Relating to the motion of objects through space (in 2 dimensions (x,y)) and time. Including concepts such as acceleration (thrust and gravity), mass, collision response, friction and more.

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4answers
922 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 ...
2
votes
1answer
131 views

How can I simulate a magnet that attracts a ball in a 2D enviroment?

I am making a top-down game where you have to move a ball from point A to point B. You are attracting the ball using magnets that are standing still. The ball needs to get pulled by multiple magnets. ...
2
votes
2answers
175 views

How do I implement friction in a billiards game?

I'm having trouble implementing friction in a billiards game. Currently, the ball only slows on collision with the edges, but I also want some friction with the background. How can I implement ...
2
votes
2answers
718 views

Physics in carrom like game using cocos2d + Box2D

I am working on carrom like game using cocos2d + Box2D. I set world gravity(0,0), want gravity in z-axis. I set following values for coin and striker body: Coin body (circle with radius - ...
2
votes
3answers
1k views

How do I move a 2D top-down racing camera smoothly and show what's ahead of the player?

I'm trying to make a camera that follows a race car. Right now, I'm smoothing the camera movement out by moving the camera's position a fixed percentage lerp'ed from the camera's position to the car's ...
2
votes
1answer
500 views

Shapes and sprites in SVGs

I understand SGV images are used in 2D games to store shape data for the physics engine of the game. I'm unsure though, should the raster sprite also be stored in the SVG or should it be separate? ...
2
votes
4answers
294 views

Using forces to reach a specific velocity

In my game, I currently move the player by directly setting its velocity on key press events. This makes the game feel very responsive and allows the user to quickly change direction. However, I ...
2
votes
1answer
165 views

Physics movement prediction is way off [closed]

I'm making a simple, non-networked game. There are two players and a ball. In implementing the AI for the second player, I've run into a huge problem predicting where the ball will hit the ground. ...
2
votes
3answers
349 views

Writing an autopilot for a 2d game with newtonian physics

The subject says it all. I am making a 2d space game with newtonian physics and I need pointers on how to write an autopilot for it. The requirements are best explained by an example. There is a ...
2
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3answers
2k views

Game physics / 2D Collision detection AS3

I know there are some methods you can use like hittestPoint and so on, but I want to see where my movieclip colliedes with another another movieclip. Any other methods I can use? by any chance does ...
2
votes
2answers
442 views

One-way platform collision

I hate asking questions that are specific to my own code like this, but I've run into a pesky roadblock and could use some help getting around it. I'm coding floating platforms into my game that will ...
2
votes
1answer
930 views

Collision Detection for a 2D RPG

First of all, I have done some research on this topic before asking, and I'm asking this question as a mean to get some opinions on this topic, so I don't make a decision only on my own, but taking ...
2
votes
3answers
2k views

How do I change my gravity and jumping logic to put the character at a specific height at a specific point in time?

I'm making a 2D platformer on Android using libGDX. One thing I've had a problem with recently is gravity and jumping. I found a few tutorials on the internet and was able to come up with this... ...
2
votes
1answer
402 views

How can I make a car follow the terrain in a 2D (side-view) game?

I'd like to create a game where a car drives over a 2D terrain. Which algorithm to use so the car will follow the mountain incline?
2
votes
1answer
1k views

How to resolve concurrent ramp collisions in 2d platformer?

A bit about the physics engine: Bodies are all rectangles. Bodies are sorted at the beginning of every update loop based on the body-in-motion's horizontal and vertical velocity (to avoid sticky ...
2
votes
2answers
1k views

Find meeting point of 2 objects in 2D, knowing (constant) speed and slope

I have a gun which fires a projectile that has to hit an enemy. The problem is that the gun has to be automatic, i.e. - choose the angle in which it has to shoot, so that the projectile hits the enemy ...
2
votes
2answers
1k views

Using box2d DrawDebugData with multi layer scene?

