Relating to the motion of objects through space and time. Including concepts such as acceleration (thrust and gravity), mass, collision response, friction and more.

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5
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1answer
268 views

Circle Collision Resolution and Angular Momentum

I have a 2D engine working pretty well that involves rectangles and circles. I just reworked parts of the collision detection/response system for better handling of angular speed/momentum. The ...
0
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1answer
278 views

Grid collision - finding the location of an entity in each box

I am trying to implement grid-based collision in a 2d game with moving circles. The canvas is 400x400 pixels. Below you can see the code for my Grid class. What I want it to do is check inside which ...
0
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1answer
70 views

Game Sprite Motion

I really like the effect that I see in this video of Mario Party 10 Jewel Drop (at 2:40). It occurs when the four green orbs join together. You'll see a four items with long trails move to the top ...
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vote
3answers
66 views

Need help with physics 2D Unity

I'm making a 2D game in Unity. Basically there's just a rocket that goes where ever the user touches. With the code that i have right now, the rocket instantly rotates towards the point and moves ...
5
votes
3answers
192 views

Determining a sensible gear-like hierarchy for a series of connected objects

I would like a series of objects to behave in similar manner to a series of connected gears. This means that each black object in the diagram below will rotate at a speed based on the ratio of their ...
2
votes
2answers
131 views

why is my enemy AI is on air while moving?

In Unity3D I have created an enemy AI and applied a script for it to move and chase the player. But when moving, the enemy hovers in the air. My character also does not have rigidbody and he just has ...
0
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1answer
87 views

Need help with Physics

I'm using Unity to develop a game. Basically i want the player/rocket to follow a point on the screen where user touches. But It's based on physics. Force must be added when user touches somewhere and ...
1
vote
1answer
100 views

Sliding DOOM style collision resolution against arbitrary 2D geometry

I've been working on a HTML5 canvas raycasting engine for the web browser, with the end goal of making a simple FPS game in the style of the early 90s. The engine sits somewhere between Wolfenstein 3D ...
2
votes
1answer
128 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 ...
12
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1answer
4k views

What is the difference between an impulse and a force related to a physics engine?

What is the difference between an application of an impulse and an application of a force in relation to a physics engine?
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2answers
70 views

Using fixed timestep and interpolating states makes physics fall behind one frame. Does that affect responsiveness?

The title says it all, but let me build more into the question: I suppose everyone by now knows the Fix Your Timestep article, and its proposal to free your physics engine steps from your rendering ...
1
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1answer
77 views

LOVE Physics - Joint Stretching

After asking a similar question yesterday I've come across another problem with using joints in box2D / LOVE and trying to create a weighted chain. Everything is set up as follows, I've tried to ...
0
votes
1answer
59 views

Move Ball to clicked direction

I have a ball as a sphere in my game and Im viewing it from top down view (birdseye). The ball is a rigid body. I want to achieve when I click somewhere on the screen, that the ball moves toward ...
1
vote
1answer
54 views

Objects phasing through each other in physics engine

I'm writing my own physics engine right now (following this tutorial), but I'm running into some problems. Sometimes on collision, objects will just phase through each other instead of bouncing off of ...
2
votes
1answer
75 views

Why is the drag force multiplied by the inverse normalised velocity vector?

In pure physics texbooks, I'm seeing this formula to calculate fluid drag force: It is clearly stated that it should be opposite to the velocity. Now to me that means, in pseudocode: fd = ...
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vote
0answers
23 views

Precision problem when doing collision detection?

I've got this problem, and I don't know what may be the cause of it. I finished reading this article on sphere-triangle collision. My character (the sphere) stops before it reaches the triangle, and ...
4
votes
1answer
184 views

Rotate a rigid body not around its centre of mass

I have a rigid body (a boat) whose centre of mass is towards the front of the object. However, this makes the rotation look strange as the rudder that is turning the object is at the back of the boat ...
-1
votes
1answer
178 views

How do i move a 2D object with angle and speed variables in unity?

I want to move an object with a certain angle and speed, is there a was to set this as an initial velocity so that it is still possible for the object to collide and bounce of other objects using its ...
4
votes
2answers
217 views

How do I separate physics from framerate?

Skyrim (Creation Engine / Gamebryo) is a prime example of a game that has its physics tied to the framerate for which it has been heavily criticized, because if you disable vsync / have a > 60 HZ ...
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0answers
72 views

Why doesn't my orbit form an ellipse?

I'm playing around and trying to build an orbit simulator. Unfortunately, it isn't working out to well. Instead of forming some sort of elliptical orbit, I get this: Here is the code I'm using to ...
4
votes
1answer
151 views

Half top-down view collision and mechanics

I'd like to create a game with a half top-down (2d RPG) view (I don't know the exact name of it). It would be 2d, but I'd like to add 3d-like collisions. For example: If the grenade lands on the ...
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votes
2answers
69 views

How to get a pleasant path accelerating to a point

I am having trouble moving an object to a target position with a maximum acceleration limit. If i just accelerate towards the target the object will fly in a doughnut a few times before hitting the ...
1
vote
1answer
66 views

How can I determine “exact moment” of collision with ray casting?

I'm currently brainstorming how the physics for my game engine is going to be handled. It's top down and I'm thinking of using ray casting for collision detection. I've reached two potential problems ...
0
votes
1answer
12 views

Is GetFixtureA() of b2Contact guaranteed to return the body on which GetContactList() was called?

