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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Game runs at different speeds in Chrome versus Firefox

I am using Box2D for physics on the server side. Player position is updated on the server, so there is nothing the client can do except give input. But running game in Chrome only, the player moves ...
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1answer
214 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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310 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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2answers
505 views

Strange LibGdx box2d body.ApplyLinearImpulse(); behavior

I have been working on this game NinjaThief and when I apply linear impulse to player body it just keeps on moving. Some of the functions are still unfinished so it looks a bit messy. Here is my code:...
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1answer
1k 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 ...
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102 views

How can I smoothly rotate a joint to an angle? [duplicate]

I would like to set the speed of my Box2D revolute joint on every update such that it rotates to a desired angle and stops. It should ramp down as its angle approaches the desired angle. My first ...
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0answers
152 views

How to make the Angry Birds “shot arch” dotted line? [duplicate]

I am making a game that includes 2D projectile flight paths like that of Angry Birds. Angry Birds employs the notion that a previous shot is shown with a dotted line "arch" showing the player where ...
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793 views

box2d reset position of falling object not behaving properly [closed]

I have been playing with box2d in libgdx and have made a falling ball. Once the ball lands on the ground I want to be able to reset it to the top with the space-bar key I have done this: ...
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2answers
1k 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
6k views

Libgdx explain steps for beginner to create and use image as a box2d body [closed]

I am basically from corona background and new to LibGdx , familiar with stage and actor from scene2D. Now wants to use physics body from box2d in the game besides using actor from scene2D. But I ...
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1answer
3k views

Maintaining velocity of free fall body using Box2D in libGDX

I want to maintain the speed of a free-falling Box2D body using LibGDX. I'd like the vertical velocity increase with the level. I've applied a linear impulse and velocity actually increases like this: ...
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1answer
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How to make a character in a Box2D world jump faster?

I have a question about using Box2D to simulate a physics-platformer. I manage to make the character move to the right and left, and jumping as well. However, jumping seems extremely slow when ...
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4answers
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Should I used Box2D for a Flash platformer or use something for gaming like Fixel or Flashpunk?

I'm trying to make a platformer with Flash/AS3 and have been looking for something to help with some of the collision etc. I've look at a few engines and Box2D/WCK seems the most sophisticated. Do I ...
2
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2answers
715 views

2D AI Engines/ Resources?

i'm wondering if there's any 2D AI source code or engines out there. I'm inspired by the Euphoria engine, and want to use whatever is already out there to make something like it in 2D, where the ...
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2answers
973 views

Should I compute impact damage with energy or momentum?

My game uses physics (Box2D in particular). Just about every object in the game can be destroyed, and the primary method of combat is by slamming objects into one another at high speed. It makes ...
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1answer
1k views

LibGDX Box2DLights shadow offset problem on bodies

Hello I just started to use LibGDX, and it's awesome. I looked at the Box2DLights library, and started to learn how the lighting work here. I got something up: (source: gyazo.com) As you can see, ...
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2answers
5k views

LibGdx sprite rotation vs Box2D physics rotation problem

LibGdx sprite rotation vs Box2D physics rotation problem Tearing my hair out on this one. I am an experienced software developer, but very new to LibGdx and Box2D development. I am writing a game ...
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1answer
117 views

Box2D relations

As far as I know, the unit in Box2D is meters. When I use Box2D in Processing with JBox2D, I set the "world size" as the window size specified in the setup(). Now I'm wondering if there is any ...
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1answer
3k views

Speed of bodies in Box2D and libgdx

I want to move my bodies at higher speeds, but they have a top speed. I have an Ortoghraphic camera defined at 800x480. My world doesnt have gravity. I apply an impulse of 1000,and a force of 1000 ...
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3answers
6k views

Clean way to detect collision of object with box2d

I have been looking into box2d (in java with libgdx) lately and have been trying to create my own custom bounce effect (I increase the Restitution after the first ...
2
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1answer
61 views

Turn a spaceship at a max rate

Using the following to turn a spaceship in a C# FarseerPhysics simulation. var turnPower = _Inventory.EngineTurnPower * time; body.ApplyTorque(turnPower); If ...
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1answer
554 views

Why do my Box2D bodies not fall, even though world.step is called?

I have SFML set up with a Box2D world that has gravity, but my bodies won't move. I std::cout'ed the position of the body in the game loop, but it's always at <...
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1answer
415 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 ...
2
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1answer
93 views

How to restrict jumping to a single jump?

I'm making a VolleyBall game in HTML5 with PandaJs GameEngine and plugin is used physics and Box2D. The problem is that players can jump, but they can jump over the net with multiple jumps. I have ...
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3answers
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How can I get the force of a collision in Love2D?

Is it possible to get the force of a collision between two objects in Love2D/Box2D? If so, how?
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1answer
1k views

Box2D: Asteroids-Like Spaceship Physics

I'm new to Box2D (JavaScript) (and the world of physics/mathematics) so I'm having a hard time working out the methods I need to use to make a spaceship act like it does in the classic arcade game ...
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1answer
1k views

Why might a body suddenly stop while moving on continue platform?

