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

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C# Monogame & Farseer Physics: Collisions

I am a begginer. I am using Monogame and Farseer Physics Library in C#. (latest versions) In my game, whenever my ball (circle) hits the corner of a rectangle, (or even another circle), it is ...
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517 views

Communication between Box2D and libGDX Stage (Scene2D) running in separate threads

I'm making a physics based 2D game using libGDX and Box2D. I want to move the execution of the simulation out of render thread. I use immutable messages and the BlockingQueue to pass the information ...
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22 views

Box2d for large game? [on hold]

I am considering developing a terraria clone for testing purposes and also as a challenge. The physics engine has always been tough for me to smooth out so I am considering using Box2d. My concern is ...
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Box2d - body size or spatial distribution matters for better simulation?

Box2D better works for limited sizes: Box2D works with floating point numbers and tolerances have to be used to make Box2D perform well. These tolerances have been tuned to work well with ...
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906 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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72 views

Explain the difference between extrapolation and interpolation

http://www.unagames.com/blog/daniele/2010/06/fixed-time-step-implementation-box2d here there are two algorithms of smoothing in case of fixed time step physics simulation. I don't understand the ...
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How do I implement one-way platforms in AndEngine and Box2D? [closed]

I'm trying to figure out one-way platforms for my doodle jump clone on AndEngine. This post helped me a lot. I've implemented similar code on my own. Platforms should be solid only when my player's ...
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33 views

Box2D pixel to meter conversion

I have a game that was written in pixels and now I want to change it to meters like(box2D do). How I need to do that. I have wached a lot of tutorials and all they have some SCALING FACTOR but when I ...
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Should I use Box2D for collision-detection only (not simulating physics)? [on hold]

I'm using Box2D only to check collisions and for no physical simulation. I create bodies (and shapes for them) and use my own code to move them, by setting their velocities and positions every frame. ...
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201 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 polygon skin

In manual is see: Polygons inherit a radius from b2Shape. The radius creates a skin around the polygon. The skin is used in stacking scenarios to keep polygons slightly separated. This allows ...
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61 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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127 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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189 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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37 views

Make a smooth curved terrain from chain shape [closed]

what have i tried: Vector2[] vs = new Vector2[6]; vs[0] = (new Vector2(-50, 7.3f)); vs[1] = (new Vector2(-18, 7.3f)); vs[2] = (new Vector2(-10, 2)); vs[3] = (new Vector2(-5, 4)); vs[4] = (new ...
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122 views

Physics don't apply on a unique body AndEngine

I am developing a game in AndEngine. So far I managed to create everything I wanted for my sprite that was connected to a BoxBody. I was rotating it, moving it, everything was great. I wanted my ...
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23 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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Change a vertices and display corner of a polygon

I'm currently building a level editor for my game and i'm having some trouble on how to change vertices of a polygon. Basicly i searched the web trying to figure out how to update the vertices of a ...
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722 views

AndEngine; Box2D - high speed body overlapping, prismatic joints

I'm trying to make good suspension for my car game, but I'm getting nervous of some problems with it. At the beginning, I've tried to make it out of one prismatic joint/revolute joint per one wheel ...
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Box2dWeb: must fixtures be destroyed explicitly when destroying the body?

I use b2WorldObj.DestroyBody(bodyObj) to destroy the body when it is not needed anymore. The body has one fixture attached to it. Do I need to destroy the fixture before destroying the body? or ...
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1answer
64 views

Creating a Player object in a physics engine

I have a working physics environment using Farseer - but how do I create a player object that can walk around? My current attempt involves applying forces to a rectangular body whenever keys are ...
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38 views

Throwing a bomb LibGDX Box2D

I am trying to create game where somenone throw a bomb. I am wondering how I can have an bomb react in a way that is represented by the following picture : Is there are any tools in Box2D that can ...
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29 views

web based networked game physics efficiency

I am writing a web based game, using websockets. its pretty simple, two players shooting at each other with bullets that have acceleration from a starting point at an angle. The client side ...
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22 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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29 views

How to make an object in box2d have constant velocity even after collision? [duplicate]

I have iOS game where I have a bouncing character. Everything is being handled by box2d. The problem is when the character hits a wall of another character it's velocity changes, but I don't want ...
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Move body LibGDX Box2D

Hello I have a body and I want to move it. When I press the mouse button my body should move at that position (on the const speed)on the screen. I have override two methods(x1, y1 - point where my ...
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56 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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26 views

Box2D pixels to meters , LibGDX

I am confused . what shall I set the orthographic camera viewport in libGDX when I use box2d , in one tutorial I saw that he divided his viewport numbers to 32 because 1meter =32 pixel , but I think ...
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183 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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74 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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52 views

Box2d C++ x velocity slowing for no apparent reason

I'm making a 2d platformer in C++, using Box2d for physics and sfml for rendering, I want the player character to move with a constant velocity in the x direction, and to jump when the spacebar is ...
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42 views

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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25 views

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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48 views

Box2D Body creation causing performance issues

I have at max 10 dynamic bodies in my world at any time. they are created at random and fired up from below they screen. when a new body is being created, the fps falls from 59 - 61 to about 35- 40 ...
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80 views

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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47 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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Why is Euler integration sometimes preferred over RK4 even if RK4 is more accurate? [closed]

Some high quality engines such as Box2d uses the Simplistic Euler integrator instead for RK4 when Eumplectic Euler commits a global error of the order of Δt whereas, RK4 has Δtˆ4 error? RK4 is not ...
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Box2D recommended step, velocity and position iterations

Here in this article there is a nice explanation that velocity iterations and position iterations settings affect the way bodies will react when they collide, and step affects on speed and how gravity ...
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Box2D shape/fixture position vs. body position

I load my rectangular shapes from a simple Tiled level into libGDX and want to create a physics world out of it via Box2D and attach sprite assets for rendering. I get the tiled object layer and ...
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How to create Elastic rope / Rubber band in box2d?

I am trying to create the rubber band type or elastic rope. i ant to do something like bellow link. http://heyalda.com/smash-turtle/ Thanks,
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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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62 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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176 views

How do I handle rope physics with fixed ends and a sliding weight?

I've been interested in rope physics recently—I've successfully implemented a simple Verlet rope with moveable ends. Now I am trying something a little different: I want to start by recreating the ...
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1answer
26 views

Get speed from vector using box2d and javascript

I need to find the speed of an object in a game. The game is made in HTML5 with jquery and jquery.box2d. For this I can use these methods: GetLinearVelocity().x; GetLinearVelocity().y; I'm then ...
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libGDX fixed object and camera do movement

I develop game to andorid and there is moving object with arrows - simple movement like in RPG games. I did: camera.position.x = PIXELS_PER_METER*man.body.getPosition().x; camera.position.y = ...
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122 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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28 views

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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73 views

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 ...