Tagged Questions

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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0answers
15 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. ...
1
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0answers
49 views

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

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. ...
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1answer
24 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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1answer
33 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
46 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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1answer
36 views

Throwing a bomb LibGDX Box2D

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
45 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 ...
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2answers
87 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 ...
3
votes
2answers
156 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
46 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 ...
0
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1answer
64 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 ...
2
votes
1answer
92 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. ...
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1answer
64 views

Creating a Player object in a physics engine

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 ...
0
votes
1answer
19 views

Should device tilt give my object a starting speed or acceleration?

I'm developing a game for iPhones, which have a body placed in the bottom center of the sreen, and I want to move that body in horizontal axis by player tilting his device in y axis. Everything ...
0
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0answers
78 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 ...
0
votes
1answer
92 views

2D physics collision/gravity problem?

I'm using Love2D and my own physics engine to create a 2D platformer. Y collision works fine, but X collision... well, it's a bit buggy. When I move off of a small platform I've created, I fall but it ...
0
votes
1answer
55 views

Trigger an event when a game object touches a non-solid game object

For a 2d game, I are currently making an AI and I want it to jump when it touches a invisible cube, which isn't solid, how do I do this?
4
votes
3answers
475 views

How do I procedurally animate a cell eating another cell?

The entities in my game are soft-body, amorphous cells. I'd like to create an animation where enemies are engulfed by the player's cell. That is, I want to generate a "cell eating another ...
3
votes
2answers
202 views

A Star pathfinding algorithm, multiple node set optimization

I'm trying to determine if this is an optimization I should pursue or if this is way to complicated to be worth my time. I've successfully implemented the A Star Algorithm for my video game. I used ...
1
vote
1answer
52 views

Numerical integration of multiple off-center forces on a solid body

I am trying to develop a little simulation (for the sake of learning a little bit about physics) involving a circle (mass m, radius r, regular density) and two forces f1, f2 that can be applied on any ...
-1
votes
2answers
64 views

Speeding up sprite the second time it passes the screen [closed]

I'm a student studying Games Development. I want a sprite to speed up on it's second passing of the screen. How do I do this? Code I wrote so far: public class Game1 : Microsoft.Xna.Framework.Game { ...
2
votes
1answer
126 views

How can I simulate a magnet that attracts a ball in a 2D enviroment?

I am making a top-down game where you have to move a ball from point A to point B. You are attracting the ball using magnets that are standing still. The ball needs to get pulled by multiple magnets. ...
0
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0answers
31 views

How to determine positions to draw lines on a screen with AndEngine

I have a screen (480x800), M(mx, my) is a static point, and N(nx,ny) is a dynamic point on screen. Position of N(nx, ny) depends position of touch. I want to determine position of P(?,?) and Q(?,?) to ...
0
votes
1answer
579 views

Unity 2D, C# - Make object move diagonally by a certain angle?

I have a sprite object which I want to move in 8 directions. Left, Right, Up, Down, Left top, Right top, Left down, Right down. The view is 2D with a isometric projection. The difficulties I am ...
0
votes
1answer
66 views

Incosistent jump, stuttering

I've written this C# code to handle movement in my testing project. The game is supposed to be 2D, some kind of a platformer, just to get me started with Unity. However, it seems there's something odd ...
2
votes
2answers
82 views

Implementing a motorized hinge joint

I have a 2d physics engine, with three boxes: "body", "left wing" and "right wing". The wing boxes are connected to the body using a hinge joint. The physics world has no gravity. I'm attempting to ...
1
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0answers
233 views

Ease Rotate RigidBody2D toward arbitrary angle

I'm trying to make a rigidbody2D circle return to an orientation after a collision. But there is a weird behavior I do not expect - it always orients to the same direction. This is what I call in ...
1
vote
1answer
170 views

Consistent Space Gravity Simulation

I have done some reading into this subject but haven't been able to come to a conclusion that I'm really satisfied with so far, so here is the situation. I have a game set in space, its top down and ...
0
votes
1answer
97 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 ...
5
votes
2answers
117 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
1answer
359 views

Unity WheelJoint2D will not rotate when increasing motor speed

I have a wheel joint 2D attached to a game object in Unity: In its associated wheel script I am increasing the motor speed as described in the tutorial. public class Wheel : MonoBehaviour { ...
1
vote
0answers
38 views

How to handle car game circuits in a top-down view?

