Questions tagged [rotation]

Rotation is the circular movement of an object around a specific axis.

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38
votes
2answers
15k views

I'm rotating an object on two axes, so why does it keep twisting around the third axis?

I see questions come up quite often that have this underlying issue, but they're all caught up in the particulars of a given feature or tool. Here's an attempt to create a canonical answer we can ...
15
votes
2answers
13k views

How can I rotate about an arbitrary point in 3D (instead of the origin)?

I have some models that I want to rotate using quaternions in the normal manner, except instead of rotation about the origin, I want it to be offset slightly. I know that you don't say, in 3d space, ...
18
votes
4answers
45k views

How can I orbit a camera about it's target point?

I'm drawing a scene where the camera freely moves about the universe. The camera class keeps track of the view (or look at) point, the position of the camera, and the up vector. These vectors/points ...
3
votes
2answers
3k views

Why is the camera tilting around the z axis when I only specified x and y?

My goal is to program a camera to point towards the mouse cursor. I attached the following script to the Main Camera. ...
8
votes
2answers
11k views

How to avoid gimbal lock

I am trying to write code with rotates an object. I implemented it as: Rotation about X-axis is given by the amount of change in y coordinates of a mouse and Rotation about Y-axis is given by the ...
6
votes
1answer
2k views

Turning a sprite such that it rotates in the direction that's most efficient

I have a sprite that moves from waypoint to waypoint. It turns to face its velocity vector, but not instantly (there's a rotation speed). The problem I'm having is, from one direction to another, the ...
11
votes
2answers
22k views

How can I move a sprite in the direction it is facing?

I'm using Java/Slick 2D. I'm trying to use the mouse to rotate the sprite and the arrow keys to move the sprite. I can get the sprite to rotate no problem, but I cannot get it to move in the direction ...
2
votes
1answer
1k views

Quaternion rotation problems [duplicate]

I want to rotate my model and I have X and Y rotations. Here is my code: ...
15
votes
6answers
17k views

How to rotate an object around world aligned axes?

I have a Vector3 which has an euler angle for each axis. Usually, when I want to create a rotation matrix I will use functions such as D3DXMatrixRotationX passing the respective angle from my ...
0
votes
1answer
103 views

Why rotating an object only on its local X axis result in sudden 180 degrees changes in Y and Z axis rotation values

I have an object (cube) in the scene and I want it to continuously rotate on its only local X axis but suddenly while rotating on X axis its Y and Z axis rotation value goes 180 degrees for some ...
5
votes
1answer
2k views

How do I make an object face the mouse position, but only on one plane?

I want a game object to turn and look towards where the mouse was clicked (in world space). It works well when considering all 3 dimensions, but I really only care for the plane formed by the ...
3
votes
1answer
1k views

Problem finding correct value for Yaw

I use an Arduino and a 9dof sensor ( gyroscope, accelerometer and magnetometer ) and i'm trying to use the pitch, roll and yaw that the sensor gives me to rotate an object in unity. I managed to ...
1
vote
2answers
2k views

Lookrotation of a gameObject in just one axis

So I am trying to orient a gameObject ( house in the picture below) which is nothing but a plane and has a 2d texture on it as you see below. The whole game is made on a hex sphere. I am using ...
1
vote
1answer
4k views

How should I rotate vertices around the origin on the CPU?

I have tried using glm::rotate and such. glm::translate works fine, but rotate doesn't work (if I rotate before/after a translation). Here is my current setup: ...
24
votes
2answers
5k views

Using Quaternions: What can I do with them? (without the maths)

I am a Game Developer and did not study Mathematics. So I only want to use Quaternions as a tool. And to be able to work with 3D rotation, it's necessary to use Quaternions (Or Matrixes, but let's ...
17
votes
4answers
7k views

How to keep my Quaternion-using FPS camera from tilting and messing up?

I am using an FPS-like camera, and it uses quaternions. But, whenever I try looking up and then sideways, it tilts, and sometimes it can turn upside down. How can I fix this?
25
votes
3answers
6k views

How can I rotate an object based on another's offset to it?

