Relating to the motion of objects through space and time. Including concepts such as acceleration (thrust and gravity), mass, collision response, friction and more.

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New Vector Calculation for Elastic Collision of Circle and Fixed Rectangle

I am writing a fairly simple breakout-style game for Android phones. I have successfully detected the collisions between the ball(s) and bricks. The problem that I am having is in calculating the new ...
29
votes
6answers
9k views

About floating point precision and why do we still use it

Floating point has always been troublesome for precision on large worlds. This article explains behind-the-scenes and offers the obvious alternative - fixed point numbers. Some facts are really ...
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3answers
620 views

Solids as high viscocity Liquids

A friend of mine and I were discussing different idea for allow materials in a world to be destroyed in a very piecemeal fashion and he proposed the idea of representing solids as very viscious ...
4
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1answer
819 views

Problem with box2d at beggining

I have problem with simple box2d physics: I have two bodies : 1 - static box , 2 - dynamic box. I only want to this dynamic box fall on this static, and lay. But now it looks like that at end , ...
8
votes
4answers
657 views

How do I make a vehicle move to a point and stop without overshooting or oscillating?

Ok so consider we have a vehicle like the one I described in my answer to this question, with a 2D position, velocity, angular velocity, and drag/friction. It can accelerate and break by a variable ...
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3answers
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Optimizing Bullet and ODE Physics on consoles and mobile phones

I'd like to use either Bullet or ODE on low powered devices (mobile and consoles), but the frame rates are below the acceptable 25-30fps for simulations. I've found that one articulated body by ...
11
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3answers
2k views

Pretty open source game/rendering engine? [closed]

It might be outside the domain of open source (as there isn't much in the way of open source games that would want/need to implement all these) but is there an existing open source game or rendering ...
66
votes
5answers
31k views

Good 2D Platformer Physics [closed]

I have a basic character controller set up for a 2D platformer with Box2D, and I'm starting to tweak it to try to make it feel good. Physics engines have a lot of knobs to tweak, and it's not clear to ...
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vote
5answers
9k views

which is the best physics engine for flash as3? [closed]

i am a game programmer and i use actionscript to do all my collision checking, boundary checking etc...but recently i noticed there are things called "physics engines" that help me concentrate more on ...
8
votes
3answers
324 views

Connecting physics simulations with different coordinate-systems

I want objects to move between two physics simulations through a "window" and collide with those from both simulations in case they intersect the window plane. The coordinate systems of the ...
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votes
2answers
442 views

two balls stick together in a pool game? [closed]

when multiple collisions occur between balls..sometimes they stick together..mostly in cases of either of the balls having high velocity..can somebody explain pls
12
votes
4answers
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How do I calculate rotation caused by bounce friction?

Following on from my previous question: I have the ball quite realistically bouncing from surfaces it hits. Now I'd like to make it spin from the friction of the hit. Showing this is simple enough: I ...
6
votes
2answers
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How to calculate the exit speed of ball bouncing off a solid surface

Hey all, I am working on a simple game to include some rigid body dynamics, involving placing (moving & rotating) some springs to bounce a falling ball into a target area. My problem is correctly ...
2
votes
4answers
959 views

Good way to implement really basic physics in Flash?

I'm making a somewhat simple side-scroller in Flash. The way I'm currently doing the really basic physics(you don't fall through floors/can't walk through walls) is that I have a big symbol of all the ...
-1
votes
4answers
985 views

Open Dynamics Engine

Has anybody used this library before? What were your experiences? Pros/Cons?
11
votes
4answers
5k views

Vehicle physics with skid

How would I go about creating vehicle physics for a car that can loose traction? I want it to seem like the driver has a flat foot, so when you press the gas, they cars driving (rear) wheels loose ...
7
votes
6answers
640 views

Physics library internals

I've seen box2d and bullet ports into javascript, but neither of them attracted me particularly, except by source code. It all seemed, after all, quite simple once I looked inside them. But what are ...
198
votes
10answers
56k views

When should I use a fixed or variable time step?

Should a game loop be based on fixed or variable time steps? Is one always superior, or does the right choice vary by game? Variable time step Physics updates are passed a "time elapsed since last ...
9
votes
2answers
7k views

Using The Box2D Polygon “Set()” function?

I'm using the Box2D physics engine. And there's a type of shape for box2D called b2PolygonShape. In this class, you can create polygons. There is also a Set() function that takes an array of points ...
7
votes
3answers
5k views

Box2D Check If Point Intersects a Body

Is there a way to check if a point is intersecting a body? For example, lets say there's a body in the world at a position of (100,100). Is there a way to check if a point at (100,100) intersects ...
10
votes
3answers
5k views

Box2D Get Bounding Box of a Body

In Box2D, I was curious if it's possible to get a bounding box of a body already created in the world. So basically, the Body is created, it's interacting with the world and such. And I needed that ...
2
votes
3answers
1k views

XNA: Deforming/Destroying a model

I want to be able to destroy and deform a car in-game. For example, I want two cars to crash and a) break the meshes apart (probably applying force to fly them apart) and b) deform the mesh (like ...
8
votes
3answers
1k views

How do I calculate the forces exerted by a taut wire wrapping 2D objects?

Assume I have a physics primitive I am going to call a "wire", wrapped around a 2D environment (as described in this question). Here's an illustration of what that might look like: In the example ...
30
votes
6answers
5k views

Implementing a wrapping wire (like the Worms Ninja Rope) in a 2D physics engine

I've been trying out some rope-physics recently, and I've found that the "standard" solution - making a rope from a series of objects strung together with springs or joints - is unsatisfying. ...
6
votes
1answer
355 views

Changing orientation by applying torques

Suppose you've got an object floating freely in space. You have a vector you want this object to point towards, and a vector representing the direction it's currently facing. From these two, you can ...