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Questions tagged [bullet-physics]

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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Issue with Bullet3 contact points on triangle edges

I'm trying to build a character controller using Bullet3 with OpenGL. I currently have a kinematic body that uses a Ghost body to get all the manifold contacts. The issue I'm facing is in the ...
Aaron Z's user avatar
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0 answers
34 views

How to move a Rigidbody forward using Bullet Physics

I'm currently developing a character controller for my game framework, and I'm utilizing the Bullet Physics engine for the physics simulation. In the process of adjusting the velocity, I aim to enable ...
Wagner Andreas's user avatar
1 vote
1 answer
72 views

When should I call the physics simulation within the game loop?

I am thinking about where to call the physics simulation. The current situation is that I first update the entities and then the physics immediately before rendering. As you can see in the following ...
Andy's user avatar
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0 votes
2 answers
54 views

How to check if an AABB is colliding or the mesh itself

I have the following problem. I would like to check in bullet whether only the AABB collides or the mesh collider itself. Unfortunately I can't find out how to do this Within the screenshot you can ...
Andy's user avatar
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1 vote
0 answers
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JBullet - Shoving around objects

Sometimes in video games the players can walk up to certain objects for example boxes and barrels and shove them around. How can I recreate this system? What function do I have to use to apply force ...
Nagy Lala's user avatar
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50 views

Bullet physics incorrect rotation with more than one axis

im try to integrate currently bullet into my game framework. But when i try to set the rotation for an rigidbody with more the 1 axis i recive the current result It looks that the rotation is ...
Andy's user avatar
  • 13
1 vote
2 answers
178 views

Bullet Physics Multi-threading Rigid Body transform jittering issues across threads

I've been working on a game using Bullet Physics for C++ as well as SDL for the windowing (with OpenGL) I've recently threaded the game, so that a separate while loop runs the Physics Simulation, ...
jasonmzx's user avatar
0 votes
1 answer
57 views

How does bullet physics filter 4+ contacts in GJK?

If the bullet GJK (Convex vs convex) collision algorithm has more than four penetrating points, then how is it filtering that down to the four it needs? What I've tried Staring at the code, but I get ...
Baer Ran's user avatar
0 votes
1 answer
53 views

Bullet physics linker error

I am trying to build my project in VS, which is a copy of HelloWorld.cpp provided by Bullet. I am getting a list of errors of sort "unresolved external symbol" when I build my project, ...
SigmaKlim's user avatar
0 votes
1 answer
28 views

Maintain constant Y position value for a dynamic body

Something obvious is skipping my mind with Bullet Physics library, so apology in advance: I have a dynamic rigidbody, which I'd like to have its Y (up/down) coordinate to be at constantly at a certain ...
Avi's user avatar
  • 188
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1 answer
281 views

Why does OnTriggerEnter2D/OnCollisionEnter2D work when there is no other collider object opposite?

my bullet: There is a Box collider (checked "is Trigger") It has Rigidbody2D (Gravity = 0, freeze rotation Z) https://i.sstatic.net/ik1IY.jpg I added the "OnTriggerEnter2D" ...
gunza's user avatar
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1 answer
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Raycasting in GameMaker Studio 2 to implement hitscan weapons?

I'm working on a 2D top-down shooter game in GameMaker Studio 2, featuring different weapons and obstacles all around the levels. Since I don't need a high degree of simulation, I'm implementing ...
liggiorgio's user avatar
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1 vote
1 answer
118 views

How to detect all vertices within collision Area?

Using collision detection algorithms such as MPR (Minkowski Portal Refinement), GJK (Gilbert–Johnson–Keerthi distance algorithm), you can calculate the penetration depth in the collision. For 2 mesh ...
Error's user avatar
  • 111
2 votes
1 answer
1k views

Simulation step size in a physics engine

I am trying to integrate a physics engine (Bullet) into my game engine, but I immediately found that I do not know how big should I make the simulation step. I think of 2 options: Use a fixed step ...
Vít Gardoň's user avatar
0 votes
1 answer
978 views

How to move a player on a sphere surface using Ammo.js and Three,js

I am moving a rigidbody (the character) on the surface of a sphere, like what is described here. I am facing the following issue that I am having hard time to solve: After moving the character, it ...
Eturcim's user avatar
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0 answers
111 views

LibGDX program crashing on on StepSimulation call

I am trying to add a Character Controller to a Discrete Dynamics World in Bullet via the LibGDX wrapper and everything seems to work, but when I attempt to update the world via the StepSimulation ...
Calvin Day's user avatar
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0 answers
111 views

How to create soft tires like in `Spintires`?

