Tagged Questions

Bullet is a professional, free 3D Game Multiphysics Library that provides state of the art collision detection, soft body and rigid body dynamics.

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6
votes
5answers
1k views

How to save and restore Bullet Physics state?

I'm looking for information on how to save the runtime state of rigid bodies with Bullet Physics. Most of my world consists of static objects, but I have a few dynamic and kinematic objects as well. I ...
1
vote
2answers
950 views

First person camera with Bullet Physics

Before integrating the Bullet Physics, the camera worked fine. But instead of using my own simple struct for transform data, I use rigid body structs provided by the physics library now. There are ...
1
vote
1answer
46 views

How to squash stretch the Bounding box so as to get Good Physics effect

I have Surrounded a game Object with a rectangular Box and applied Physics properties to that Box so that load on the computation gets reduced. But i have a problem, whenever in animation if the Game ...
2
votes
1answer
465 views

Bullet physics: how to make a soft body “static” (kind of)?

I'm fairly new to Bullet and started using it a week ago. I mainly played with rigid bodies and everything works as expected but now that I also need to add soft bodies into my simulation, things got ...
1
vote
1answer
3k views

How to implement bullet physics in libgdx

I am new at game development want to know that how can I implement bullet physics in libgdx. I searched lot of things on Internet but nothing found worthy.
0
votes
2answers
438 views

Distance between two objects?

We are trying to determine the distance (a scalar, double) between two objects' surfaces in Bullet. We are new to the Bullet engine, and we've been looking into the demo projects, but couldn't find ...
3
votes
2answers
461 views

Choosing a correct collisionshape for a voxel engine

I am building a voxel engine on Ogre with bullet as a physics engine. I separated my blocks into chunks to help batch together render calls. At the moment, each chunk's physics is handled by a ...
8
votes
1answer
464 views

How can I extend btCollisionAlgorithm to enable collision with a voxel terrain?

I am using Bullet, and am attempting to make a collision algorithm that generates contact points off of a cube-based terrain along with the appropriate collision response. I also plan to extend this ...
2
votes
0answers
212 views

Inverse Dynamics How to [closed]

I have some motion capture data (kinect) that records all body joints (32fps) and I want to take particular positions (for example when a person moves both of his hands up in the sky in celebration ...
2
votes
1answer
708 views

Bullet Physic: Transform body after adding

I would like to transform a rigidbody after adding it to the btDiscreteDynamicsWorld. When I use the CF_KINEMATIC_OBJECT flag I am able to transform it but it's static (no collision response/gravity). ...
3
votes
2answers
358 views

How to account for speed of the vehicle when shooting shells from it?

I'm developing a simple 3D ship game using libgdx and bullet. When a user taps the mouse I create a new shell object and send it in the direction of the mouse click. However, if the user has tapped ...
2
votes
2answers
1k views

What is the best way to check if there is overlap between player and static, non-collidable items in bullet physic engine

I'd like to add non collidable objects (eg: power ups, items, ...) in a game world using Bullet Physics Engine and to know if there is collision between player and them. Some info : there is a lot ...
0
votes
0answers
558 views

What is the best way to implement collision detection using Bullet physics engine and a track generated from a curve?

I am developing a small racing gam, the track is generated from a curve. As said above, the track is generated, but not infinite. The track of one level could fit with no problem in memory and will ...
3
votes
1answer
334 views

Moving the jBullet collision body to with the player object

I am trying to update the location of the rigid body for a player class, as my player moves around I would like the collision body to also move with the player object (currently represented as a ...
1
vote
1answer
422 views

Rotating a cube using jBullet collisions

How would one go about rotating/flipping a cube with the physics of jBullet? Here is my Draw method for my cube object: public void Draw() { // center point posX, posY, posZ float ...
0
votes
1answer
180 views

jBullet Collision/Physics not working as expected

Below is the code for one of my objects in the game I am creating (yes although this is a cube, I am not making anything remotely like MineCraft), and my issue is I while the cube will display and is ...
1
vote
0answers
364 views

3D game editor with C++ support and Bullet Physics [closed]

