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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4
votes
3answers
696 views

Calculating buoyancy force

I am trying to simulate a buoyancy force for objects submerged/suspended in a fluid in a 2D environment. According to Game Physics: Engine Development: How to Build a Robust Commercial-Grade Physics ...
1
vote
2answers
293 views

Throw object towards predefined place? [duplicate]

I have a 2D side-view game with object attributes such as x, y, speedX, etc. Now I want to throw a given object from any place on the screen onto a defined goal place, in such a way that its ...
0
votes
1answer
138 views

Collision and gravity problems

So this is an easy question. I need to implement gravity in my game but where I'm stuck is what variables do I need in my Entity object for the calculations and a good algorithm that I can use for ...
1
vote
1answer
314 views

Swarm/crowd movement with box2d?

Apart from using b2Body::setTransform(), are there other ways to move a body around while keeping its dynamics ? I want to move several bodies at the same time into one direction, pretty much like ...
3
votes
1answer
347 views

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 ...
1
vote
2answers
150 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 ...
4
votes
2answers
279 views

Creating stable tentacle structures

I am using verlet integration to simulate some tentacles. So far it works great and I am satisfied with how it looks in general. Here is how a tentacle is built: The very stiff sticks are colored ...
1
vote
0answers
322 views

Why won't my Box2d bodies collide? [closed]

I'm doing something wrong when trying to get bodies to collide using jBox2d & Slick2d. Here is have just my basic init, update, and render methods. Render and update seem to work fine for drawing ...
3
votes
1answer
335 views

Fluid Particle Grid

So recently I have been looking at some fluid simulation techniques, specifically Smoothed Particle Hydrodynamics. One of the key components is a grid to avoid O(n^2) searches. I have been having some ...
0
votes
2answers
287 views

Making The Player Stop Bouncing And Stop Sinking In The Ground In A Platformer XNA

Heres a problem i've been having. I have a platformer, and whenever my player hits the ground he keeps bounding. Here's the falling code iceBoy.moveY++; iceBoy.position.Y += moveY; Now heres the ...
1
vote
2answers
161 views

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 ...
-1
votes
1answer
123 views

Bullets Spawning in same direction [closed]

I'm using XNA to make a Bullet Hell Shooter game, and I'm running into some troubles when I try to change the direction in which the bullets move. Been trying to debug for awhile, but haven't gotten ...
1
vote
1answer
279 views

Debug Render In Cocos2d Android

I want to implement debug render for cocos2d android.So I can view how bodies are created. Right now I use gdx.jar file for box2d and load that jar file following way. static { ...
0
votes
2answers
145 views

Problem with sensor in box2d [closed]

I have two bodies: one green static sensor (spikes) and one orange dynamic body (brick). I have bullet and it's a dynamic body too, but with bullet flag set. My problem is that when the bullet is ...
2
votes
1answer
415 views

Simple 2D hair simulation/manipulation

I would like to simulate very simple hair in a 2D environment, and will need to be able to "brush" the hair. What I want to do: A 2D character is facing squarely towards the player. The player can ...
0
votes
2answers
84 views

Checking bounds of a quad

I want to know how would I tell if a quad touches another quad in my game built in Slick2D. I have a class that I named "Bounds" which has 4 "Point" objects which just store an X and a Y value and a ...
1
vote
1answer
385 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 ...
1
vote
2answers
179 views

Distribute circles evenly on Screen - circle packing

I want to evenly distribute a random amount of circles with random diameter on the screen for. This level doesn't scroll so the users screen resolution sets the limits. Further I would like the ...
2
votes
1answer
159 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. ...
5
votes
2answers
573 views

Whats the physics behind the doodle jump game?

I'd like to know how we can achieve the doodle jump type physics using andengine. I mean the character is not colliding with the ground blocks when he moves upwards but will collide when he came ...
1
vote
1answer
127 views

Increase restitution (bounciness) of an object in a JavaScript formula

I'm going slightly around the houses on this one. I originally started a thread over on Stack Overflow about it but then it seemed to diverge into mathematics, with no joy from the SO community over ...
1
vote
2answers
189 views

Collision detection for Monotouch [closed]

What I want to have for my Monotouch 2D projects: simple collision detection and collision polygons working with UIViews Sounds simple, isn't it? I've evaluated a lot of engines available on the ...
12
votes
3answers
1k 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 ...
5
votes
2answers
481 views

Ball bouncing infinitely and constantly

Alright, so I've got hold of some simple physics mechanics, and am currently trying to implement bouncing. Based on the first answer of this question, I've developed the following algorithm: ...
1
vote
1answer
461 views

Collision detection against specific sprite shape using XNA with Farseer Physics?

