JBox2D is a java physics engine often used in games an other physics simulations, and is a port/extension of the C++ physics engine, Box2D.

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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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118 views

LibGdx - Move sprite in the direction of other sprite

I'm kind new to LibGdx and I'm still learning. I'm working on a small game project to learn this nice framework. However, I'm having some issues with my game. My game is a top down shooter. There is a ...
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Simulate juggling : how throw and grab objects with JBOX2D

There is an object which simulates a ball and another which simulates a hand (square).I want to be able to catch the ball and throw it with a projection force with the hand on JBOX2D. Any sample code ...
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61 views

How to restrict jumping to a single jump?

I'm making a VolleyBall game in HTML5 with PandaJs GameEngine and plugin is used physics and Box2D. The problem is that players can jump, but they can jump over the net with multiple jumps. I have ...
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Relative movement in Box2D (keep object from falling off planet)

I'm creating a game with planets orbiting around a sun, like this: The brown square is the earth, rotating around its center and around the sun. The yellow square is the sun, which doesn't move. Now ...
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32 views

Permeable objects in Box2d

In Box2d, can I make a static object to be permeable by dynamic objects? Can I simulate something like water in a way that it lets rigid bodies to dive into it but at the same time pushes them off ...
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46 views

Set world boundaries in box2d

So far I've seen the only way to set boundaries on box2d world which is to create rectangular shapes and place them at the edges of the screen, is there any other way? Perhaps I can set boundaries ...
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65 views

Rotating towards a point in Box2D

I'm using Box2d as my physics engine and I'm trying to solve what would normally be a simple problem but what has become a nightmare for me and preventing me from finishing my app. (6 months work) ...
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254 views

LibGDX camera position shifted on movement

I'm programming a game with LibGDX and Box2D and I want my camera to follow my player. But as I zoom in (because Box2Ds metric system, using camera.zoom = x) the camera is shifted when the player ...
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155 views

Seeking Advice: Collision with JBox2d for Top-Down or Isometric Maps

I Hope I can make this as clear as possible! Currently working on an action RPG game, very early stages, more just the basic ideas down and written in. So i'll start on with my setup: Using Java ...
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36 views

Box2DLight position seems to Floor

I am creating a top down game and i'm using raycasted lights from Box2Dlights, My light is all set up and working. its attached to the player's Body, and when the player moves, the sprite I attached ...
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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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Using debugdraw in jbox2d

I've created a class which implements org.jbox2d.callbacks.DebugDraw. And implemented the abstract methods too. DebugDrawHandler extends org.jbox2d.callbacks.DebugDraw I've instanciated it with: ...
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Why do my Box2D bodies occasionally get stuck and separate forcibly?

I'm making a space game with LibGDX and Box2D. I made a video here to illustrate the issue. Verbal description: When objects collide, they sometimes get stuck together and are then suddenly separated ...
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JBox2D Objects moving slowly (pixel to meter conversion) (SOLVED) [closed]

This problem is solved When trying to program a game using Box2D, I ran into a problem with Box2D. I filled in pixel numbers for the lengths of the the textures and sprites to create a box around it. ...
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220 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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98 views

Correctly identifying a Fixture from an extended class in Box2D's ContactListener

Sorry for the confusing title, I dont know how to resume it that much. Im making a game, and I have a simple class Mob which is extended by Warrior and Enemy. A Mob has a Body, and that body usually ...
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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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67 views

In JBox2d when dragging a Body, why is the direction is flipped vertically?

Why is it when I drag a JBox2d Body with the mouse, the vertical component is flipped? e.g. If I drag down-right, the Body moves up-right. Is this expected behaviour, a bug in JBox2D, a Mac ...
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32 views

Drawing jbox2d shapes in slick2d

How would be the best way to go about drawing polygons in slick after forces where applied to them via jbox2d? There seems to be no way to get the vertices of a body defined in jbox2d...
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70 views

JBox2D bodies don't collide?

I have two objects. A dynamic player and a static ground object. It was working for a while until I did some refactoring and suddenly my play falls right through my ground object. Is there anything ...
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How can I avoid duplication of jBox2D physics attributes?

