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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35
votes
3answers
7k 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
291 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
49 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
72 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
174 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 ...
3
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
448 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
973 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
votes
1answer
142 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
481 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 ...
22
votes
6answers
2k views

How can I Intercept object with a circular motion

I am creating a 2d space game and need to make the spaceship intercept a planet. I have working code for straight line intercepts but cannot figure out how to calculate the planets location in a ...
1
vote
1answer
207 views

Spaceship acceleration for following waypoints

I'm creating a turn based space ship strategy game with simultaneous turn resolution similar to Steam Birds. After all the orders are given, the ships run through a real time simulation where they ...
0
votes
0answers
192 views

Realistic collisions with a kinematic rigidbody?

I have a car game where player drives a car; this car has a collider and a kinematic rigidbody attached and is completely controller by script (i.e. a script sets its position and rotation). In the ...
1
vote
2answers
279 views

Unity - Across the wall

I have a problem here. I animated my main character and is working. It walks run and jump however it goes across walls and ground. As in every single video I watch in unity tutorials I put a ...
1
vote
1answer
51 views

How to convert strict limit in position into gradual slow down?

The player moves a spell object, the spell must stay withing a certain range of the player. The spell is moved using a physics system and it has mass and velocity. Currently when the spell goes out ...
3
votes
3answers
370 views

Throwing a ball and estimating its path using a Physics engine

The problem: A player entity wishes to throw a ball from a known position with a known initial velocity. The surrounding environment contains physical objects that can alter the trajectory of the ...
1
vote
0answers
182 views

How do I combine multiple squares into one Tetris block?

I am learning Phaser by making a simple game—Tetris. I'm having difficulties: Can I use simple rectangles as tetrominoes or they should be sprites? I don't know how make the figure's block ...
0
votes
1answer
227 views

Determine speed of sprite

I'm trying to calculate the speed of my sprites in Cocos2d but I'm having some difficulties. I'm not sure which units of time/speed cocos2d uses. My background sprite moves 2 positions to left each ...
1
vote
1answer
321 views

How can I unify the collision handling of melee/spell attacks in a networked environment?

I am trying to figure a good way to create the battle system of a game. The game is fast paced and the gameplay needs to be precise (think hack n slash) What I would like to achieve is a simple and ...
0
votes
1answer
140 views

Having issues with pong physics, is my approach wrong?

I've been working on a pong clone, i've made games in the past but they have all been very hacky. This time I was trying to go for a better approach in terms of using OOP or patterns. So far the games ...
1
vote
1answer
177 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 ...
2
votes
1answer
243 views

How do I make a sprite appear to sway with the wind?

I'm trying to find a method to simulate the effects of wind on various sprites in a side-view 2D scene. What relatively simple technique could I use for this? What I have in mind is to give these ...
0
votes
1answer
80 views

How long does the collision take?

I want to simulate a simple force-acceleration (rather than impulse-velocity) physical world made up entirely of disks and I'm having an irritating problem with my physics. When two disks collide, I ...
0
votes
1answer
303 views

Circle vs. Rect Collision accuracy problem

The blue ball is dynamic and is supposed to bounce off the walls, as well as the rectangle. Currently, the green rectangle is adding an invisible line to the scene, which doesn't let my ball go where ...
-3
votes
2answers
134 views

what is the ducking ability? [closed]

In my game framework I have this property: canDuck : Boolean = true Determines whether or not the hero's ducking ability is enabled. What does it mean ? regards
2
votes
2answers
239 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 ...
11
votes
4answers
4k views

Physics engine recommendation which can simulate pool game correctly? [closed]

I'm making a pool-game like game. This game requires correct (or very accurate) reflective bounces. I tried Box2D and Bullet Physics, but they both have this problem. If there is a wall on top of ...
0
votes
0answers
67 views

setChaseEntity freezes or jitters the AnimatedSprite

I'm trying to implement setChaseEntity method in a physics based app. I wrote the below code which has an animated sprite ans as the player. The player is movable and it can jump. When i try to focus ...
0
votes
1answer
134 views

Relative Position/Rotation calculation

I have 2 objects each with a 3x3 Matrix (Orientation) and a Vector3 (Translation). Both are relative to world coordinates. How do I calculate the position and orientation of object B in relation to ...
0
votes
1answer
68 views

Is there any reasons to make sprites and bodies line up?

So in LibGDX the Sprite objects position is where it's 0,0 mark is in the word. In Box2D a a bodies position is in it's center. So to line these up when you update the sprites position with the ...
2
votes
2answers
102 views

Can I make a character solid but not lose non-physics behaviour?

My character can walk around in the world, but walks through other objects, for example a cylinder (stand-in for a cannon). To fix this I added a capsule collider to each of the character and ...
0
votes
0answers
150 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 ...
2
votes
1answer
207 views

Calculating/Predicting a way

I'm just starting with physics, so I'm not always sure about what I'm doing. It's a 2D project but I'm using 3D physical objects like SphereCollider etc.. What I have: Objects floating in space and ...
0
votes
1answer
98 views

How to make character gain acceleration?

I want to create more realistic physics for my 2D games. Currently, the character and the other game objects in my games start moving instantly (achieve maximum speed instantly) and stop instantly ...
1
vote
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, ...
0
votes
0answers
176 views

How to design basic physics and movement behavior for 2D platformer?

I want to make a simple 2D platformer. I know some basic 2D physics and how to implement them in a game. How to make a character jump, accelerate, decelerate, etc. But I have no idea how to actually ...
1
vote
1answer
103 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 ...
1
vote
0answers
101 views

How do you calculate the rate of rotation using the accelerometer values in Android for a particular axis?

I am developing a simple game which involves a character moving up and down only along the Y axis. Currently I am using the accelerometer readings to change the Y velocity of the character. The game ...
1
vote
0answers
1k views

Why do restitution values less than one still cause infinite bouncing in Box2D?

I'm currently trying to implement basketball bouncing into my game using Box2d (jBox2d technically), but I'm a bit confused about restitution. While trying to create the ball in the testbed first, ...
0
votes
0answers
20 views

Handling gyroscope data

I'm working on a mobile game that allows user to rotate player around an axis using accelerometer. In addition to that, to allow fast, almost instant, rotation I thought of using gyro data. It seems ...
0
votes
3answers
120 views

How can I calculate force and acceleration?

I have problem of calculating the movement of the object. At the moment, I have a vectors calculated from the center of the screen minus the position of the object. direction vector = centerScreen ...
0
votes
2answers
128 views

Artillery Simulation [duplicate]

I need some help on a simulation of an Artillery like this one https://www.youtube.com/watch?v=YktWSKo_UbA. I cant figure out how to make the "tomato" to get to the selected spot. Where can I get ...
3
votes
1answer
139 views

How do you prevent AABBs from passing through each other?

I know what an AABB is, but I don't know how you would check for collision with an object that is going really fast. If an object goes fast enough, it can skip over other bounding boxes without it ...
24
votes
2answers
2k views

How do I make a character capable of walking on walls?

I am trying to get a character to move like a spider: Given a rising slope which a ball would normally not be able to roll up, the spider would slowly crawl up. Similarly, given a mid-air rectangular ...
4
votes
1answer
325 views

How do I make a cube move by rolling?

I am learning jMonkeyEngine by making some small games with it. I have a simple rectangular cube that I want the player to be able to roll around the game world. When he presses the arrow keys, the ...
0
votes
1answer
428 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 ...