I have a 32x32 sprite and I make some to be platform like this ...
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2answers
277 views

Moving 2d camera in the y direction

I'm developing a simple game for the iphone and am struggling to work out the best way for the camera to follow the main character. The following picture hightlights the three main components: There ...
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2answers
1k views

Box2d debug render

How can I render the body and joints in the physics world? During research I found the class called Box2dDebugRenderer. But when I put it into use it was full of errors. I do not found some classed in ...
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2answers
1k views

Physics in carrom like game using cocos2d + Box2D

I am working on carrom like game using cocos2d + Box2D. I set world gravity(0,0), want gravity in z-axis. I set following values for coin and striker body: Coin body (circle with radius - 15/...
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1answer
3k views

Bodies are colliding but refusing to rotate in Box2D

I'm running box2d in C++ and hooking it up to C# via p/invoke. All physics stuff occurs in C++. My problem is that bodes know when they are colliding and do so with great precision. However if I have ...
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1answer
334 views

How detect collision between two bodies?

I'm using LibGDX with Box2D and I've two bodies. I just need to know that they have collided. So, I just need a boolean output. Example: ...
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2answers
581 views

Jump-through & drop-down platform

I'm creating platforms in my game where the player can: 1) Jump through them from the bottom and land on top of them 2) While on top of them, drop down through them I've been able to get #2 working ...
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2answers
644 views

Box2DLights in libGDX - Bad quality of the light gradient on Android

I am facing a problem while porting one of my libGDX project from desktop to Android : My game uses Box2DLights. While the light effect look very fancy on the desktop version of the game, it looks ...
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2answers
374 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 ...
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2answers
3k views

How can I attach a libGDX actor to a box2D body?

I'm creating game like hill climb racing. I created my car with the help of shapes and joints but I don't know how to attach graphics to it. I used actors and sprites before for the sake of learning, ...
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3answers
2k 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 ...
2
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1answer
772 views

Using Box2D / Physics with Tiles?

Here is my issue. I currently have Box2D setup and working. But, it works with my Entity system. So I can create static objects and dynamic moving ones, and they simulate fine. However, my world is ...
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1answer
5k views

coloring box2d body in LibGDX

I want to color polygon of box2d in LibGDX. Found below useful class for that. http://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/graphics/glutils/ShapeRenderer.html But, it is not ...
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1answer
212 views

Efficiently storing game states history for physics?

I would like to store the history of a box2d simulation. Currently I can't find any built-in mechanism for that. I need to store the states of all non static objects in the last second, mainly for ...
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2answers
7k views

Applying Forces to Box2D Bodies

In full disclosure, I am VERY new to box2D let alone the Java version of it. I have a box (here of type Hero) that I am trying to move. I did this by trying to apply a force as follows... ...
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1answer
3k views

Specifying force and angle in ApplyImpulse in box2d

I need to apply an impulse on a object with a particular force and at a particular angle in Box2d. If I am right the syntax would be the following: body.GetBody().ApplyImpulse(new b2Vec2(direction, ...
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1answer
1k views

Pathfinding and BSP with Box2D

I'm looking into implementing AI in my 2D side-scrolling platformer, and I'm looking into using algorithms such as A*. For many kinds of pathfinding, we need some sort of grid or systems of nodes or ...
2
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1answer
1k views

AndEngine Physics: Shape rotating but not updating physics effects

I was looking at PhysicsExample from AndEngine's Examples. I made the following change that I added a vertical line shape and created a fixture for it. Then I registered a rotation modifier for that ...
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1answer
1k views

Box2D + Love2D (Lua) - Assertion fail with polygon meshes

When I try to create a triangle collider for my game it sometimes leads to an assertion fail. I use the physics engine that comes with love2d (Box2D). That's the error message that appears when the ...
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2answers
856 views

Efficient Bullet Firing Class

I've been struggling with this for a while. I have been trying to create a bullet pool class for a game I have made that doesn't cause a significant fps drop. I have tried creating a bullet pool ...
2
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1answer
742 views

Box2D/Farseer - Moving fixtures on a Static Body

I am attempting to create a Pool of Fixtures, in order to reduce memory consumption. My problem is that when I attempt to return a Fixture to the Pool and re-assign its position on the Parent Body, ...
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2answers
2k views

Using box2d DrawDebugData with multi layer scene?

In my Game, a Scene is composed by several layers. Each layer has different camera transformations. This way I can have a layer at z=3 (GUI), z=2 (Monsters), z=1 (scrolling background), and this 3 ...
2
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1answer
52 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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2answers
357 views

Merge two or more PolygonShapes

This is a simple sprite rock and on my LibGDX game I would create a PolygonShape like the following image Like you see, I need 22 vertices and Box2D doesn't allow me create a PolygonShape with ...

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