# Tagged Questions

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

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### Calculating rotation matrix for an object relative to a planets surface in MonoGame

I have a 3D planet and I would like to place models on the planet and have them start with a base rotation relative to the planet surface at their location. So a model at the north pole will have zero ...
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### Euler adjustments between two quaternions

I have two quaternions, q1 and q2. If my object's current rotation is at q1, but I need to get it to q2, what would be the process to figure out how much rotation I apply to x, y, and z in order to ...
1k 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 ...
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### Separate rotation transform from parent

I have a hierarchy like this Body - Head - Arms Currently this works fine in that the Body's transformation is reacting as it should. Being children, the Head and Arms match the Body's ...
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### How do I keep my orbiting camera upright?

I am working on code that rotates the camera around a point on the in-game map when dragging the mouse. I understand how to lock it so it stays above the map surface. However, if I keep rotating the ...
300 views

### Project rotated matrix to isometric coordinate

I have a group of soldiers, and each has a vector describing their position in the squad. When the group rotates, I do this math to calculate the desired position of each soldier. var unitPositions : ...
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### Bullets won't shoot out of barrel in top-down shooter

So I am working on a top down shoot and have been stumped on why my bullets refuse to come out of the barrel of the gun. I know about the rotation equation which is x2 = x * cos(theta) - y * sin(...
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### How to make bullets follow a rotating sinewave pattern

I am trying to replicate the wave gun from Super Metroid where the bullets fly along a sine wave path. The cool part is that you can shoot in 8 directions and the bullet still follows the sine as if ...
165 views

### How do I rotate a bounding box together with a sprite?

I have a game object with a sprite that can rotate. It's a rectangle. I need its bounding box to rotate with it. How do I make sure that they can both rotate, but they're always both at the same angle?...
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### Rotation independent rotation

I came up with some cube rotating, but I could not make it smooth and easy to use because as the cube turned - the keys that handle the turning changed their purpose. Link to demo. The demo rotation ...
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### How to make a stack stable? Need help for an explicit resting contact scheme (2-dimensional)

Previously, I struggle with the sequential impulse-based method I developed. Thanks to jedediah referring me to this paper, I managed to rebuild the codes and implement the simultaneous impulse based ...
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### Rotate sphere in Javascript / three.js while moving along x/z plane

I have a sphere/ball in three.js which I want to "roll" around on the x/z plane. For the z axis I could simply do this no matter what the current x and y rotation is: sphere.roll_z = function(...
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### Finding a suitable axis-angle to avoid gimbal lock

In OpenGL the camera faces the -z axis with the +y axis pointing up. I am using quaternions to represent the orientation of my objects (which works well) and am trying to do the same for the camera. I ...
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### How can I create my mesh so that textures applied to it are NOT rotated 90 degrees in Unity 3D?

I'm trying a really simple test in Unity 3D. I want to render a texture on the simplest plane possible. So, I've created a two-triangle plane in Blender, then imported it into Unity. From there, I ...
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### Image spinning in c#

I'm currently in the process of making a top-down shooter for my programming class, and one idea I had, but don't exactly know how to implement is image rotation in order to spin the object ...
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### XNA - Use Mouse To Rotate & Arrow Keys To Scroll A Linearly Wrapped Texture:

Using XNA I'm working on my first, relatively simple, videogame for the PC. At the moment my game window is 1024 X 768 and I have a 'Starfield' linearly wrapped background texture 1280 X 1280 in ...
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### 2d tank movement and turret solution

I'm making a simple top-down tank game on the ipad where the user controls the movement of the tank with the left "joystick" and the rotation of the turret with the right one. I've spent several hours ...
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### Can't figure get the conversion from cartesian to spherical(“polar”) correctly for my orbiting camera

The two angles from the polar coordinate system are defined as hRotation and vRotation This is how they are converted from polar to cartesian: // Get the distance between the object and the ...
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### How to make one 3D object face another?

I'm writing a simple 3D engine myself and I cannot figure out how to make one object face another. The problem begins with identifying which direction the target object is in relation to the second. ...
129 views

### Given a 3d goal point and a turn rate in radius, find max speed to reach goal

I'm working on a 3d space sim with AI agents flying ships through space. I am trying to get them to follow a waypoint path nicely, which involves figuring out how fast they can be travelling and still ...
22 views

### Finding specific coordinates on a rotating line

I'm currently working on a mobile game which mainly consists of a rotating line and a ball. The line rotates 0.500 degrees clockwise around its center every frame. The ball is at first positioned in ...
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### OpenGL 2.1 rotation , Gimball lock

I'm working on a little app for a school project , which should be manipulating 3D objects. And i'm stuck with the rotation , as i'm facing what i think is called the gimball lock ? here's a video I ...
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### How to calculate if a point is contained in rectangular camera viewport with rotation?

