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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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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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 ...
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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 ...
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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 = ...
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475 views

LibGDX - Box2D: Realistic Light and Layers

I'm having some problems with my current game. Short description: It's a 2D game where you have to avoid the lights or you lose HP. My problem is the following one: Here is the rendering process: ...
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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 ...
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26 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 ...
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409 views

Changing Box2D Body from Kinematic to Dynamic after contact

What is the correct way to change a Kinematic body into a dynamic body? context - I have a dynamic body as a projectile which has to be fired at a kinematic body (it is kinematic because i am ...
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395 views

Wheel Joint Implementation in AndEngine

I am currently developing car game in AndEngine. In which I was using revolute joint for car wheel and chassis attachment. But my friend suggest me that use wheel joint for that purpose for better ...
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78 views

How to convert pixels to meters in Box2d with Cocos2d-x 3.5?

I am using Cocos2d-x 3.5. I created a simple game with edge bodies and one circular body to test box2d. Physics wasn't working well, so i thought i should convert pixels to meters and use that meters ...
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73 views

Pole vault with Box2D?

I would like to replicate the behavior of a flexible pole as used for pole vault. Can somebody give me some inspiration how to simulate that with Box2D? Would I cannot multiple objects with flexible ...
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33 views

Marketing PC/Android 2d Physics Game

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 ...
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121 views

LibGDX Box2D Lights - Illuminate background

I have a box2D world made of tiles. I use a custom DirectionalLight for light up the scene from above (It shines through transparent blocks [eg.: the water] more deeply). The problem is (as expected), ...
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1k 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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335 views

Lighting shadow casting sprites with box2Dlights

I currently have something like this using box2Dlights Ideally, I would like objects casting shadows to be lit, so the object is lit but there is still a shadow cast around it. Right now the object ...
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23 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(); ...
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48 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 ...
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85 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 ...
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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 ...
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75 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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251 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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111 views

box2d ChainShape into curved line

i need to draw a curved line , i searched the internet and found nothing , maybe someone with knowlegde on the subject can help me with a link , i used chain shape and did this , and i don't know ...
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Using Box2D in LibGDX, is there a reason a fixture set to be a sensor would only -sometimes- detect a collision?

I am working on a 2D game in LibGDX. Currently, I am testing interactions between a player's weapon and enemies - in particular, a sword and an enemy monster. The player has a hurtbox and the sword ...
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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?
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Box2D Issues determining the side of collision

I'm trying to determine which side of my object a collision is happening. In all of my searching, I have found 2 different proposed solutions, but each one has a major issue. I'm hoping that someone ...
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35 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 ...
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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) { ...
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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 ...
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31 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, ...
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305 views

Move Box2D body towards mouse click

In a top down game using Box2D, I would like the player's Box2D body to rotate towards the mouse click, and then move to a point on mouse click (move, not teleport). I have worked out the rotation ...
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279 views

Libgdx box2d crashing

im making a game in libgdx which i having a bunch of circle bodies floating around in space and when the player's body crashes into another body, that body deletes and creates two smaller bodies ...
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108 views

What are the steps for creating level in Libgdx with Box2d?

I have been trying to learn game programming for a week, although I have a good knowledge of programming. I don't understand some steps of game design. I'm recently working to clone the iSlash ...
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156 views

libgdx - Box2d debug draw not correct

I have a problem where the bodies in my debug draw does not draw correctly, take a look: As you can see, there is some space between the dynamic body and the ground. I have checked the contact ...
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196 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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139 views

Good collision resolving mechanism

In my game i have plenty of objects that can collide. Literally, most of them can collide with each other.The problem I'm facing is that i can't come up with some good collision resolving way. How can ...
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491 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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114 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 + ...
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555 views

How to render a vertex buffer in DirectX11 C++ (specifically with box2d's b2Draw)

I have all the DirectX11 devices etc setup and working with DirectXTK's SpriteBatch and currently attempting to implement a b2Draw class to draw my box2d physics worlds. I have little idea on how to ...
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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" ...
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51 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 ...
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61 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 ...
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28 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 ...
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455 views

Why does my ball always bounce perpendicular to walls?

I'm using Box2D. I think it's something to do with wall's fixture definition, but when a ball goes toward a wall at a 45 degree angle, I would expect it to bounce off at 135 degrees, but it always ...
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54 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() ...
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69 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) ...
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54 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 ...
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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 ...
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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 ...
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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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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 ...