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

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1answer
483 views

Cocos2d: Tongue effect like in Munch Time

I'm wanting to do a tongue effect for my character like the one in Munch Time( shown in pic ). The player does some action and his tongue attaches to the nearest platform. I'm thinking this is ...
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0answers
249 views

Design pattern for procedural terrain assets

I'm developing a procedural terrain class at the moment and am stuck on the correct design pattern. The terrain is 2D and is constructed from a series of (x,y) points. I currently have a method that ...
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2answers
1k views

Simple 2D Flight Physics with Box2D

I'm trying to build a simple side scroller with an airplane being the player. As such, I want to build simple flight controls with simple but realistic-feeling physics. I'm making use of cocos2D and ...
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1answer
994 views

RevoluteJoint Stop Rotating when Some Physics Body Collide in Andengine + Box2d?

I am making a Game from andengine + box2d in Which i am using RevoluteJoint in that case i am facing some problem that when physics body or Sprite Collide with this Revolute joint body then Revolute ...
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4answers
1k views

Should I used Box2D for a Flash platformer or use something for gaming like Fixel or Flashpunk?

I'm trying to make a platformer with Flash/AS3 and have been looking for something to help with some of the collision etc. I've look at a few engines and Box2D/WCK seems the most sophisticated. Do I ...
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4answers
2k views

How do I make my rain effect look more like rain and less like snowfall?

I am making a game in that game I want a rain effect. I am little bit far from this right now. I am creating the rain effect like below: particleSystem.addParticleInitializer(new ColorInitializer(1, ...
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2answers
948 views

How can I create a rain effect?

I'm making a game in which I want a rain effect, like rain is coming and game play normally.
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1answer
2k views

How to simulate a water splash effect?

I need to achieve the effect of a ball falling down into a pool then splashing in the water. At first, I made a sensor to detect the collision between the ball and the water and then show the sprite ...
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1answer
2k views

Setting a Box2D Bodies Center?

How do I set the center of a fixture/body consisting of multiple shapes (triangles)?
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1answer
491 views

Store and create game objects at positions along terrain

I have a circular character that rolls down terrain like that shown in the picture below. The terrain is created from an array holding 1000 points. The ground is drawn one screen width infront and ...
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2answers
239 views

Moving 2d camera in the y direction

I'm developing a simple game for the iphone and am struggling to work out the best way for the camera to follow the main character. The following picture hightlights the three main components: ...
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2answers
862 views

Box2d debug render

How can I render the body and joints in the physics world? During research I found the class called Box2dDebugRenderer. But when I put it into use it was full of errors. I do not found some classed in ...
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3answers
566 views

Box2d Collision problem

I'm not good with words so here's a picture to describe my problem: In my game there is this big ball which the user can move on x-axis only. Now, if the ball is falling like the red one, it's ...
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1answer
199 views

JointDef Modify at Runtime

In my game, I want run time modification in object body so I want to modify the joint def according to situation. So provide comment for how to modify jointdef run time.
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3answers
4k views

Remove gravity from single body

I have multiple bodies in my game world in andengine. All the bodies affected by gravity but in that I want my specific body does not affected by the gravity. For that solution after research I found ...
0
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1answer
578 views

in box2d how to decrease joint's reaction force?

I'm trying to make a game like cut the rope and meet some problems. when I create a float bubble and connect with a rope(a sets of bodies connected with revoluteJoint), the rope will become longer and ...
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2answers
1k views

Constant rotation of a revolute joint in box2d

I would like to have a line with one end attached to a location and have it rotate constantly (with the same speed) with a maximum of 45 to -45 degrees (i.e. I would like to have it swing like a rope ...
5
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1answer
496 views

Do I need to roll my own polygon segmentation algorithm to automate Box2d body creation from a tile map?

Before re-inventing the wheel I figured I'd ask: I'm working on a tile-based 2d-maze level generator for cocos2d + box2d. The idea is: I'm using one of the well-known graph traversal algorithms to ...
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2answers
747 views

Continuous Movement of gun bullet

I was using box2d for the movement of the body. When I apply gravity (0,0) the bullet continuously move but when I change gravity to the earth the behavior was changed. I also try to apply continuous ...
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1answer
2k views

How to apply impulse to a body to make it fly away?

I'm playing around with jbox2d and can't really make a body "fly away" as if from an explosion. From what I have found on the net, making the body fly away from the world center (0,0), should have ...
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2answers
1k views

Determinism in multiplayer simulation with Box2D, and single computer

I wrote a small test car driving multiplayer game with Box2D using TCP server-client communcations. I ran 1 instance of server.exe and 2 instance of client.exe on the same machine that I code and ...
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0answers
372 views

how to attach a body to a rope and making it swing to another rope [closed]

I've set some ropes (using cocos2d and box2d) and would like to attach a body to one rope in such a way that it can swing to another rope. I am not sure how to go about this. I read making and object ...
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1answer
432 views

JBox2D - how to get vertex positions?

I've created a triangle for jbox2d... public void createTri(){ PolygonDef shape = new PolygonDef(); shape.density = 2.0f; shape.friction = 0.8f; shape.restitution = 0.3f; ...
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3answers
601 views

Why does creating dynamic bodies in JBox2D freeze my app?

My game hangs/freezes when I create dynamic bullet objects with Box2D and I don't know why. I am making a game where the main character can shoot bullets by the user tapping on the screen. Each touch ...
3
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1answer
140 views

Smoothly move between bodies

I'm not sure if the title is correct (please comment if it is not). I have a sprite (rectangle body), and I'm applying force on it to make it move from left to right and then go backward. The platform ...
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1answer
261 views

Why set the position of both b2Body and Box2DSprite?

