# Tagged Questions

A process of adjusting game objects position after collision.

3answers
135 views

### Strategies for dealing with crowds at choke-points

I've recently switched my game engine over from steering behaviours to impulse based movement with proper time based collision resolution. This has solved so many problems (no more tunnelling, yay) ...
1answer
84 views

### How to handle collision detection

So the way that I am doing the movement for my game is that you can left click a unit (which is just a rectangle object), and then it is selected. While it is selected, you can right click and that ...
0answers
34 views

### Game Physics: Calculating a collision response using the Separating Axis Theorem?

I am working on a project in which I have implemented the Separating Axis Theorem to detect collisions between objects. My current collision response is an object that contains whether it is ...
4answers
147 views

### Lunar Lander calculating gravity, acceleration and collision in GameMaker

I've already asked this on the GameMaker forums but had no response so far. I'm making a little Lunar Lander game as my first foray in to GameMaker, I'm wanting to have the ship land and take off ...
1answer
332 views

### Cocos2d - Physics bodies randomly loosing Velocity along an axis after impact

This just started occurring and seems to randomly happen during, and between, game sessions. A dynamic moving body collides with a static body and instead of bouncing off looses (almost completely) ...
0answers
37 views

### Handle floating point precision errors in collision detection and resolution

I am experimenting with a continuous collision detection and response of points on a tile map. This are my results for now: I did this by shooting a ray (red line) from the current position (red ...
2answers
5k views

### Microsoft XNA Platformer Example, is the Collsion Detection implemented accurately?

The example provided by Microsoft seems as if the collision detection (from what I can see) will have a small error. When the user collides with an Unpassable tile, the depth of the intersection is ...
2answers
89 views

### How to make the character cannot pass through other randomly moving objects when they are collided?

As the title above, how can i make my random wallImg solid enough so that my birdImg cannot pass through it from any sides of the wallImg? Here's the code of Processing's Crappy Bird that i've altered ...
1answer
425 views

### Collision in PyGame for spinning rectangular object.touching circles

I'm creating a variation of Pong. One of the differences is that I use a rectangular structure as the object which is being bounced around, and I use circles as paddles. So far, all the collision ...
0answers
52 views

### Collisions between players in multiplayer racing game

I'm creating a simple racing game (spaceships, no gravity) using p2.js, phaser and node.js. What I have done: Client receives world state from server: extrapolate other players based on latest ...
4answers
3k views

### Collision between AABB and Circle

I'm programming collision systems for a 2D game engine. The idea is that different systems can interact with each other. So one of the cases would be check collisions between axis aligned bounding box ...
1answer
216 views

### Collision between a sphere and a mesh(height-map)

I am trying to implement a method that detects the collision between a sphere and a mesh and reflects the vector of speed. I have a method, that detects a collision between a sphere and a triangle and ...
1answer
691 views

### Cocos2dx+Chipmunk: Fully elastic collision between moving bodies

I'm using Cocos2dx and the built in Chipmunk physics engine, and currently I've got my PhysicsBodys' materials set up with: Density=0 Restitution=1 Friction=0 in order to get fully elastic ...
1answer
70 views

### How to use collision masks and overlap_area in pygame?

So, I've been prototyping a game, and I've been using sprite collision, and it's not cutting it any more. I read up on the documentation about masks and overlap area: ...
1answer
277 views

### Collision detection doesn't register until player sprite jumps

I have implemented a shooting mechanic into my game, and the act of shooting works fine. The shooting work is done in my "game1" class. The issue that arises is when I incorporate collision detection ...
1answer
234 views

### AABB Collision Problems in SFML

I have a problem with AABB collision. I am making a top down rougelike in SFML and my collision algorithm does't quite work properly. HERE IS A GIF OF THE PROBLEM. It mostly works, except for when ...
1answer
24 views

### Canvas/Paint Mechanic

I am currently working on an idea for a unity game app with a canvas mechanic. I understand I may have to use particles for the brush/paint f/x however I can not think of a way to add collision ...
4answers
2k 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 ...
2answers
2k views

### Storing coordinates of every object in server side in MMOs

In an MMORPG: Is it typical or feasible to store the coordinates of every tree, bush rock.. etc in the server side for collision detection? If so, what would be a feasible way to store such a huge ...
0answers
26 views

### Detecting collision between 2 convex meshes in 3D

For the past couple of weeks I've been trying to implement physics in my engine, and I am currently stuck on the collision detection phase. In short, I can perform a triangle-triangle intersection ...
0answers
33 views

### Doing collisions on both axis with java overlap

I'm making a top down game from scratch and just found out about the java rectangle overlap method that would work great for collisions. However, after the overlap happens, I need to check for which ...
1answer
58 views

