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Questions tagged [box2d]

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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Why is my client's body drifting even after using data from the server, and how do I fix it?

I am trying to use Box2d on nodejs server with libGDX client. What I am trying to apply is authoritative server model so clients are just sending input data to server, server is running simulation and ...
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Box2D LibGDX Cant Create ChainShape Static Body in server side with same position client side

I am trying to create walls in server side which i have already created in client side.This is how i create them in client side: ...
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52 views

Box2D physics are different on server and client

I'm using C# Box2D library for my server and client, they have similar world.step(), iterations and update function. At the same time they have different physics' results, difference is not fixed, it ...
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How to differentiate between colliding objects in Box2D?

I need to differentiate between different points of contact in my racing game. I currently have staticSensors which determine if the car is on the track or not, but I have created a second sensor to ...
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51 views

Server Side Movement Box2D LibGDX

I am trying to implement server-side movement using box2d on libgdx client and planck-js(box2d for javascript) on nodejs server. I am running box2d world on both client and server. Before server i ...
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Libgdx Box2D Triangle Joint behaviour

I have 3 Bodies (Nodes) that are connected in a triangualr shape using DistanceJoint's (Muscle). I'm increasing the length of the bottom Muscle(m). At a given point the "triangle" collapses and all 3 ...
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1answer
47 views

Rendering Tilemap Tile Layer Side by Side for Infinite/Endless Runner Game

I was strugeling this for days how to implement tilemap into libgdx and box2d with infinite/endless scheme. I can load a single map and display everything on screen. But placing 2 or more tilemap side ...
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1answer
40 views

Rotate object around a dynamic object

I'm trying to rotate an object (shield) around another object (player) like this question. My use-case is this: I have players moving around a field. Their respective shield is orbiting in a constant ...
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38 views

Mirror effect on isometric map

I'm trying to make an isometric game with LibGDX and Box2D for collisions. The map and collisions lines are made in Tiled, but when transforming orthogonal coordinates to isometric with this code I ...
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1answer
57 views

LibGDX Box2dlights - Body Shadow Problem

While playing around with the box2dlights with libGDX, I have managed to get it all up and running, but have a problem with the shadow rendering. This is what I currently have atm: With the lighting ...
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2answers
133 views

How do I implement efficient collision avoidance in 100 enemies

I am developing a libgdx game. It is a top down shooter and I am trying to make a good AI. I have tried to implement A* from the AI library from libgdx and it works fine but when i have a lot of ...
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191 views

What is the physics behind a 2D gravity tunnel?

In Portal 2, there is a concept of an "excursion funnel", a beam of light that moves physical objects in a certain direction. Here is a link to a demonstration. I added a simple implementation that ...
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89 views

How to implement a camera for a TiledMap with SDL2 and Box2d?

I m writing a game engine using mainly SDL2 and box2D, I implemented TiledMap class that loads a tmx map and everything is fine it even support animation and objects that later will generate Box2D ...
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1answer
47 views

How to make a motorcycle running on a vertical circular track(loop-da-loop) without falling down due to gravity?

I am currently developing a game, motorcycle type game. Of course, my map is not just made up of simple line or curve. For example: a vertical circular track in the map. i've seen most 2D motorcycle ...
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1answer
83 views

How do I set the gravity of a plane world

As you can see in the image, the character is set to move on a ground plane, however that causes an issue with Box2d's gravitational pull. The player can go sideways, upwards and downwards on the ...
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32 views

box2d get velocity with which the body collide

I need to know with which velocity an object collide to test if the body is destroyed. For example, if a vase collide and getLinearVelocity() > 10 the vase will ...
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2answers
192 views

Top-down conveyor belt with Box2D

I'm trying to code a conveyor belt for a project made with LibGDX and Box2D and I would like to make it like this one from Bomberman Land Touch. As you can see, the entities standing on it should be ...
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1answer
82 views

How can i collide two bodies without filtering(collision filtering)?

I have two bodies with fixtures. One is platform or ground and other is the player itself.I want to collide the player to the platform without bit filtering.How can i do that?I can see the rectangular ...
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1answer
67 views

Does destroying body also destroys the sprite?

Suppose a sprite is attached to a box2d body. And world.destroyBody(b); is getting called then the sprite also get destroyed or it stays there in memory. In my ...
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1answer
151 views

How to set a box2d body to follow a strict path

I'm making an infinite runner type game and I want one of my enemies (when it's created) to swoop down in a sort of U motion where it'll hit the player if they don't react quick enough once the enemy (...
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1answer
227 views

How to remove horizontal black bar at the bottom of the game screen in libgdx?

Here is the screenshot .Here is my Play constructor in Play class.
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1answer
97 views

Tuning physics for a “worms”-like game

I'm using LibGDX and Box2D for my physics but my characters bounce all over the place when moving and if there is a small slope in the terrain they launch off of it. I've tried tweaking settings but ...
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25 views

Box2d detect separated none blocking floor as blocking wall

I'm trying to make my character walk on walls, it all goes okay-ish currently until this situation. Here's an image to show you how the wall looks like https://www.dropbox.com/s/5oyn55qpzljlhnl/...
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228 views

What does linearDamping mean in Box2D?

If I set linearDamping on a body, it's velocity will be decreased slowly, until it stops. The documentation says, that the units are 1/time, which is unclear for me. If the velocity of a body is 10 m/...
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1answer
226 views

Is there a “Least Terrible Method” for sharing Entities over Network?

(Preface: Using C++, Box2D, and built UDP client and server classes that are reasonable efficient for a built-from-scratch game using client-server model.) This question is specifically in regards to ...
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1answer
186 views

Simulate wind affecting a boat using a 2D physics engine like Box2D or SpriteKit?