Here is an screenshot of a deformed tire in the game Spintires. I would like to achieve a similar effect in my game I'm using Bullet as the physics library, if that matters.
Тёма Басов's user avatar
1 vote
1 answer
402 views

PyBullet & OpenGL - Rotations are reversed in OpenGL [closed]

Project description: I am writing a basic game engine to help with my PhD topic on multi-agent learning. I am using PyBullet as the backend physics engine and OpenGL for visual display. I have OpenGL ...
Ed Adcock's user avatar
1 vote
0 answers
101 views

Subtract a circle on a rectangle - OpenGL

I am writing a game using GLFW, GLEW, GLM and Bullet3 in C++. Its a Maze with holes. I am doing the floor with rectangles (wich is 2 GL_TRIANGLES). I want to make some woles (circles), to the ball ...
David Pires's user avatar
-1 votes
1 answer
148 views

Can't get basic example working with Bullet 3 (haxebullet port)

Example of my code: ...
Janis Taranda's user avatar
0 votes
1 answer
152 views

Bullet Physics Invalid Pointer on Free

I'm writing a game engine in C++ with Irrlicht and Bullet Physics. All of my Irrlicht code works perfectly, but upon creating Bullet Physics objects with new, and later freeing them, my program throws ...
lilcutthroat's user avatar
0 votes
1 answer
347 views

Bullet Physics Step Simulation Crash when maxSubSteps is not 0

I am using Bullet physics along with Irrlicht. My program consistently crashes when maxSubSteps is not set to zero when calling ...
lilcutthroat's user avatar
1 vote
0 answers
128 views

Real-time 3D Scene-reconstruction into Physics Engine

I am trying to create a game where the user scans the room using RGBD camera and reconstructs 3D scene. This scene would be integrated into physics engine, after an object recognition algorithm tells ...
AJAY PRATAP SINGH's user avatar
1 vote
0 answers
222 views

Bullet Physics stops detecting collision after a few steps

Let me start off by saying that the usage of Bullet here is slightly unconventional. I'm writing a server emulator for a game, and the server is only keeping track of the triggers, players and enemies....
gie005's user avatar
  • 11
2 votes
1 answer
119 views

Angle between character and mouse, and giving bullets velocity in the correct direction

I've been trying to work for a few days, on a little weapon system where you can aim with your mouse and shoot bullets in the direction you're aiming. This is all in 2D to be clear. Right now, I can ...
Aquaphor's user avatar
0 votes
1 answer
294 views

Soft Body rendering from OBJ model

As part of my master thesis I have to do an softbody simulation. I 'm using Bullet Physics engine. I'm trying to render softbody, create from Meshes, with Shaders in OpenGL but the object doesnt ...
franadam's user avatar
1 vote
0 answers
103 views

Bullet Physics ignore collision from bottom

I'm currently using BulletSharp a wrapper for Bullet physics. I'm using Bullet Physics for a 2D project. Many platform games allow the player to pass through a platform as they jump upwards, and then ...
David Neves's user avatar
1 vote
0 answers
467 views

Bullet physics convex hull center of mass

I am trying to make a convex hull collider for bullet physics. I am using BulletSharp.CompoundShape and BulletSharp.ConvexHullShape. This is model of a chair in unity with rigidbody and convex mesh ...
some rand's user avatar
  • 118
0 votes
1 answer
361 views

Bullet Physics DebugDraw Unexpected Results

I'm integrating Bullet Physics into my project for collision detection and have just gotten some debug draw functionality to work. However, the results are not what I'm expecting. I have tried to draw ...
whitwhoa's user avatar
  • 201
1 vote
0 answers
300 views

Bullet Physics StepSimulation really slow when smaller TriangleMeshShape is inside bigger BoxShape

I observed that bullet physics StepSimulation is very very slow when a rigidbody with a TriangleMeshShape is fully inside a rigidbody with a simple BoxShape. I noticed that when I move the ...
D3d_dev's user avatar
  • 338
2 votes
1 answer
197 views

Should your world map have it's own collision object?

I am attempting to understand collision detection at the moment. I have seen many examples of a simple flat plane with boxes or cubes which move around on the plane and react when the touch each other ...
whitwhoa's user avatar
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0 votes
0 answers
201 views

Solve Constraints with linear factor of 0 in Bullet Physics

In my code I need to set the linear factor for velocity to 0 (sometimes). For example, game->rigidBody->setLinearFactor(btVector3(0, 0, 0)); When this is done,...
Vitulus's user avatar
  • 121
1 vote
0 answers
137 views

btBvhTriangleMeshShape useQuantizedAabbCompression Crash

I use btBvhTriangleMeshShape for static world collision. Generally this works fine, but recently I have encountered situations where the construction of btBvhTriangleMeshShape would crash. In debug ...
rioki's user avatar
  • 2,866
2 votes
0 answers
100 views