I am very new to game development and hence the question. Is there any open-source game editor that uses Bullet Physics engine with C++ code edit support.I have read about blender but it allows python ...
1
vote
0answers
106 views

colliding btRigidBody objects behave strangely when moving slowly

I'm trying to use Bullet Physics in my iOS game. The engine appears to be correctly compiled in that the demos work fine. In my game I have the player's ship and some enemy ships. They're defined as ...
6
votes
1answer
1k views

Bullet Physics - Casting a ray straight down from a rigid body (first person camera)

I've implemented a first person camera using Bullet--it's a rigid body with a capsule shape. I've only been using Bullet for a few days and physics engines are new to me. I use ...
5
votes
1answer
740 views

Bullet Physics implementing custom MotionState class [closed]

I'm trying to make my engine's camera a kinematic rigid body that can collide into other rigid bodies. I've overridden the btMotionState class and implemented setKinematicPos which updates the motion ...
1
vote
1answer
329 views

Offset Forward vector of object based on Rotation

I'm using the Bullet 3D physics engine in a iOS application running openGL ES 1.1 Currently I'm accepting info from the gyroscope to allow the user to "look around" a 3d world that follows a bouncing ...
7
votes
3answers
2k views

Physics not synchronizing correctly over the network when using Bullet

I'm trying to implement a client/server physics system using Bullet however I'm having problems getting things to sync up. I've implemented a custom motion state which reads and writes the transform ...
-1
votes
1answer
537 views

How do I perform collision tests between two 3D oriented bounding boxes?

I want to test two 3D oriented bounding box objects against each other and stop them if there is a hit detected. How can I accomplish this using only the collision detection functions in the Bullet ...
1
vote
1answer
363 views

Roughly how many rigid bodies can I expect to have interacting in Bullet?

On my Phenom II desktop machine (about 3 years old) with 8GB of RAM, it seems that I can only throw around a hundred or two boxes before it starts to go slow. I'm using the built-in DbvtBroadphase. ...
1
vote
1answer
559 views

What algorithms can I use for bullet movement toward the enemy?

I'm developing 2D strategy game. There are weapons that shoot at enemies. From what I've read in this, this, this and this post I think that I need linear algebra, but I don't really understand what ...
2
votes
2answers
906 views

How to load a terrain of connected caves into bullet-phisics engine?

I have a terrain that can not be represented as height map. Say a mountain with caves. I have it in one large .obj file. How do I load such a terrain into bullet-phisics engine? Or I shall generate ...
0
votes
1answer
323 views

What is the best Broadphase Interface for moving spheres?

As of now I am working on optimizing the performance of the physics and collision, and as of now I am having some slowdowns on my other computers from my main. I have well over 3000 btSphereShape ...
0
votes
3answers
340 views

How would I successfully split a vector to increase game performance?

Okay so I have a vector for all of the monsters that are spawned in my game. All of these monsters are in a single vector and are "active" according to what zone they are in relative to the player's ...
6
votes
3answers
1k views

Jitter during wall collisions with Bullet Physics: contact/penetration tolerance?

I use the bullet physics engine through Panda3d. My scene is still very simple, think 'Wolfenstein3d': tile-based, walls are solid cubes. I expect walls to block the player, and I expect the player ...
1
vote
1answer
285 views

3D/perspective Top down shooter bullet issues

I'm developing a top-down shooter with multiple levels (ground for ground units, middle level for buildings, top level for air unity). The problem is the collision. Though I can make the collider ...
3
votes
0answers
398 views

Setting Orientation of Character in Bullet/Ogre [closed]

I've been suffering from an issue regarding the implementation of orienting characters in a game I'm implementing using Ogre3D and Bullet physics. What I have: A Direction Vector that the character ...
8
votes
3answers
3k views

How do I implement a Bullet Physics CollisionObject that represents my cube like terrain?

