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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2answers
408 views

Character bounces/stutters down hills

I'm using Unity3D (not 4) and I'm experiencing a bit of a problem with character movement. I'm using a cylinder as a First Person player with a child Main Camera. In this cylinder is the stock ...
0
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1answer
28 views

Moving multiple hingejoints based on joystick input

I'm controlling a 2D side-viewed (facing right) stickman with a joystick. The movements are fairly intuitive: Joystick down -> Stickman crouches down Joystick up -> Stickman stretches out ...
4
votes
3answers
345 views

How do I resolve a sphere-triangle collision in a given direction?

I am trying my hand at game physics. I understand that the basic way to pull back a sphere when it collided is to negate the penetration distance: // If collided... // `distance`: distance form ...
6
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2answers
207 views

Timestep schemes for physics simulations

The operations used for stepping a physics simulation are most commonly: Integrate velocity and position Collision detection and resolution Contact resolution (in advanced cases) A while ago I ...
2
votes
1answer
133 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 ...
0
votes
1answer
146 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
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0answers
80 views

PhysX - Revolute joint around unit vector

I'm using a right-handed coordinate system with (0,0,-1) = forward, (1,0,0) = right and (0,1,0) = up. PhysX version is 3.3.0. I have a unit vector which represents the axis around which my actor is ...
3
votes
2answers
221 views

Why are my Box2D wheels slipping on ground?

I have a car, set up in Box2D as a rectangle connected with two wheels using WheelJoints: The wheels are defined as follows: FixtureDef wheelFixtureDef = new FixtureDef(); ...
8
votes
3answers
728 views

Can I jump from A to B?

I'm making some rudimentary AI for my side-scroller and I need to know whether an AI unit can reach point B from point A simply by taking a jump. Flight trajectory of my characters is a bit unusal as ...
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0answers
61 views

CCTextField won't appear

I can't seem to add a CCTextField in my physics node, I tried all different methods, but it's still not happening. Here's my code: CCTextField *tf = [[CCTextField alloc] init]; tf.contentSize = ...
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2answers
403 views

How to add a constant horizontal force just like gravity?

I want to add a constant horizontal force, just like gravity to a projectile or a sphere moving in 3d space, which will make the projectile or ball or sphere or whatever be influenced by this force so ...
3
votes
1answer
202 views

Unity's default integration method

Which method(s) does Unity provide for physical integration? RK4? Verlet? Euler?
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vote
1answer
6k views

LibGDX Box2D Body and Sprite AND DebugRenderer out of sync

I am having a couple issues with Box2D bodies. I have a GameObject holding a Sprite and Body. I use a ShapeRenderer to draw an outline of the Body's and Sprite's bounding boxes. I also added a ...
1
vote
1answer
485 views

2D Collision in JavaFX - Bad accuracy with .intersects()

I have several Shape objects - Circle, Rectangle and Polygon. I use the built-in .intersects(Bounds1, Bounds2) method to detect collision but it's quite inaccurate. Circle c1 = new Circle(20); ...
0
votes
0answers
161 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
1answer
154 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 ...
5
votes
1answer
200 views

Self colliding cloth physics

I've previously simulated cloth using Verlet integration but couldn't successfully get the cloth to collide with itself in an efficient way. The reason being is because I used a brute force algorithm ...
2
votes
2answers
59 views

How can I add an impulse to specific rigid bodies at rest?

Scenario Rocks falling down a rocky slope, with a flat surface at the bottom. When they land on the surface, the rocks move slightly before coming to a rest. GLESDebugDraw shows the bright orange ...
2
votes
1answer
451 views

Is there a way to view all colliders in a unity project at runtime (after the game have been deployed)?

I'm have created a small Unity project but physics has weird behavior (bug). Unfortunately it only happens on some specific hardware (after build), not on development machine. I don't know what is ...
0
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1answer
78 views

How to resolve OBB collision penetration?

I would think this is a common issue, but I couldn't find an answer that helped me. Help would be appreciated. In my game I have rectangular objects. They have rotating bounding box, aka not AABB but ...
0
votes
1answer
55 views

How can I avoid type checking in the physics side of collision handling?

I have a class responsible for handling the physics side of collisions. When the collision detector spots a collision, it notifies both entities in the collision to take care of gameplay. It also ...
5
votes
2answers
278 views

How can I synchronize ocean waves over the network?

I've been performing a little bit of research in my spare time on ways to increase the interactivity of environments in a networked game or simulation. One of my areas of research is fluid-dynamics ...
1
vote
1answer
36 views

Forces on entities: remove all each update step, or remove on demand?

Following the answer to my question here, the way I apply forces on an entity, is each entity has a Map of forces (Vectors) and their IDs. Every update step, the acceleration vector is set to the sum ...
5
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6answers
507 views

Increasing efficiency of N-Body gravity simulation

I'm making a space exploration type game, it will have many planets and other objects that will all have realistic gravity. I currently have a system in place that works, but if the number of planets ...
2
votes
2answers
160 views

How to correctly implement player acceleration caused by player input

In my game I implement movement in the Player class like so: // called from Player's update() method, which is called from the gameloop. void move(){ velocity.x += acceleration.x; velocity.y ...
1
vote
1answer
95 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 : ...
4
votes
2answers
204 views

2D Enemy AI reacting to sound

I'm currently working on a 2D top-down survival game and I'm trying to figure out a good method for enemies to detect player sounds. For instance - if the player fires his gun it should play a sound ...
1
vote
1answer
59 views

Accelerated Motion

I'm making a menu for my game with SDL, when you click on an option a sub menu slides down and is shown, just sliding down is really boring, so I want it to accelerate(like if gravity was pulling it) ...
3
votes
1answer
223 views

How do I run a callback when all objects have stopped moving?

