes. Rectangle I use to detect ground and it is a sensor. Is some point for ...
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1answer
50 views

How to move a body from one world to another?

I have a Box2D world for each level in my game. When a level is completed, I want the player to be removed from the completed level's world and added to the next level's world. How do I do this?
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202 views

Rotating an object about a point (2D) using box2d

i just started developing using box2d on flixel and i realise the pivot point of the rotation of an object in box2d is set to the center of an object. i had read on forums and i found out that ...
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1answer
575 views

LibGdx sprite rotation vs Box2D physics rotation problem

LibGdx sprite rotation vs Box2D physics rotation problem Tearing my hair out on this one. I am an experienced software developer, but very new to LibGdx and Box2D development. I am writing a game ...
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24 views

Speed seems random with constant impulse

I'm shooting an object from the top vertex of a triangle using Box2dWeb. The issue I'm having is that the projectile speed seems to be fairly random, even with applyimpulse set to a constant. The ...
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16 views

Box2D.js b2ChainShape

I'm using box2d.js (asm.js ported) and need to create a b2ChainShape. var bodyDef = new Box2D.b2BodyDef(); var fixDef = new Box2D.b2FixtureDef(); bodyDef.set_type(Box2D.b2_staticBody); var chain = ...
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66 views

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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1answer
397 views

Box2D Static-Dynamic body joint eliminates collisions

I have a static body A, and a dynamic body B, and a dynamic body C. A is filtered to not collide with anything, B and C collide with each other. I wish to create a joint between B and A. When I ...
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39 views

Drawing a object with Box2D and HTML5 canvas on current mouse position

I'm attempting to create a air hockey type game with HTML5 canvas and JavaScript, using Box2dWeb for the physics calculation. I need a way to draw the puck at the current mouse x and y position every ...
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1answer
97 views

Box2D body rotation with setTransform

I' having a problem rotating a body with setTransform(), The body has multiple sensors that should rotate with the player. The rotation works but it rotates around the bodys local 0,0 position instead ...
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4answers
2k views

Fix joint length in Box2D?

I'm having some difficulties with Box2D DistanceJoints, I'm trying to create a rope using DistanceJoints connecting some bodies together but the length of joints between bodies change due to weight of ...
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3answers
252 views

How do I change the relative origins of a Box2D World and a TiledMap in Libgdx?

I'm playing around with Box2D and TiledMaps and I've come across this minor annoyance. As you can see, both Box2D and TiledMap render at the center of the screen. This forces me to compensate by ...
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1answer
102 views

Making Player Jump

I have been editing a piece of code and I have already implemented gravity so I would like to know how i could make the player jump when the screen is touched. I would like the player bucket to jump. ...
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1answer
119 views

Ball bouncing with box2d in libgdx

I just started using Box2d and libgdx. I followed this tutorial, https://github.com/libgdx/libgdx/wiki/Box2d And a ball would bounce if I run the following code I took from the tutorial. // ...omit ...
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1answer
55 views

“Running” against a steep slope on a Box2D Platformer

Ive seen alot of pages talking about how to emulate a platformer on Box2D, specially about how people dont want to slide down a slope. Well, my problem is different and Im surprised I cant find ...
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2answers
641 views

How to get width and height from a body in box2d?

I am working on a game in Libgdx framework. I have to get width and height from a body in box2d. is their any way to get width an d height from a body in box2d??
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1answer
720 views

Libgdx import bin/xml/json from physics editor

I'm using Libgdx. I did a simple json file in Physics Body Editor and I don't have any idea how could I import it into my physic world in libgdx. Any idea will be appreciated. P.S: Sorry if there ...
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31 views

[LibGdx]Moving a fixture on a body

I'm working with Box2D and I have a basic platform and a box bounces off of it. // Static Platform bdef.position.set(160 / PPM, 120 / PPM); bdef.type = BodyType.StaticBody; Body b = ...
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76 views

Box2DLights - the center of sprites are always 100% unlit (black) unless Xray is on

I'm using a ConeLight at 180 degrees, with this setup: pl = new ConeLight(rayHandler, 256, new Color(0.5f, 0.5f, 0.5f, 1f), 280f, 400 - x, 300 - y, 0, 180); And the object I'm casting a shadow on ...