# Tagged Questions

Software for simulating physics like collisions, forces, mass, joints, motion etc. Examples of physics engines are PhysX, Havok, Bullet and ODE.

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### simple collision detection with box2dweb

im beginner in box2dweb that version of box2d for javascript i wrote simple gravity system and i want to detect the collision between the box and the ground , when the falling box hit the ground ...
163 views

### Storing rigid body collision shapes in local or world coordinates

I'm writing the beginnings of a lightweight 2d rigid body engine (in javascript, as a hobby project), and i'm debating whether to store collision shapes in local or in (updated as needed) world ...
716 views

### Calculating impulse with multiple collision points

In my amateur 2D rigid body physics engine for a game I react on collisions between two bodies with an impulse j (formula 11) as explained here. To calculate this impulse I need one contact point P ...
412 views

### Friction due to gravity in an impulse based physics engine

In my physics engine, I'm using impulses to solve collisions. I'm basing all calculations on these equations: impulse = desired_velocity_change * mass impulse = force * time friction_force <= ...
532 views

### RK4 integration and Continuous Collision Detection

I'm using this method to detect collision between two AABBs. The algorithm is simple, fast and works great. It uses the relative velocity between the two objects to calculate TOI. This works fine with ...
238 views

### Replicating no. of sprites without letting the app to slow down and crash

Is it possible that if I'm making a a simple drag-n-drop game, does making a new sprite via constructor with texture as a parameter makes the game slower and depletes more memory until it crashes or ...
228 views

### Farseer - Difference between Position, GetLocalVector, and GetWorldVector

I have used Box2D extensively, and am used to just calling body.GetPosition(). But Farseer does not have this. Instead it has a property Position, as well as methods GetLocalVector and GetWorldVector. ...
335 views

### Lunar lander: How to calc acceleration in each step

I'm trying to make a lunar lander simulator. I'm going to use a simple Euler integration. AFAIK all I've to calculate is the acceleration in each step, and then I should be able to update velocity and ...
932 views

### Cross Game Engine Compatibility - Multiple Game Engines for one Game

I am new to Game Development, infact getting started with it, so reading as much as I can. I came across game engines. Now atleast I have an idea of what a game engine is, and what it does. In order ...
61 views

### Check every body's position and delete or not (box2d performance specific)

I have a simple game with a platform (a ground that's not infinitely long). During the game I have about 10-30 balls on average that'll fall off the platform. There's gravity so I think they'll keep ...
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### Make fast thing look slow (Box2D)

I'm working on a game that you control a trebuchet to throw balls to the opponent. It's like a game called 'Medieval Siege'. When the trebuchet is swinging its arm, player need to seize the best ...
11k 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 ...
3k views

### Calculation of Inertia Tensors

Bit of a complex and lengthy question that, I'll admit, I don't quite understand very well yet so I will try and explain as best as I can. Short Version: Is there a general c++/physx formula out ...
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### Mobs living in the physics engine

So, yeah. Mobs (including, and indeed especially, the player), physics engine running (cannon.js), first-person perspective, fairly low-poly-count world because I'm targeting WebGL. I'm trying to ...
2k views

### animating roulette ball

I'm trying to achieve something like netent's roulette (which is a great product in my opinion). It's going to be implemented in html5. I wonder which path should I take to have such a great ...
359 views

### Pick and Drop the Ball Testing Without Replicating the Physics Frame

I am making a program that pick, drag, and drop the ball. In real life, once you pick the ball and drop it, whenever the available object is (what you see is what you get) will only be picked and ...
669 views

### How should I invoke a physics engine?

I'm new to writing games. I'm planning to write a 2D battle game which may require an physics engine. Suppose I've written one, but how can I combine it with the main routine of my game? Should I ...
2k views

### Are collision detection always O(n^2)?

Are physics engine able to decrease that complexity, for example by grouping objects who are near each other and check for collisions inside this group instead of against all objects ? (for example, ...
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### Is there any physics engine for XNA? [closed]

I am an XNA game developer. I am now starting to develop physics games on XNA but the problem is that I don't know about any physics engine desinged for XNA. Please if you know about it kindly help me....
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### 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 ...
6k views

### 2D games on Unity and collision detection performance

I'm developing a 2D game for the iOS platform. I have seen a lot of packages on asset store that makes 2D asset creation for unity easier. I have narrowed my selection to just 2, 2d toolkit and ex2d. ...
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### Realistic 2D Planetary Physics Engine?

