# Tagged Questions

A process of adjusting game objects position after collision.

335 views

### 2D Platformer AABB collision issues

Before anyone say that this questions already has a answer, I will list all the questions I read and tried: AABB collision resolution issues Trouble with AABB collision response and physics Hard ...
646 views

### Sensor based vs. AABB based collision

I'm trying to write a simple collision system, which will probably be primarily used for 2D platformers, and I've been planning out an AABB system for a few weeks now, which will work seamlessly with ...
297 views

### How do I deal with collision resolution causing another collision?

I'm making a simple 2D, top-view simulation of an evacuation, sprites running around, looking for exits, going at it, all that good stuff. I have no control over them when the simulation is running, ...
569 views

### Collisions between moving ball and polygons

I know this is a very typical problem and that there area a lot of similar questions, but I have been looking for a while and I have not found anything that fits what I want. I am developing a 2D ...
248 views

### How to calculate faces involved in collision (Separating Axis Theorem)

I have a game engine created in javascript (https://jsfiddle.net/4gqsq8wf/) which uses collision detection via the Separating Axis Theorem. Currently, it does not have any means of resolving velocity ...
428 views

### Collision detection for sloping tiles

I've been looking into adding 'sloping' tiles into my platform game and my first attempt at collision detection with these tiles has produced some promising results (considering it's a first attempt), ...
2k views

### 2D Rectangle/Circle Continuous Collision Detection

I'm looking for a fast 2D continuous collision detection algorithm for circles and rotated rects. It needs to determine the time of collision. Both shapes may be moving at high speed, so the ...
317 views

### 2D collision resolution: works on each axis individually, but not with both combined

My collision detection method is solid and detects box to box collision every time. Then comes the resolve part which I'm struggling with quite a bit. It works perfectly when I'm manipulating the x-...
336 views

### When to detect and respond to collisions?

I've usually implemented collision detection like this in the past: Move entity Check if it collides with anything Resolve the collision by moving it back That's also the approach employed by most ...
643 views

### Collision resolution - Character walking on ascendent ground

I don't know if the solution to this problem is quite straight-foward but I really don't know how to handle collision resolution on a game where the player walks on an ascendent floor which is not ...
743 views

### 2D Motocross physics

I'm looking into making a 2D motocross bike game with plausible physics. It should look like this: For a first try, I've created only the player (a motocross driver) and the map (consisting of ...
60 views

### Collision resolution when moving in two directions

I am making a bomberman clone and I'm having problems regarding moving on both x and y axis (pressing down+left, down+right, up+left). Here is a video to demonstrate the problem. I use Tiled for the ...
135 views

### Resolving collisions with float precision errors

I'm facing a problem when I try to resolve the collision between two units using floats as positions of the units in my game. I am detecting the collisions using the SweptAABB algorithm and if there ...
161 views

### How to prevent accelerating along wall during 2d sliding collision response

I'm writing a simple 2d physics system using a circle colliding with edges. When the user presses a key the circle's velocity is incremented by some amount in the direction they pressed. There is ...
539 views

### Changing direction after collision

In the first tutorial for GameMaker (catch the clown), I want to set the direction of the clown after the collision with the wall. I want to do it by pressing the wall object with the mouse (before ...
251 views

### 2D Collision Resolution getting stuck on walls

I've been writing this collision detection system using a tutorial from an article I read and I just cannot for the life of me get it to function 100% correctly. Here's the code for starters: ...
284 views

### Is it possible to get the colliding sides using the separating axis theorem?

The title says it all, is it even possible to get the colliding sides? I'm checking for collisions between two OABBs, which works fine using SAT. Now I want to set the moving object's velocity to the ...
248 views

### How can I easily model semi-realistically human movement and collision in a 2D game?

I am writing a sports simulation game in which the simulated players will interact physically with each other (i.e. tackle, push, bump...) as well as do individual actions such as changing direction ...
187 views

### Collision and Graphics integration

I'm a little confused about the integration between collision and graphics. They both need to share the same position in the world. The most obvious choice is the center of the entity, which is good ...
415 views

### SAT and then what?

I am on my way to make another Arkanoid game but this time I decided that I want it a little bit more realistic than just checking intersections between AABB and inverting one vector's component on ...
914 views

### How do I avoid 3D AABB collision response getting stuck at block edges?

I want the player to be able to slide along cubes, but without getting caught at the seam between 2 adjacent cubes. I've gotten it so that I can do x collision, with sliding, and y, and z, but I can'...
1k views

### Resultant Vector Algorithm for 2D Collisions

I am making a Pong based game where a puck hits a paddle and bounces off. Both the puck and the paddles are Circles. I came up with an algorithm to calculate the resultant vector of the puck once it ...
671 views

### How are collision and collision callback systems usually implemented?

I'm writing my own game engine for learning purposes and was wondering about common ways to handle collision callbacks/responses. I'm NOT looking for ways to resolve collisions (no math needed here), ...
243 views