In my Game, a Scene is composed by several layers. Each layer has different camera transformations. This way I can have a layer at z=3 (GUI), z=2 (Monsters), z=1 (scrolling background), and this 3 ...
2
votes
1answer
64 views

Implementing character movement using real physics

This is the first time I'm seriously developing a game so apologies if I'm missing the obvious. In my 2D platformer I adopted Box2D since it seemed like a natural solution to model gravitational ...
2
votes
1answer
93 views

My pool balls often jump around when there are two or more balls colliding/touching

I'm working through the book 'Introduction to Game Physics with Box2D' and I've created a little pool game with the example code. Despite the name, there is NO box 2D used in this particular exercise. ...
2
votes
1answer
420 views

Unity WheelJoint2D will not rotate when increasing motor speed

I have a wheel joint 2D attached to a game object in Unity: In its associated wheel script I am increasing the motor speed as described in the tutorial. public class Wheel : MonoBehaviour { ...
2
votes
1answer
156 views

Frame-rate independent friction on movement in 2d game

I have been trying to implement a simple physics system for a 2D space game I am making. I have it pretty much working, but I have encountered an issue with the way I apply friction. I have tried ...
2
votes
1answer
247 views

Inverse Explosion with Unity2d

I am currently trying to make all other objects push away from the player when the player explodes. It currently works, but it pushes close objects a little and far objects very far. What I want is ...
2
votes
1answer
214 views

Using Box2D / Physics with Tiles?

Here is my issue. I currently have Box2D setup and working. But, it works with my Entity system. So I can create static objects and dynamic moving ones, and they simulate fine. However, my world is ...
2
votes
2answers
994 views

Non-physics character movement in a Box2d Environment

I am in the process of creating a physics platformer. However, I want the player movement to feel very old-school(as in: non-physics like), which means that the character: Should always move equally ...
2
votes
1answer
390 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 ...
2
votes
1answer
451 views

android game-logic for shooter

Im creating a 2d game for android. I'll just get right to it. I have a sprite controlled by a joystick that needs to shoot, sofar Ive managed to get direction and movement on my bullet, but then I ...
2
votes
2answers
982 views

Canvas Rotation collision detection on a sprite

I am using this code to detect collisions between two rectangular sprites. intersect: function(other) { return this.x < other.x + other.width && other.x < this.x + this.width ...
2
votes
3answers
2k views

2d Collision detecton axis aligned boxes

I have recently run into some trouble with my collision detection. My game is composed of a map made out of axis aligned squares. The player has an x and y velocity, and I want to know how I can find ...
2
votes
2answers
95 views

Implementing a motorized hinge joint

I have a 2d physics engine, with three boxes: "body", "left wing" and "right wing". The wing boxes are connected to the body using a hinge joint. The physics world has no gravity. I'm attempting to ...
2
votes
1answer
109 views

Best practice for organizing the physics of objects?

Apologies because this is a long post and I am inexperienced. I would really appreciate the input from some experienced developers. These are my two goals for this project: To learn the best ...
2
votes
1answer
186 views

2D physics rotation w/ XNA

I'm creating a simple game with space ships made of blocks that are all the same size. After having looked at this: Calculating the rotational force of a 2D sprite I have created the following code ...
2
votes
1answer
191 views

How do I convert a partially transparent image into polygons?

I'm using GLEE2D, a level editor allowing me to import images, scale them, rotate them, and position them onto layers and export the data into XML format. However, it does not tell me objects' ...
2
votes
1answer
2k views

Understanding Torque in Unity

This is (hopefully) a simple question that should avoid me asking a more complex question. This is in Unity (2D) but hopefully this is a general physics principle I am not getting. I am applying a ...
2
votes
1answer
139 views

How to calculate new velocities between resting objects (AABB) after accelerations?

lately I have been trying to create a 2D platformer engine in C++ with Direct2D. The problem I am currently having is getting objects that are resting against each other to interact correctly after ...
2
votes
1answer
660 views

What's the best way to handle slopes for a platfomer game using Box2D

I would like to know if there is any known solution for handling the player's movement on slopes using Box2D engine. I tried to do it using a circle as the player. Everything was fine until I tried ...
2
votes
5answers
968 views

How do I set up moving platforms in a 2D side scroller to interact with the player properly?

