The determination of whether or not two or more entities make contact with each other during gameplay.

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10
votes
2answers
518 views

How do I make good guy attacks only hit bad guys and vice versa?

My game has many different type of good guys and many different type of bad guys. They will all be firing projectiles at each other but I don't want any accidental collateral damage to occur for ...
10
votes
4answers
1k views

Collision rectangle response

I'm having difficulties getting a moveable rectangle to collide with more than one rectangle. I'm using SFML and it has a handy function called intersects which takes 2 rectangles and returns the ...
7
votes
5answers
1k views

How to determine which cells in a grid intersect with a given triangle?

I'm currently writing a 2D AI simulation, but I'm not completely certain how to check whether the position of an agent is within the field of view of another. Currently, my world partitioning is ...
7
votes
3answers
688 views

Your recommendation for path construction from a single background image?

So I currently have my background as a single PNG and some obstacles (like blocks as part of that PNG). In order to create a path, I currently store pixels above a unique green color (my hill) and use ...
6
votes
2answers
2k views

How do I handle collision detection so fast objects are not allowed to pass through walls?

I'm creating a 2d sidescrolling shooter, and I'm having a little trouble with collision detection for the bullets. Everything including the bullets are objects with their own polygons / update ...
6
votes
4answers
2k views

How do I find the intersection of two lines

I have a bounding box on my character, its position in the previous frame an the current frame. The bounding box is axis aligned. My character is running around inside a cave, I have a list of ...
5
votes
2answers
291 views

How to handle collisions without ugly conditionals and type checking?

(I asked a similar question, but this one is far more specific). How can I handle collisions without having to do a lot of type checking and if statements? People here suggested that when spotting a ...
5
votes
1answer
3k views

how get collision callback of two specific objects using bullet physics?

I have got problem implementing collision callback into my project. I would like to have detection between two specific objects. I have got normall collision but I want one object to stop or change ...
5
votes
2answers
799 views

Collision response for 2D racing game

The title is fairly self-explanatory. I have a 2D racing game that utilizes per-pixel collision detection (the track is essentially two bitmaps, one for the graphics, one for collision data). The ...
4
votes
1answer
673 views

Character jittering with this tile based collision code

I have been trying to get my collision code working for hours now but with every resource I have tried my character still jitters. First I tried using the platformer sample but my character still ...
4
votes
1answer
1k views

2D Collision: Check before or check after?

I'm using velocity to move my character, I just add/subtract 0.4f and then update the players position in the update loop. I was wondering, when would be the best place to check for collision? Do I ...
4
votes
1answer
897 views

Are there any good engines for isometric collision detection and platforming?

I've decided to resurrect an old game idea I had years ago. I currently have zero experience with programming, but I'm going to begin studying either C#, Python or both in the near future. The issue ...
4
votes
1answer
3k views

Line-Rectangle Collision Detection and Response

I've looked through Google and none of the solutions seem to pinpoint my idea. Ultimately, I want to create a level editor where I can draw lines and have them exported to a file for my engine to ...
3
votes
1answer
1k views

Platformer Starter Kit - Collision Issues

I'm having trouble with my game that is based off the XNA Platformer starter kit. My game uses smaller tiles (16x16) then the original (32x40) which I'm thinking may be having an effect on collision ...
3
votes
2answers
2k views

Algorithm to fit shapes to 2D grid?

Let's say you have an n-by-m grid. Some squares are occupied, some are not. You want to know where in the grid you can fit arbitrary shapes such as to not hit an occupied square. The shapes would ...
3
votes
4answers
629 views

How to avoid collision detection to enter infinite loop in this case?

I am writing a collision detection system which uses the logic mentioned by Trevor here But I have anticipated a problem which I have shown as a diagram How do we handle this problem?
2
votes
1answer
142 views

When is a quadtree preferable over spatial hashing?

I'm making a 2d platformer with lots of objects at the same time. They're all AABB collision detected. I first tried a quadtree to decrease the number of of objects to check, tried a few different ...
2
votes
2answers
495 views

How do I detect multiple sprite collisions when there are >10 sprites?

I making a small program to animate the astar algorithm. If you look at the image, there are lots of yellow cars moving around. Those can collide at any moment, could be just one or all of them could ...
2
votes
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
3answers
663 views

Collision Detection Problems

So I'm making a 2D tile based game but I can't quite get the collisions working properly. I've taken the code from the Platformer Sample and implemented it into my game as seen below. One problem I'm ...
2
votes
1answer
478 views

3D RTS pathfinding

I understand the A* algorithm, but I have some trouble doing it in 3D to suit the needs of my RTS Basically, in the game I'm making, there will be agents with different sizes of OBB collision boxes. ...
1
vote
1answer
440 views

Box2D: Efficient method to create b2Chainshapes for a tile-based map?

I'm working on a platforming game with tile based levels. I store the collision model for my tileset in an array. This is how the collision model for a 4x4 tilesheet would look like (I can't post ...
1
vote
1answer
159 views

How can I make it so that my player object doesn't penetrate world collision when I'm holding down movement keys in that direction?

Right now I have a player object and an obstacle, both with bounding box rectangles around them. The issue is that when my player runs into this obstacle, as long as I'm holding down the movement key, ...
1
vote
1answer
624 views

How to detect screen boundary using AndEngine GLES1?