I have a 3D model of a turret that con rotate around the Y-axis. This turret has a cannon that is significantly off the center of the object. I want the cannon, not the turret, to aim at a specified ...
12
votes
2answers
5k views

Arbitrary Rotation about a Sphere

I'm coding a mechanic which allows a user to move around the surface of a sphere. The position on the sphere is currently stored as theta and ...
4
votes
1answer
1k views

Arcball Problems with UDK

I'm trying to re-create an arcball example from a Nehe, where an object can be rotated in a more realistic way while floating in the air (in my game the object is attached to the player at a distance ...
2
votes
1answer
2k views

Convert quaternion to a different coordinate system

OSVR has a right-handed system: x is right, y is up, z is near. I need to convert orientation data from a sensor in OSVR to a different right-handed system in which x is forward, y is left, and z is ...
2
votes
1answer
63k views

Rotate an object smoothly on the Y axis in Unity

I am attempting a simple script to swing a door open in Unity. This requires a smooth rotation of 90 degrees around the Y axis. I have seen that one way to do this is using Unity's Quanternion ...
0
votes
1answer
59 views

how do I move an object based on rotation of another object?

This question is related to my other question about camera rotation. I hope its acceptable to ask a second question. I cannot figure out the math of how to calculate moving the camera to stay behind ...
6
votes
4answers
32k views

Unity3D Orbit around orbiting object (transform.RotateAround)

The best way to explain this is I'm attempting to make a small model solar system (not to scale or anything complicated, just simple rotation as a learning exercise). There's a sun, a planet, and that ...
7
votes
1answer
7k views

Why is my sprite displayed offset from its Box2D body?

I found out about this using a debug renderer. When the game starts, everything is in order. But when a collision happens, the sprite's rotation is way larger than its body. The sprite and body match ...
4
votes
1answer
4k views

Movement and rotation of bodies in top down game

We are developing a 2D top down game with libgdx using the included box2d as physics engine. We don't want our bodies to accelerate but to instantly move with the wanted velocity. The bodies are ...
6
votes
1answer
7k views

How do I rotate a sprite so that it is 'pointing' in the direction it is moving?

I have a sprite, e.g a missile, heading in a certain direction (using a velocity vector). How do I figure out its how much to rotate it so that it gets drawn 'pointing' in the direction it is heading?...
5
votes
3answers
3k views

How to Align Gun with Bullets

I have a top-down 2D shooter. I have an image of a player holding a gun, that rotates to face the mouse. Please note that the gun isn't a separate image tethered to the player, but rather part of the ...
3
votes
2answers
6k views

Cocos2d rotating sprite while moving with CCBezierBy

I've done my moving actions which consists of sequences of CCBezierBy. However I would like the sprite to rotate by following the direction of the movement (like an airplane). How sould I do this with ...
4
votes
3answers
844 views

How to calculate origin and position of a weapon which should be “in hands”?

I'm currently stuck with my game, which is from the top perspective. I'm currently using these sprites for player: (using the second at the top): And here's what I use for my gun My problem is that ...
1
vote
1answer
2k views

Understanding SpriteBatch.Draw overload XNA

I'm talking about the public void Draw (Texture2D texture, Vector2 position, Nullable sourceRectangle, Color color, float rotation, Vector2 origin, float scale, SpriteEffects effects, float layerDepth)...
0
votes
2answers
448 views

Unity : how to Rotate GameObject back to Indentity position?

Hello i m trying to rotate my object smoothly over MouseButtonDown and rotate to identity position on MouseButtonUp and this code rotate my GameObject smoothly but it won't come back to identity ...
8
votes
1answer
1k views

How To Approach 360 Degree Snake

I've recently gotten into XNA and must say I love it. As sort of a hello world game I decided to create the classic game "Snake". The 90 degree version was very simple and easy to implement. But as I ...
4
votes
1answer
2k views