I am making a 2D XNA Game, using Farseer Physics for collisions. I need collisions to be resolved against the actual shape of the sprite image, ignoring transparent pixels, rather than against the ...
-2
votes
1answer
119 views

Help finding a good XNA physics library? [closed]

I'm looking for a good physics library for XNA. Can anyone help me find something good, simple and easy to learn for XNA?
3
votes
1answer
127 views

What to do after detecting OBB-OBB intersection

I'm using this code to detect intersections between two OBBs. The problem is that i don't know what to do after detecting it. I tried using a simple algorithm: if (collision detected) { ...
1
vote
2answers
439 views

Find the Contact Normal of Rectangle Collision

It seems a lot of people have asked similar questions on this site, and every time it seems like a whole bunch of answers that don't work are given. Basically, I have two rectangles (AABBs) that ...
1
vote
1answer
295 views

Am I implimenting a sweep and prune broadphase correctly? [closed]

The code that I am using is: std::vector <PhysicsBody*> physicsChildren; //containing all objects ... std::sort(physicsChildren.begin(), physicsChildren.end(), sortByLeft); ...
2
votes
2answers
832 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 ...
9
votes
2answers
1k views

How can I make a character walk on uneven walls in a 2D platformer?

I want to have a playable character who can "walk" on an organic surface at any angle, including sideways and upside-down. By "organic" levels with slanted and curved features instead of straight ...
0
votes
1answer
138 views

Separating Axis Theorem fails at certain angles

I'm currently attempting to add an overlap tester for an axis aligned and orientated bounding box but the solution only seems to work accurately when the OBB's angle is between -10 and +10. As the ...
0
votes
2answers
130 views

Circle Collision class not positioning itself correctly

Ok I am using unity3D and the Futile framework. I have everything drawing and working correctly with Futile, but I am trying to attach a circle collision class to the FSprite that I have. I must be ...
1
vote
1answer
236 views

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 ...
-3
votes
1answer
261 views

Implementation of planets in top-down space shooter [closed]

I am working on a top-down space shooter, and I have come to the point where I need some input on a mechanic. I have implemented enough that I can make this choice; either way will not change the code ...
2
votes
1answer
355 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 ...
8
votes
1answer
290 views

Calculate bike heading from front wheel heading and velocity

I have a simple top down bike game that I'm trying to add steering to. I would like to know how I use the heading of the front wheel to determine the heading and velocity of the bike. void Update () ...
5
votes
1answer
193 views

Physics/Logic behind self-bounce

I have a game that I am currently working on and I have a problem. What would a ball look like when it makes itself bounce. Say, for example that the ball had its own "inner power", was made out of ...
7
votes
1answer
267 views

How do engines avoid “Phase Lock” (multiple objects in same location) in a Physics Engine?

Let me explain Phase Lock first: When two objects of non zero mass occupy the same space but have zero energy (no velocity). Do they bump forever with zero velocity resolution vectors or do they ...
9
votes
3answers
570 views

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 ...
3
votes
1answer
363 views

2D Smooth Turning in a Tile-Based Game

I am working on a 2D top-view grid-based game. A ball that rolls on the grid made up of different tiles. The tiles interact with the ball in a variety of ways. I am having difficulty cleanly ...
2
votes
5answers
1k views

How to Make Objects Fall Faster in a Physics Simulation

I used the collision physics (i.e. Box2d, Physics Body Editor) and implemented onto the java code. I'm trying to make the fall speed higher according to the examples: It falls slower if light object ...
2
votes
2answers
250 views

Procedural generation of physics-enabled structures (in a 2D world)

Is it possible to procedurally generate stable structures out of rigidbody objects at a reasonable runtime speed? Imagine Angry Birds's levels kind of structures but generated procedurally.
1
vote
1answer
210 views

What is going on in this SAT/vector projection code?

I'm looking at the example XNA SAT collision code presented here: http://www.xnadevelopment.com/tutorials/rotatedrectanglecollisions/rotatedrectanglecollisions.shtml See the following code: private ...
1
vote
3answers
377 views

Implementing distance joint

I would like to implement something that behaves much like a distance joint / revolute joint in Box2D, however I do not want to throw a whole physics engine at this problem. I'm curious where I might ...
4
votes
4answers
634 views

Point of contact of 2 OBBs?

I'm working on the physics for my GTA2-like game so I can learn more about game physics. The collision detection and resolution are working great. I'm now just unsure how to compute the point of ...
2
votes
3answers
324 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 ...
1
vote
1answer
215 views

Game Physics: Implementing Normal Reaction from ground correctly

I am implementing a simple side scrolling platform game. I am using the following strategy while coding the physics: Gravity constantly acts on the character. When the character is touching the ...
2
votes
1answer
563 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 ...
5
votes
3answers
585 views

'Spring' physics

I'm trying to put together a struct or a method of some sort that will allow me to check the relative position between two objects, and if they're too far apart, apply a force that will draw them ...