# Tagged Questions

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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### Resources of realistic water simulation?

I want to study water simulation, with a a demo with source code which using physically-based methods(Eulerian approaches or Lagrangian approaches). How can I get some examples?
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### How could I constrain player movement to the surface of a 3D object using Unity?

I'm trying to create an effect similar to that of Mario Galaxy or Geometry Wars 3 where as the player walks around the "planet" gravity seems to adjust and they don't fall off the edge of the object ...
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### Powder games: how do they work?

I recently found these two gems: http://powdertoy.co.uk/ http://dan-ball.jp/en/javagame/dust/ My question is: How are the physics with so many elements efficiently handled? Am I just severely ...
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### Pathfinding on a uneven planetary surface

My question is what would be the best approach to pathfinding on an uneven planetary surface? Background Information I have created a planet from displacement mapping 6 sphere projected planes. ...
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### Ball Physics : Smoothing the final bounces as the ball comes to rest

I've come against another issue in my little bouncing ball game. My ball is bouncing around fine except for the last moments when it is about to come to rest. The movement of the ball is smooth for ...
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### Physics engine recommendation which can simulate pool game correctly? [closed]

I'm making a pool-game like game. This game requires correct (or very accurate) reflective bounces. I tried Box2D and Bullet Physics, but they both have this problem. If there is a wall on top of ...
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### 2D game collision response: SAT & minimum displacement along a given axis?

I'm trying to implement a collision system in a 2D game I'm making. The separating axis theorem (as described by metanet's collision tutorial) seems like an efficient and robust way of handling ...
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### Animated examples of different interpolations formulas: any link? [closed]

I remember having spotted a link to a huge page with different equations to non linear interpolation curves, for example if you want to stop a car smoothly, etc. Those can sometime be useful to ...
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### What is the difference between an impulse and a force related to a physics engine?

What is the difference between an application of an impulse and an application of a force in relation to a physics engine?
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### Is there an algorithm for a pool game?

I am looking for algorithm to calculate direction and speed of balls in a pool game. I am sure there has to be some type of open source code for this since pool games are some of the oldest computer ...
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### 2D platformers: why make the physics dependent on the framerate?

"Super Meat Boy" is a difficult platformer that recently came out for PC, requiring exceptional control and pixel-perfect jumping. The physics code in the game is dependent on the framerate, which is ...
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### How do I simulate a doppler effect in a game?

I am trying to simulate the doppler effect in a game (a car racing game). I am not using a specific sound library that simulate the effect, I only have a callback function where I mix the data. I ...
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### Implementing a homing missile [duplicate]

I'm having some trouble implementing a homing missile that satisfies what I'm looking for. I have already tried the Seeking and Arrival behaviours described in this link, but none of them were what I ...
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### Separating physics and game logic from UI code

I'm working on a simple block-based puzzle game. The game play consists pretty much of moving blocks around in the game area, so it's a trivial physics simulation. My implementation, however, is in ...
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### Creating Rope Physics for Unity [closed]

I want to create a bungee jumping-like game in Unity and therefore I need a rope physics. I especially need elastic ropes with capability to pull objects with velocity after a little extension. Do you ...
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### How to get object to lose less velocity as its speed increases

I'm developing a game in Flash and I need a little help. It can be considered a math problem. My object is flying with speed X and my object can collide with stones. When it collides with a stone, I ...
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### How to make my 2D character stand normally on slope?

I've got this character in Unity3D (2D Mode)... in a a slope which looks like this, But I want the character to stand along the red line..Like below How can I make it in Unity3d? I've got this ...
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### 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 ...
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### Gravity strength in first person games

In our game, we set the acceleration due to gravity to the appropriate value of 9.8 m/s^2. Although physically correct, it feels more like moving around on the moon.. It feels about right at a value ...
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### When should I use a physics engine?

Since I found out Box2D, I'm using it for kind of any game-like application I try to write, from very small prototypes or small programs to test something, to actual projects. Thanks to it it's so ...
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### Run a physics simulation on both client and server?

I'm implementing a multiplayer asteroids clone to learn about client/server network architecture in games. I have spent time reading GafferOnGames and Valve's publications on their client/server tech....
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### Impulsioned jumping

There's one thing that has been puzzling me, and that is how to implement a 'faux-impulsed' jump in a platformer. If you don't know what I'm talking about, then think of the jumps of Mario, Kirby, and ...
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### 2D character controller in unity (trying to get old-school platformers back)

This days I'm trying to create a 2D character controller with unity (using phisics). I'm fairly new to physic engines and it is really hard to get the control feel I'm looking for. I would be really ...
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### 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 ...
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### 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 ...
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### How to simulate pressure with particles?

