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

learn more… | top users | synonyms

2
votes
0answers
50 views

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, ...
1
vote
1answer
239 views

Soft Body Collision with Box2d (libGDX)

I've made a few classes to create soft body objects in libGDX using Box2D (specifically a circle and rectangle similar to these links). The objects are constructed of a number of circle shaped Box2D ...
0
votes
1answer
65 views

Drawing the box2D rectangles

i'm using SDL2.0/OpenGL + Box2D with C++ to learn some stuff about games, so i created two rectangles bodies: a small box(dynamic) wich will fall into the second body: the ground(static), i draw them ...
0
votes
1answer
27 views

Box2d java contact point reference changes after collision

I am trying to hold the contacts made during a collision in an array list. After I add n amount of contacts, when I try to retrieve them later on, they point to the last contact made in the world. ...
0
votes
1answer
166 views

LibGDX: Issue with unitScale for Tiled and Box2D

I've got the following: I use a TiledMap (loaded from a .tmx), each tile 32x32 pixels in size and generate the Box2D bodies for collision from the TiledMap's ObjectLayer. That all works fine, no ...
1
vote
1answer
37 views

Why is my Box2D Body only colliding with one type of Object after a new level has been built?

So developing for an android mobile game, using Android Studio and developing for the API 17, with Box2D implemented. FIRST LEVEL For some reason, one the first level everything is running okay: ...
1
vote
1answer
48 views

dynamic body jumping out of water object

In my game I have my main object, a jetski, which will dive down into water, when the screen is touched. I managed to code the jetski diving down, with Box2d and some buoyancy forces. But when the ...
1
vote
2answers
36 views

applyForce as long as display is pressed

In my project I have my main character body. I want it to move down on the y-axis as long as the screen is pressed. I tried it with public boolean touchUp(int screenX, int screenY, int pointer, int ...
3
votes
1answer
35 views

In Box2D, what exactly does a fixture represent?

In Box2dWeb, when we create a body we attach a fixture to the body object. We make the shape, friction, restitution and so on by tinkering with the fixture object. So from this can we conclude that ...
0
votes
1answer
50 views

Black screen when launching on phone

I am coding a game in libgdx. While adding the background I used the html module to watch the results fast and easy on my computer. But when I try to see it on my phone I just get a black screen. My ...
1
vote
2answers
51 views

Camera controll in Libgdx

I've a condition in my game where, I want my camera to follow the Player(its a body from Box2d) and in some not. This is the start screen of my game: Now, when i press a button(space) the player ...
0
votes
1answer
60 views

TypeError: R[o5R.F6s] is not a function in changing states in phaser box2d

i build my game using phaser.2.4.3.min.js and phaser.2.2.2.box2d.min.js When trying to change states this error is being raised TypeError: R[o5R.F6s] is not a function and i can't seem to figure out ...
5
votes
1answer
487 views

Why do my game objects jitter when moving the camera?

I'm moving from Qt Widgets' QGraphicsScene to Qt Quick's QQuickItem for rendering my game objects. One of the things this involves is setting up a scene and the view onto that scene, as this was ...
0
votes
0answers
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 ...
0
votes
1answer
32 views

Box2d Coordinate System

In the game I'm trying to code I got to have two bodies. One StaticBody and one DynamicBody. I want to have the DynamicBody on top of the StaticBody. Somehow all I get is this: Is it possible that ...
1
vote
1answer
67 views

Box2d jetski on water

At the moment I am trying to code a 2d game in java, where a jetski is riding on water. If you press on the screen the jetski should dive down and jump back up on release. How do I have to do this in ...
2
votes
1answer
69 views

Viewport and Camera setting

For my first game in LibGDX and Android I got a Problem: I have a background picture which is 2560px * 720px. The screen is 1280 * 720. How do I have to set the viewport and camera in order to get ...
1
vote
0answers
30 views

Model a helium balloon on Box2D + libgdx [closed]

I want to make so that the bigger the balloon is, the faster it goes upwards, and if it's not big enough it will fall down. I tried applying a force greater than the gravity but it doesn't work as I ...
1
vote
3answers
159 views

Collision Detection/Response Issues in Unity

Sprite A: Box Collider 2D and Rigidbody 2D. Sprite B: Box Collider 2D. Both sprites have a Sprites/Default material with Pixel Snap enabled. The textures being used are set to Truecolor Format and ...
2
votes
1answer
58 views

Why are my Hello World Box2D project's collisions off by twice the size of my boxes?

