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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Get GameObject to bounce of colliders [duplicate]

I am making a Atari Breakout game with unitys 2d tools and I need to get the ball to bounce of colliders in the scene. If you havent played the game before how it works is if the ball hits the wall at ...
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2answers
1k views

Throw object towards predefined place? [duplicate]

I have a 2D side-view game with object attributes such as x, y, speedX, etc. Now I want to throw a given object from any place on the screen onto a defined goal place, in such a way that its ...
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1answer
604 views

In 2d game logic, should I use pixels or world coordinates?

Currently in my game I handle the logic (collisions, movement) using pixels but I find it very limiting espiecially when thinking about variable speed. For example Box2D requires you to use ...
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2answers
7k views

How to implement explosion in OpenGL with a particle effect?

I'm relatively new to OpenGL and I'm clueless how to implement explosion. So could anyone give me some ideas how to start? Suppose the explosion occurs at location $(x, y, z)$, then I'm thinking of ...
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5answers
10k views

which is the best physics engine for flash as3? [closed]

i am a game programmer and i use actionscript to do all my collision checking, boundary checking etc...but recently i noticed there are things called "physics engines" that help me concentrate more on ...
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2answers
229 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
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3answers
150 views

Character animation in physics-simulated environment

What are the standard solutions for animating characters in physics-simulated environments? Let me explain what I mean - in most games characters are pretty much excluded from physics simulation - ...
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2answers
837 views

How to Calculate Velocity in a 2D space game

I am currently using screenpos.X = (float)(screenpos.X + velocity * Math.Sin(r)); screenpos.Y = (float)(screenpos.Y - velocity * Math.Cos(r)); For my Movement with r being the Rotation in Radians. ...
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2answers
319 views

Perpendicularity of a normal and a velocity?

I'm trying to fake angular velocity on my vehicle when it hits a wall by getting the dot product of the normal of the edge the car is hitting and the vehicle's velocity: Vector2D normVel =...
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3answers
848 views

Implementing distance joint

I would like to implement something that behaves much like a distance joint / revolute joint in Box2D, however I do not want to throw a whole physics engine at this problem. I'm curious where I might ...
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3answers
3k views

collision resolve sphere-aabb and aabb-aabb [closed]

I am currently working on a basic physics engine which does not consider rotations. At the moment I work on collision resolving between aabbs and spheres. Unfortunately I have no idea what a collision ...
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1answer
153 views

Anybody remember this webpage? [closed]

I remember visiting a webpage some time ago (1 year ago maybe) It contained many java applets, describing how certain mathematical functions like sin, cos, arcsin, exp would make an object move, with ...
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2answers
719 views

Variable physics step, bad idea?

Currently, when I update the entities I calculate the time passed since the last update, and then pass that to their update function. They will in turn pass that duration to all their components. ...
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3answers
2k views

Collision Detection for 2D

I am working on a simple game, where I need to do a collision detection of two Texture2D. The code I have written is: bool perPixelCollission = false; Texture2D texture1 = sprite1.Texture;...
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4answers
107 views

Performing movement per game tick

Assume we have a player on a map, whereby the grid is represented as a floating point. When a player is moving, they have an x and y velocity. How to do you properly apply their movement each ...
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1answer
45 views

2D circle against a corner change in direction

I have a 2D Ball that might go against a wall. If the Ball goes against the wall perpendicularly, it will just invert its direction (assuming no air resistance and no bounces that should make its ...
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1answer
85 views

2D sunrise in Unity

I see a lot of guides on how to create sunrise in 3D space, but I can't find much information on how to do it in 2D. In 3D, you rotate a lightsource around itself, but in 2D, I need to move the object ...
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1answer
99 views

Acceleration problems

Im trying to make a car game, but i cannot get the acceleration code right. With this code: if(gas){ speed += 3; }else if(break_ && !(speed < 6)){ speed -= 3; ...
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2answers
508 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 ...
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1answer
316 views

Simulation of ball movement in a 3d landscape. The easiest way?

I have a landscape(generated via Perlin noise) and a ball. I want the ball to move along the geodesic(implementation of basic physics: gravitation, friction). I thought to do raycast around the ball ...
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1answer
362 views

Estimate the time it takes for an object to travel from point A to point B

I have an object with vec2 position, velocity, and destination with 2 variables maxspeed and acceleration. In each step, its position is calculated as follows: vec2 desiredVel = destination - ...
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1answer
34k views

Simple collision detection in Unity 2D

I realise other posts exist with this topic yet none have gone into enough detail for me. I am attempting to create a 2D game in Unity using C# as my scripting language. Basically I have two objects, ...
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1answer
263 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 ...
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1answer
107 views

Box2D relations

As far as I know, the unit in Box2D is meters. When I use Box2D in Processing with JBox2D, I set the "world size" as the window size specified in the setup(). Now I'm wondering if there is any ...
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1answer
104 views

How to reduce the time it takes to speed up an object?

I have a body that I am applying a force to every step. However, I it takes a significant amount of time for it to speed up, which I do not want. Is there some value I can adjust to help with this?
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3answers
1k views

How to move around a player in a curved tunnel?

