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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2
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2answers
66 views

why is my enemy AI is on air while moving?

In Unity3D I have created an enemy AI and applied a script for it to move and chase the player. But when moving, the enemy hovers in the air. My character also does not have rigidbody and he just has ...
1
vote
2answers
38 views

Need help with physics 2D Unity

I'm making a 2D game in Unity. Basically there's just a rocket that goes where ever the user touches. With the code that i have right now, the rocket instantly rotates towards the point and moves ...
0
votes
1answer
88 views

Collision between a sphere and a mesh(height-map)

I am trying to implement a method that detects the collision between a sphere and a mesh and reflects the vector of speed. I have a method, that detects a collision between a sphere and a triangle and ...
1
vote
1answer
257 views

Cocos2dx+Chipmunk: Fully elastic collision between moving bodies

I'm using Cocos2dx and the built in Chipmunk physics engine, and currently I've got my PhysicsBodys' materials set up with: Density=0 Restitution=1 Friction=0 in order to get fully elastic ...
0
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2answers
269 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
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2answers
52 views

Preventing a Combination of Rigidbody Jump Force & Bounce Magnitude in Unity3D

I'm building a fairly simple marble racing game in Unity3D. The ball is a 3D physics object that moves only on the X and Y axes. It has the ability to roll left and right, and to jump. Pretty basic ...
1
vote
1answer
899 views

Spritekit - gradually apply force vector in different direction (space ship turning)

I have a space ship that I'm applying a force vector to using a joystick for control. I would like this to smoothly fly around when I'm switching directions.. Exactly like minisquadron if you've ...
1
vote
1answer
326 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 ...
0
votes
2answers
165 views

Moving one object from one point to another with acceleration

How would someone implement moving an object from one point in 2D space to another using these formulae to update objects: m_position.setX/Y( m_position.X/Y() + m_velocity.X/Y() * dt + 0.5 * m_acc * ...
0
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0answers
56 views

How to get rid of “ghost mode”?

I've got few Spatials (mostly boxes) in my space. Player is able to move main Spatial using mouse or keybord. But now every Spatial can go through another. Like in a ghost mode. How can I get rid of ...
0
votes
1answer
75 views

Need help with Physics

I'm using Unity to develop a game. Basically i want the player/rocket to follow a point on the screen where user touches. But It's based on physics. Force must be added when user touches somewhere and ...
1
vote
1answer
56 views

Sliding DOOM style collision resolution against arbitrary 2D geometry

I've been working on a HTML5 canvas raycasting engine for the web browser, with the end goal of making a simple FPS game in the style of the early 90s. The engine sits somewhere between Wolfenstein 3D ...
2
votes
1answer
64 views

How does matrix based game physics (collision detection & response) work?

I'm familiar with how to do collision detection and response using shape intersection tests, the separating axis theorem, and by using MPR and GJK with minkowski sums and support vector defined ...
11
votes
1answer
2k views

What is the difference between an impulse and a force related to a physics engine?

What is the difference between an application of an impulse and an application of a force in relation to a physics engine?
1
vote
2answers
41 views

Using fixed timestep and interpolating states makes physics fall behind one frame. Does that affect responsiveness?

The title says it all, but let me build more into the question: I suppose everyone by now knows the Fix Your Timestep article, and its proposal to free your physics engine steps from your rendering ...
0
votes
1answer
18 views

Kinematic equations script fail

I added the kinematic equations to my code and now none of it works. I get the error rigidbody.torque assign attempt for 'Enemy' is not valid. Input torque is { 0.000000, NaN, 0.000000 }. ...
2
votes
1answer
202 views

Create a 2D orbit trajectory like in angry birds space and a circular orbit

I am working on a 2D game, and I am working on adding some space physics : I need to find a way to create a circular orbit and an orbit like angry birds space ( the spiral trajectory ) . So there is 2 ...
1
vote
1answer
48 views

LOVE Physics - Joint Stretching

After asking a similar question yesterday I've come across another problem with using joints in box2D / LOVE and trying to create a weighted chain. Everything is set up as follows, I've tried to ...
0
votes
1answer
51 views

Move Ball to clicked direction

I have a ball as a sphere in my game and Im viewing it from top down view (birdseye). The ball is a rigid body. I want to achieve when I click somewhere on the screen, that the ball moves toward ...
1
vote
1answer
34 views

Objects phasing through each other in physics engine

I'm writing my own physics engine right now (following this tutorial), but I'm running into some problems. Sometimes on collision, objects will just phase through each other instead of bouncing off of ...
2
votes
1answer
28 views

Why is the drag force multiplied by the inverse normalised velocity vector?

In pure physics texbooks, I'm seeing this formula to calculate fluid drag force: It is clearly stated that it should be opposite to the velocity. Now to me that means, in pseudocode: fd = ...
0
votes
0answers
15 views

Precision problem when doing collision detection?

I've got this problem, and I don't know what may be the cause of it. I finished reading this article on sphere-triangle collision. My character (the sphere) stops before it reaches the triangle, and ...
4
votes
1answer
103 views

Rotate a rigid body not around its centre of mass

I have a rigid body (a boat) whose centre of mass is towards the front of the object. However, this makes the rotation look strange as the rudder that is turning the object is at the back of the boat ...
0
votes
1answer
148 views

LibGDX - Executing 2 different touchDown events in the same method

On the bottom left of my screen is a circle with an Arrow and on the bottom right is a circle with a gun. If the player is in jetpack mode and the Arrow "button" is clicked he flies like flappy bird ...
-1
votes
1answer
33 views

How do i move a 2D object with angle and speed variables in unity?

