Tagged Questions

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

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1
vote
2answers
491 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 ...
0
votes
1answer
303 views

How to implement uniform grids

Up until now, I implemented all-against-all collision detection in my games. It worked fine. But I reached a point where implementing this kind of collision detection, makes the game run poorly, ...
18
votes
6answers
2k views

How to optimize the distance function?

While developing a reasonably simple RTS-like game, I noticed my distance calculations were causing an impact in performance. At all times, there are distance checks to know if a unit is in range to ...
0
votes
0answers
422 views

NavMesh agents pushing other NavMesh Agents in Unity Pro

Using the NavMesh system in Unity, I created pathing system for my player character as well as the enemy AI. When a group of enemy NavMesh Agents surround my player character, they can be pushed out ...
2
votes
1answer
124 views

How do I compute the point of a triangle-ray intersection?

I have a line (the direction vector of the player) and a triangle representing the face of a model (so composed of 3 points). I can't find the mathematical operation to check if that vector is ...
1
vote
0answers
61 views

Does anyone know a good knockback algorithm? [closed]

I was just wondering if someone had a good knock back algorithm for a top down shooter game. I was hoping for not as much as a knock back but more of a push. that would be great.
0
votes
1answer
279 views

Using PhysX, how can I predict where I will need to generate procedural terrain collision shapes?

In this situation, I have terrain height values I generate procedurally. For rendering, I use the camera's position to generate an appropriate sized height map. For collision, however, I need to have ...
1
vote
2answers
391 views

Sprite collision with color?

Is this possible? To elaborate, I am making a PacMan offshoot. Essentially it is a "zoomed in" version of the game, but the board is randomly generated. I have 11 .png files each to be used as a ...
-1
votes
2answers
122 views

Java Tilemap Collision

I have tilemaps represented by values from 0 to 4. How can I make the player collide with tiles represented by 3 and stop the player from passing through it ? Here is my code for the player and ...
0
votes
1answer
619 views

OBB Collision Resolution: Jittering with Long Rectangles

I have been working on a physics simulation module. Almost everything works properly, but I am having an issue, which I have demonstrated in the following video. http://youtu.be/2L17y9Lme0Q As you ...
1
vote
1answer
49 views

A Sensor’s ContactList Keeps Old / Ignores New Contacts, When That Contact Is still

Okay this is a hard one to explain so I’ll try my best. Basically every time my enemy class updates, it runs a SightCone Sensor Contact List test, so this is every single frame it checks for all the ...
1
vote
1answer
138 views

How to prevent a sprite to move in an angle that will lead to collision

I have two sprites that can move in any angle. The sprites are rectangular. I created bounding boxes for both the sprites. These boxes rotate whenever the sprite rotates. They always surround the ...
6
votes
1answer
197 views

Separating axis theorem with multiple polygons?

I am attempting to implement the separating axis theorem in C#. I have a function that can calculate the minimum translation vector between two polygons. However, I can't seem to create a function ...
0
votes
2answers
117 views

Floating point precision issue with Box2D

I'm using Box2D and I am putting edge tiles as b2Bodies so that the tile world can have physics: The problem is that there are 3 b2_kinematic bodies under the player right beside each other. Every ...
1
vote
2answers
460 views

Calculating wall angle and sliding in 2D

Got a new project recently where I don't use any physics engine, but it requires some basic phyiscs. Basically it's a 2d "top-down" game type. I would like to add a smooth wall collision which feels ...
1
vote
0answers
35 views

Calculating contact points with SAT [duplicate]

after detecting collision between two convex shape by using separating axis theorem and calculating MTV, how can i calculate the contact points ?(for applying torque to the rigid body).
3
votes
1answer
164 views

Directional, Triangular Collision Detection in Pygame [duplicate]

I am trying to create a game in Pygame, with Python 3, and am trying to figure out an algorithm that will tell me which direction a rectangle is colliding with a rectangle, so that I can push it back ...
0
votes
1answer
111 views

How to loop through objects in class (XNA)? [closed]

In my game I have an Enemy class, and in that I have a constructor which I use to make Enemy objects. How do I add all Enemy objects to a list or loop through all of them using a foreach loop? I ...
2
votes
1answer
265 views

Collision detection in libgdx

I am currently writing a little zelda like game and have a little bit of a problem with collision detection. It works but the the character stands to far away from the object. Here is my player ...
1
vote
2answers
161 views

Detecting collision of two sprites that can rotate [duplicate]

I have a problem with collision detection in a 2D Java game. Normally, what I would do is create a getBounds() method for an object that can collide with other objects. This method would return a new ...
0
votes
2answers
213 views

How to get surrounding tiles in a tile array

I've created a tiled map that holds two layers, one for the tile type, and the other for whether it is solid or not. I plan on creating very big maps, and checking every tile seems like it would slow ...
0
votes
1answer
220 views

2D Tiled Map - Small tiles or big tiles with pixel-precise movement

I am using Java - LWJGL - Slick2D . I have tried to do a proper collision detection with 32 x 32 tile size but failed three times. I just cant get it to work! I found a youtube video that was using ...
0
votes
1answer
299 views

XNA 3D Unable to Position Bounding Sphere

I have a collision method which seems like it would work, and it does, but the bounding sphere is always at 0, 0, 0. How do I fix this? Any more code and or details are avaliable upon request. Any ...
3
votes
1answer
281 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), ...
1
vote
1answer
522 views

JavaScript - 2D Top-down Collision Detection issue

I'm developing a 2D Top-down Game using HTML5 Canvas and a custom Game Engine. I'm implementing the Quad-intersection detection (Function below, if it helps) on different areas of the Sprites (As ...
0
votes
1answer
675 views

Top-Down Tilemap Rendering and Collisions in Libgdx

I'm sorry if this question has been previously answered, but I was unable to find an answer here or through google. I'm trying to make a simple roguelike-like that would feature a top-down tile map, a ...
2
votes
3answers
307 views

Strategy for detecting hits from a “cylinder ray”?