I'm using jBox2D for physics and collision detection in a game engine with an entity-component system. It works, but I'm unsure how to structure my code with respect to the values represented in the ...
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143 views

How do I create a Fixture in Andengine and assign it user data?

I´m following this tutorial: How do I use ContactListener in JBOX2D? in order to get input from player's bottom part including a fixture in player's main body. My problem is that I´m initializing ...
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268 views

Box2d world width and height ratio with screen width and height

I have view, for example GameView which extends SurfaceView . I have integrated Box2D physics in GameView. I have two widths , GameView width, height and Box2D physics world width ,height. I need to ...
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How do I get the position of a static body in Jbox2D?

I'm trying to get the position of a static body in JBox2D, how do I do that?
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445 views

libgdx default saving mechanism for box2d world

I want to save my game in libgdx, and I have no problem using Kryo to save everything, except the box2d Worlds and the RayHandlers from box2dlights - these are not Serializable and do not have default ...
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41 views

Using texture() in combination with JBox2D

I'm getting some trouble using the texture() method inside beginShape()/endShape() clause. In the display()-method of my class TowerElement (a bar which is DYNAMIC), I draw the object like ...
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98 views

Box2D relations

As far as I know, the unit in Box2D is meters. When I use Box2D in Processing with JBox2D, I set the "world size" as the window size specified in the setup(). Now I'm wondering if there is any ...
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218 views

JBox2D Polygon Collisions Acting Strange

I have been playing around with JBox2D and Slick2D and made a little demo with a ground object, a box object, and two different polygons. The problem I am facing is that the collision-detection for ...
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414 views

2D Polygon Triangulation

I am creating a game engine using the JBox2D physics engine. It only allows you to create polygon fixtures up to 8 vertices, To create a body with more than 8 vertices, you need to create multiple ...
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111 views

Which .jar has JBox2d's p5 package?

Using Eclipse, I'm trying to write a simple hello world program in processing that simply draws a rectangle on the screen then has gravity drop it as seen in this tutorial. The problem is that when ...
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559 views

How do I use a JBox2D ContactListener to check if my character is standing on the ground?

I want to know when my character is touching a wall or floor. I've had no luck searching for information on this. I saw a few things about ContactListeners and getContactList(), but I don't understand ...
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470 views

Camera scrolling and game boundaries

I am making a platformer game in JBox2D and LWJGL that has a scrolling camera, but I have hit a wall with the boundaries of the camera. Essentially what I have right now is a Box2D world that is ...
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518 views

Why won't my Box2d bodies collide? [closed]

I'm doing something wrong when trying to get bodies to collide using jBox2d & Slick2d. Here is have just my basic init, update, and render methods. Render and update seem to work fine for drawing ...
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613 views

How to translate from Slick2d coordinates to jBox2d

I read through this question to try and get a grasp on the topic, but I can't figure out how to apply this to my Slick2d window. I'm trying to do something as simple as place an edge on the bottom of ...
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1answer
371 views

Debug Render In Cocos2d Android

I want to implement debug render for cocos2d android.So I can view how bodies are created. Right now I use gdx.jar file for box2d and load that jar file following way. static { ...
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Box2D - Do these simple objects need to be in the simulation?

I would like to get input from the community regarding how best to represent simple objects in a Box2D based simulation. Some background: Without going into too much detail, think of a top down game ...
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392 views

2D js physics engine for HTML4

Is there any engine for Javascript like box2dweb that does not use Canvas? I need to build a game that works in HTML4 browsers.
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645 views

Box2D and Slick2D: Graphics bug [closed]

The bug The physics ground represented by a horizontal line. The object is stationary, and seems to be pretending that the ground is lower. This is because the center of the Shape is incorrectly ...
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Applying Forces to Box2D Bodies

In full disclosure, I am VERY new to box2D let alone the Java version of it. I have a box (here of type Hero) that I am trying to move. I did this by trying to apply a force as follows... private ...
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257 views

OutOfBounds Exception when creating a PolygonShape using jbox2d

So here's the deal, i'm parsing a file that contains the vertices for a polygon, that i want to create in box2d. I create a new PolygonShape() and then call .set() giving it a defined array of Vec, ...
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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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482 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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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 ...