I'm already using a physics engine (box2d) but i have no idea about how should I implement circuit's path with wall collision. I tought about checkpoints but this doesn't solve the wall collision.
1
vote
1answer
274 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 ...
0
votes
1answer
340 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 ...
1
vote
2answers
262 views

How to detect collision on specific part of the sprite node

I have a spike and a ball is falling down, when the ball touches the top point of the spike, I want to make the ball invisible, and when it touches on the other part i.e on the sides I don't want to ...
2
votes
1answer
108 views

Best practice for organizing the physics of objects?

Apologies because this is a long post and I am inexperienced. I would really appreciate the input from some experienced developers. These are my two goals for this project: To learn the best ...
-1
votes
1answer
247 views

Trajectory Projectile with Collision Detection

Right now I am trying to create projectile for cannon in which I want to detect collision also. At present I have simple working projectile after using two references Unity – How to display ...
2
votes
1answer
125 views

Frame-rate independent friction on movement in 2d game

I have been trying to implement a simple physics system for a 2D space game I am making. I have it pretty much working, but I have encountered an issue with the way I apply friction. I have tried ...
0
votes
0answers
82 views

Box2D collision damage calculation from postSolve or not?

I'm using postSolve to get impulse then calculate damage base on that impulse. But there's some issue: Stability The damage isn't stable. When the same ball is hitting with same speed, the damage ...
1
vote
2answers
140 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. ...
0
votes
0answers
58 views

Particle friction with variable timestep in XNA

Alright, so I'm working on an engine of sorts in XNA (yes, it's deprecated, I know) and I'm implementing my own particle system. I've defined a "ParticleEffect" such that when it's supplied a GameTime ...
2
votes
1answer
215 views

Inverse Explosion with Unity2d

I am currently trying to make all other objects push away from the player when the player explodes. It currently works, but it pushes close objects a little and far objects very far. What I want is ...
0
votes
1answer
109 views

Resolution independent physics

I'm making a game like Doodlejump but don't know how to make the physics scale on multiple resolutions. I also can't find anything related to this on Google. Right now I'm scaling the game using ...
1
vote
1answer
71 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 ...
0
votes
2answers
218 views

How can I make an object's hitbox rotate with its texture?

In XNA, when you have a rectangular sprite that doesnt rotate, it's easy to get its four corners to make a hitbox. However, when you do a rotation, the points get moved and I assume there is some kind ...
0
votes
1answer
146 views

Bouncing ball slowing down over time

I use the unreal engine 4 to bounce a ball off of walls in a 2D space, but over time the ball gets slower and slower. Movement happens in the tick function of the ball FVector location = ...
2
votes
2answers
174 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 ...
-1
votes
1answer
149 views

simple collision detection with box2dweb

im beginner in box2dweb that version of box2d for javascript i wrote simple gravity system and i want to detect the collision between the box and the ground , when the falling box hit the ground ...
0
votes
1answer
141 views

Can I have a fixed-angle sprite with a non-fixed-angle CircleCollider2D?

In Unity2D, can I have a fixed-angle sprite with a non-fixed-angle CircleCollider2D? I would like to move my character using the circle physics (without fixed-angle), but display him always as if he ...
0
votes
0answers
38 views

Box2d not showing consistent behaviour with sprites

Box2D newbb here. My question is in regards to this create js project:http://mboyeman.com/dashingdog/ (runs best in IE...:3) I wrote a function(assignBlockBodies) to give 2D Edges to sprites based on ...