I was planning on using ray casting for collision detection in my game. However, when I use an attack similar to this: (which would project something like a cylinder), how would I go about ...
2
votes
1answer
218 views

Using latest TiledMap, how do you get a specific tile from x and y index?

Seems basic enough, but I can't seem to find the answer: I am trying to implement collission detecton and for that I need the properties of the tile the player is currently entering. I am using ...
1
vote
1answer
172 views

AABB vs Rectangle

I'm trying to wrap my head around 2D physics and stumbled upon Axis Aligned Bounding Boxes, and I have a couple of questions regarding them. In all AABB structs I could find out there, people prefer ...
1
vote
1answer
69 views

Shape collision checking

I want to check in an shape, wether an point is in it or not. The shape is descriped with one Array of float vectors. The vectors are added in clock direction. The first I can check very easy, the ...
1
vote
2answers
157 views

Collision Scenario, Detection and Response

I have AABB, BSphere, a Polygon Soup, a Triangle, a Plane, a Point and a Ray objects with a collision test that returns 'bool' if two objects collide or not. How can I use the above objects to ...
0
votes
2answers
85 views

When and how should I update my collision grid?

When and how should I update my collision grid? Current implementation: buildGrid(): add all entities with collision to the grid handleCollision(timePerFrame, entities): handle all collisions ...
2
votes
1answer
243 views

Collision Shapes Abstraction Design

Straight to the facts. I have a base CEntity class for different entities in my game: Static entities ( those do not move, simply props and items ) Dynamic entities ( these move, jump ) Each of ...
1
vote
2answers
388 views

Detecting walls or floors in pygame

I am trying to make bullets bounce of walls, but I can't figure out how to correctly do the collision detection. What I am currently doing is iterating through all the solid blocks and if the bullet ...
0
votes
1answer
114 views

AABB SAT code detects collision wrongly [closed]

I've been having trouble getting my SAT code working using AABBs, and I've been trying to find a solution but, I'm scratching my head. For some reason, it detects collisions very wrongly, as shown by ...
0
votes
1answer
103 views

Passing through edges of AABB collision

When I move, I grab the tile in front of the player, but when the player is colliding between two tiles, I grab the wrong tile due to rounding error. I made a video explaining what I mean. As you can ...
0
votes
1answer
209 views

AABB collision detection not detecting in some cases

I'm using simple AABBs in a tile based world, and for some reason the algorithm does not detect collisions when moving towards the left and then down. I actually upload a video to YouTube to ...
1
vote
2answers
183 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 ...
0
votes
1answer
103 views

Map color collision problem

Hello i'm doing a game in WPF, 2D version (top view) I have the map and i'm trying to check for color collision in pixel each time the timer is activated Well...with 1 object it works fine but with ...
0
votes
2answers
148 views

Creating a collision shape for a complex model

I'm currently creating the collision system for my 3D XNA game. To check collisions with models (especially complex ones) like trees or other plants, I thought about rendering a low poly version of ...
0
votes
1answer
209 views

Predicting trajectory collisions for multiple moving objects [duplicate]

For the most simple of 2D games, I have implemented a posteriori collision detection (overlapping rectangles) on the xy Cartesian plane, but am now interested in understanding the basics of a priori ...
6
votes
1answer
218 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 ...
0
votes
1answer
631 views

implementing collision detection and handling for tiled 2D world with smooth wall sliding

Im using SFML 2.1 for graphics and my game structure follows SFML book quite closely (SceneGraph implementation etc) My world consists mostly of characters (around 1-400, moving around) and tiles ...
0
votes
2answers
280 views

How to properly handle attacks in an 2D Platformer?

I am building an 2D Engine in JavaScript and if my actor attacks an enemy, a hitbox appears for a certain amount of time and then disappears. If the target keeps standing inside of the hitbox he gets ...
0
votes
1answer
322 views

LWJGL Collision Detection

I cannot find LWJGL collision detection with a camera and walls. Like making it to where you can not walk through walls and other different shaped rectangular prisms and cubes. How do I set up LWJGL ...
2
votes
2answers
242 views

What are “distance fields” and how are they applicable to collision detection?

I was looking at some efficient methods for collision detection in a scene with both static and dynamic objects when I came across "distance fields." I tried to search and understand this concept, ...
1
vote
3answers
203 views

Lag created when detecting collision

I'm fairly new to gamedev and have encountered a problem with the collision detection system. The collision is essentially worked out like this: for (int x = 0; x < playerprojectiles.Count; x++) ...
0
votes
1answer
197 views

Circle-Rectangle collision velocity adjustment

I created my circle vs. rectangle method based on this algorithm: http://stackoverflow.com/questions/401847/circle-rectangle-collision-detection-intersection Currently, I have a dynamic ball with ...
0
votes
1answer
294 views

Circle vs. Rect Collision accuracy problem

The blue ball is dynamic and is supposed to bounce off the walls, as well as the rectangle. Currently, the green rectangle is adding an invisible line to the scene, which doesn't let my ball go where ...
0
votes
2answers
237 views

Best collision shape for rooms

I'm wondering what is the most efficient collision shape to use with APIs like Bullet or Havok for rooms/interiors. Rooms tend to be boxes but are concave since the normals point inward which means no ...