# Questions tagged [collision-resolution]

A process of adjusting game objects position after collision.

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1answer
778 views

### Pattern for collision handling?

I am writing a game with Java. There are many different kinds of entities on the screen, like the player, NPCs, monsters, bullets, items, shiftable blocks and so on. This question is not about ...
1answer
213 views

### Rigidbody physics concept: Why translate collision shape on-the-fly instead of mutating it?

Crossposting at https://stackoverflow.com/questions/29993547/rigidbody-physics-concept-why-translate-collision-shape-on-the-fly-instead-of-m I've spent some time going through physics engine's ...
1answer
318 views

### Implementing collision response, current implementation does too many checks

I don't know how I should handle my collision response when collision between two entities leads to second collision with third entity. Blue arrow is velocity of the rightmost entity and numbers ...
3answers
270 views

### Determining which edge a collision occurred on in a platformer

First of all, this will be Open Source, and you will be mentioned for the help. We've been programming a Super Mario Remake for the iPhone with Cocos2d for school. It looks pretty great, and we ...
2answers
3k views

### Find the Contact Normal of Rectangle Collision

It seems a lot of people have asked similar questions on this site, and every time it seems like a whole bunch of answers that don't work are given. Basically, I have two rectangles (AABBs) that ...
2answers
572 views

### Physics engine and squishing of stacked objects

I have a general question that seems to apply to most physics Engines (Box2D, Unity, Matter.js, …). I'm trying to make a tower of rectangular objects that are stacked on the [static/mass=infinity] ...
1answer
279 views

### How to calculate max region/area of 2d circles?

I have some 2d circles on a plane, each has its own minRadius and maxRadius. When two circles collides, both of them will shrink their radius, so the actual radius of a circle is in range [minRadius, ...
2answers
2k 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. ...
2answers
1k 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 ...
1answer
421 views

### Have the character automatically slide around obstacle corners [duplicate]

Like this: The player is only holding right, however the character still moves up a bit to go around an obstacle. My current collision system has access to: The entity's previous position The ...
2answers
992 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 ...
2answers
201 views

### Typical collision detection

I would like to know how is the typical collision detection of most games. For example, you control a character which can move in 2 dimensional directions (except up and down). Now lets asume he walks ...
3answers
342 views

### Collision organization problems

I just started playing around with c++ and some SFML. I'm going to create a 2D game with top view to test my ability and I came across a very big problem: collision detection and physics. So I see at ...
1answer
2k views

### How to resolve concurrent ramp collisions in 2d platformer?

A bit about the physics engine: Bodies are all rectangles. Bodies are sorted at the beginning of every update loop based on the body-in-motion's horizontal and vertical velocity (to avoid sticky walls/...
1answer
783 views

### How to handle collision detection & response in voxel engine with slopes?

Voxels are fairly small An object can span an area of 8x8x8 or more Vertices of Voxel Type are always snapped to the grid: Voxel types are convex (except the ...
2answers
996 views

### Circle-Circle collision resolution

This seems easy but I can't figure it out, when I have one circle(c1) collide with another(c2) I give the c2 circle the heading of c1 and send the c1 circle on the normal vector to the heading (the ...
1answer
185 views

### My pool balls often jump around when there are two or more balls colliding/touching

I'm working through the book 'Introduction to Game Physics with Box2D' and I've created a little pool game with the example code. Despite the name, there is NO box 2D used in this particular exercise. ...
1answer
3k views

### Collision/Intersection of (2D) Ray to Line Segment

Given a ray (r0, r1) and a line segment (a, b), I need to calculate the normal of the line segment based on the direction of the ray. For example, in the following picture: The correct normal given ...
1answer
345 views

### How do I resolve a collision involving more than two objects?

I have working functions that compute the overlapping polyhedron, contact points, depth of penetration (DOP), etc. of the overlap between two objects with convex polyhedra shapes. I know how to ...
1answer
527 views

### Get intersected volume of two planes in 3D

I'm working on AABB - AABB collision response and I'm having trouble figuring one part out. My situation is as follows (see image). I have a player AABB (blue) and an object which collides (brown). ...
1answer
791 views

### How to make a stack stable? Need help for an explicit resting contact scheme (2-dimensional)

Previously, I struggle with the sequential impulse-based method I developed. Thanks to jedediah referring me to this paper, I managed to rebuild the codes and implement the simultaneous impulse based ...
1answer
213 views

### How can I resolve collisions at different speeds, depending on the direction?

I have, for all intents and purposes, a Triangle class that objects in my scene can collide with (In actuality, the right side of a parallelogram). My collision detection and resolution code works ...
2answers
282 views

### How should I do my collision response?

I'm making a small lockpicking simulator. Obviously I'll need the pick to not pass through the lock, and I'll need the pins to move when you tap or push them with the pick. Here's what I have so far, ...
1answer
79 views