I am using the AnalogOnScreenControl to move my sprite around the screen. I would like to restrict the sprite so it can not move outside the screen boundaries. I have tried putting a line at the ...
1
vote
1answer
895 views

Java 2D Tile Collision

I have been working on a way to do collision detection forever, and just can't figure it out. Here's my simple 2D array: for (int x = 0; x < 16; x++) { for (int y = 0; y < 16; y++) { ...
1
vote
1answer
417 views

How can we match polygon data structure with a background image

I am referring to this fireball game. The ball will collide with background, which is in polygon form. I was wondering, how I can match my polygon data structure with the background image. Say, I ...
1
vote
3answers
2k views

How to detect which edges of a rectange touch when they collide in iOS

I'm creating a basic "game" in iOS 4.1. The premise is simple, there is a green rectangle ("disk") that moves/bounces around the screen, and red rectangle ("bump") that is stationary. The user can ...
0
votes
1answer
406 views

How can I determine which direction a 2D collision is occurring from?

The problem is as follows: Think 2D Zelda (Links Awakening, A Link to the Past) style movement where you can run into walls from any of the four cardinal directions, or basically up, down, left, and ...
-2
votes
1answer
244 views

Detailed Modern Opengl Tutorial? [duplicate]

I am asking for a specific modern opengl tutorial. I need a tutorial that does not skip to explain any lines of code. It should also include different independent objects moving/rotating (most ...
9
votes
4answers
5k views

Ignore collisions with some objects in certain contexts

I'm making a racing game with cars in Unity. The car has a boost/nitro powerup. While boosting, I wouldn't want to be deviated when colliding with zombies, but I do want to be deviated when colliding ...
7
votes
1answer
2k views

How do I calculate collision response between a sphere and a plane?

I'm trying to create a simple 3D game and need to constrain the player within the limits of the game world. When the player hits the sides of the world I want the player's ship to bounce off slightly. ...
7
votes
3answers
698 views

Polygon editor to draw collision data over image

I need an editor to plot a polygon over the texture for of a ship in my game. It would look like this.. Where the red is the collision outline and the image is the texture. I want to store the ...
5
votes
2answers
827 views

Swept AABB vs Line Segment 2D

I've really exhausted as much as Google has to give, I've spent a solid week googling every combination of words for an "AABBvsLine sweep", downloaded countless collision demos, dissected SAT ...
4
votes
1answer
483 views

Collision Filtering in Box2D

I have four bodies in my Box2D World. Each are polygon shape, with some physics parameters. Now when the game start, I need one of the bodies from the World (BodyA) to not be allowed to collide with ...
4
votes
2answers
735 views

I need help with 2D collision response (of stacking rotating polygons, with friction and gravity, for a game)

Hi I am looking for suggestions on how to write a collision response for game programming purpose (so not a scientific simulation). I am dealing with 2D polygons that are rotating, and I want them to ...
4
votes
1answer
883 views

Closest point on an ellipsoid

I need to know how to get the closest point on the surface of an ellipsoid to another point. I had an idea, but apparently i was wrong, and oversimplfying. What i did was squash the ellipsoid and ...
4
votes
1answer
709 views

Ellipsoid v. Box collision detection

I'm trying to write some collision detection code. ATM i have the code properly resolving Ellipsoid v. Ellipsoid collisions, and Box v. Box collisions, but Ellipsoid v. Box collisions doesnt work. ...
4
votes
3answers
3k views

Why do we use physics engines for collision testing or raycasting?

There is a thing I don't understand about game engines: why it is so common to use physics engines to do raycasting or collision testing? Say that you have a 3D scene loaded in your scene manager ...
3
votes
1answer
889 views

Create bullet physics rigid body along the vertices of a blender model

I am working on my first 3D game, for iphone, and I am using Blender to create models, Cocos3D game engine and Bullet for physics simulation. I am trying to learn the use of physics engine. What I ...
3
votes
3answers
1k 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 ...
3
votes
2answers
1k views

Collision Detection problems in Voxel Engine (XNA)

I am creating a minecraft like terrain engine in XNA and have had some collision problems for quite some time. I have checked and changed my code based on other peoples collision code and I still have ...
2
votes
2answers
148 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, ...
2
votes
2answers
1k views

Efficient collision detection - tile based HTML5/Javascript game

I'm building a basic RPG game and I'm looking at collisions/pickups etc now. It's tile based and I'm using HTML5 and Javascript. I use a 2D array to create my tilemap. I'm currently using a switch ...
2
votes
1answer
829 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
2answers
368 views

Tile map collision is not working properly

I am having problems setting collision between my sprite and the tiles. I have only done the code for colision for moving upwards but some places on the map it moves up and some places it doesn't. ...
2
votes
1answer
1k views

2D platformer multiple rectangle collision cause jitter

I posted this question two weeks ago: 2D platformer corner collision and I implemented NoobsArePeople2's solution. Problem is, when player intersects two rectangles that are inside each other, he ...
2
votes
4answers
4k views

How do I detect pixel-level collision using andEngine?

I'm developing a game for Android using andEngine, and I need to detect collisions only when two objects visually collide (not in blank space of the image). In J2ME, I'm able to do that using ...
2
votes
2answers
914 views

Tile based map and collision; getting stuck

I'm trying to make my character move around a tile map with collisions. Everything works fine except for one thing. I show you a picture with the problem: http://i.stack.imgur.com/ZWI7x.jpg That is, ...
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
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 ...