Handling strange physics behaviour while sliding between coplanar surfaces

We've got a character setup based around manually resolving collisions, and we're using bullet to do so. Our characters have a kinematic rigidbody to push things around, but their movement and ...
Mick Derks's user avatar
1 vote
1 answer
1k views

Bullet Physics Integration - direct movement of rigid bodies

I'm adding bullet physics to my engine. The physics simulation bits are all working nicely, but one bit I'm struggling with is being able to move objects using their co-ordinates, and then have them ...
Figwig's user avatar
  • 196
3 votes
1 answer
2k views

Integrating Bullet3 into a C++ project - Linking to libraries

I've been following the BulletQuickstart guide and I get as far as generating the vs2010 solution and converting to newer. I've also been following this very good answer from a few years ago and have ...
dlp_dev's user avatar
  • 61
0 votes
1 answer
218 views

bullet raycast vehicle - understanding coordinate system

Bullet world space coordinate system is the same as opengl world coordinate system. I have noticed that raycast vehicle has the following function: ...
Irbis's user avatar
  • 103
1 vote
1 answer
482 views

Detect collision with bullet physics, to make a character controller

I inherited from btCollisionWorld::ContactResultCallback but I really have no idea how to use this virtual function: ...
djofriend's user avatar
0 votes
0 answers
347 views

btRigidBody world transform and scale issue

When I create a collision shape for rigid body (in this case box) I use vertices positions and scale from the opengl matrix, the code looks this way: ...
Irbis's user avatar
  • 103
0 votes
1 answer
163 views

Body inside other body after collision

I'm using bullet to create a 2D topdown game. In my physics proof of concept, I can walk around and push a box. However, if I walk too fast the character goes through the box, instead of colliding ...
Aart Stuurman's user avatar
0 votes
1 answer
66 views

How to deal with standing/walking models?

I'm developing a game using bullet for the physics logic, but rendering using my own isometric algorithm (sprites). I'm currently dealing with the issue of how the physics object of the player would ...
BlueCP's user avatar
  • 25
1 vote
2 answers
815 views

How to access coordinates of objects in bullet physics (libGDX)?

I need to access the x, y and z coordinates of a bullet physics object. I'm assuming this is done via the transform matrix, but I have no idea which values mean what. There doesn't seem to be any ...
BlueCP's user avatar
  • 25
0 votes
1 answer
158 views

Bullet Spray RNG

So I have a Nuclear-Throne like weapon system in my game, and I'm working on bullet spray. Originally, there was equal odds that the bullet sprayed at any angle within the spray range. That felt ...
Houston Webb's user avatar
2 votes
1 answer
912 views

How do I create a HeightField in pybullet?

I've been looking for documentation on PyBullet, the python implementation of Bullet, but I haven't yet found a way to implement the btHeightfieldTerrainShape collision object, which I need to make, ...
C1ff's user avatar
  • 61
0 votes
1 answer
199 views

Bullet Physics too many rigid bodies framerate drops

I have a question regarding rigid bodies in bullet physics. At the moment I have low-poly asteroids, which I create a convex Hull shape. Then I add a motion state and give them a linear velocity. ...
Anima's user avatar
  • 155
0 votes
1 answer
43 views

Having trouble with btGeometryUtil::isPointInsidePlanes

I'm in the process of parsing a BSP file to create btConvexHullShape objects for each brush. I've seen a few examples of how to do this on Github and they all use the getVerticesFromPlaneEquations ...
Tom Sweeney's user avatar
1 vote
0 answers
336 views

Handling character with world object collision in libgdx and bullet

I am using libgdx and bullet for my 3d mmo project. I have been able to detect collisions using a collision world with collision objects. This was working fine for things like detecting players ...
jgelderloos's user avatar
0 votes
1 answer
99 views

Eliminate 0.25 unit 'force fields' around Bullet Physics soft bodies

When I create soft body assemblies in Bullet Physics they will fall under gravity and then float about 0.25 units above a ground plane rigid body, and other rigid bodies all appear to push and ...
Lucas Walter's user avatar
1 vote
1 answer
1k views

Get GameObject which instantiated me in Unity

How can I get a GameObject from another GameObject? If I know, that the GameObject I want to get instantiated(using function Instantite()) the GameObject from which I want to get it. If there is no ...
hellomates's user avatar
1 vote
1 answer
10k views

Rifle bullets/projectiles in Unity, raycasting or rigidbody?

Hello again gamedevers :) I'm trying to create a fairly simple FPS shooter game. Im using a Rigidbody FPS Controller prefab from ...
Big T Larrity's user avatar