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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2
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1answer
266 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
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1answer
118 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
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2answers
240 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
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1answer
178 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
184 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
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1answer
166 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
185 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
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0answers
40 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 ...
4
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2answers
461 views

How to circle a target at a constant distance

I have an AI ship that stops approaching when it gets within firing range, and starts strafing around its target. The problem is that it doesn't circle its target very well. The following code ...
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2answers
753 views

Platformer Collision Detection Order

I'm attempting to create a 2D Platformer Game and I'm having difficulty with the physics I have implemented. Each loop my code does the following: Apply the physics to a temporary X and Y ...
1
vote
1answer
148 views

Mixing interpolation with extrapolation in multiplayer game

I am creating a multiplayer drag racing game and have difficulties mixing extrapolation and interpolation. To save network bandwidth i am getting information from the opponent only on his button ...
2
votes
1answer
187 views

2D physics rotation w/ XNA

I'm creating a simple game with space ships made of blocks that are all the same size. After having looked at this: Calculating the rotational force of a 2D sprite I have created the following code ...
2
votes
2answers
178 views

How do I implement friction in a billiards game?

I'm having trouble implementing friction in a billiards game. Currently, the ball only slows on collision with the edges, but I also want some friction with the background. How can I implement ...
1
vote
2answers
53 views

Custom Physics: Preventing objects from losing velocity in certain situation

Illustration: http://s22.postimg.org/7agd30vap/Untitled.png So the little box is my character. The red arrow shows the current velocity(Some force to right + gravity). Below it are 2 blocks which has ...
1
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0answers
72 views

Storing rigid body collision shapes in local or world coordinates

I'm writing the beginnings of a lightweight 2d rigid body engine (in javascript, as a hobby project), and i'm debating whether to store collision shapes in local or in (updated as needed) world ...
0
votes
1answer
131 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. ...
1
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2answers
157 views

How to know when all 2d rigid bodies have stopped in unity3d?

Is there anyway to know if all 2d rigid bodies in untiy 3d phisics world have stopped?
0
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0answers
124 views

Moving objects smoothly, bad perfomance

I just finished developing my mini-game on Android and I got some questions about perfomance and generally "how to": If I have 25+ objects on the creeen (just a polygon with 7-8 angles) its starts to ...
2
votes
1answer
192 views

How do I convert a partially transparent image into polygons?

I'm using GLEE2D, a level editor allowing me to import images, scale them, rotate them, and position them onto layers and export the data into XML format. However, it does not tell me objects' ...
-1
votes
1answer
45 views

How to predict physics movement [duplicate]

How to predict the movement of the body when a force is applied on it like in the https://play.google.com/store/apps/details?id=com.game.basketballshoot I have attached screen shot as reference.
0
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0answers
136 views

How to find correct offset to adjust sprite to the position of box2D body after rotation

I am trying to implement phsyics with the as3 box2d port. I currently have a b2body for each of some certain sprites in my game and I am able to update the sprite's positions correctly from the ...
0
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0answers
53 views

Apply impulse to ball to a fixed height Jbox2D android

I have to hit a ball to a fixed height repeatedly as shown in the following image. This game is similar to 1983 Hitit The difference is the hitting y axis will be variable. I wanted to hit the ...
0
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0answers
20 views

Artificial physics : ball angle bouncing (Vector2) [duplicate]

My question is : how can I manage to move my object (ball) on a trajectory , and onContact with another object, it bounces, respecting the angle
1
vote
1answer
906 views

Movement and rotation of bodies in top down game

We are developing a 2D top down game with libgdx using the included box2d as physics engine. We don't want our bodies to accelerate but to instantly move with the wanted velocity. The bodies are ...
1
vote
1answer
87 views

Calculating the point(s) at which two moving objects are a certain distance from each other

Problem This is similar to a Closest Point of Approach calculation, but instead of the closest point(s), I want the points at which the objects are a given distance away from each other. (Imagine two ...
3
votes
1answer
163 views

Calculate point of circle–circle collision between frames

I need to find the exact XY coordinate where a circle collides with another circle calculated between frames. This means that I take the coordinate of the moving circle on the previous frame and take ...
8
votes
3answers
2k views

Is a separate thread for game loop compulsory for simple games?

