How can I lock my camera Z axis rotation in Unity?

Question

I am using my mouse position to rotate my camera:

void FixedUpdate()
{
    transform.Rotate(-Input.GetAxis("Mouse Y") * rotationspeed * Time.deltaTime, Input.GetAxis("Mouse X") * rotationspeed * Time.deltaTime, 0);
}

The problem is that after rotating it for a time the camera starts rotating on the Z axis as well. What should I do to lock the Z axis rotation of the camera?

Answer 1

If you want to rotate a object in two axis the third axis will rotate by default, you can not lock this because its the fact of real world . Try this in real world 3d object rotate any two axis third will rotate automatically.If you rotate one axis other two will be fixed . Thanks.

Answer 2

Transform.Rotate has an optional parameter

Space relativeTo = Space.Self

so by default it is set to Sapce.Self so it rotates around the local axes of the object.

So what happens is once you look down changing the local X-axis your local Y-axis doesn't point straight up anymore but is rather pointing a bit forward now. So if you now rotate around that local Y-axis your local horizont is suddendly not aligned with the world's horizont anymore.

---

What you want to do instead (you can actually see it also in the example in the link above) is rotating around the Y-axis in world space but rotate around X-axis in local space

like this

[SerializeField] private float rotationspeed;

private void FixedUpdate()
{
    // rotate around global world Y
    transform.Rotate(Input.GetAxis("Mouse X") * rotationspeed * Time.deltaTime, 0, 0, Space.World);

    // rotate around local X
    transform.Rotate(0, -Input.GetAxis("Mouse Y") * rotationspeed * Time.deltaTime, 0);
}