How to calculate and use new direction angle as a new forward direction.

Question

My player is a cube tumbling forward/backward and sideways.

This script calculates the edges of my cube and make it rotate around its edge.

 void FixedUpdate()
         {
             bound = GetComponent<BoxCollider>().bounds;
 
             left = new Vector3(-bound.size.x / 2, -bound.size.y / 2, 0);
             right = new Vector3(bound.size.x / 2, -bound.size.y / 2, 0);
             up = new Vector3(0, -bound.size.y / 2, bound.size.z / 2);
             down = new Vector3(0, -bound.size.y / 2, -bound.size.z / 2);

//These are the 'positionToRotations' when pressed by arrows) }

         IEnumerator Roll(Vector3 positionToRotation)
         {
             isRolling = true;
 
             float angle = 0.0f;
             Vector3 point = transform.position + positionToRotation;
             Vector3 axis = Vector3.Cross(Vector3.up, positionToRotation);
 
             while (angle < 90f)
             {
                 float angleSpeed = Time.deltaTime + rotationSpeed;
                 transform.RotateAround(point, axis, angleSpeed);
                 angle += angleSpeed;
                 yield return null;
             }
             transform.RotateAround(point, axis, 90 - angle); 
             isRolling = false;
         }

(What I like about this function is that I can change the size of the cube and make it a rectangle too)

But when my cube is randomly rotated (Y axis) in the world space, it tries the find the wrong 'point' and 'axis'. So I need to calculate where these are and (even more complicated for me) write a line how to use them. This picture illustrates what I'm stuck at.

alt text

I have no idea how this works in the mathematical way. I tried a lot of Quaternion.AngleAxis stuff, but I don't fully understand the math behind it.

Answer 1

Well, since I figured out how this works, I'd just answer it myself for everyone who might encounter this post in the future....

This is how it works

      IEnumerator Roll(Vector3 positionToRotation)
         {
             isRolling = true;
     
             //GroundLevel
             RaycastHit hit;
             Physics.Raycast(thisRigidBody.position, Vector3.down, out hit);
     
             //RB gravity
             thisRigidBody.useGravity = false;
     
             Vector3 cam = Camera.main.transform.forward; cam.y = 0;
     
             float angle = 0.0f;
             //This calculates the perpendicular of the cam forward
             float angleNeeded = Mathf.Atan2(Vector3.Dot(Vector3.up, Vector3.Cross(newUp, cam)), Vector3.Dot(newUp, cam)) * Mathf.Rad2Deg;
             
     Vector3 point = transform.position + positionToRotation; 
             Vector3 groundPoint = new Vector3(point.x, hit.point.y, point.z);
     
             Vector3 axis = Vector3.Cross(Vector3.up, positionToRotation);
             Vector3 camAxis = Quaternion.AngleAxis(angleNeeded, Vector3.up) * axis;
     
             while (angle < 90f)
             {
                 float angleSpeed = Time.deltaTime + rotationSpeed;
                 transform.RotateAround(groundPoint, camAxis, angleSpeed);
                 angle += angleSpeed;
                 yield return null;
             }
             transform.RotateAround(groundPoint, camAxis, 90 - angle);
     
             thisRigidBody.useGravity = true;
             isRolling = false;
         }

How to calculate and use new direction angle as a new forward direction.

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