For example, in the code below, will the assert ever fail? for (const b2ContactEdge *contactEdge = playerPhysicsBody->GetContactList(); contactEdge; contactEdge = contactEdge->next) { ...
2
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1answer
105 views

Organizing movement, collision detection, and collision resolution

There's many articles on the internet focusing on how to implement movement, collision detection, or collision resolution. What I'm wondering is how to put them together, specifically in what order to ...
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votes
1answer
81 views

Applying velocity to objects in a specified direction

How to apply velocity to a particular direction? Data which I have: object position (P1) destination (P2)
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1answer
106 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 ...
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0answers
55 views

Static blocks - phaser isometric plugin

I'm creating isometric game like minecraft with phaser engine with rotates isometric plugin and I need colliding with player, but when I turn off physics, blocks is not static. Question: How to ...
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votes
1answer
129 views

Using Physics.Raycast inside OnCollisionEnter2D function

void OnCollisionEnter2D(Collision2D collision) { foreach(ContactPoint2D contact in collision.contacts) { RaycastHit raycastInfo; ...
2
votes
1answer
258 views

Implementing character movement using real physics

This is the first time I'm seriously developing a game so apologies if I'm missing the obvious. In my 2D platformer I adopted Box2D since it seemed like a natural solution to model gravitational ...
7
votes
2answers
699 views

Modular spaceship control

I am developing a physics based game with spaceships. A spaceship is constructed from circles connected by joints. Some of the circles have engines attached. Engines can rotate around the center ...
1
vote
1answer
122 views

LOVE Physics - Breaking Joint Chains (LUA / Box2D)

Wasn't sure whether to post here or on SO so please move if needed. I've been having a look into the box2D physics API provided by LOVE to try and create a swinging flail or weighted rope but I'm ...
1
vote
1answer
114 views

How to move sprite mimicking mouse/touch position on some part of the screen?

I am having a difficulty and I am been doing it wrong, I think. I want to move sprite relatively to touch. Just like when you are playing space shooter like 1943. I just learning some math and try to ...
1
vote
0answers
96 views

Implement car handling in Phaser [closed]

I'm experimenting on implementing a GTA 2 like game with Phaser. I started using Arcade physics but since the body boxes do not rotate the collision detection was very poor. In order to have better ...
0
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0answers
40 views

Which Box2D-like physics engine parameters need pixel conversion?

The official guide does not have any useful details on the matter: http://www.box2d.org/manual.html Position is an obvious one. What about velocity? Density? Anything else? Update: the context is ...
3
votes
2answers
486 views

Why does my ball always bounce perpendicular to walls?

I'm using Box2D. I think it's something to do with wall's fixture definition, but when a ball goes toward a wall at a 45 degree angle, I would expect it to bounce off at 135 degrees, but it always ...
4
votes
1answer
340 views

2D Collision response - rotating, moving polygon hitting a wall

I'm trying to bounce a polygon that has both velocity and angular velocity off a (immovable) wall when one of the vertices collides with it. I can detect the collision, and I've worked out how to ...
3
votes
1answer
113 views

Box2d Body to follow mouse movement

I am trying a box2d body to rotate following the mouse. Here's an image to clarify what I mean. The red and blue circles are current point of the mouse and the body (of corresponding color) ...
0
votes
1answer
35 views

Bouncing projectile off of sprite, the sides work but top and bottom do not

I'm having a problem bouncing a projectile off a sprite, we've been asked to move the projectile using the equations of motions which makes things a little more difficult but as far as I can see what ...
2
votes
2answers
326 views

How can I calculate the future position of my moving object?

I'm relatively new to games development and I have a 2D game where the playing area is an enclosed rectangle with width w and infinite height. In the playing area there is a ball. A gravity force of ...
3
votes
3answers
3k views

Car movement in arcade racing game

I am finishing a very basic 2D racing game with top-down perspective. I can't get the appropriate formulas to make the movement of the cars fun and addictive... Do you have tips on how to achieve that ...
1
vote
2answers
487 views

Testing Unity 2D Physics

I am looking to push the 2D physics in Unity to the extent where when so much is going on that there becomes noticeable lag in a game. This is for testing purposes, so that when so much is going on ...
0
votes
1answer
592 views

LibGDX Bounding Rectangles

I'm creating some rectangles surrounding my sprites for my player and bullet class to detect collisions with the overlaps method in Intersector class of LibGDX. I have a question: When I instantiate ...
1
vote
1answer
201 views

How do I make circles bounce off each other realistically?

I'm trying to create bouncing balls with realistic physics. At the moment, when the balls hit each other, they bounce back in the same direction they came from. How do I make them more realistic? I ...
3
votes
5answers
2k views

Simulating water droplets on a window

How do I simulate water droplets realistically falling, gathering, and flowing down a window? For example, see http://www.youtube.com/watch?v=4jaGyv0KRPw. In particular, I want to simulate how smaller ...
6
votes
2answers
186 views

Pathfinding with inertia

I'm currently working for pathfinding for a game where units are moving, but they have inertia. Most typical pathfinding algorithms (A*, Djikastra, etc.) are simply designed to minimize the length of ...
4
votes
4answers
626 views

How do I resolve a sphere-triangle collision in a given direction?

I am trying my hand at game physics. I understand that the basic way to pull back a sphere when it collided is to negate the penetration distance: // If collided... // `distance`: distance form ...
3
votes
2answers
145 views

How do I integrate drag over distance?

In my game I want to model kind-of-accurate bullet physics. I have the following drag equation (in C#): float drag = 0.235f * density * velocity*velocity * Mathf.PI * sizeMM*sizeMM/4000000; In ...
2
votes
1answer
60 views

Is it dramatically more efficient to have less BoxCollider2D's (for raycasting/custom physics)?

I have a temporary tile system for my platformer where I simply duplicate the same tiny box sprite with a BoxCollider2Don it over and over again. Like I said this is a temporary procedure for design ...
0
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3answers
152 views

How to change the gravity with a click

How to change the gravity of a ball upward with a click Then change it again downward with another click And so on In unity