I've been implementing Box2D into my engine but have run into a snag. I decided to rebuild the helloworld project inside of my own engine (it is almost identical), of which I will snip here in a ...
2
votes
2answers
132 views

Movement through forces and impulses

I'm trying to get some decent-looking movement in my game using this tutorial. In the image below... something crazy is going on. What should happen is that the NPC should start on the left side of ...
1
vote
1answer
122 views

libgdx - Check if body is touch

I have some bodies around the screen(Ball[] balls), and I would like to delete them when user touches them. Also, I have an Image as userData of the bodies. I dont want to make a function to all ...
2
votes
0answers
43 views

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 ...
0
votes
1answer
46 views

Marketing PC/Android 2d Physics Game [closed]

I've been working on a game for couple years now, its fairly original, has definite potential within an indie market, and appeal for the masses also. I want to deploy on Android and PC, green-light ...
1
vote
1answer
75 views

How do I query a LibGDX Box2DLights “light” and “dark” regions?

I have lighting implemented using Box2dLight. I want to update/render things inside the player's PointLight area. Stuff in the dark area should not be rendered. How can I find which areas are lit or ...
0
votes
0answers
83 views

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(); ...
0
votes
1answer
78 views

Box2D - Platformer tiled map problem

I'm using C++, Box2D and SFML. I convert a Tiled map to world in my platformer game and I get stuck when I go against a block when I go forward like that : I can use a circle as foot of my ...
0
votes
0answers
32 views

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?
0
votes
1answer
12 views

Is GetFixtureA() of b2Contact guaranteed to return the body on which GetContactList() was called?

For example, in the code below, will the assert ever fail? for (const b2ContactEdge *contactEdge = playerPhysicsBody->GetContactList(); contactEdge; contactEdge = contactEdge->next) { ...
3
votes
1answer
93 views

Should I initialize a Box2D World per Level?

I'm using a LevelManager to load Tiled maps in my libGDX game, which stores: Static: final Size of map in Tiles final Size of map in Pixels final Size of an individual tile TiledMap ACTIVE_MAP ...
0
votes
0answers
24 views

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 ...
3
votes
1answer
113 views

Running and Jumping using Box2d and libgdx

.this is my first trial on making a 2d game and currently struglling how to run and jump smoothly. My problem is when the player keep pressing on left or right botton then jump. the player won't jump, ...
-1
votes
1answer
186 views

C++ SFML and Box2D: Move world or move player?

I'm currently making a top-down shooter game and it's my first time developing with SFML. I came across and issue and I want to know if there is a better way to solve it. I need to get the "camera" ...
2
votes
0answers
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 ...
1
vote
1answer
77 views

LOVE Physics - Joint Stretching

After asking a similar question yesterday I've come across another problem with using joints in box2D / LOVE and trying to create a weighted chain. Everything is set up as follows, I've tried to ...
1
vote
1answer
122 views

LOVE Physics - Breaking Joint Chains (LUA / Box2D)

Wasn't sure whether to post here or on SO so please move if needed. I've been having a look into the box2D physics API provided by LOVE to try and create a swinging flail or weighted rope but I'm ...
2
votes
3answers
150 views

How to make sure that when two bodies collide, there is only one collision detection on box2d?

I'm using LibGDX with box2d, and when to bodies collide collision is detected multiple times. here's the code `public void preSolve(Contact contact, Manifold oldManifold) { Body a = ...
0
votes
0answers
40 views

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 ...
3
votes
1answer
113 views

Box2d Body to follow mouse movement

I am trying a box2d body to rotate following the mouse. Here's an image to clarify what I mean. The red and blue circles are current point of the mouse and the body (of corresponding color) ...
0
votes
1answer
142 views

Libgdx Scene2d and Box2d light

Currently I am using scene2d and I want to implement shadows using Box2d light. I want shadows under characters but when I draw something after render() , it draws nothing. For example, in draw() ...
1
vote
1answer
90 views

Box2D No Gravity when moving against wall

I use Box2D in my current project and I have a problem with the gravity.. You can see my problem here: https://www.youtube.com/watch?v=2_kv9LkKwN4&feature=youtu.be when i jump normal everything ...
8
votes
4answers
398 views

Creating a Melee Weapon in Box2D (libGDX)

I am struggling with how to implement a melee weapon that can swing when a key is pressed. I am imagining two different attacks (stab and swing) I have tried creating two fixtures (character + ...
0
votes
0answers
59 views

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 ...
0
votes
0answers
55 views

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 ...
0
votes
0answers
61 views

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 ...
0
votes
2answers
372 views

Libgdx using Box2d with TiledMap to create collision detection

I'm fairly new to Libgdx and have some good basic knowledge on Java. Right now I am stuck on how to add collision to my TiledMap, I am using the Mapeditor to create the tilemap. I read so many ...
1
vote
0answers
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: ...
1
vote
1answer
83 views

LibGDX, Box2D , Destroy body into parts [closed]

I am developing a game using libGDX game engine and box2d physics engine. There are asteroids in my game, I want to destroy their bodies randomly and fill with texture. How can I do it?
0
votes
0answers
108 views

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 ...
0
votes
1answer
31 views

Box2d joints still attached after Explosion simulation

I ported simple Box2d Explosion simulation the function is called once when there is some event with the "Truck Car" the problem is that the Explosion working fine but it looks like when the explosion ...