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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1answer
77 views

CGVectorMake to move SKNode at a certain speed towards the middle of screen?

I am trying to launch my ball sprite towards the middle of the screen at the same speed every time I launch it. let vel: CGFloat = 1000 dx = size.width / 2 - ball.position.x dy = vel - size.height / ...
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2answers
69 views

Gravity Simulation failing at short distances

I have a 2D space simulation with gravity acting on three bodies (e.g. sun and 2x planets). The simulation seems pretty stable with RK4 (was unstable with Euler). The problem arises if the orbit of ...
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1answer
185 views

Dynamic body in Box2D with fixed position

I need to fix the dynamic body position so that it would not rotate and would not move even if there are other forces, collisions and so on. Let me first explain why I need this. I have a dynamic ...
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1answer
72 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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3answers
96 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
152 views

How to make an object oscillate left and right?

I can't seem to make an object move left and right, back and forth, on room start whilst on solid ground. Codes I used: Step Event: if image_index is greater than 5, then physics_apply_force ...
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1answer
98 views

Simplified aerodynamics for 2d (top-down) airplane

I am writing a top-down 2d game, in which the player can control an airplane via the WASD keys. The W key should move the plane upwards (north), the A key to the west, and so on. Now I need a ...
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1answer
57 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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1answer
36 views

Altering Animation Playback Given Terrain Information

Say my character has a jog animation. Assuming Y is vertical, his feet leave the ground at Y=0 and hit the ground again at Y=0. This works fine in a world like that of Minecraft, where every surface ...
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1answer
128 views

How can I have a Mecanim animation with displacement and physics?

I have 3D wolf models from my animator with displacement (i.e the wolf transforms with animation, not in-place). I have added rigid bodies to the models. I am facing following issues while executing ...
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2answers
105 views

Adding gravity to arrival steering behavior

I trying to write an autopilot for the classic Lunar Lander or its clones. According to this paper, the arrival behavior is exactly what I need for a soft landing. In this example, it accelerates at ...
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1answer
168 views

How can I implement smooth digging effects in a tile-based game?

I'm trying to make a Dig Dug styled game where you will be digging into a material. This is going to be a tile-based HTML5 game and I have decided to use the Phaser framework. One way to do the ...
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1answer
96 views

Ground in AndEngine

I'm quite a newbie to AnEngine and I have a problem. I have been searching a lot, but I couldn't find answer. I'm trying to make my first game, but I have no idea how to make ground. I'd like to make ...
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2answers
1k views

Unity - Mecanim & Rigidbody on Third Person Controller - Gravity bug?

I'm working on a third person controller which uses physX to interact with the other objects (using the Rigidbody component) and Mecanim to animate the character. All the animations used are baked to ...
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1answer
448 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 ...
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1answer
126 views

Irregular oval collision detection

I am using a physics library based on the Bullet physics engine. How do I create an egg shaped object or a cylinder where the width differs from the depth (i.e. with an oval shape)? I'm not looking ...
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1answer
366 views

What is the appropriate way to implement wobble/balance mechanics in Unity 3D?

We are trying to implement a minigame where the player character sits on a bouncing ball, and needs to a) hit forward to move forward and b) hit left/right to adjust against the the ball's natural ...
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1answer
403 views

How can I implement a more realistic momentum system in Unity 4.5?

I'm just starting out with Unity and am making a simple environment where there is a sphere and a ramp. When the sphere approaches the ramp everything is fine. As soon as the sphere hits the ramp is ...
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2answers
700 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 ...
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4answers
519 views

What is the easiest way to make an object follow the edge of a sprite?

I have a rounded rectangle sprite and another sprite that's just a circle. I want the center of the circle to follow the edge of the rounded rectangle. Is there any easy way to accomplish this task? ...
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1answer
96 views

2D how to add graphics for liquid physics?

I was always wondering how to add the graphics to a a blob body for example, regardless of what engine or library you are using, i want to know (theoratically) how to move from this state : ...
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1answer
387 views

Unity: Rolling a ball around a spherical planet with forces

I'm trying to make a game in Unity where the player character is a ball (a sphere), and the game world is a planet (a very large sphere) that the ball can roll around on. The ball can be rolled in any ...
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2answers
2k 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 ...
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1answer
203 views

How to correctly handle multiple movement key presses resulting in double the speed?

I am trying to implement acceleration and drag into my top-down 2D game. The player can move using the WASD keys. Acceleration works fine, but the way I handle the directional velocity causes the ...
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2answers
271 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?
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1answer
100 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 ...
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1answer
119 views

How to apply steering to a physics body correctly when using a physics engine?

I have a top down 2d game that uses a physics engine (Farseer). I'm using the standard steering behaviors to make the AI move around but I'm not sure the correct way to take the so called "steering ...
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3answers
1k views

Do two balls of different mass bounce different heights?

