Why does my mouse look spike after a display switch?

On display change, the OS reports an unusually large pointer delta as the cursor 'jumps' to the new position. Reading raw delta the next frame produces a large look snap. Reset accumulated delta on focus changes.

Should I read delta from Pointer.delta or Mouse.delta?

Mouse.delta is per-tick raw movement. Pointer.delta similar. Either works; both can spike on focus changes. Wrap in a clamp or filter to bound the maximum per-frame delta.

How do I detect focus regain?

OnApplicationFocus(true). Reset your accumulated delta and skip one frame of input to discard the OS snap.

Fix: Unity Mouse Delta Doubled After Display Switch

Quick answer: Skip one frame of mouse delta on OnApplicationFocus(true). Clamp per-frame delta to a sane maximum (e.g. 200 px) to prevent spike-induced view snaps.

User alt-tabs to another window, comes back; the camera spins wildly for one frame. The OS reports the cursor’s new position as a single huge delta.

The Symptom

Camera snaps after focus loss/regain or display change. Repeatable. Not present in normal play.

The Fix

private bool _skipNextDelta;

void OnApplicationFocus(bool hasFocus)
{
    if (hasFocus) _skipNextDelta = true;
}

void Update()
{
    if (_skipNextDelta)
    {
        _skipNextDelta = false;
        return;
    }

    Vector2 d = Mouse.current.delta.ReadValue();
    d.x = Mathf.Clamp(d.x, -200, 200);
    d.y = Mathf.Clamp(d.y, -200, 200);
    RotateView(d);
}

Skip one frame of input on focus regain; clamp deltas to bound any other anomalies.

Verifying

Alt-tab and return. Camera should not snap. Test multiple monitors / display swaps. Without the fix: snap. With: stable.

“Skip on focus. Clamp delta. Camera holds.”

Related Issues

For multi-touch fingerId, see touchId. For input action double-fire, see double-fire.

Skip the spike. Clamp the rest.