### Collision Managers and bitmaps

I am rewriting a game I made to use a (custom) collision manager that uses the minimum displacement method. As of now, my simple manager can only recognize and act on a couple of shapes - Circles and ...
82 views

### Is there an algorithm for collision resolution that factors in velocity?

I'm trying to program collision detection between moving convex polygons. To detect collisions, my program uses the GJK algorithm, and to resolve the collisions, it uses EPA. The problem with EPA is ...
186 views

### How do you get the collision plane when using AABBs? [duplicate]

My collision detection initially seemed to work well enough, but my answer to this question shows that I have went with SAT testing now instead. My goal was to find the plane at which to slide the ...
4k views

### Circle-Rectangle collision resolution

I have a non axis aligned rectangle, like a car, in my game. I have to check and resolve the collision between the rectangle and circle, which is stationary. I have found lots of ways to determine ...
3k views

### Do two balls of different mass bounce different heights?

There are two balls and the only difference between them is the mass. Both are dropped from the same height on to the floor (static object with infinite mass), would both balls bounce up to the same ...
158 views

### Rigidbody physics concept: Why translate collision shape on-the-fly instead of mutating it?

Crossposting at http://stackoverflow.com/questions/29993547/rigidbody-physics-concept-why-translate-collision-shape-on-the-fly-instead-of-m I've spent some time going through physics engine's ...
235 views

### Determining which edge a collision occurred on in a platformer

First of all, this will be Open Source, and you will be mentioned for the help. We've been programming a Super Mario Remake for the iPhone with Cocos2d for school. It looks pretty great, and we ...
164 views

### How to calculate max region/area of 2d circles?

I have some 2d circles on a plane, each has its own minRadius and maxRadius. When two circles collides, both of them will shrink their radius, so the actual radius of a circle is in range [minRadius, ...
525 views

### Point vs Convex Hull

I'm trying to implement a simple collision response to a point intersecting a convex hull. So far I can detect if the point is inside the hull. But now I want a collision response that translates ...
241 views

### Have the character automatically slide around obstacle corners [duplicate]

Like this: The player is only holding right, however the character still moves up a bit to go around an obstacle. My current collision system has access to: The entity's previous position The ...
187 views

### Typical collision detection

I would like to know how is the typical collision detection of most games. For example, you control a character which can move in 2 dimensional directions (except up and down). Now lets asume he walks ...
308 views

### Collision organization problems

I just started playing around with c++ and some SFML. I'm going to create a 2D game with top view to test my ability and I came across a very big problem: collision detection and physics. So I see at ...
507 views

### How do I avoid causing more collisions, when resolving multiple AABB collisions?

I have a lot of AABB bouncing on the screen. Doing collision/response between 2 AABB is fairly easy, but how do you handle this when you can be pulling AABB's apart but making them getting into ...
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 walls/...
123 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. ...
150 views

### How do I resolve a collision involving more than two objects?

I have working functions that compute the overlapping polyhedron, contact points, depth of penetration (DOP), etc. of the overlap between two objects with convex polyhedra shapes. I know how to ...
642 views

### Collision detection - make sure the player touches the object exactly

I know this is really something I should be able to figure out on my own, but a solution is evading me. Okay, here are a few relevant parts of my code. bool Game::Col(int x1,int y1,int w1,int h1, ...
390 views

### Get intersected volume of two planes in 3D

I'm working on AABB - AABB collision response and I'm having trouble figuring one part out. My situation is as follows (see image). I have a player AABB (blue) and an object which collides (brown). ...
552 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 ...
200 views

### How can I resolve collisions at different speeds, depending on the direction?

I have, for all intents and purposes, a Triangle class that objects in my scene can collide with (In actuality, the right side of a parallelogram). My collision detection and resolution code works ...
277 views

### How should I do my collision response?

I'm making a small lockpicking simulator. Obviously I'll need the pick to not pass through the lock, and I'll need the pins to move when you tap or push them with the pick. Here's what I have so far, ...
173 views

### How does matrix based game physics (collision detection & response) work?

I'm familiar with how to do collision detection and response using shape intersection tests, the separating axis theorem, and by using MPR and GJK with minkowski sums and support vector defined shapes....
213 views

### 2D multiple circle collision response

I'm trying to implement simple 2D circle collision system. There are circles with different radiuses and velocities (the larger the circle the slower it is). Contrary to all the questions on the Stack,...
161 views

### Collision detection between axis-aligned bounding box and bitmap (pixel perfect) terrain

Working on a Worms-type game, I have my objects in bounding boxes and they sit on the pixel terrain. Currently I am able to successfully do the collision detection for objects when they enter the ...
644 views

### 2D AABB vs AABB side of collision and collision depth

I realize there have been a multitude of questions involving 2D AABB vs AABB collision, but the questions and responses always avoid the simple questions that make it difficult. To keep things ...