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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3answers
1k views

How do you properly implement level boundaries in a physics room?

I have an issue with creating a proper boundary in GameMaker Studio when using a physics enabled room. My room has a gravity of 0, as it is in Space. My player object has the default values, but a ...
1
vote
3answers
150 views

Character animation in physics-simulated environment

What are the standard solutions for animating characters in physics-simulated environments? Let me explain what I mean - in most games characters are pretty much excluded from physics simulation - ...
1
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2answers
1k 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
43 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 ...
2
votes
1answer
724 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 ...
2
votes
2answers
1k 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
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1answer
213 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 ...
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1answer
920 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 ...
4
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4answers
831 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 ...
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0answers
145 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 ...
2
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2answers
601 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 ...
4
votes
2answers
427 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(); wheelFixtureDef....
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0answers
76 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 = ...
0
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2answers
629 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
428 views

Unity's default integration method

Which method(s) does Unity provide for physical integration? RK4? Verlet? Euler?
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vote
4answers
806 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? I'...
8
votes
1answer
366 views

How can I predict player-to-projectile collisions in Box2D?

I'm making a real time shooting game with Box2D as the physics engine. The gameplay is mostly about trajectory, like Angry Birds. I want to make a slow motion effect and move camera to the player when ...
6
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1answer
403 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
1answer
1k 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 ...
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1answer
564 views

Bullet 3D Physics Objects Not Rotating?

So I've got Bullet 3D controlling the motion of objects rendered with DirectX. In the clipping below I've got 2 identical rectangles & 5 balls. The lowest rectangle has a mass of 0 and doesn't ...
2
votes
2answers
61 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 ...
1
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2answers
835 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
1answer
178 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
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0answers
101 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 ...
0
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1answer
77 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 ...
2
votes
1answer
895 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 ...
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1answer
41 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 ...
6
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2answers
354 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 ...
2
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2answers
215 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 +...
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vote
1answer
117 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 : http://...
1
vote
1answer
77 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) ...
1
vote
1answer
581 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 ...
0
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2answers
154 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 ...
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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 ...
0
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1answer
174 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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1answer
96 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
603 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 ...
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0answers
62 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
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1answer
525 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 = ...
0
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1answer
166 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
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1answer
435 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 ID3DXMesh....
4
votes
2answers
424 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 ...
6
votes
1answer
3k 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 ...
35
votes
2answers
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 ...
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1answer
701 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 ...
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 (...
0
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1answer
209 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 ...
0
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2answers
586 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 ...
3
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1answer
372 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 ...
23
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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 ...