Questions tagged [collision-resolution]

A process of adjusting game objects position after collision.

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How do you get the collision plane when using AABBs? [duplicate]

My collision detection initially seemed to work well enough, but my answer to this question shows that I have went with SAT testing now instead. My goal was to find the plane at which to slide the ...
7k 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 ...
2k views

AABB to AABB collision response

I am currently trying to resolve collision between two AABBs. I already have a function that can detect if the the two boxes are colliding and returns true if the two boxes are colliding. The problem ...
1k views

How do I resolve a collision of a circle with two rectangle corners?

I'm writing a simple non-physical one-circle-to-many-rectangles collision detector/resolver. For collision detection, I'm using a very common algorithm, and it's working pretty well. For collision ...
10k 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 ...
995 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] ...
1k 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 ...
234 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 ...
332 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 ...
280 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 ...
4k 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 ...
1k 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 ...
1k 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 ...
283 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, ...
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. ...
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 ...
437 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 ...
1k 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 ...
206 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 ...
351 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 ...
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/...
1k views

Unity3d physics stability with low fixed timestep

I'm developing a vehicle simulator game for mobile platforms. This vehicle has some hydraulic arms. I use hinge joints and configurable joints. There can be collisions to walls etc. When I set a low ...
594 views

Using Farseer Physics, how can I get objects to bounce at the correct angle

I am using the Farseer Physics engine in my MonoGame project. I have static walls which have "body" friction 0 and "body" restitution 1. I have dynamic objects, which are circles, with "body" friction ...
199 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. ...
4k 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 ...
474 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 ...
4k 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 ...
533 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). ...
860 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 ...
218 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 ...
288 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, ...
189 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 ...
411 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}{...
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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 ...
100 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 ...
158 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 ...
1k 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 ...
943 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....
2k 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,...
188 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 ...
338 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 ...
111 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 ...
295 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 ...
1k views

How do I implement space partitioning in entity component system?

My systems work on components without needing to now anything about entities. I want to implement simple grid partitioning, so each entity will be given a cell based on its current position. But how ...
224 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 ...
809 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 ...
935 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 ...
390 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 ...