Collision detection is the determination of whether or not two or more entities make contact with each other during gameplay.

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12
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6answers
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How do I handle Isometric collision detection?

I would like to make an isometric run-jump style platformer. The player should be able to jump on top of platforms above the floor, hit the side of objects etc. I'll be using a 2D game engine so I ...
14
votes
2answers
1k views

Best/Efficient way to implement a 3d Collision

I've already programmed a 2d based collision system for a previous game. It was my first collision system and it was ugly. I was looking for collision between objects by checking all objects with all ...
10
votes
1answer
792 views

How do I make a curved surface out of rectangular blocks?

For a Peggle-like game, I want to make blocks that follow a curve, like this: The blocks would then disappear as the ball hits them. I managed to draw some horizontally, but I'm having trouble ...
9
votes
1answer
4k views

Circle-Line Collision Detection Problem

I am currently developing a breakout clone and I have hit a roadblock in getting collision detection between a ball (circle) and a brick (convex polygon) working correctly. I am using a Circle-Line ...
6
votes
4answers
2k views

Is there a way to increase the collision check efficiency of a system of n objects?

I'm making a game that consists of many onscreen objects, one of which is the player. I need to know which objects are colliding every iteration. I made something like this: for (o in objects) { ...
5
votes
4answers
7k views

2D Platformer Collisions

I've basically asked this question before, and I know it's been asked probably a billion times, but I still can't seem to do it. All I want to know is how I should go about doing basic 4-way, ...
12
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6answers
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How do I calculate distance from a point to a rectangle?

I have a 2D rectangle with x, y position, height and width, and a randomly positioned point nearby. Is there a way to check if this point might collide with the rectangle if it is closer than a ...
6
votes
3answers
6k views

Efficient Tile-based collision detection for a lot of squares?

currently I am working on my own take of a tile-based game (think Terraria, but less fantastical (I think that's a word? Sorry if it isn't)). Anyway, I currently have collision detection working ...
8
votes
2answers
4k views

How to handle pixel-perfect collision detection with rotation?

Does anyone have any ideas how to go about achieving rotational pixel-perfect collision detection with Bitmaps in Android? Or in general for that matter? I have pixel arrays currently but I don't know ...
7
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2answers
4k views

Stuck in Wall after rectangle bounding box collision

Using XNA's built in Intersects() on two Rectangles, I can detect a collision and set my velocity to zero. However, the object is stuck there and can't get out! How can I resolve this collision ...
8
votes
2answers
5k views

2D object-aligned bounding-box intersection test

I have two object-aligned bounding boxes (i.e. not axis aligned, they rotate with the object). I'd like to know if two object-aligned boxes overlap. (Edit: note - I'm using an axis-aligned bounding ...
6
votes
1answer
2k views

Minecraft-style player-gound collision detection

The title pretty much says it all... (Minecraft is a game consisting of evenly-spaced cubes for terrain, like voxels) Note: I am using C# XNA. I am pretty sure AABB is the way to go, yet I don't know ...
5
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1answer
1k views

2D collision-detection middleware

(This question was split off from http://gamedev.stackexchange.com/questions/3345/) Are there any recommendable middleware available for 2D collision detection? I believe I've heard that Box2D could ...
4
votes
1answer
296 views

How do I simulate a trampoline?

I'm quite new to game development. I was pretty impressed with the elastic effect I saw in this flash game when the ball hits the trampolines and I'm wondering how to recreate it. I've done some ...
3
votes
4answers
5k views

Side detection on Rectangle collision detection?

How can I determine which of the sides on a Rectangle that was hit by another Rectangle (or Circle if that's easier)? I originally tried creating 8 subrectangles for my main rectangle - one for each ...
2
votes
1answer
365 views

How do I create a player movement system in Farseer?

My group of students is helping produce a a 2D platformer. We tried making a pixel-based collision system which fell through. Now I am trying this physics engine on for size and see new ways to create ...
9
votes
4answers
4k views

In Cocos2D, how do I check for collisions against an arbitrary user-drawn shape?

I want to detect a collision between a sprite and a user-generated shape of some sort. For example. There are 3 objects on the screen. The user takes their finger and draws an abnormal shape around 2 ...
8
votes
1answer
3k views

Given a plane and a point, how can I determine which side of the plane the point is on?

Given the point Vector pos = new Vector(0.0, 0.20156815648078918, -78.30000305175781, 1.0); and the plane (triangle) Vector a = new Vector(-6.599999904632568, 0.0, -78.5, 1.0); Vector b = new ...
6
votes
1answer
281 views

Finding roots/zeros for collision detection?

For the most simple of 2D games, I have implemented a posteriori collision detection (overlapping rectangles) on the x/y Cartesian plane, but am now interested in understanding the basics of a priori ...
6
votes
4answers
3k views

2D Platformer Collision Handling

I am trying to create a 2D platformer (Mario-type) game and I am some having some issues with handling collisions properly. I am writing this game in C++, using SDL for input, image loading, font ...
4
votes
6answers
2k views

Should my game handle collisions in the Player object?

I'm making a 2D platform game. Right now I'm just working on making a very generic Player class. I'm wondering if it would be more efficient/better practice to have an ActionListener within the Player ...
2
votes
1answer
897 views

How can I test if my rotated rectangle intersects a corner?

I have a square, tile-based collision map. To check if one of my (square) entities is colliding, I get the vertices of the 4 corners, and test those 4 points against my collision map. If none of those ...
2
votes
2answers
980 views

How to calculate the direction a ball must bounce

I have a tile engine I have made. I can detect collision between the ball(the player) and the tiles. When a collision is detected all the colliding tiles are stored inside a list. My question now is, ...
2
votes
2answers
791 views

SAT, How Do I Find The Penetration Vector?