Edit: I changed the way that gravity was applied so that it is applied even when a player is standing on a block, so instead of the game outputting that you are stepping on a tile as true and false ...
2
votes
2answers
485 views

Physics in a 2D oblique perspective game

So, just to clarify, because I'm still fuzzy on the terms for perspectives in older games myself, examples of an oblique perspective can be seen in many older RPGs (Earthbound, Final Fantasy, Secret ...
2
votes
1answer
594 views

Need help with collision detection/resolution in a 2D simulation of 'worm-like' creatures

(originally posted this on regular stack overflow, somebody pointed this forum out :-) ) Hi there, I'm implementing a physics engine for the simulation of worm-like creatures. Problem is, is that ...
2
votes
1answer
857 views

Converting 2D Physics to 3D

I'm new to game physics and I am trying to adapt a simple 2D ball simulation for a 3D simulation with the Java3D library. I have this problem: Two things: 1) I noted down the values generated by the ...
2
votes
2answers
182 views

Sprite Kit - containsPoint for SKPhysicsBody?

I have a ball bouncing around the screen. I can pick it up and drag it onto a "bucket". When my touches finish, I use the containsPoint function to check and see if I have dropped the ball onto the ...
2
votes
1answer
162 views

How to impale and stack targets correctly according to the collider and its coordinate?

I'm making another simple game, a catch game, where a spawning target game object must be captured using a skewer to impale it. Here how: At the start, the falling object (in red) will fall in a ...
2
votes
0answers
53 views

How should I model rotation caused by bounce friction? [duplicate]

In my Java2D simulation, I have a disc which, when it bounces off the boundary of a 2D region, begins to rotate, as if it had gotten some spin from the wall. I'm having trouble relating the ...
2
votes
1answer
2k views

AndEngine - Moving Rectangle using Accelerometer

I'm learning how to create games with this great engine and I'm trying to put my knowledge in order to create a simple game. My first goal is to make a Rectangle moving using accelerometer and create ...
2
votes
1answer
1k views

How to implement Ragdoll physics to 2D characters in XNA?

I'm starting a new project with XNA. I want to create a game where the main character is subject to ragdoll physics when killed. I was wondering if anyone can give me any tips on how should I ...
2
votes
0answers
385 views

how to attach a body to a rope and making it swing to another rope [closed]

I've set some ropes (using cocos2d and box2d) and would like to attach a body to one rope in such a way that it can swing to another rope. I am not sure how to go about this. I read making and object ...
2
votes
1answer
2k views

Farseer Physics collision detection vs intersection detection with sensors

I'm trying to make a game that uses Farseer physics engine as its main collision detection engine. I have a 2d circle body object that has a matching fixture (I used the CreatCircle method. I did not ...
1
vote
1answer
277 views

Determining relative velocities on impact?

I'm trying to figure out a way to determine the relative velocity of a body colliding with another in a 2D environment. For example if one body is moving at (1,0) and another traveling behind it ...
1
vote
1answer
2k views

How can I cancel a contact in a b2ContactListener?

To know when contacts happen we can derive from b2ContactListener and implement our own solution which is great. I'm wondering is there anyway we can cancel a contact, that is to say when we hit begin ...
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vote
2answers
2k views

Box2D Platform body not moving player body along with it

I am creating a game using Box2D (Javascript implementation) - and I added the ability to have a static platform, that is moved along an axis as a function of a sine. My problem is when the player ...
1
vote
1answer
415 views

In 2d game logic, should I use pixels or world coordinates?

Currently in my game I handle the logic (collisions, movement) using pixels but I find it very limiting espiecially when thinking about variable speed. For example Box2D requires you to use ...