There are two balls and the only difference between them is the mass. Both are dropped from the same height on to the floor (static object with infinite mass), would both balls bounce up to the same ...
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1answer
157 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 ...
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1answer
1k 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 ...
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1answer
261 views

How can I implement jumping in a 2D game using bounding box collision?

Problem: I'm trying to implement basic jumping to my 2D game engine, but have failed several times. Basically what I've done so far is disabling gravity and using a separate function moving the player ...
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1answer
2k views

Basic Car Movement, Converting 2D Vectors to 3D problems

I'm trying to follow this guys method for steering a basic car. Link. It's the first example I can sort of get my head around and I'm trying to convert it to a working 3D version. To get some scope, ...
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1answer
241 views

Block player movement

What do i need to keep my player model from going through environment objects like walls, trees etc? Im trying to figure out if should use rigid bodies and the built in physics but i feel that its ...
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3answers
510 views

Bouncing ball isssue

I am currently working on the 2D Bouncing ball physics that bounces the ball up and down. The physics behaviour works fine but at the end the velocity keep +3 then 0 non-stop even the ball has stopped ...
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1answer
122 views

Adding Leniency to Jumping Mechanic

I have written some jumping code for my player in a platformer game. At the moment it has some basic logic which says that the player can jump if he is on the ground. The pseudocode looks something ...
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1answer
1k views

2D Destructible Terrain with Box2D / Cocos2D -> Image Tracing

Bear with me as this will be a rather lengthy post. For the last month I have been working on an open source Cocos2D, Box2D Destructible Terrain Engine. I have some questions regarding its ...
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2answers
577 views

Jump without bouncing in physics engine

I am using Ogre3D as my rendering API, and OgreBullet as my physics engine. I have an test entity that when the y part of the velocity is 0 and spacebar is pressed, the velocity changes to, lets say: ...
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1answer
196 views

How to make a character “jump” when leaving an up slope?

I have developed a game in Android using a tile-based system. I´ve implemented 22º, 45º and 67º up and down slopes and everything works (almost) perfect. The problem now is that, when the character ...
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1answer
214 views

Farseer: How can I remove a body?

I have many sensors(coins) in each level and I want to remove the sensors(coins) when the player rectangle(Mario) touches them. I check in OnCollision if Mario touches a coin, if he touches it, it ...
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1answer
388 views

Getting BEPUphysics to draw its entities

Isn't there a way, to force BEPUphsyics to show what it is doing? I am here with my existing XNA project, starting to put in BEPUphysics, but I am not seeing what it is doing. Take my model for ...
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1answer
288 views

Simple 3D particle gravity in javascript? [closed]

I'm trying to do some simple gravity handling in my 3D environment (I'm using three.js). I've got some code, but it doesn't work. I'm hoping it's just a silly bug somewhere. Note: This is a ...
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2answers
250 views

limiting jump forces to achieve a maximum jump height [duplicate]

A player and the world are modeled using a physics engine. Jumping is modeled by applying a vertical upward force to the player's physics body when the jump button is pressed. The upward force is ...
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1answer
387 views

Debug Render In Cocos2d Android

I want to implement debug render for cocos2d android.So I can view how bodies are created. Right now I use gdx.jar file for box2d and load that jar file following way. static { ...
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1answer
259 views

C++ Using clock() with IsKeyDown

I am trying to replicate the game Asteroids as a class project. I am having trouble measuring the time elapsed while the "W" key is pressed. This code is supposed to increase the force applied to the ...
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2answers
356 views

Basic plane kinematics

I never did physics in my life and this is really hard for me. I am currently trying to implement movement in the X and Y axis of a plane, in a video game I am making. What I want to do is, given a ...
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1answer
92 views

Looking for a peer reviewed article that details the benefits of a physics simulation within interactive media [closed]

I'm hoping this is the correct place to ask this question as it is video game related and can be seen as a key ingredient in modern game development. Does anyone know of a peer reviewed article that ...
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1answer
373 views

XNA (BEPU) Physics Performance

Im using XNA 4.0 with the BEPU physics engine v1.2 and I have encountered some performance problems on Xbox. Im not sure if the my mesurements are an expected result of the Xbox (with alot of dynamic ...
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1answer
301 views

What physics engine support force fields and bodies represented as points?

I need a game engine that supports force fields in 2d or 3d, but suitable for 2d calculations, like bullet. Each body I want to simulate is represented as a set of points. Each point has positive ...
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1answer
405 views

Point inside Oriented Bounding Box?

I have an OBB2D class based on SAT. This is my point in OBB method: public boolean pointInside(float x, float y) { float newy = (float) (Math.sin(angle) * (y - center.y) + Math.cos(angle) * ...
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1answer
289 views

What is going on in this SAT/vector projection code?

I'm looking at the example XNA SAT collision code presented here: http://www.xnadevelopment.com/tutorials/rotatedrectanglecollisions/rotatedrectanglecollisions.shtml See the following code: private ...