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

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584 views

Boat passing under a bridge in a 2D tile based RTS

I'm writing a 2D tile based RTS. And I want to add a 'pseudo 3D' feature to it - bridges over the rivers. I havent't start any coding yet, just trying to think how it fits the collision detection ...
5
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2answers
1k views

Correct order of operations in a platformer game loop

I've run into an issue with my Mega Man engine, and the structure of my game loop is making it very difficult to fix. With Rush Jet, or any falling platform, Mega Man needs to stay attached to the ...
2
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3answers
1k views

Coarse Collision Detection in highly dynamic environment

I'm currently working a 3D space game with A LOT of dynamic objects that are all moving (there is pretty much no static environment). I have the collision detection and resolution working just fine, ...
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5answers
2k views

Collision detection logic

Edit 2 In the following picture sprite1 (the red square) is hitting the platform from the left, so: sprite1_rightEdge>platformSprite leftEdge would be true, so I can simply reposition ...
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1answer
2k views

Java/Android pixel perfect hit detection

I am making a game for android which I need hit detection between two objects. The first bitmap I have is a flying superhero, and the second bitmap is anything that he collides with. The superhero ...
12
votes
4answers
15k 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 ...
4
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2answers
3k 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 ...
2
votes
1answer
2k views

How do you implement 2D collision detection?

I would like to know the best or most efficient way to test for 2D collision. I am currently using AABBs, but the problem with this, is that your objects will be hitting things when they shouldn't. ...
2
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2answers
1k views

Projectiles in tile mapped turn-based tactics game?

I am planning to make a Laser Squad clone and I think I have most of the aspects covered. But the major headache is the projectiles shot/thrown. The easy way would be to figure out the probability of ...
10
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2answers
447 views

Extrapolation breaks collision detection

Before applying extrapolation to my sprite's movement, my collision worked perfectly. However, after applying extrapolation to my sprite's movement (to smooth things out), the collision no longer ...
10
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1answer
895 views

Are there well-known algorithms for fitting a polygon to an arbitrary shape?

I'm using the Chipmunk physics engine to make the levels for a 2D C game. I'd like to be able to fit a polygon to an arbitrary shape to serve as the collision mask. Given a black and white collision ...
9
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5answers
2k 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 ...
8
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2answers
403 views

Platform jumping problems with AABB collisions

See the diagram first: When my AABB physics engine resolves an intersection, it does so by finding the axis where the penetration is smaller, then "push out" the entity on that axis. Considering ...
4
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5answers
636 views

Collision detection performance problem

Using python and pygame I've built a collision detection system according to the instructions in this YouTube tutorial. This is updated 40 times per second and controls movement and collision ...
4
votes
1answer
392 views

Moving the jBullet collision body to with the player object

I am trying to update the location of the rigid body for a player class, as my player moves around I would like the collision body to also move with the player object (currently represented as a ...
4
votes
2answers
1k views

Sliding collision response

I have been reading plenty of tutorials about sliding collision responses yet I am not able to implement it properly in my project. What I want to do is make a puck slide along the rounded corner ...
4
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1answer
2k views

How can I convert a 2D bitmap (Used for terrain) to a 2D polygon mesh for collision?

So I'm making an artillery type game, sort of similar to Worms with all the usual stuff like destructible terrain etc... and while I could use per-pixel collision that doesn't give me collision ...
3
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3answers
258 views

Physics System ignores collision in some rare cases

I've been developing a simple physics engine for my game. since the game physics is very simple I've decided to increase accuracy a little bit. Instead of formal integration methods like fourier or ...
3
votes
2answers
2k views

3D Ball Physics Theory: collision response on ground and against walls?

I'm really struggling to get a strong grasp on how I should be handling collision response in a game engine I'm building around a 3D ball physics concept. Think Monkey Ball as an example of the type ...
2
votes
2answers
987 views

2D AABBs and resolving multiple collisions

Okay, so this is a problem I've been trying to figure out for quite some time. Mine is a 2D platformer game with a world made up of (usually) immobile tiles and mobile sprites, both of which use AABBs ...
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
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1answer
2k views

Would someone please explain Octree Collisions to me?

I've been reading everything I can find on the subject and I feel like the pieces are just about to fall into place, but I just can't quite get it. I'm making a space game, where collisions will ...
10
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2answers
552 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
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4answers
2k 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
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2answers
939 views

Identifying quad patterns in a two-dimensional array

In the tech demo I'm trying to make, tetrominoe-style blocks will be placed by the player, at which point the game checks to see if they've made a quad with any existing shapes on the board (a 2D ...
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4answers
3k 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 ...
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3answers
713 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 ...
5
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2answers
458 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
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1answer
4k 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
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2answers
897 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 ...
5
votes
2answers
1k views

Tile based collision detection failing when player is going too fast

I'm creating a side scroller and I'm have a problem with my collision detection. The collision detection works perfect when the player is falling at a constant speed, but when I implement more ...
4
votes
1answer
709 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
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1answer
1k 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
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1answer
4k 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
3answers
222 views

Lerping character moving up and down slope tiles

So, when interpolating position against a standard 'horizontal' platform, everything works great. What happens is something like this..... (Question continues after graphic) Now, the question I ...
3
votes
1answer
185 views

How to detect if a ball will collide with another, and the normal vector of the collision?

So I have a 2D game involving balls (circles) colliding. I want to be able to detect if two balls will collide before it happens, and the normal vector of the collision if a collision is going to ...
3
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3answers
379 views

Using uniform grids for collision detection - Efficient way to keep track of what a cell contains

I was looking for an efficient way to implement collision detection in a 2D game. A way that won't result in an O(n^2) level of complexity. A lot of people recommend to use Uniform Grids for this ...
3
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1answer
153 views

How do you prevent AABBs from passing through each other?

I know what an AABB is, but I don't know how you would check for collision with an object that is going really fast. If an object goes fast enough, it can skip over other bounding boxes without it ...
3
votes
1answer
816 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 ...
3
votes
2answers
476 views

Collision Detection - Slide Around Sprite

I'm creating an RPG using XNA/C# and am trying to add some complicated collision detection code. I have the playable character 'Wizard' and when it collides with something, a method gets called in his ...
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
4answers
787 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?
3
votes
3answers
2k views

Collision detection of convex shapes on voxel terrain

I have some standard convex shapes (cubes, capsules) on a voxel terrain. It is very easy to detect single vertex collisions. However, it becomes computationally expensive when many vertices are ...
2
votes
2answers
3k views

How to check for cube collisions?

I want a method, which takes two "ObjectBox" objects (A "ObjectBox" has .getX() .getY() .getZ() .getSizeX() .getSizeY() .getSizeZ() methods) as a parameter and return true if the two Boxes are ...
2
votes
2answers
256 views

Tools to generate convex collision geometry

Does anyone know tools to generate convex collision geometry from given 3D model? For example, UDK's Static Mesh Editor can do this; Valve instead recommends to use smoothing in 3D editor. Desired ...
2
votes
2answers
990 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
736 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
552 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. ...
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0answers
121 views

Storing rigid body collision shapes in local or world coordinates

I'm writing the beginnings of a lightweight 2d rigid body engine (in javascript, as a hobby project), and i'm debating whether to store collision shapes in local or in (updated as needed) world ...