I'm using Bullet and want to take some action once all objects in a dynamic world have reached 0 velocity (or at least a value that's very close). I was trying to iterate over all of them all the ...
9
votes
2answers
1k views

What is the best way to handle simultaneous collisions in a physics engine?

I'm writing a 2d physics engine in javascript so that I can learn more about physics in video games. I have it working correctly for rigid body collisions, except for if any body collides with two or ...
16
votes
2answers
5k views

Why is RK4 better than Euler integration?

At the end of these great slides, the author compares all the different integrators presented. One way or another, they all fall short except for Improved Euler Integration and Runge Kutta 4 ...
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1answer
351 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 ...
-1
votes
3answers
534 views

Can these game be fully coded in html5/javascript? [closed]

I mean the mechanics of the game. Would it be possible? -Pokemon GBA series, rendering the world would be easy, but what about battle mechanics? -MapleStory, after seen dragonbound.net which is an ...
0
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2answers
144 views

Without using a pre-built physics engine, how can I implement 3-D collision detection from scratch? [closed]

I want to tackle some basic 3-D collision detection and was wondering how engines handle this and give you a pretty interface and make it so easy ... I want to do it all myself, however. 2-D ...
6
votes
1answer
414 views

2D Polygon Triangulation

I am creating a game engine using the JBox2D physics engine. It only allows you to create polygon fixtures up to 8 vertices, To create a body with more than 8 vertices, you need to create multiple ...
5
votes
3answers
1k views

Is it a good plan to use 2D physics for a 3D racing game? [closed]

I am working on a 3D racing game using SDL and OpenGL. I thought it would be easier to use a 2D physics engine, since I really don't need the 3rd dimension. There will be no flying cars or jumps, they ...
35
votes
3answers
8k views

Why do we use the Pythagorean theorem in game physics?

I've recently learned that we use Pythagorean theorem a lot in our physics calculations and I'm afraid I don't really get the point. Here's an example from a book to make sure an object doesn't ...
28
votes
6answers
8k views

About floating point precision and why do we still use it

Floating point has always been troublesome for precision on large worlds. This article explains behind-the-scenes and offers the obvious alternative - fixed point numbers. Some facts are really ...
1
vote
1answer
75 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
3answers
325 views

How do I prevent other dynamic bodies from affecting the player's velocity with Box2D?

I'm working on my player object for my game. PhysicsBodyDef def; def.fixedRotation = true; def.density = 1.0f; def.position = Vec2(200.0f, 200.0f); def.isDynamic = true; def.size = ...
1
vote
0answers
51 views

Bullet Physics ConvexDecomposition?

I've looked at Bullet Physics ConvexComposition Demo and would like to implement that in my game but the code is so undescriptive and it's hard to understand what is going on. Would any of you people ...
0
votes
1answer
82 views

Inertia in flight simulation using box2d

I'm trying to simulate flight using box2d and libgdx. The main problem I am currently experiencing is with inertia: since there is no air, the plane looks like it were drifting. I wasn't able how to ...
0
votes
1answer
207 views

Load Meshes with Bullet Physics

I just started implementing some physics in my game with Bullet Physics and I was just wondering how would i use bullet physics to load in meshes. For my for DirectX I load in x files into a ...
5
votes
1answer
1k views

Unity falling body pendulum behaviour

I wonder if someone could provide some guidance. Im attempting to create a pendulum like behaviour in 2D space in Unity without using a hinge joint. Essentially I want to affect a falling body to ...
4
votes
3answers
5k views

Collision detection in 3D space

I've got to write, what can be summed up as, a compelte 3D game from scratch this semester. Up untill now i have only programmed 2D games in my spare time, the transition doesn't seem tough, the ...
4
votes
2answers
1k views

Why isn't this physics code scaling velocities separately?

I'm working my way through this book and I'm trying to work this code out: var squaredVelocity = this.velocity.x*this.velocity.x + this.velocity.z*this.velocity.z; if ...
6
votes
1answer
483 views

How do I make a slot car game?

I new to game development with Unity and my first project is a slot car racer. For a realistic slot car-like-driving experience, I first build a track with a channel in the track and a pin on the car. ...
0
votes
2answers
1k views

Libgdx: movement of scrolling background is not smooth even at 60fps

I'm developing a game and I want to make a sliding background. The background is not scrolling smoothly. I logged the fps, but it was ok. This is my code, I don't know what I'm doing wrong, any ideas? ...
0
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1answer
148 views

Making particles accelerate toward a mouse point

I'm currently working on a particle simulation program that makes pixels move towards a mouse point continually accelerating, but i'm running into some math issues. Currently my particle will ...
2
votes
1answer
532 views

Conceptual - What is the optimal way to combine steering behaviors with rigid body physics?

I am working on a simple 3D space simulator that makes use of the Bullet physics engine. The spaceships are rigid bodies that have a mass and hitbox so that they can be considered for collisions. At ...