I've just successfully implemented Separating Axis Theorem (SAT) in my game but I was wondering how do I find the penetration vector? I heard it can be useful for collision response. e.g. The harder ...
1
vote
2answers
4k views

Collision detection - Smooth wall sliding, no bounce effect

I'm working on a basic collision detection system that provides point - OBB collision detection. I have around 200 cubes in my environment and I check (for now) each of them in turn and see if it ...
8
votes
3answers
924 views

Ball vs 45-degree slope collision detection

I have a simple game in which the player moves a ball around. The ball bounces off of walls. Right now I have square walls(■) implemented: I use simple bounding-box collisions to check if the player ...
5
votes
1answer
972 views

box2d with lines

I have a very simple platform game builder and I've specified the ceilings, walls and floor as line segments. A line has a winding, or normal; you can determine the direction that a line should be ...
5
votes
1answer
2k views

Circle-Rectangle collision in a tile map game

I am making a 2D tile map based putt-putt game. I have collision detection working between the ball and the walls of the map, although when the ball collides at the meeting point between 2 tiles I ...
4
votes
3answers
1k views

Collision Detection in Java for a game

Im making a game in Java with a few other people but we are stuck on one part of it, making the collision detection. The game is an RPG and I know how to do the collision detection with the characters ...
4
votes
1answer
2k views

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 ...
3
votes
1answer
270 views

Collision Detection Efficiency

I've just written my first successful collision detection code, and it works great for a small scene of actors (player + 4-5 obstacles). However, I realize that since it checks every possible ...
2
votes
1answer
394 views

Collision detection between 2 irregular shapes

I need to implement a collision system for a vertical-shotter and the bullets can have any type of shape; i've implemented the shape class with an array of choords and an array of lines which have the ...
2
votes
4answers
3k views

per pixel based collision detection

I was wondering if anyone had any ideas on how to get per pixel collision detection for the android. I saw that the andEngine has great collision detection on rotation as well but couldn't see where ...
1
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2answers
284 views

Updating entities in response to collisions - should this be in the collision-detection class or in the entity-updater class?

In a game I'm working on, there's a class responsible for collision detection. It's method detectCollisions(List<Entity> entities) is called from the main gameloop. The code to update the ...
1
vote
4answers
2k views

Checking for collisions on a 3D heightmap

I have a 3D heightmap drawn using OpenGL (which isn't important). It's represented by a 2D array of height data. To draw this I go through the array using each point as a vertex. Three vertices are ...
1
vote
2answers
3k views

Breakout collision using 2D Rectangles?

Here is my code: using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.Xna.Framework; namespace BreakOut { class Field { public static ...
1
vote
2answers
715 views

Which axis-aligned line does an AABB collide with first?

I am making the collision resolution system for my 2d top-down game, and I managed to find a solution where I query which surfaces of other AABBs the current entity can collide with in the next frame. ...
-5
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
55
votes
9answers
5k views

How to avoid circular dependencies between Player and World?

I'm working on a 2D game where you can move up, down, left and right. I have essentially two game logic objects: Player: Has a position relative to the world World: Draws the map and the player So ...
31
votes
6answers
3k views

Hexagon collision detection for fast moving objects?

A object has a position and a speed vector. Usually only the position is used to check if two objects collide, this is problematic for very fast moving objects as it can happen that the object moves ...
11
votes
1answer
4k views

How can I define a complex collision area on top of a tile map?

As many people recommended, I am using Tiled map editor to create a map for my game and it's great particularly because libgdx framework also provides with API for maps from Tiled. I understand I can ...
17
votes
7answers
3k views

How do I make A* agents avoid other agents?

I'm implementing a multi agent A* algorithm on a tile map. Agents move only in the X and Y axes. I avoid collisions between them by checking where the others are when calculating paths. It works fine ...
9
votes
2answers
4k views

How many and which axes to use for 3D OBB collision with SAT

I've been implementing the SAT based on: http://www.geometrictools.com/Documentation/DynamicCollisionDetection.pdf for 3D collisions On page 7, in the table, it refers the 15 axis to test so we can ...
6
votes
2answers
1k views

Triangle-triangle continuous collision detection

I am making a 3D game engine and I use continuous collision detection. I am using Sphere-Trees to cull primitive collision checks to a minimum. However, I'd like to perform continuous ...
16
votes
5answers
7k views

Collision Resolution

I know quite well how to check for collisions, but I don't know how to handle the collision in a good way. Simplified, if two objects collide I use some calculations to change the velocity direction. ...
14
votes
5answers
1k views

Optimizing collision engine bottleneck

If this is your first time on this question, I suggest reading the pre-update part below first, then this part. Here's a synthesis of the problem, though: Basically, I have a collision detection ...
10
votes
2answers
2k views

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 ...
9
votes
3answers
4k views

Collision detection with curves

I'm working on a 2D game in which I would like to do collision detection between a moving circle and some kind of static curves (maybe Bezier curves). Currently my game features only straight lines ...
3
votes
2answers
528 views

How can I improve my collision detection's performance?

I'm new to programming and want to speed up the collision detection in my C++ 2D platformer game engine. Currently, only the player's collision detection works: Every frame, the player's update ...
16
votes
2answers
4k views

How do I test if a circle and concave polygon intersect?

I have a polygon (sometimes convex, but often concave), and a bunch of circles with different radii. How can I find out if a circle is intersecting/overlapping with the polygon? I could split my ...