Tagged Questions

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

learn more… | top users | synonyms

0
votes
0answers
15 views

Use Box2D for collision only?

Is it a good idea to create Box2D bodies in the game and shapes for that bodies for not doing physical simulation but moving them manually with setting velocity or position in each frame and getting ...
0
votes
0answers
38 views

How can I fix my implementation of one way platforms? [on hold]

I'm trying to figure this out for my doodle jump clone on andengine. I found this post http://stackoverflow.com/questions/12267562/one-way-walls-in-andengine which helped me a lot. I've implemented ...
0
votes
0answers
35 views

Make a smooth curved terrain from chain shape [on hold]

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 ...
0
votes
1answer
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 ...
0
votes
0answers
19 views

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 ...
0
votes
0answers
42 views

What is the best framework for 2d side scrolling game (with physics support like box2d) [closed]

I have previous knowledge in Libgdx since I developed a game in it. So the learning curve will be a bit less. Still, if there is a better platform for side scroller (preferably Java), then I would ...
0
votes
0answers
48 views

simple but powerful 2D physics engine c++ [closed]

The two big 2D physics engines out there are Box2D and Chipmunk, which can create a lot of complicated collisions. but the only collisions I need to do are grid-aligned AABB collisions, so I just ...
0
votes
1answer
10 views

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 ...
0
votes
1answer
36 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 ...
0
votes
0answers
18 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 ...
1
vote
1answer
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 ...
0
votes
0answers
14 views

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 ...
0
votes
1answer
24 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 ...
0
votes
1answer
72 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 ...
1
vote
0answers
41 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 ...
2
votes
0answers
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 ...
0
votes
1answer
47 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 ...
0
votes
1answer
11 views

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 ...
0
votes
1answer
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 ...
3
votes
2answers
153 views

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 ...
0
votes
1answer
42 views

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 ...
0
votes
0answers
43 views

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 ...
1
vote
0answers
30 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 ...
3
votes
0answers
166 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 ...
0
votes
1answer
25 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 ...
0
votes
0answers
39 views

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 = ...
0
votes
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 ...
0
votes
0answers
25 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; ...
0
votes
1answer
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 ...
0
votes
0answers
15 views

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 ...
0
votes
0answers
27 views

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 ...
1
vote
1answer
25 views

Is there a Box2d b2World::ShiftOrigin function in Libgdx?

Is there an equivalent Box2d b2World::ShiftOrigin function in Libgdx? I can't seem to find it.
1
vote
1answer
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 ...
0
votes
1answer
46 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 ...
0
votes
0answers
91 views

How can I make a swinging rope?

Base question: How can I make a swinging rope in box2d? Context: The idea is to have a rope where the player can grab it, swing a little bit to get more "momentum" and reach the next platform. Like ...
-1
votes
1answer
100 views

Box2D platformer: Why does horizontal movement stop jumping?

I'm writing my sBox2D game character's movement code, but my implementation of jumping is failing: When I press the Jump key, the character jumps OK. However, when I press jump and another key (like ...
0
votes
0answers
53 views

Client-server architecture with box2d

I am running a client-server architecture with an authoritative server running box2d and the client running box2d as well. If gravity is set to 0, is there any point to linear interpolation and ...
0
votes
1answer
50 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 ...
1
vote
2answers
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 ...
0
votes
1answer
52 views

How to move a body from one world to another?

I have a Box2D world for each level in my game. When a level is completed, I want the player to be removed from the completed level's world and added to the next level's world. How do I do this?
2
votes
3answers
93 views

Box2d bodies that are really close together, are getting “stuck”

I'm using a tiled tmx map, and I created a class that adds bodies to each tile within a certain layer. This has been working great so far except for when a character or an enemy moves around on the ...
0
votes
0answers
25 views

Speed seems random with constant impulse

I'm shooting an object from the top vertex of a triangle using Box2dWeb. The issue I'm having is that the projectile speed seems to be fairly random, even with applyimpulse set to a constant. The ...
0
votes
0answers
21 views

Box2D.js b2ChainShape

I'm using box2d.js (asm.js ported) and need to create a b2ChainShape. var bodyDef = new Box2D.b2BodyDef(); var fixDef = new Box2D.b2FixtureDef(); bodyDef.set_type(Box2D.b2_staticBody); var chain = ...
0
votes
0answers
98 views

Libgdx/Box2D PolygonShape has no position… well, what now?

As my prototype works perfectly fine I want to advance to more fun areas of the project and add a more complex player-character body. So for Box2D I figured I'd need multiple fixtures, like one for ...
0
votes
1answer
60 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 ...
0
votes
0answers
48 views

Drawing a object with Box2D and HTML5 canvas on current mouse position

I'm attempting to create a air hockey type game with HTML5 canvas and JavaScript, using Box2dWeb for the physics calculation. I need a way to draw the puck at the current mouse x and y position every ...
1
vote
1answer
183 views

Box2D body rotation with setTransform

I' having a problem rotating a body with setTransform(), The body has multiple sensors that should rotate with the player. The rotation works but it rotates around the bodys local 0,0 position instead ...
0
votes
1answer
116 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 ...
0
votes
1answer
109 views

Making Player Jump

I have been editing a piece of code and I have already implemented gravity so I would like to know how i could make the player jump when the screen is touched. I would like the player bucket to jump. ...
0
votes
1answer
177 views

Ball bouncing with box2d in libgdx

I just started using Box2d and libgdx. I followed this tutorial, https://github.com/libgdx/libgdx/wiki/Box2d And a ball would bounce if I run the following code I took from the tutorial. // ...omit ...