In a game, we add a body for each sprite, the method is: createBodyAtLocation:(CGPoint) forSprite:(Box2DSprite*)sprite In which we create the body and we attach it to the sprite in parameter: ...
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2answers
1k views

Making body (box2d) a sprite (andengine) in Android

I can't make body (box2d) a sprite (andengine) and at the same time apply MoveModifier to sprite which is body. If i can make just body, it works namely the sprites can collide. If I apply just ...
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1answer
2k views

Best way to create a level editor in java [closed]

I am creating an iPhone game using cocos2d + box2d that needs a lot of levels. My friends and I are creating the game and most of them have no programming experience and end up with nothing to do. I ...
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2answers
4k views

Box2dWeb and Images

How do I import and attach a PNG or GIF to a shape in Box2dWeb? The best resource I could find online is at: http://www.jeremyhubble.com/box2d.html However, this "tutorial" doesn't give much ...
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1answer
695 views

Check for bodies within a specific circle in Box2D

I'm trying to find positions to insert new bodies into my world. For that, I'd like to have a "free" spot where this body wouldn't overlap with anything else. So my plan was to sample "random" ...
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1answer
551 views

Box2D how to implement a camera?

By now i have this Camera class. package GameObjects; import main.Main; import org.jbox2d.common.Vec2; public class Camera { public int x; public int y; public int sx; public int sy; public ...
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1answer
605 views

Box2D platformer movement. Should i mess with velocity?

I have a platformer game in which I implemented the movement using a wheel attached to the hero. For jumping I use this: player.body.applyLinearImpulse(new Vec2(0, 30000000), ...
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5answers
11k views

What is the proper way to remove a box2d body from the world in libgdx?

I'm wondering how to remove the body from the world, because I found an error when I tried. I found following error. java: ...
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1answer
1k views

How do I implement smooth movement in a Box2D platform game?

I have implemented a character in JBox2D which moves with the help of a wheel rotating at the bottom of it. The movement is the best result I've had 'till now but it's a little glitchy when the ...
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1answer
887 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 ...
4
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1answer
1k views

Box2D platformer movement. Are joints a good idea?

So i smashed my brains trying to make my character move. As i wanted later in the game to add explosions and bullets it wasn't a good idea to mess with the velocity and the forces/impulses didn't work ...
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1answer
1k views

JBox2D applyLinearImpulse doesn't work

So i have this line of code: if(input.isKeyDown(Input.KEY_W)&&canJump()) { body.applyLinearImpulse(new Vec2(0, 30), cam.screenToWorld(body.getPosition())); ...
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1answer
706 views

box2d resize bodies arround point

I have a compound object, consisting of a b2Body, vector-graphics and a list polygons which describe the b2body's shapes. This object has its own transformation matrix to centralize the storage of ...
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1answer
4k views

LibGDX Box2D Body and Sprite AND DebugRenderer out of sync

I am having a couple issues with Box2D bodies. I have a GameObject holding a Sprite and Body. I use a ShapeRenderer to draw an outline of the Body's and Sprite's bounding boxes. I also added a ...
5
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1answer
3k views

Box2D Difference Between WorldCenter and Position

So this problem has been brothering for a couple of days now. First off, what is the difference between say Body.getWorldCenter() and Body.getPosition(). I heard that WorldCenter might have to do ...
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1answer
2k views

How would I use JBox2d in Java?

So I did some research and a found Box2d. I then proceeded to download it and the testbed. Now that i have it, I don't know how to properly use it. I'm looking for a clear simple answer on how to ...
4
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1answer
720 views

How to make an object fly out of a slingshot?

At the moment I'm improvising a slingshot, the user can click and drag the projectile and let go. The force on the object is calculated by getting the distance between the vector of the slingshots two ...
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1answer
498 views

How to fake flipping a skeleton in Box2D?

Imagine I have a skeleton — that is a set of bodies held together through various constraints and joints — and I want to flip it. Bodies cannot be flipped in Box2D, so how can I fake that? ...
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2answers
675 views

Calculate impulse need on object to throw i Y meters into the air, with varying mass

Say I have an object that has a variable mass. Now I want to apply a vertical impulse (straight up into the air) onto the object, so it always flies up to the same height. How do I calculate this? So ...
2
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1answer
739 views

Box2D + Love2D (Lua) - Assertion fail with polygon meshes

When I try to create a triangle collider for my game it sometimes leads to an assertion fail. I use the physics engine that comes with love2d (Box2D). That's the error message that appears when the ...
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5answers
2k views

Errors happen when using World.destroyBody( Body body )

on Android application using libgdx, when I use World.destroyBody( Body body ) method, once in a while the application suddenly shuts down. Is there some setting I need to do with body collision or ...
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1answer
2k views

Creating lots of sprites dynamically in libgdx

I´m creating Groups that contains Sprites and adding bodies with box2D, but when I create many of this my animation gets very slow. How can I handle it?
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4answers
2k views

Include Box2D libraries to a cocos2d project (iOS)

I have a problem including box2D to my cocos2d project. I've tried different ways to do it with no success. This is what I've done: I downloaded Box2D (Box2D_v2.2.1) to my project directory. Dragged ...
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1answer
1k views

b2Body moves without stopping

I got a quite strange bug. It is difficult to explain it in two words, but i'll try to do this in short. My b2Body has restitution, friction, density, mass and collision group. I'm controlling my ...
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1answer
802 views

Scaling bodies in box2d and libgdx

Is there a way to scale the bodies made from vertexes (like a guitar), i was trying to multiply each vertex point by the scale value but c++ mark an assertion failed, is there a mehtod to do this? I ...