0
votes
0answers
4 views

XNA 2d weird rotation from quaternion in scene-graph

I have been trying to set up a scenegraph in XNA. It uses matrix transformations to accomplish this. So far, I got position and scale working perfectly, however rotation is behaving weirdly and I'm at ...
0
votes
0answers
23 views

GLM Rotating Combining Multiple Quaternions?

I have a camera which I want to control with my mouse. I want the mouse to control the pitch and yaw of the camera but not the roll. To avoid loss of significance, I am storing the quaternions for ...
0
votes
0answers
72 views

Custom rotateTowards function and rotating only around two axises

I'm building a framework for my WebGL project and at the moment I have a problem with a function which will rotate an object towards a target vector with a given angular speed. In Unity engine it's ...
1
vote
1answer
159 views

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 ...
0
votes
1answer
115 views

How to get plane rotation by known normal vector

I have a FPP quaternion Camera and Plane with known normal vector. I want to find the orientation of this Plane so I can replace it to the Camera orientation to put the camera forward vector to a ...
1
vote
2answers
93 views

How can obtain the relative orientation between two quaternions?

How do I obtain the relative orientation given two orientations (represented by quaternions q0 and q1)?
0
votes
1answer
83 views

up vector for quaternion

First, I know there's a question exactly like mine, and some ohter really close, but my implementation of the solutions didn't work at all. Ok, now to the question. I created some forms of camera ...
1
vote
1answer
152 views

Making player movement direction follow players facing direction

if (controller.isGrounded) { moveDirection = new Vector3 (Input.GetAxis ("Horizontal"), 0, Input.GetAxis ("Vertical")); moveDirection = ...
7
votes
3answers
338 views

Slerping rotation mirrors

I rotate my game character to watch at the target using the following code: transform.rotation = Quaternion.Slerp(startQuaternion, lookQuaternion, turningNormalizer*turningSpeed/10f) ...
1
vote
1answer
307 views

Correct rotation with Quaternion

I have some problems with a rotating marble. I've tried it with Matrix.CreateFromYawPitchRoll and Matrix.CreateRotation but there were some problems, I think it's due to the Gimbal lock effect. So, ...
3
votes
2answers
197 views

Using quaternions, how do I determine if an object is upside down from an original rotation?

Imagine this scenario: An object is laying flat on a horizontal surface, from this an original rotation is determined. Then the object is moved, and at some point flipped upside down and put back down ...
1
vote
0answers
103 views

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 ...
3
votes
1answer
112 views

How to map absolute Joystick position to object rotation?

In my (Ogre) 3d scene I have an object that should be rotated locally based on Joystick input. I have a Joystick with min/max values of [-32767, 32767] on both X and Y axes. When the Joystick is in ...
0
votes
1answer
218 views

Mouse Aiming Causing Rotation Jitter

When our game's ships move around, mouse aiming causes them to shake around a lot. The body being aimed is moved kinematically. I think we've narrowed it down to this block of mouse tracking code. ...
1
vote
1answer
201 views

Moving an object toward another object on sphere knowing their quaternions

I have a sphere centered in world origin. On the sphere surface I have two objects and I know their quaternions (rotation around sphere). Currently my movement works on Vector2 inputs (cannot change ...
0
votes
1answer
1k views

Rotating Objects in OpenGL: glRotate or Quaternions?

I'm coding my first engine and I'm trying to have performance in mind since I'll probably use it for mobiles, and I have this question, should you use glRotate or Quaternions for rotating objects in ...
7
votes
3answers
652 views

Routes on a sphere surface - Find geodesic?

I'm working with some friends on a browser based game where people can move on a 2D map. It's been almost 7 years and still people play this game so we are thinking of a way to give them something ...
1
vote
1answer
369 views

How to get a point to the left/right of a vector

I have a position vector of a point in space and a quaternion for it's rotation. What i'm trying to calculate is a point too the left and a point to the right. I have the position and ...
10
votes
2answers
1k 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 phi, where theta is the angle between the z-axis and the ...
3
votes
1answer
775 views

Convert rotation from Right handed System to left handed

I have Euler angles from a right handed system that I am trying to convert to a left handed system. All the information that I have read online says that to convert it simply multiply the axis and ...
2
votes
2answers
1k views

Rotating a child shape relative to its parent's orientation

When rotating a shape using a quaternion value I also wish rotate its child shape. The parent and child shapes both start with different orientations but their relative orientations should always be ...
0
votes
1answer
298 views

(Quaternion based) Trouble moving foward based on model rotation

Using quaternions, I'm having trouble moving my model in its facing direction. Currently the model moves can move in all cardinal directions with no problems. The problem comes when I rotate the move ...
3
votes
2answers
394 views

How to derive euler angles from matrix or quaternion?

Currently working on steering behavior for my AI and just hit a little mathematical bump. I'm in the process of writing an align function, which basically tries to match the agent's orientation with ...
1
vote
2answers
2k views

Rotation matrix derived from quaternion is opposite of expected direction

When I calculate a rotation matrix from a quaternion, it seems to be in the opposite direction. For instance: For a rotation of +45 degrees about the Y-axis, I would expect to get the following ...
1
vote
3answers
301 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: Quaternion a = Quaternion.Invert(getRotation(m)); ...
2
votes
1answer
403 views

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 ...
7
votes
3answers
2k 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?
0
votes
1answer
276 views

Quaternion to axis-angle, or ripping apart a full transform matrix

My game entities currently hold a quaternion for their orientation with the ability to return either a 3X3 full rotation matrix (based on that quaternion), or a full 4X4 transform matrix. though what ...
7
votes
2answers
1k views

Calculating a quaternion so a bone points in a specified direction

In an attempt to solve this question, I decided to figure out the absolute (world space) directions of each joint in the source pose (as normalized unit vectors), and then rotate the joints of the ...
2
votes
1answer
1k 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 ...
4
votes
1answer
565 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 ...
0
votes
1answer
405 views

Rotate an existing quaternion around an axis?

I have an existing quaternion (Java Quat4f). I would like to rotate this quaternion around an axis (i.e. 90 degrees around the x axis, 25 degrees around the y axis, 10 degrees around the z axis, 180 ...
0
votes
2answers
1k views

from normal to rotation matrix

(i'm on OPENGL) i have a mesh O (object) and a mesh T (terrain). i know a single triangle in T and i want to orient O to be aligned to that triangle (torate O to align to T in that point). i have ...
9
votes
2answers
4k 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, ...
2
votes
3answers
453 views

How should I model exact 90-degree rotations in 3D?

I'm familiar with quaternions... have used them in the past to model arbitrary rotations in 3D, as for a plane flying around with full pitch/yaw/roll freedom. Works great. Now I'm working on a 3D ...
1
vote
2answers
2k views

How can I rotate a sphere in response to mouse movement?

I'm using jMonkeyEngine to develop a game. I'm good at scripting, but math usually goes over my head. I tried the Wiki page for Quaternion, but I was far too confused to figure this out myself :P My ...
2
votes
3answers
473 views

Create quaternion based on where a unit is hit (shield effect as in Starcraft 2) [duplicate]

I'd like to implement a shield effect like that done for Protoss units in Starcraft 2. I'm guessing that the technique involved uses a partial sphere that is rotated to reflect where a unit is hit. ...
3
votes
2answers
628 views

Quaternion understanding

I have some understanding problem concerning quaternions. In order to have my world object rotate in the correct way, I need to invert their quaternion rotation while refreshing the object world ...