Moving a rotated model in XNA

This seems like a simple problem with an equally simple solution that is invisible to me. I have a model that spawns at the origin and looks at my player model wherever it goes. I would like it to ...
2
votes
4answers
5k views

per pixel based collision detection

I was wondering if anyone had any ideas on how to get per pixel collision detection for the android. I saw that the andEngine has great collision detection on rotation as well but couldn't see where ...
2
votes
2answers
5k views

Make camera follow and rotate with player without childing it

I want to have a camera, that follow the player, without childing it to the player object. So far I have this one line, that follows the player, but does not rotate with it (meaning the camera should ...
2
votes
3answers
634 views

Inverting matrix then decomposing gives different quaternion than decomposing then inverting the quat

I'm getting different signs when I convert a matrix to quaternion and invert that, versus when I invert a matrix and then get the quaternion from it: ...
1
vote
3answers
3k views

How to rotate to a target position over time

I know how to do rotations to vectors, but how do I rotate over time? For instance say I made a function RotateTo(vec2 iPosition, float iTime); so it rotates to ...
0
votes
1answer
8k views

How can I make my player move in the direction the camera faces?

I have a 3rd person camera which can rotate around the player. My problem is that wherever camera is facing, players forward is always the same direction. For example when camera is facing the right ...
0
votes
2answers
372 views

Keep Mini map static after rotating / zooming with camera

Hi I am making a 2D game, where the Camera is able to rotate / zoom in or out on the camera focus (the player usually). However my game also contains a mini-map, and so far whenever I have to rotate ...
0
votes
1answer
334 views

Unity smooth local rotation around one Axis, oriented toward a target

I want to acheive the same rotation you see in the inspector. In short: a smooth local Y rotation, toward a target I have a Vector3 orientation: ...
35
votes
2answers
5k views

Calculating the rotational force of a 2D sprite

I am wondering if someone has an elegant way of calculating the following scenario. I have an object of (n) number of squares, random shapes, but we will pretend they are all rectangles. We are ...
17
votes
4answers
17k views

How to rotate blocks in tetris

I have a gameboard grid which is 20 rows high and 10 columns wide with the origin (0,0) being in the top left hand corner. I have a tetrimino in play, which is composed of four blocks. I have the x,y ...
17
votes
8answers
44k views

How to calculate corner positions/marks of a rotated/tilted rectangle?

I've got two elements, a 2D point and a rectangular area. The point represents the middle of that area. I also know the width and height of that area. And the area is tilted by 40° relative to the ...
9
votes
3answers
12k views

How can I rotate pixel art sprites without the aesthetics getting ruined?

I'm right now in front of a huge "Game Design" question. I'm making a pixel-art-ish game and using bilinear interpolation could solve lots of animation-issues. On the other hand, its not a "pixel-game"...
10
votes
2answers
8k views

How do I rotate a structure of hexagonal tiles on a hexagonal grid?

My 2D isometric game uses a hexagonal grid map. In reference to the image below, how do I rotate the light blue hexagon structures by 60 degrees around the pink hexagons? EDIT: Main hex is (0,0). ...
8
votes
2answers
4k views

How to implement friction in a physics engine based on “Advanced Character Physics”

I have implemented a physics engine based on the concepts in the classic text Advanced Character Physics by Thomas Jakobsen. Friction is only discussed very briefly in the article and Jakobsen himself ...
9
votes
3answers
19k views

How do I make an entity move in a direction?

I have an Entity instance which is updated every game tick. Let's just assume that entity moves forward constantly. I'd like to be able to give the entity's angle ...
9
votes
1answer
26k views

How to calculate a 3x3 rotation matrix from 2 direction vectors?

I've got 2 direction vectors, for the X axis and the Y axis of the object. How do I calculate the rotation matrix of the object using these?
7
votes
2answers
6k views

Rotate billboard towards camera

I'm trying to create a particle system in OpenGL, and as such I need to use billboards. I need these billboards to face the camera at all times. The tutorials I've been following only rotated the ...
8
votes
2answers
1k views

Render 3d object to 2d surface (embedded system)

i am working on an embedded system of a sort, and in some free time i would like to test its drawing capabilities. System in question is ARM Cortex M3 microcontroller attached to EasyMX Stellaris ...