I'm doing a spaceflight simulator in C++ (using Allegro 5), and I realised that I could just use a physics engine instead of writing my own physics. So that's what I'm doing. Since this is going to ...
164 views

### Moving Sprite With Physics Frame

Normally, a physics frame in pink (see image below) gives the body for detecting hit signal. It usually either falls down or lifts up depending on the gravity orientation. The question is: Is it ...
5k views

### Do any open source JavaScript 3D physics engines exist? [closed]

I'm working on a web-based 3D FPS game using WebGL, HTML5 and JavaScript. It is supposed to target PCs and net-books with WebGL-enabled browsers installed. I'm wondering if there's an existing open ...
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### limiting jump forces to achieve a maximum jump height [duplicate]

A player and the world are modeled using a physics engine. Jumping is modeled by applying a vertical upward force to the player's physics body when the jump button is pressed. The upward force is ...
12k views

### How do I build a 2D physics engine? [closed]

The most advanced games I've made are a 8-ball pool game made with the physics engine Box2dFlashAS3 and a platform game with levels. When I did platform games, I've always wished to know how to make ...
4k views

### Resolving a collision with forces

In my 2D physics engine, I can detect AABB vs AABB collisions, and resolve them by finding the shortest penetration vector and adding it to the AABB's position. Doing this "pushes" the first AABB ...
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### What physics engine support force fields and bodies represented as points?

I need a game engine that supports force fields in 2d or 3d, but suitable for 2d calculations, like bullet. Each body I want to simulate is represented as a set of points. Each point has positive ...
926 views

### Need Guidance Making HTML5 Canvas Game Engine

So I have some free time this winter break and want to build a simple 2d HTML5 canvas game engine. Mostly a physics engine that will dictate the way objects move and interact(collisions, etc). I made ...
1k views

### Sharing data between graphics and physics engine in the game?

I'm writing the game engine that consists of few modules. Two of them are the graphics engine and the physics engine. I wonder if it's a good solution to share data between them? Two ways (sharing ...
551 views

### How to make a stack stable? Need help for an explicit resting contact scheme (2-dimensional)

Previously, I struggle with the sequential impulse-based method I developed. Thanks to jedediah referring me to this paper, I managed to rebuild the codes and implement the simultaneous impulse based ...
307 views

### How to implement physical effect, perspective effect on Android

I'm researching about 2D game for Android to implement an Android Game Project. My project looks nearly like PaperToss. Instance of throwing a page, my game will throw a coin. Suppose that I have a ...
3k views

### Advice needed for a physics engine

I've recently started a project, building a physics engine. I was hoping you could give me some advice related to some documentation and/or best technologies for this. First of all, I've seen that ...
855 views

### Semi Fixed-timestep ported to javascript

In Gaffer's "Fix Your Timestep!" article, the author explains how to free your physics' loop from the paint one. Here is the final code, written in C: double t = 0.0; const double dt = 0.01; double ...
6k views

### 3D open source physics engine suitable for mobile platforms (Android and iOS)

I have made some research and found that bullet, ode, newton and some others are open source physics engines that should be portable enough (but I have never tried to comile/use anyone of them on ...
267 views

### Physics System ignores collision in some rare cases

I've been developing a simple physics engine for my game. since the game physics is very simple I've decided to increase accuracy a little bit. Instead of formal integration methods like fourier or ...
4k views

### What's the difference between a Game Engine and a Physics Engine?

What's the difference between a Game Engine and a Physics Engine? How do they work together, and what's the meeting point between them?
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### Stopping an object after applying an impulse or force?

I'm having a small issue where after applying an impulse or force it is impossible to actually get an object to stop, i.e. a velocity of zero. This code is run every 1 / 60 of a second: void ...
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### How should I handle tiny objects in a physics engine?

I am making a 3D physics engine for throwing dice. Up until now a dice has been 1x1x1m and gravity has been 9.82 m/s^2. This of course does not look realistic as the dice will respond to everything in ...
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### What's the best open source physics engine to use with JOGL? [closed]

I have a past with jbullet but the existing jogl compatible sources and demos seems uncompleted. I have managed to implement it to an extent but still looking for a better documented engine with more ...
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 ...
2k views

### Physics engine that can handle multiple attractors?

I'm putting together a game that will be played mostly with three dimensional gravity. By that I mean multiple planets/stars/moons behaving realistically, and path plotting and path prediction in the ...
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### JiglibX addition to existing project questions

Got a very simple existing project, that basically contains a lot of cubes. Now I am wanting to add a physics system to it and JiglibX seemed like the simplest one with some tutorials out there. My ...
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### Design patterns in Game Physics

In the frames of a number crunching compatible programming language (say.. C++), what would be an elegant solution for adding self collision, external collision and integration step (Euler, etc.) ...
1k views

### What is a “solver” in a physics engine?

I am self-taught and have successfully coded simple collisions of planes, spheres, rays and up until interactive cloth simulations so I do have some basic sense of which part of the physics goes where ...
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### Why does a physics engine produce different results each run through?

There are no random numbers in the engine and everything is calculated the same way. How can it happen differently each time? This is on my own small physics engine that I made earlier that is ...
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### Want to develop my own primitive physics engine, don't know how to start with its high-level architecture. Suggestions? [closed]

Few years ago I tried to make a simple 3D game - billiards. Completed like 50%, stuck with physics. Basically, I only need to calculate balls rolling over flat surface, but it would be nice to make ...
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### Game with static scene and bouncing balls. How to?

How to make a game with a static scene and balls that can bounce on it? What is used for this, generally? Physics engines? Even if this is a simplistic example?