Question Problem rotating an object on its local orientation

Hello i am new in the forum! I hope i am in the right section! Im trying to rotate a camera (that rapresent the player POV) using the mouse delta and im rotating the camera in local coordinates not world coordinates and i want avoid gimbal lock effect. I read somewhere on the internet that for that purpose i have to use quaternions, and i read how to do that. The problem is that axis rotations works well moving in local orientation but one of the axis is losing its local orientation and it rotate following the world coordinates orientation. I will post the code and i hope someone can help me and telling me where im doing things wrong. Thanks!

Code (CSharp):

1. [Header("Camera")]
2. [SerializeField] private Camera _camera;
3. [SerializeField] private Vector2 _xMinMaxRotation = new Vector2(-90, 90);
4. [SerializeField] private Vector2 _yMinMaxRotation = new Vector2(-90, 90);
5. [SerializeField] private float _mouseXSensistivity = 1;
6. [SerializeField] private float _mouseYSensistivity = 1;
7. [SerializeField] private float _mouseZSensistivity = 1;
8. [SerializeField] private float _xStartRotation = 0;
9. [SerializeField] private float _yStartRotation = 0;
10. private Vector2 _mouseDelta;
11. private float _rotY, _rotX, _rotZ;
12.  
13. // Start is called before the first frame update
14. void Start() {
15.     Cursor.lockState = CursorLockMode.Locked;
16. }
17.  
18. // Update is called once per frame
19. void Update() {
20.     _mouseDelta = new Vector2(Input.GetAxis("Mouse X"), Input.GetAxis("Mouse Y"));
21.     MoveCamera();
22. }
23.  
24.  
25. private void MoveCamera() {
26.     _rotX += _mouseDelta.x * _mouseXSensistivity * Time.deltaTime * 100;
27.     _rotX = Mathf.Clamp(_rotX, _xMinMaxRotation.x, _xMinMaxRotation.y);
28.     _rotY += _mouseDelta.y * _mouseYSensistivity * Time.deltaTime * 100;
29.     _rotY = Mathf.Clamp(_rotY, _yMinMaxRotation.x, _yMinMaxRotation.y);
30.  
31.     //Calculation for RotZ
32.     if (Input.GetKey(KeyCode.Q)) {
33.         _rotZ += +_mouseZSensistivity * Time.deltaTime * 50;
34.         if (_rotZ > 25) _rotZ = 25;
35.     }
36.     else {
37.         if (_rotZ > 0) {
38.             _rotZ -= 2 * _mouseZSensistivity * Time.deltaTime * 50;
39.             if (_rotZ < 0) _rotZ = 0;
40.         }
41.     }
42.     if (Input.GetKey(KeyCode.E)) {
43.         _rotZ += -_mouseZSensistivity * Time.deltaTime * 50;
44.         if (_rotZ < -25) _rotZ = -25;
45.     }
46.     else {
47.         if (_rotZ < 0) {
48.             _rotZ -= 2 * -_mouseZSensistivity * Time.deltaTime * 50;
49.             if (_rotZ > 0) _rotZ = 0;
50.         }
51.     }
52.  
53.     Quaternion currentRotation = Quaternion.identity;
54.     currentRotation = Quaternion.AngleAxis(_rotX, transform.up) * currentRotation;
55.     currentRotation = Quaternion.AngleAxis(-_rotY, transform.right) * currentRotation;
56.     currentRotation = Quaternion.AngleAxis(_rotZ, transform.forward) * currentRotation;
57.     _camera.transform.rotation = currentRotation;
58. }

The last part with quaternions is where im trying to calculate angles in order to properly rotate in local coordinates, but as i said there is someting wrong. If i watch the rotation gizmos on the scene of unity sometimes axis are not following the local coordinates.

 

Change those last few lines to be:

Code (CSharp):

1.         Quaternion currentRotation = Quaternion.identity;
2.         currentRotation = currentRotation * Quaternion.AngleAxis(_rotX, transform.up) ;
3.         currentRotation = currentRotation * Quaternion.AngleAxis(-_rotY, transform.right);
4.         currentRotation = currentRotation * Quaternion.AngleAxis(_rotZ, transform.forward) ;
5.         _camera.transform.rotation = currentRotation;

 

And if you'd like to not get bogged down in camera work, I suggest using Unity's Cinemachine package.

 

Close man! Now the Y and Z axis rotate exactly as i want locally but X rotation looks follow the global X! It's kinda weird!
There is another oddity in Unity. If i try to rotate an object from another object (like a manager or a parent) it rotate in global coordinates but if i try to rotate the object attaching the SAME script in that object it rotate locally, i mean why? It's looks a bit crazy hehe... This is the function i used in the last problem i described. I It's very similar to the one i'm using for the camera rotation but instead using the delta mouse to calculate the angles i have a fix speed running every frame that represents the angle of rotation.

Code (CSharp):

1. public void RotatingWithQuaternion() {
2.         Quaternion currentRotation = GO_To_Rotate.transform.rotation;
3.             if (x) {
4.                 currentRotation = Quaternion.AngleAxis(Time.deltaTime * speed, transform.right) * currentRotation;
5.             }
6.             if (y) {
7.                 currentRotation = Quaternion.AngleAxis(Time.deltaTime * speed, transform.up) * currentRotation;
8.             }
9.             if (z) {
10.                 currentRotation = Quaternion.AngleAxis(Time.deltaTime * speed, transform.forward) * currentRotation;
11.             }
12.          
13.         }
14.         GO_To_Rotate.transform.rotation = currentRotation;
15.     }

 

Thanks and sorry! I was not sure where to post it and i thought rotation and quaternion was somehow releted to phisycs but actually they are more about math and trigonometry filed.

 

Using Quaternions to avoid Gimbal Lock.

You're rotating like it's an euler.

Code (CSharp):

1. Quaternion.AngleAxis(Time.deltaTime * speed, transform.right) * currentRotation;

So in euler your * by current rotation is replaced with your Objects.forward, but aside this in euler you are saying Forward = Forward + (Right * (Time * Speed));

Not sure what you are doing to be honest. There are some Quaternion loyalists floating around that could take you through step by step why its not achieving the result, but from my take it seems like you are using euler technique to rotate in quaternion and this is what's confusing things.

 

There's so many examples of FPS look scripts, I'm not sure it makes sense to try and reinvent the wheel with speculation about Quaternions. If you just need a player controller, here's one:

It is a super-basic starter prototype FPS based on Character Controller (BasicFPCC):

https://forum.unity.com/threads/a-basic-first-person-character-controller-for-prototyping.1169491/

It has run, walk, jump, slide, crouch... all the good bits.

 

I dont' need this but thanks! I know how to create a fps controller. My problem is very specific and is related to an issue with local rotation. I read many topics and solution about quaternions but none of them is helping me in this specific contest.

EDIT: Btw the guy in the script you posted me is doing exactly what i am doing but he dosen't have my problem because he moving the camera only in the x and y axis but i move the camera in all 3 axis because i rotate it also with Q and E keybind but the problem is that one of the three axis is not following the local coordinate but the world coordinates.

 

Stack the Transforms so you can control individual local axes with each.

Player

  CameraLookLeftRightUpDown

     CameraTiltAroundLocalZAxis

         ActualCamera

Works every time.