Fix OrbitControls crash on multi-touch gestures (Issue #32116)

[Mostafa-Khairy0]

Problem

OrbitControls crashes intermittently on touch devices during two-finger gestures.
The error occurs when one finger is lifted while the other remains, causing _getSecondPointerPosition() to return undefined and trigger:
TypeError: Cannot read properties of undefined (reading 'x')

Solution

• Added null checks in _getSecondPointerPosition()
• Updated all touch handlers (rotate, pan, dolly) to safely handle single-finger lift
• Prevents crash when one finger is removed mid-gesture

Related Issue

Closes #32116

[Mugen87]

The error occurs when one finger is lifted while the other remains, causing _getSecondPointerPosition() to return undefined and trigger:

There is actually a logic in place that should correct the state when a pointer is lifted. It has been added via #27445.

three.js/examples/jsm/controls/OrbitControls.js

Lines 1526 to 1527 in e6084f9

	// minimal placeholder event - allows state correction on pointer-up
	this._onTouchStart( { pointerId: pointerId, pageX: position.x, pageY: position.y } );

We have to find out why the existing logic does not work. The PR in its current state more of a bandage that does not fix the root cause in the controls.

@sciecode I'm not sure you have the bandwidth but could you help us here (see #32116)?

[Mugen87]

Closing. A potential issue needs to be fixed differently. Let's continue the discussion in #32116.