### Collision between free player and tilebased map

so I'm working on some sort of platformer in javascript where the map is tilebased but the player can move freely. Now, i have a problem with collision detection/response. It's kind of obvious what ...
2answers
325 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 ...
2answers
389 views

### How to deal with pushing objects out of collision in a physics engine

I'm developing a 3D physics engine (I know, I should use one of the many good existing physics libraries, however my collision detection is optimised for objects with highly ordered highly complex ...
0answers
51 views

### Problem with collision detection also affecting collision resolution

Hi I am making a 2d scrolling beat em up, I am working on the collision with obstacles like drums and platforms. So far I have the player jumping and falling from platforms but having problem ...
2answers
152 views

### Can I make this physics simulation any faster?

I've made a little real time physics simulation that solves some bodies. CirclevCircle && CirclevOrientedRect I would like someone to tell me if I'm doing something drastically wrong. I know ...
3answers
481 views

### Tile Based Collision Checking In Java?

I have my map stored in 2 arrays: Tiles : Tile names TileTypes : SOLID or BASIC I want to be able to walk through BASIC Tiles (Like ground tiles). But not the SOLID Tiles (Like wall tiles). I ...
2answers
476 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 ...
1answer
59 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 ...
0answers
18 views

### Collision Handling between two Sets of Polygons?

So I'm making a minecraft mod that allows you to build crafts out of blocks and move them around. I've been stuck on this issue for months now though, which is that I can't get the crafts to collide ...
1answer
61 views

### Tile-based collision problem with corners

I am currently making a tile based collision system. But I encountered a big problem I can't seem to figure out. Use the image bellow for reference. Gray lines represent the border between tiles. ...
2answers
75 views

### Collision works except for when coming from right side

I am trying to make a bomberman clone. I'm having problems with the collision on the walls that is not on the sides of the map (see image). When I come from the right (going left), the red square ...
0answers
32 views

### Circle velocities stay the same after elastic 2D collision

I am following this paper in trying to create elastic 2D collisions among two circles. The problem is that my end velocities are the same as my start velocities. I've looked over my code and don't see ...
2answers
116 views

### 2D Collision Response

I am trying to implement collision response in my libgdx game. I'm using Rectangle objects as my bounbing boxes. This makes collision detection very easy, however I can't quite get the response ...
1answer
130 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 ...
1answer
93 views

### Ball's velocity vector, reflect against a point

I need to calculate the new velocity vector when the ball collides with one of the paddle's corners. Let d be the velocity vector of the ball, r the target velocity vector and n the surface normal ...
0answers
34 views

### Touch and Collisions not working together in AndEngine when i set a custom Physics Handler

I have a set of custom sprites which implement a custom physics handler. The aim is to allow the user to move them by touch, then upon release they should act like a spring is connecting them to the ...
1answer
138 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 ...
0answers
78 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 ...
2answers
215 views

### Unity Renderer.bounds issue?

I would like to make rend.bounds.max.y be always equal to 20 on collision no matter what, using the script below. But it seems that I can't set it manually and the script has no effect on my ...
1answer
35 views

### 2d Tile Based Collision Response

Right now I am trying to make a 2d collision response system for a platformer, and the algorithm I have for it works quite well. The only problem is that if the player is standing exactly on a tile, ...
1answer
49 views

### Collision resolution moving Point to AABB with raycasting

This is probably trivial, but I'm having trouble making it work. I have a 3-coordinate world of particles simulated with Verlet Velocity. I only care for collision between their centers and a few ...
2answers
74 views

### simple solution for 3d collision detection and response

I'm having great difficulty trying to implement collision detection and response in a 3d game What are some simple solutions someone can use to implement smooth collision and response similar to ...
1answer
294 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, ...
1answer
140 views

### Finding new position after collision with multiple colliders

What is the most accurate way to find the correct position to where a moving character should be re-positioned as a collision-resolution, after it has collided with multiple colliders? The figure ...
2answers
239 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 ...
1answer
581 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 ...
4answers
2k views

### How do I restrict the movement of a point to within a radius of another?

I have a situation where a sprite's center point needs to be constrained within a certain boundary in 2D space. The boundary is circular, so the sprite is constrained within a radius. This radius is ...
3answers
396 views

### Collision Response in Entity Components Systems

This question seems to be a duplicate of mine, but I don't think it is. I'm trying to build a game using an ECS, but I want this ECS to be as simple as possible, therefore I am eschewing messages. ...
0answers
41 views

### Detecting the two Vector3 that determine the bottom-edge of the side of a box-collider that had collision (with C#)

So, I understand that plenty of questions have been posted on how to detect which side of a Box Collider had collision. However, what I am trying to achieve is a little different. I want to find out, ...