Relating to the motion of objects through space (in 2 dimensions (x,y)) and time. Including concepts such as acceleration (thrust and gravity), mass, collision response, friction and more.

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20 views

Relative movement in Box2D (keep object from falling off planet)

I'm creating a game with planets orbiting around a sun, like this: The brown square is the earth, rotating around its center and around the sun. The yellow square is the sun, which doesn't move. Now ...
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1answer
440 views

Spritekit - gradually apply force vector in different direction (space ship turning)

I have a space ship that I'm applying a force vector to using a joystick for control. I would like this to smoothly fly around when I'm switching directions.. Exactly like minisquadron if you've ...
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2answers
104 views

2D Boat controlling physics

I'm working on a top-down 2D boat game with Unity3D. I couldn't able to understand how to implement physics of rudder controlling. My physics knowledge is not enough to think how rudder dynamics work. ...
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1answer
122 views

Explain the difference between extrapolation and interpolation

http://www.unagames.com/blog/daniele/2010/06/fixed-time-step-implementation-box2d here there are two algorithms of smoothing in case of fixed time step physics simulation. I don't understand the ...
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0answers
12 views

How to experiment for the value of gravity in Libgdx? [duplicate]

I am following a guide on how to play a flappy bird clone in the LibGdx framework. -http://www.kilobolt.com/day-5-the-flight-of-the-dead---adding-the-bird.html I am currently on the part where the ...
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1answer
46 views

How do I derive an appropriate acceleration value for my game?

I am creating a Flappy Bird clone from this tutorial. I have a question about acceleration in libgdx. The author assigned the bird a constant acceleration vector in the constructor of the bird ...
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1answer
130 views

2D animated sprite jumping and gravity physics

I'm currently writing a Megaman clone for my school project. So far all I did was making the character run and stay put when needed. Know I want to be able to make him jump using the 'X' button. I ...
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0answers
30 views

Farseer: Friend/Foe Collision - cannot push foes but friends

we are using Farseer in our project and I try to find a setup to achieve the following quite complicated collision behavior: Friendly Units can push each other aside. However, the push should be a ...
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0answers
17 views

Implementing projectile motion on Android's canvas [on hold]

I'm going to Implement projectile motion on Android's canvas with an image like ball or something but I really have no idea how can I exactly do it. I know these formulas: X(t) = speed * Cos(alpha) * ...
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1answer
57 views

Lots of bouncing balls sink into each other [closed]

I'm trying to model a system that simulates an arbitrary number of bouncing balls with some gravity. So far I've come up with a solution that can be seen here: ...
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1answer
143 views

Mobile: Physics and movement actions

I've been using spritekit for a while for a few small games. One thing I've noticed is that spritekit is the first game framework I've used that allows me to apply move actions to physics bodies. ...
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0answers
25 views

Is there a successor to Farseer for C# 2D physics? [closed]

I'm currently relying on Farseer Physics 3.3.1 and was recently considering to upgrade to 3.5, but it appears that the project has been abandoned by its author - which makes me a little insecure on ...
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1answer
74 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 ...
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2answers
56 views

Unity2D Collision Issue

I have a crate setup (in pic below) with a rigid body component, box collider and 3 circle colliders(they allow me to push the crate most of the time without getting stuck on the floor textures which ...
63
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5answers
27k views

Good 2D Platformer Physics [closed]

I have a basic character controller set up for a 2D platformer with Box2D, and I'm starting to tweak it to try to make it feel good. Physics engines have a lot of knobs to tweak, and it's not clear to ...
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1answer
51 views

2D bouncing formula doesn't work properly

am new to unity, and i am trying to create a bouncing ball, so i've did many researches about bouncing realted physics and i found a formula : Formula: -2*(V dot N)*N + V Where V is the velocity ...
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1answer
971 views

Slope polygon collider 2D causing box collider 2D to 'bump' while sliding on it

I'm doing procedural terrain generation. So far I've created the mesh, and attached a 2D polygon collider to it. The terrain is made up of hills going up and down. After doing so, I put a 2D rigid ...
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1answer
405 views

Swinging a sword in Xcode with Sprite Kit

I'm working on making an RPG in Xcode, and I'm having a major gameplay issue when it comes to having my character swing his sword in a way that is realistic and gameplay compatible. Right now, when ...
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4answers
1k views

How do I implement deceleration?

I say "deceleration" because I'm not using acceleration at the moment; what I mean is moving the velocity back towards zero, eventually stopping. I'm new to vectors and not so great with physics and ...
2
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1answer
100 views

How can I manage the deceleration of units so that they arrive on-target?

When I first started trying to set up my air units' movement in my RTS game, I thought it was going to be easy with simple Euler method linear acceleration. This was far from the case as the ship ...
2
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1answer
171 views

How to impale and stack targets correctly according to the collider and its coordinate?

I'm making another simple game, a catch game, where a spawning target game object must be captured using a skewer to impale it. Here how: At the start, the falling object (in red) will fall in a ...
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1answer
40 views

How to reposition a bouncing ball after it has passed through a surface

I have a bouncing ball which can collide with lines of a random slope. The ball passes through the lines a bit and I need to set the ball back some distance from the line. The ball (defined by ...
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2answers
198 views

Sprite Kit - containsPoint for SKPhysicsBody?

I have a ball bouncing around the screen. I can pick it up and drag it onto a "bucket". When my touches finish, I use the containsPoint function to check and see if I have dropped the ball onto the ...
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2answers
467 views

Use both AddForceAtPoint and change velocity property?

