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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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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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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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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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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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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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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81 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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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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238 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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88 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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179 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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186 views

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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53 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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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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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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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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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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92 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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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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1k 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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266 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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133 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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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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232 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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79 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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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 ...
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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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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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59 views

Bodies going through the walls of a box

I have a game where the user controls a box to collect falling balls. However, very often the balls will just fall through the walls of the box and be flung away. What could be causing the balls to do ...
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103 views

Multiple gravity “zones” in a world

I have a world that I want to divide in two like this: ____________________ | | | | | A | | | | | ...
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331 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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Why are my Box2D wheels slipping on ground?

I have a car, set up in Box2D as a rectangle connected with two wheels using WheelJoints: The wheels are defined as follows: FixtureDef wheelFixtureDef = new FixtureDef(); ...
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148 views

Get position of Fixtures

I'm constructing a Body (a box2d body using AndEngine) using multiple Fixtures and later I need to get the world position of these Fixtures. Currently I am trying something like this; // ...
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587 views

LibGDX Box2DLights shadow offset problem on bodies

Hello I just started to use LibGDX, and it's awesome. I looked at the Box2DLights library, and started to learn how the lighting work here. I got something up: As you can see, it works, but the ...
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162 views

Love2D Box2D RevoluteJoint and Anchors

and apologies in advance for this fairly random question. I'm using Love2D 0.9.1 and Box2D to create two bodies joined by a revolute joint. A simplified representation of the two bodies is a Sphere ...
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In JBox2D, where is the correct place to interact with Body objects? step() method?

QUESTION: In an application, where is the appropriate place to put the code to interact with the Body objects? By 'interact' I mean Get position Determine actions Apply impulse Would it be ...
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58 views

What's the difference between Box2D and tweening?

It seems like Box2D can be used to move sprites across the screen, so how does this differ from tweening? Is it that Box2D is for physical collision detections and tweening is just animations?
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Box2D collision damage calculation from postSolve or not?

I'm using postSolve to get impulse then calculate damage base on that impulse. But there's some issue: Stability The damage isn't stable. When the same ball is hitting with same speed, the damage ...
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220 views

How can I predict player-to-projectile collisions in Box2D?

I'm making a real time shooting game with Box2D as the physics engine. The gameplay is mostly about trajectory, like Angry Birds. I want to make a slow motion effect and move camera to the player when ...
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How can I add an impulse to specific rigid bodies at rest?

Scenario Rocks falling down a rocky slope, with a flat surface at the bottom. When they land on the surface, the rocks move slightly before coming to a rest. GLESDebugDraw shows the bright orange ...
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313 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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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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85 views

Inertia in flight simulation using box2d

I'm trying to simulate flight using box2d and libgdx. The main problem I am currently experiencing is with inertia: since there is no air, the plane looks like it were drifting. I wasn't able how to ...
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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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171 views

How to make player rotate towards mouse [duplicate]

I'm making a top down shooter with Three.js and Box2d. I'm displaying all of the graphics in 3d, but all of the physics are done in 2d, so it's sort of like super smash bros in a way. Anyway, how can ...
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512 views

How to optimize a box2d simulation in action game?

I'm working on an action game and i use box2d for physics. The game use a tiled map. I have different types of body: Static ones used for tiles Dynamic ones for player and enemies Actually i ...
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309 views

simple collision detection with box2dweb

im beginner in box2dweb that version of box2d for javascript i wrote simple gravity system and i want to detect the collision between the box and the ground , when the falling box hit the ground ...
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157 views

revolutejoint doesn't seem to rotate

I have a revolute joint set up as such in libgdx + box2d: RevoluteJointDef rjd = new RevoluteJointDef(); rjd.initialize(body1, body2, arm.getWorldCenter()); rjd.motorSpeed ...
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how do I create a moving type of block like in Mario[box2d]

I want to create a block which only moves up and only when hit from below. I am trying out a distance joint and I read it can be used as a spring, is this the correct solution? the way I have tried ...
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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 ...