I am new to game development. In order to learn I am recreating this game on android platform. You can observe the game-play video at the above link. It is a simple game. I have read a lot of ...
2
votes
1answer
163 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 ...
4
votes
1answer
569 views

Algorithm for randomly generating reachable platforms

I want to randomly generate reachable platforms on the fly for a 2D game. Right now, I am just creating platforms at random x,y positions. Only 4 platforms can exist at once, so once the 5th one is ...
0
votes
1answer
355 views

How do I determine a good path for 2D artillery projectiles?

I'm building a little "tank wars" game (like this one). I understand the math, and I am able to define a parabola from the launcher to the objective I want to reach. The parabola depends on the ...
0
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0answers
171 views

Calculate mass moment of inertia of two 2D polygons

For a small 2D physics engine I need to know the following. I wasn't able to find an answer even after a week of research. Hope you can help me. I have multiple concave 2D polygons that are tight ...
3
votes
1answer
172 views

Calculating impulse with multiple collision points

In my amateur 2D rigid body physics engine for a game I react on collisions between two bodies with an impulse j (formula 11) as explained here. To calculate this impulse I need one contact point P ...
4
votes
1answer
259 views

How do I simulate a trampoline?

I'm quite new to game development. I was pretty impressed with the elastic effect I saw in this flash game when the ball hits the trampolines and I'm wondering how to recreate it. I've done some ...
2
votes
2answers
211 views

Collision detection via adjacent tiles - sprite too big

I have managed to create a collision detection system for my tile-based jump'n'run game (written in C++/SFML), where I check on each update what values the surrounding tiles of the player contain and ...
5
votes
3answers
354 views

How do you calculate the rotational velocity of a flying object?

When a arrow shaped object is fired it slowly adjusts it's rotation to match the direction it is moving. But what is the actual physics behind it? The question is: How many degrees does the ship ...
0
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0answers
54 views

Lateral Friction Phisics

I am trying to create a physics engine for my game, and need to cancel out any lateral velocity for when entities turn. I have tried to mimic this page's example, but it is not working. I have objects ...
0
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0answers
50 views

Memory Management on Physic Body Frames in Unity

Compared from the Android programming with the help of LibGDX and Eclipse programming software in making 2D physics based game from this previous question, what if I'm throwing lots of game objects ...
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0answers
43 views

Calculating Friction due to rotation from ball bounce? [duplicate]

In this question asked by codemonkey, The rotation will depend upon: upon impact, on: Initial Speed of the ball hitting the surface (magnitude of ball velocity vector) Friction co-efficient of ball ...
2
votes
0answers
53 views

How should I model rotation caused by bounce friction? [duplicate]

In my Java2D simulation, I have a disc which, when it bounces off the boundary of a 2D region, begins to rotate, as if it had gotten some spin from the wall. I'm having trouble relating the ...
-3
votes
1answer
390 views

Simple collision detection implementation [closed]

I'm making a game with C++ where the program extracts the lines out of an image (via openCV), stores them in an std::vector< std::vector< int > > and the builds a tile map out of it which is ...
0
votes
1answer
894 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 ...
0
votes
3answers
675 views

Applying a torque to a different centre of mass

In Unity I have an object with a circle collider attached to it and when I apply a torque to this object's rigidbody2D, it rotates as expected. However, I have now attached a sub-object to this object ...
0
votes
1answer
2k views

How do I get parabolic movement in Unity using Rigidbody2d?

EDIT: It was the Animator after all. Apply Root Motion basically nullifies any physics based work. I "know" this answer but I can't figure out what can possibly be wrong. My code is in FixedUpdate(). ...
2
votes
3answers
450 views

How should I implement basic spaceship physics?

I am new to 2D game development. I've made several games, but they've made almost no use of physics. Now I want to try making a game that uses some basic physics to look more realistic. The game ...
1
vote
1answer
152 views

How do I calculate the motion of 2 massive bodies in space?

I'm writing code simulating the 2-dimensional motion of two massive bodies with gravitational fields. The bodies' masses are known and I have a gravitational force equation. I know from that force I ...
0
votes
2answers
442 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 ...
0
votes
1answer
700 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 ...
2
votes
1answer
2k views

Understanding Torque in Unity

This is (hopefully) a simple question that should avoid me asking a more complex question. This is in Unity (2D) but hopefully this is a general physics principle I am not getting. I am applying a ...
2
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2answers
162 views

How to obtain “gravity” and “initial impulse” given “desired time to reach max height” and “desired max height”?

I'm developing a 2d fighting game, using time steps based on frames ie, each call to Update() of the game represents a frame so, no variable time at all. My jump physics code doesn't need to consider ...