In a scenario where the player moves freely along the walls of a tunnel (like this), what is the best way to move the player along the walls of the tunnel? I'm using Unity3d game engine. I've tried ...
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1answer
2k views

Box2d contant speed before and after collision

I want to make my body fly at constant speed, how to make it fly at constant speed before and after collision? I set restitution of my body to 1.0 but after some direct and powerful collisions my ...
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3answers
295 views

Gravity independent of game updates per second

Edit Just for clarification, my sprite's 'movement' isn't the problem. If I set my Time variable to 4 seconds, then it will cross the screen in exactly 4 seconds regardless of logic updates rate per ...
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2answers
442 views

How can I manage large numbers of objects in a physics engine? [duplicate]

MY friend and I are programming a game and I decided to give the physics engine a try. I was able to get a class working where it would calculate out the total force on a model and apply the correct ...
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2answers
219 views

Distribute circles evenly on Screen - circle packing

I want to evenly distribute a random amount of circles with random diameter on the screen for. This level doesn't scroll so the users screen resolution sets the limits. Further I would like the ...
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2answers
199 views

Collision detection for Monotouch [closed]

What I want to have for my Monotouch 2D projects: simple collision detection and collision polygons working with UIViews Sounds simple, isn't it? I've evaluated a lot of engines available on the ...
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4answers
385 views

What different ways are there to model restitution in a physics engine?

In my physics engine I give a body a value for restitution between 0 and 1. When two bodies collide there seems to be different views on how the restitution of the collision should be calculated. To ...
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2answers
1k views

Calculating angle between two vectors to steer towards a target

I have been trying to implement a path following steering behaviour for AI in a 2D racing game. I have two vectors: futurePosition represents the predicted future position given the car's current ...
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1answer
3k views

Best 3D Physics Engine to use with Ogre [closed]

I am looking for a good physics engine to use with an Ogre game I'm writing. I would prefer for it to be free, open source, mature, simple to use, easy to learn, and flexible. I'm currently thinking ...
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1answer
341 views

Calculating the force of an impact?

I'm trying to figure out a way to determine the force two objects collide in. I have two vectors defining their linear velocity at the time of impact, their mass and their angular velocity. Keep in ...
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2answers
26 views

What is a good practice for deciding when to use transforms instead of applying force?

I was making several games. I don't understand when I should use addTorque instead of rotate. AddForce instead of position The latest game was a pinball game. I wasn't sure the best way to active ...
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1answer
40 views

Gravity wells that go with finger [duplicate]

I have a simple particle game, where all the particles are arranged in a grid. This game is for touch devices so to take advantage of it I am trying to have a multitouch gravity field thing going on. ...
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3answers
89 views

Calculating the angular momentum of rigidbody in Unity3D

Knowing that angular momentum in 3D is L = Iω (moment of inertia times angular velocity), how do I calculate it in video game world? In unity3d I have the diagonal inertia tensor rigidbody....
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3answers
2k views

Invalid AABB aabb

Invalid AABB aabb UnityEditorInternal.InternalEditorUtility:CalculateSelectionBounds(Boolean, Boolean) I've got this error ...
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1answer
170 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 ...
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3answers
151 views

Calculate intersect point / aim point

I'm working on a simple game, and I need to calculate the position to aim. Since my math days are a bit behind me, I put together a simple example to illustrate: So given that I know the position ...
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2answers
477 views

Leapfrog integration vs Euler integrator

I am looking at various integration methods for my n-body simulation and I'm slightly confused about actual implementation of leapfrog integration. According to the wikipedia page leapfrog method is ...
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1answer
130 views

What is the purpose of integration in physics engines?

All online resources seem to assume that you know what this means and/or state that this is related to object movement in some way. How does this differ than just position.x++ and position.y++ and ...
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1answer
325 views

Wandering motion in Unity

I am trying to come up with a smooth wandering motion for my game-object using Unity. What I currently doing is rotate the object by some random angle calculated every 1.5 second delay. But I am ...
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1answer
96 views

Reflection velocity

I'm trying to get a moving circular object to bounce (elastically) off of an immovable circular object. Am I doing this right? (The results look right, but I hate to trust that alone, and I can't ...
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2answers
624 views

How can I get the force of a collision in Love2D?

Is it possible to get the force of a collision between two objects in Love2D/Box2D? If so, how?
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2answers
77 views

Controls: Rolling on a ceiling

Currently I'm writing an iOS game where the basic movement is rolling. Technically you make the player turn clockwise or counterclockwise. When you tilt the device to the right, you will rotate ...
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1answer
1k views

Need to translate a Rotation Matrix to Rotation y, x, z OpenGL & Jitter for 3D Game

I am using the Jitter Physics engine which gives a rotation matrix: M11 M12 M13 M21 M22 M23 M21 M32 M33 And I need it so OpenGL can use it for rotation GL.Rotate(xr, 1, 0, 0) GL.Rotate(yr, 0, 1, 0)...
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1answer
672 views

How should I invoke a physics engine?

I'm new to writing games. I'm planning to write a 2D battle game which may require an physics engine. Suppose I've written one, but how can I combine it with the main routine of my game? Should I ...
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1answer
754 views

Making Ball Fling in a Curve Direction

I was wondering how to figuring out how to slice a ball (banana kick) by flinging it curve-ways. However, according to the LibGDX's gesture listener, the method for flinging only focuses on a straight ...