I'm trying to simulate pressure with a collection of spherical particles in a Unity game I'm building. A couple notes about the problem: The goal is to fill a constantly changing 2d space/void with ...
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### Angle of Reflection

I have this "Breakeout style" game. I have a cannon at the center, blocks around the cannon and pads around the blocks. This is how the game looks like: I've managed to get the collision per ...
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### Should I write my own physics engine, because of networking integration?

I'm currently developing a top down, realtime, zombie shooter. I'm coding this in Java, using JBox2D as my physics engine. I have been coding the networking this week, and am now up to the physics ...
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### How do you do AI path following within a 2d physics engine like farseer/box2d?

I'm in the process of moving a 2d top down game I've been working on into a proper rigid body physics engine like Farseer. Up until now, I had just hacked together my own physics code where needed. I'...
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### How is RTS Local Avoidance Done?

Currently, I'm simulating physics impact forces for local avoidance of units but this method sometimes pushes units out of formation and has very undesirable effects when units clump up. For RTS ...
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### How do I implement deceleration?

I say "deceleration" because I'm not using acceleration at the moment; what I mean is moving the velocity back towards zero, eventually stopping. I'm new to vectors and not so great with physics and ...
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### Player moving up, is he jumping or climbing?

In a 2D physics-based platformer game that has ladders in it, how do you determine whether the player moving up is caused by a jump or him climbing a ladder, such that you know what animation to play? ...
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### How do fluid dynamics work?

How would I go about implementing fluid dynamics in a game, such as can be seen in this video?
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### Random map generation - strategies for scattering/clustering random nodes

I am doing a simple 4X strategy game in space where each node is a point-of-interest (a planet, an asteroid and etc.). To randomly generate a map, I would follow the steps below Decide how many ...
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### A simple flight simulator

In a 3D flight simulator with a Crimson Skies level of realism (as in, arcade level rather than realistic), how do you determine the movement of an aircraft each game clock tick? (Crimson Skies is an ...
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### How to implement collision detection of portals?

For example, take this scenario (excuse my horrible drawing skills): This is based on "Portal", where the stickman is going through the blue portal (which is linked to the red portal), but there is ...
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### Is a separate thread for game loop compulsory for simple games?

I am new to game development. In order to learn I am recreating this game on android platform. You can observe the game-play video at the above link. It is a simple game. I have read a lot of ...
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### How do I prevent raycast car wheels sliding sideways?

I've been writing a non-realistic car physics engine as a learning exercise, using this article as a reference. I have a car that correctly collides with a terrain and applies the correct suspension ...
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### Getting a 2D “pixel” cloud to follow a mouse

I'm working on a 2D game trying to get a "cloud" of a few hundred tiny cubes or discs to follow my mouse cursor without overlapping each other. However, using the physics engine introduces ...
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### How does pixeljunk shooter simulate its liquids?

I am really impressed by the liquids in pixeljunk shooter. I would love to know how they do it.
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### 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 ...
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### How to build a bones animation engine?

I want to develop a flash game. It would draw a stick man, and edit his pose. I think what I need to learn are bones animation and physics engine. Can anyone introduce some good resources to learn ...
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### What is the best way to handle simultaneous collisions in a physics engine?

I'm writing a 2d physics engine in javascript so that I can learn more about physics in video games. I have it working correctly for rigid body collisions, except for if any body collides with two or ...
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### Are there well-known algorithms for fitting a polygon to an arbitrary shape?

I'm using the Chipmunk physics engine to make the levels for a 2D C game. I'd like to be able to fit a polygon to an arbitrary shape to serve as the collision mask. Given a black and white collision ...
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### 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 ...
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### Deforming surfaces

I try to accomplish an deforming physic behaviour for levelsurfaces, but don't get an idea how to start with the implemenation so far. Regardless of the shape from the surface (planes, cubes, spheres…)...
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### Continuous Physics Engine's Collision Detection Techniques

I'm working on a purely continuous physics engine, and I need to choose algorithms for broad and narrow phase collision detection. "Purely continuous" means I never do intersection tests, but instead ...
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### Web workers for HTML5 game physics simulation?

A bit related to this question. The idea is to guarantee the same physics behavior as much as possible. Would it be possible to run fixed time step physics on a web worker? The UI would update ...