I've successfully integrated the Bullet Physics library into my entity/component system. Entities can collide with each other. Now I need to enable them to collide with the terrain, which is finite ...
4
votes
2answers
406 views

Intersection points of plane set forming convex hull

Mostly looking for a nudge in the right direction here. Given a set of planes (defined as a normal and distance from origin) that form a convex hull, I would like to find the intersection points that ...
1
vote
2answers
611 views

Bullet physics in python and pygame

I am programming a 2D sidescroller in python and pygame and am having trouble making a bullet go farther than just farther than the player. The bullet travels straight to the ground after i fire it. ...
2
votes
1answer
1k views

Bullet Physics Terrain

Im trying to Load an RGB image (.BMP) into bullet's btHeightfieldTerrainShape Im using a loader that creates a openGL height map, it stores the data in a vector float, but I cant get the ...
7
votes
2answers
4k views

How would I move a character In an RPG with Bullet Physics/Ogre3D?

lately I have been having problems with moving my character in my Ogre3D game. Basically I am moving the character with bullet's RigidBody->translate() function, but when doing so and bumping into ...
2
votes
2answers
764 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 ...
3
votes
1answer
6k views

How do I integrate bullet physics into my game?

I downloaded the release file found here, but I'm just not sure where to start. In my game I have a number of oblongs and a sphere, I want all of these to collide with one another. (They all have ...
2
votes
3answers
2k views

How do I check collision when firing bullet?

I'm currently creating 2D game from top perspective. I'm having problems with bullets. Yes, I currently simulate their movement so user can see them (about 2x ). Moving them with // this is static ...
3
votes
1answer
213 views

How do I run a callback when all objects have stopped moving?

I'm using Bullet and want to take some action once all objects in a dynamic world have reached 0 velocity (or at least a value that's very close). I was trying to iterate over all of them all the ...
5
votes
1answer
3k views

how get collision callback of two specific objects using bullet physics?

I have got problem implementing collision callback into my project. I would like to have detection between two specific objects. I have got normall collision but I want one object to stop or change ...
4
votes
2answers
856 views

Simulating the effects of wind

I am developing a mobile game for Android. It is a 3D jumping game (like ski jump) where wind plays a important role so i need to simulate it. How could I achieve this? The game uses libgdx for ...
8
votes
2answers
3k views

How to disable Y-axis movement in the Bullet physics engine

I want to create an object than only moves along the the X and Z axes, while keeping the Y-axis disabled (it's like movement in 2D, and the object wont fall down). I'm currently using a 6 dof ...
1
vote
1answer
2k views

Detect two specific objects collision with bullet physics

I have got some problem with defining collision between objects in my game using bullet physics. I know that objects are colliding with each other simultaneously and I don't have to do anything more. ...
2
votes
1answer
2k views

Object rotating error in Bullet Physics with OpenGL

I have got some problem in my OpenGL game. I am using bullet physics and I want to achive quite simple effect - I want one object (a sphere) to roll and hit another (box) which will fall down. I have ...
1
vote
1answer
708 views

Change collision body position in Bullet Physics Hello World project

I have got stupid and annoying problem in my app. I am using bullet physics and I've started with hello world example on wiki: http://bulletphysics.org/mediawiki-1.5.8/index.php/Hello_World There is ...
-1
votes
1answer
770 views

Bullet physics with OpenGL

I have got some problem implementing bullet physics into my opengl game. The thing is that it doesn't want to update my translatef value continously but only at the end. The code for bullet looks like ...
0
votes
1answer
644 views

Allegro Game Won't Fire 2D Projectile

To begin with I am developing a PSP application so I have no clue how to debug a PSP application. That doesn't mean I do not know how debug period. Anyway, when I run the game everything runs fine but ...
0
votes
1answer
1k views

android game using bullet and libgdx

i'm developing a android project for school and i'm currently using libgdx for rendering. It performs quite well, but it lacks a 3d physics library. So i searched and found that Bullet physics engine ...
1
vote
3answers
1k views

How do you stop OgreBullet Capsule from falling over?

I've just started implementing bullet into my Ogre project. I followed the install instructions here: http://www.ogre3d.org/tikiwiki/OgreBullet+Tutorial+1 And the rest if the tutorial here: ...