I am working with my camera, and am trying to improve it so that I can calculate if a world point is on screen, taking rotation into account. Currently, my camera rectangle is calculated as so: ...
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### Problem with Rotation - C#/XNA

I have a projecile(Hook) and the tail of the projectile(yellow balls) TailProjectile class draws a ball at the exact position of the projectile(hook) and let it there until the projectile ends I'd ...
440 views

### How to rotate an object along its trajectory path?

I have a missile launcher that uses initial velocity for the trajectory. I edit the launch angle from the editor, and then the script calculates the initial velocity required to land the missile to ...
124 views

### Combining two independent rotations relative to the world frame

I am implementing a mouse rotation which works by accumulating the X-Y delta between frames to yaw and pitch rotation angles. The problem is that I wish rotations to be independent of each other. But ...
184 views

### Get quaternion between two objects on sphere

In a planetary gravity environment objects are represented in the following way: struct object { struct quaternion quat; // quaternion to represent the rotation between the object and the center ...
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### How can I trigger an event each time the rotation of my rigidbody2D is at a given value?

I would like to trigger an event each time my rigidbody2D is at a particular value. The event should only be triggered once for each given value per complete object revolution. Initial attempts at ...
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### Three.js camera turning leftside right

In Three.js I am trying to implement an orbiting camera can be rotated around the x and the y axis. I am using these two functions: function rotateX(rot) { var x = camera.position.x, ...
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### How do I apply 2 rotations about different points to a single primitive using OpenGL

I'm working on a 2D top-down shooter game that has a rotation feature like Realm Of The Mad God such that if you press e the camera rotates around the character in a clockwise direction and q rotates ...
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### Rotating a 2D Skeleton

I am currently implementing a 2D skeleton system in C# with XNA, but got stuck in how I would rotate the bones around a skeleton's axis. A basic algorithm that I have figured out already would ...
3k views

### Flip rotation matrix

I'm doing character control with kinect. I need to mirror the joint orientation because the character faces the player. Somehow by Googling through internet I've done it and everything works very well....
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### Positioning a 2D image after rotation

Using SDL_gfx's rotozoomSurface function to rotate a 38x58 sprite....naturally when it rotates it creates a new surface with a new size, and the rotation isn't going around the center point. I am ...
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### How to correct this issue with a top-down aiming angle in Unity - 2D?

I'm trying to build my first project and I'd like some input for a math correction. The game is a top down 2D shooter, a bit like the iconic "chaos engine" from SNES. The issue is that either the ...
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### 2d vector flips during rotation

I have a 2d game (C++ and SDL) and I want the player object rotate to follow the mouse. The player object and the mouse location are both stored in 2d vectors. In order to have the player's rotation ...
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### Rotating kinematic object around a moving point Box2D

I'm new at Box2D and I am making a simple game where you control the rotation of the maze and the gravity leads the ball to the exit. The game looks like: The problem: I want to rotate the maze, ...
663 views

### In UE4, how do I turn my character's body together with the camera?

I made a simple punch animation in Blender and exported it into Unreal Engine 4. In-game, the character appeared from a 3rd-person perspective, but I made it look like first-person by adjusting the ...
306 views

### Quaternion - rotating rigidBody to particular angle over time

Using Bullet Physics. There's a rigid body that is rotated. For some delta-time I need to rotate that body to have rotation of (0, y, 0) - keep the old y value rotation but reset x and z. The ...
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### How can I restrict the rotation of an object to a subset of axes using quaternions?

I've got a question about quaternions in my WebGL application. How can I rotate an object only around two axes? For example, how can I exclude/nullify rotation about the Y axis? The problem is that ...
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### Xna 4 Model Rotation with inertia not working as expected with variable updates

I am trying to rotate a model with inertia damping with the keyboard. The code works great with a fixed time step but it doesn't behave the same with a variable update frequency. Update method: ...
1k views

### How do I determine the look-at vector of a free-look camera?

I'm trying to create a free-look camera with DirectX 10. I've figured out how to get the directions for forward and back and left to right. However, I don't know how to rotate the look-at vector of ...
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### How should I model rotation caused by bounce friction? [duplicate]

In my Java2D simulation, I have a disc which, when it bounces off the boundary of a 2D region, begins to rotate, as if it had gotten some spin from the wall. I'm having trouble relating the ...
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### How to set speed of circular motion

Edit 2 - clarification Just to clarify, the issue I have at the moment is how I specify a time (in seconds) for a complete revolution to occur. My delta is fixed and is 1/ticks per second (1/60). ...
2k views

### Arcball 3D camera

I have checked multiple threads before posting, but i havent been able to figure this one out. Ok so i have been following this tutorial, but im not using glm, ive been implementing everything up ...
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### How do I ADD gravitation to a rotation matrix?

I have ported the Matlab script from https://instruct1.cit.cornell.edu/courses/bionb441/LSystem/ to POV-Ray and everything works fine (although I'm not quite sure why). To navigate a "turtle" through ...
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### Problem using glm::lookat

I am trying to rotate a sprite so it is always facing a 3D camera. Object GLfloat vertexData[] = { // X Y Z U V 0.0f, 0.8f, 0.0f, 0.5f, 1.0f, -0.8f,-0.8f, 0.0f, 0....
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### How to set object's / node's absolute rotation correctly?

Usually when I want to rotate an object/node in my Ogre scene I call the node's rotate() method. That rotates the node locally relative to it's current rotation. So for example, when I start with 0 ...
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### Scaling and rotating texture onto another texture by raw buffer data

I've been messing with C++ AMP and OGRE in attempt to make writing to/altering textures to my liking easier on my behalf. In this I've been trying to draw a texture onto my "dynamic" texture with ...