when clamping rotation with opposite quaternion parameters, how to determine which side will be clamped?

Questions & Answers
1

for example,

transform.rotation = Quaternion.Euler (Mathf.Clamp (transform.rotation.x, 90, 270,), 0, 0);
2

Perhaps you can more clearly explain your question.

“What is a rotation with opposite quaternion parameters?”
A rotation ‘is’ a quaternion.

“how to determine which side will be clamped?”
Which side of what?

Clamping works like this:

B = Mathf.Clamp(A, min, max);

  • If ‘A’ is within min/max, ‘B’ will equal ‘A’.

  • If ‘A’ is outside min/max, it is brought back to within min/max, and then stored in ‘B’.
    The value of ‘A’ does not change in this case, it is only used to determine the value of ‘B’. If you want it to change, simply assign the result of Clamp back to itself.

    ‘A’ = Mathf.Clamp(‘A’, min, max);

In your example, you are taking your current rotation, clamping makes sure your x value stays between 90 and 270, and you’re keeping your y and z values at 0.

A few examples for your case:

--------
transform.rotation = Quaternion.Euler(90, 100, 200)
transform.rotation = Quaternion.Euler(Mathf.Clamp(transform.rotation.x, 90, 270), 0, 0);
// transform.rotation = 90, 0, 0
--------

--------
transform.rotation = Quaternion.Euler(-2, 75, 85)
transform.rotation = Quaternion.Euler(Mathf.Clamp(transform.rotation.x, 90, 270), 0, 0);
// transform.rotation = 90, 0, 0
--------

--------
transform.rotation = Quaternion.Euler(181.65, -10, 10)
transform.rotation = Quaternion.Euler(Mathf.Clamp(transform.rotation.x, 90, 270), 0, 0);
// transform.rotation = 181.65, 0, 0
--------

--------
transform.rotation = Quaternion.Euler(410, 0, 0)
transform.rotation = Quaternion.Euler(Mathf.Clamp(transform.rotation.x, 90, 270), 0, 0);
// transform.rotation = 270, 0, 0
--------

If that doesn’t help, you’ll have to be more specific and I’ll edit my answer.