I'm using Rigidbody2D for some game objects. It seems that when I AddForce() or AddForceAtPoint(), the game objects are mostly affected on the Y axis and hardly at all on the x axis. I don't ...
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3answers
60 views

Unity2D: Apply gravity to some items, when everything else is gravity-free?

Sorry for the incredibly vague title: Let's say you have an NPC, and when he dies he'll spawn items, coins for example. Instead of just pushing the coins in random directions it would look a lot ...
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3answers
103 views

Unity rigidbody2d.velocity jumping causes weird bouncing

Im working on a game 2d game that has some platforming. I followed this video as guidance and produced the following code: public class PlayerControler : MonoBehaviour public float ...
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3answers
125 views

Formula for Planetary Alignment

I am attempting to create a game where there is a universe of two 16-bit addresses ranging from -32768, -32768 to 32767,32767, or in hexadecimal, each value can run from $8000 to $FFFF then 0 to ...
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2answers
138 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 ...
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0answers
31 views

SpriteKit: Is applyImpulse not working correctly?

I am writing a free throwing system and because of this, I created a ball using following code. self.ball.position = CGPointMake(posX, posY) self.ball.fillColor = SKColor.blueColor() ...
7
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1answer
949 views

How to simulate feather fall in box2d?

I am working with AndEngine with Box2d extension, but general answer or a concept idea will be appreciated too. I have feather-like objects in a 2D side view world that I want to be part of the ...
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1answer
45 views

Anchoring HingeJoint2D to clicked upon spot

I'm creating a 2D game where the user can click and drag objects around. This is done by connecting a 'Hand' object to the object the user is current clicking on with a HingeJoint2D. Right now it ...
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0answers
18 views

How to tell if the ball is on the floor (in nape)?

What I wish to do in pseudo code: points = Get the set of all points (x, y) where the ball is touching other surfaces. point = Get the point out of that set with the minimal (y) value. Check if that ...
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1answer
104 views

Creating a Player object in a physics engine [duplicate]

I have a working physics environment using Farseer - but how do I create a player object that can walk around? My current attempt involves applying forces to a rectangular body whenever keys are ...
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1answer
67 views

Throwing a bomb LibGDX Box2D [closed]

I am trying to create game where somenone throw a bomb. I am wondering how I can have an bomb react in a way that is represented by the following picture : Is there are any tools in Box2D that can ...
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0answers
92 views

How to render multiple objects as a single object for fluid simulation?

I'm trying to do fluid simulation using particles in 2d game. I have larger particles, which interactive each other physically, those particles collide with environment (e.g wall,obstacles) to ...
2
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1answer
70 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 ...
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1answer
34 views

Reduce bounciness of dynamic bodies in Box2D

In my 2D platformer game my player character is modeled using a Box2D dynamic body. One thing I thought feels off though is that even though the restitution of the fixture applied is zero, the player ...
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2answers
52 views

Irregular gravity bouncing

I am working in a simple bouncing ball game. The ball moves right to left at a constant speed and back when it collides with the border of the display. But it jumps every time the the user clicks and ...
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0answers
16 views

Box2d - body size or spatial distribution matters for better simulation?

Box2D better works for limited sizes: Box2D works with floating point numbers and tolerances have to be used to make Box2D perform well. These tolerances have been tuned to work well with ...
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0answers
40 views

Calculation technique for 2D inertia tensors?

Just wondering what the techniques are out there. It's only 2D so I figured there'd be a good chance for there to be a "one size fits all" solution out there that's essentially an analytical solution. ...
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0answers
86 views

Should I use Box2D for collision-detection only (not simulating physics)? [closed]

I'm using Box2D only to check collisions and for no physical simulation. I create bodies (and shapes for them) and use my own code to move them, by setting their velocities and positions every frame. ...
0
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1answer
107 views

Cocos2dx - Physics - Abort() When Changing Dynamic PhysicBody to Static?

I just learned cocos2dx v3.3 integrated chipmunk physics engine. Here ,as you see, I create a simple circle with physic as: auto sprite = Sprite::create("circle.png"); auto body = ...
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0answers
65 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 ...
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0answers
68 views

Breakout Clone: Ball isn't bouncing as expected

So I'm working on a Breakout Clone using Unity 2D Physics only, and I'm having some trouble with the bouncing effect. Every object in my Scene has a Bounciness of 1. First, this is the code of my ...
2
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1answer
95 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. ...
8
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4answers
17k views

2D character controller in unity (trying to get old-school platformers back)

This days I'm trying to create a 2D character controller with unity (using phisics). I'm fairly new to physic engines and it is really hard to get the control feel I'm looking for. I would be really ...
3
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2answers
189 views

Why is Euler integration sometimes preferred over RK4 even if RK4 is more accurate? [closed]

Some high quality engines such as Box2d uses the Simplistic Euler integrator instead for RK4 when Eumplectic Euler commits a global error of the order of Δt whereas, RK4 has Δtˆ4 error? RK4 is not ...
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1answer
150 views

Box2D recommended step, velocity and position iterations

Here in this article there is a nice explanation that velocity iterations and position iterations settings affect the way bodies will react when they collide, and step affects on speed and how gravity ...
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1answer
107 views

How to make an object that has no rigidbody2d component smoothly fall on the ground in Unty2d?

I have two character in my game: enemy and main character. Enemy can throw different objects into the main character. For this moment i am doing this action in such way: void FixedUpdate(){ if ...
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1answer
132 views

Bullet - objects falling through

I have problem with bullet collisions. You can see problem on this video (around 0:18): http://goo.gl/DiVP8l Objects are "embeded" inside vertical bars - that is not correct - they should be ...