### Issues with AABB on a platformer game

i'm facing an issue at the moment in my javascript/html platformer game that despite searching for this issue i can't solve. The problem is this: When i place two platforms next to each other and the ...
1answer
185 views

### Impulse resolution for purely rotational collisions (relative linear velocity = 0)

I've been writing a basic physics engine, (loosely) following Randy Gaul's online tutorial. I have been using this equation that he derives: j=\frac{-(1+e)((V^A-V^B)*t)}{\frac{1}{{mass}^A}+\frac{1}{...
1answer
86 views

### How to detect and prevent the resolution of fake collisions?

I'm creating my own physics engine and I came across a small inconvenience. Here how it goes: when a body tries to push into something it really can't push, it gets pushed back (which is completly ...
1answer
59 views

### Achieve same effect as a FixedJoint2D but also match RigidBody2D forces

Trying to make an object that is affected by rigidbody physics in exactly the same way as the object it's linked to. So torque, velocity, and any resultant torque or velocity from a collision. This ...
1answer
155 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 ...
1answer
836 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 ...
1answer
379 views

### Continuous Collision Detection

So I'm playing around with the separating axis theorem and collision. Obviously the problem of what face it collided with arose. I need the unit normal which is tangent to that face it collided with ...
1answer
715 views

### How does matrix based game physics (collision detection & response) work?

I'm familiar with how to do collision detection and response using shape intersection tests, the separating axis theorem, and by using MPR and GJK with minkowski sums and support vector defined shapes....
2answers
1k views

### 2D multiple circle collision response

I'm trying to implement simple 2D circle collision system. There are circles with different radiuses and velocities (the larger the circle the slower it is). Contrary to all the questions on the Stack,...
3answers
180 views

### Bringing islands close together programmatically

I generate island/continent maps and I want to make a grand archipelago of sorts where all these islands are located. The problem is that I don't know a smart way to place the islands programmatically ...
1answer
306 views

### Collision detection between axis-aligned bounding box and bitmap (pixel perfect) terrain

Working on a Worms-type game, I have my objects in bounding boxes and they sit on the pixel terrain. Currently I am able to successfully do the collision detection for objects when they enter the ...
1answer
2k 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 ...
2answers
107 views

### How to preserve topology for penetration correction?

I have a sorted list of blocks - some may overlap some may not. Each block has an ideal starting position and may be constrained to one axis. There are no velocity or acceleration or other forces ...
2answers
226 views

### Rendering after interpolating, renders inside/outside other objects

So, we're working out our interpolated render-coordinates during our render call and it's doing a fantastic job of smoothing everything out. All is great and collision detection is working to a ...
1answer
220 views

### How to calculate new velocities between resting objects (AABB) after accelerations?

lately I have been trying to create a 2D platformer engine in C++ with Direct2D. The problem I am currently having is getting objects that are resting against each other to interact correctly after ...
2answers
721 views

### Pixel perfect collisions for platforms

I'm trying to create pixel perfect collision detection but I don't know how to handle collisions when there is a jump. Here I have one image of a sample map: But maybe I had a bad supposition ...
1answer
843 views

### Collision Resolution: How to avoid Interpenetration/Tunneling Caused by Prior Collision Handling? [duplicate]

My game processes world collisions followed by entity collisions. The problem here is that entities can break through walls the next frame when world checks are run again as a result of the prior ...
1answer
324 views

### Box 2d and really complex big shapes

I intended to use jbox2d for my project. But as I went deeper into it's manual I'd found out that it supports dynamic objects between 0.1 and 10 meters (if use scaling and assume that 0.1 is smallest ...
1answer
2k 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 ...
0answers
57 views

### How to resolve a sphere-mesh collision?

I'm making a rolling-ball type game, and I can't seem to get my sphere-mesh collision code working properly. Currently what I have for the main loop (in regards to collision) is the following: ...
0answers
763 views

### Implementing Separating Axis Theorem to Detect and Handle Sliding Collisions

I am having a bit of difficulty detecting collisions properly with separating axis theorem. My code seems to be giving a lot of false alarms. Also, I've looked into implementing sliding collisions ...
0answers
160 views

### 2D Polygon Collision push direction with large polygons

I have a collision detection/resolution implementation that uses the Separating Axis Theorem. Detection and such works perfectly fine, as well as resolution for most objects/shapes in my game. ...
0answers
676 views

### 2D Distance Field as collision handler method

Pixeljunk Shooter has really cool fluid simulation. I found the dev's video explaining what they did. Here I understand that it is particle based simulation Smoothed Particle Hydrodynamic I can ...
0answers
65 views

### Calculating contact points with SAT [duplicate]

After detecting a collision between two convex shapes by using separating axis theorem and calculating MTV. How can I calculate the contact points?(for applying torque to the rigid body).
1answer
595 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 ...
2answers
3k views

### Breakout collision using 2D Rectangles?

Here is my code: ...
2answers
252 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 ...