I want to move an object with a certain angle and speed, is there a was to set this as an initial velocity so that it is still possible for the object to collide and bounce of other objects using its ...
4
votes
2answers
136 views

How do I separate physics from framerate?

Skyrim (Creation Engine / Gamebryo) is a prime example of a game that has its physics tied to the framerate for which it has been heavily criticized, because if you disable vsync / have a > 60 HZ ...
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vote
0answers
49 views

Why doesn't my orbit form an ellipse?

I'm playing around and trying to build an orbit simulator. Unfortunately, it isn't working out to well. Instead of forming some sort of elliptical orbit, I get this: Here is the code I'm using to ...
1
vote
1answer
63 views

How to calculate faces involved in collision (Separating Axis Theorem)

I have a game engine created in javascript (https://jsfiddle.net/4gqsq8wf/) which uses collision detection via the Separating Axis Theorem. Currently, it does not have any means of resolving velocity ...
0
votes
1answer
510 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 ...
4
votes
1answer
133 views

Half top-down view collision and mechanics

I'd like to create a game with a half top-down (2d RPG) view (I don't know the exact name of it). It would be 2d, but I'd like to add 3d-like collisions. For example: If the grenade lands on the ...
2
votes
1answer
215 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 ...
2
votes
2answers
280 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
votes
2answers
60 views

How to get a pleasant path accelerating to a point

I am having trouble moving an object to a target position with a maximum acceleration limit. If i just accelerate towards the target the object will fly in a doughnut a few times before hitting the ...
0
votes
1answer
199 views

Custom arcade physics rate (e.g. bullet time)?

Is there a way to modify the rate that physics is applied, either globally or on a per-sprite basis in Phaser? That is, how can I slow down or speed up the rate at which sprites move around, or fall ...
1
vote
1answer
50 views

How can I determine “exact moment” of collision with ray casting?

I'm currently brainstorming how the physics for my game engine is going to be handled. It's top down and I'm thinking of using ray casting for collision detection. I've reached two potential problems ...
0
votes
1answer
7 views

Is GetFixtureA() of b2Contact guaranteed to return the body on which GetContactList() was called?

For example, in the code below, will the assert ever fail? for (const b2ContactEdge *contactEdge = playerPhysicsBody->GetContactList(); contactEdge; contactEdge = contactEdge->next) { ...
0
votes
2answers
590 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
110 views

Moving CCNode with constant speed in cocos2d

I want to move the object (CCNODE) with constant speed in any direction , what i have did till now is applied a force to object at start to get it moving and set elasticity as 1 and friction as 0 to ...
0
votes
1answer
64 views

Twin-stick controls for a cohesive group of agents

I'm trying to implement a classic twin-stick controller for a group of physics-based game objects. Here are the rules I'm trying to follow: Agents always stay close to each other within a certain ...
0
votes
2answers
410 views

3D collision physics. Response when hitting wall, floor or roof

I am having problem with the most basic physic response when the player collide with static wall, floor or roof. I have a simple 3D maze, true means solid while false means air: bool ...
2
votes
1answer
61 views

Organizing movement, collision detection, and collision resolution

There's many articles on the internet focusing on how to implement movement, collision detection, or collision resolution. What I'm wondering is how to put them together, specifically in what order to ...
-1
votes
1answer
40 views

Applying velocity to objects in a specified direction

How to apply velocity to a particular direction? Data which I have: object position (P1) destination (P2)
2
votes
1answer
78 views

Physics: calculating angular acceleration in world vs local space

I have a pretty simple rigid body simulation written in Python. In my code I calculate the angular acceleration using formula: angAcc = torque * inertiaTensor^-1 (note row-major matrix order) Now, ...
0
votes
1answer
122 views

Immovable object impact physics

I am trying to do some physics calculations from scratch, and as a result am creating a small bouncing ball example. However, I have some issues getting correct results from my impact physics when the ...
1
vote
3answers
3k views

Collider2D and Rigidbody2D, how do they work?

I have been learning JavaScript and Unity for a week now. I learned how to make Cube as a Ground and another Cube as a player and I used this code to make the Player Cube move forward and backward and ...
0
votes
1answer
56 views

wheeled 2D character controller platform edges problem

I have built a little wheeled 2D character controller (a rectangle for the body and a circle for the legs with a motor joint). Everything is ok but the problem is that when the player reaches the edge ...
1
vote
1answer
39 views

Using Farseer Physics, how can I get objects to bounce at the correct angle

I am using the Farseer Physics engine in my MonoGame project. I have static walls which have "body" friction 0 and "body" restitution 1. I have dynamic objects, which are circles, with "body" friction ...
2
votes
1answer
74 views

Change in direction should slow down object and accelerate in new heading

I'm trying to implement some sort of faux space physics in my 2D game. I have a top down view of my space ship. You can change direction and set a speed up to a maximum which then accelerates the ship ...
1
vote
1answer
57 views

Correct way to integrate scaled axis angular velocity into a quaternion

Across my travels on the internet I have came across to ways of integrating a scaled axis angular velocity into a quaternion. The first way converts the angular velocity into an axis angle quaternion ...
0
votes
0answers
17 views

Static blocks - phaser isometric plugin

I'm creating isometric game like minecraft with phaser engine with rotates isometric plugin and I need colliding with player, but when I turn off physics, blocks is not static. Question: How to ...