I'm looking for a way to simulate the forces created by wind and how it affects a boat. In a nutshell: if wind hits a boat (sailing yacht), the bow is aligning with the wind and if the wind is strong ...
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2answers
103 views

Why is the sprite so offset from the physics body?

I'm trying to make a sprite object that has physics, but once the game runs the physics body is drawn at an unknown offset from the sprite, which varies based on the size of the sprites texture. ...
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24 views

LibGdx TouchScreen Movement Logic with Box2D

I'm trying to implement some touch screen controllers to my game and i'm having a few issues :( i don't really understand what's the right way to do it, i can't figure out how to press simultaneously ...
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1answer
39 views

Box2D and OrthographicCamera working incorrectly

I'm trying to build a simple game where TileMapRenderer renders a labyrinth, a ball moves in it and camera follows it. I'm currently having the following bug: For some reason, the game renders the ...
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1answer
69 views

Box2d punch detection

So working on a 2d fighting game and wondering whats a good method for detecting punch collision. Ive got a few questions on how to implement the attack stuff. Im using box2d (and Libgdx) for the ...
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1answer
88 views

Drawing Explosions Respecting Walls

I am creating a tiled game (2D top down) and I created explosions working this way: The blue lines are walls, the white grid is accessable space. The red dot is the origin of the explosion with the ...
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1answer
121 views

Box2D simulation running slower on lower FPS(even when the desired FPS is lower than the actual)

I´m playing around and trying to make myself an easy platformer using the Box2D physics, before that I was not using it and was using my own physics implementation(just simple movements with timestep)....
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1answer
98 views

libgdx draw/animate curve (tentacle) according to Box2D spring wavering

The horizontally placed Box2D spring is made of distantJoint connected bars, and can bend up and down just like airplane wing does when you flight (bigger amplitude ...
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60 views

Why does my rendering not correspond with my Box2D world?

I've decided to try to use the Box2D physics engine in my game, and as I started I'm facing weird behaviour. I've followed a video tutorial where we setup the Box2D world with world gravity, and then ...
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1k views

LIBGDX Let me know how to pause a game

I tried to make pause button. When users click Pause button on a screen, a window came out then, game is frozen until users press continue button in the window . my code is able to pop up window, ...
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2answers
96 views

let me know how to save an integer for game stage level?

I am trying to make a game which there are many stages. For example, If users are done stage 3 of the game, and then turn off the game, they can play the game at stage 3 anytimes. simply, I tried ...
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267 views

libGDX, box2d, Ashley ECS - Collision Detection using Box2d does not work when using components with Ashley ECS

I've just recently learned of Ashley ECS while searching up tutorials on the libGDX wiki and I've been replacing many aspects of my code with the Ashley ECS components which has made life a lot easier,...
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1answer
54 views

Frame independent box2d object movement

In my game I use box2d objects and, as I understand it, you can move them only in two ways, SetLinearVelocity, and ApplyImpulse. I need to move the object 32 pixels in 1 turn. So I make a constant ...
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1answer
419 views

How can I generate vertex data from an SVG?

I am trying out the Phaser game engine, and am interested in making a vector graphics game (simple black and white like Asteroids), but I want to use vector graphics instead of raster PNGs. I was ...
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1answer
283 views

Unable to get Box2dlights to cast shadows

I'm trying to use box2dlights to add lighting to my game and I have everything working except I am unable to have shadows cast with my box2d bodies. I also have collision working using category/...
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1answer
61 views

How to make body flying

I am trying to make a body flying is there any way to change gravity or hold the circle levitating? Here is the code i'm using: ...
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1answer
82 views

Translating ChainShape to world coordinates according to touch drag input

I'm trying to draw a ChainShape according to touch screen coordinates, however the coordinates are slightly off from my touch coordinates. I translate the chain drawn on the screen to world ...
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1answer
63 views

How to destroy multiple bodies

In my game(2D game) I have these fireball objects. When I launch a fireball I want to destroy the object (because I'm not going to use it anymore). I tried deleting the fireballs, but, from what I can ...
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1answer
115 views

crashing generating fire-balls(bullets) with Box2D

I got crash, making fire-balls as bullets. I guess I should not use "private Array fireballs" in player class. it seems like when I add one more fire as index of 1 into the list, the first index ...
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1answer
398 views

LibGDX player movment

I'm working on a project in LibGDX. It's a 2d platform game; you can say it's like Super Mario. So this is how I move my player to the right: ...
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0answers
190 views

How to render texture into box2d objects from Tile Map? Libgdx

I have a problem, when i try to render textures. I read positions of gameObjects, for example coin and create box2d objects circle shape. I have wrote game logic and began make a graphic. But for some ...
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1answer
94 views

Object in Box2d doesn't sit perfectly on top of other object

I have a rectangle in my player class with the following properties ...
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1answer
234 views

Box2D - Constant Movement without ignoring Physics

I am developing a small game with LibGDX and Box2D. I want to move a body at a constant speed, lets say 2 m/s (meters per sec). The body should accelerate to that speed immediately when pressing the ...
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67 views

Fatal error… LIBGDX [duplicate]

I have an issue to launch fireball. when I launch fireball more than 10 swiftly, I got an error. especially, when my character becomes big which means to do redefine body.. I am still not sure why ...
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1answer
257 views

to remove body…in libgdx

I need to fix my destroyed fireball part. so, briefly, you can see there is condition, when fire ball takes 0.5 seconds, it will be destroyed, but the problem is that when I launch fireball more than ...