Function _initCore

src/Observer.js:123–142

		ScrollTrigger && ScrollTrigger.core && _integrate();
	},
	_initCore = core => {
		gsap = core || _getGSAP();
		if (!_coreInitted && gsap && typeof(document) !== "undefined" && document.body) {
			_win = window;
			_doc = document;
			_docEl = _doc.documentElement;
			_body = _doc.body;
			_root = [_win, _doc, _docEl, _body];
			_clamp = gsap.utils.clamp;
			_context = gsap.core.context || function() {};
			_pointerType = "onpointerenter" in _body ? "pointer" : "mouse";
			// isTouch is 0 if no touch, 1 if ONLY touch, and 2 if it can accommodate touch but also other types like mouse/pointer.
			_isTouch = Observer.isTouch = _win.matchMedia && _win.matchMedia("(hover: none), (pointer: coarse)").matches ? 1 : ("ontouchstart" in _win || navigator.maxTouchPoints > 0 || navigator.msMaxTouchPoints > 0) ? 2 : 0;
			_eventTypes = Observer.eventTypes = ("ontouchstart" in _docEl ? "touchstart,touchmove,touchcancel,touchend" : !("onpointerdown" in _docEl) ? "mousedown,mousemove,mouseup,mouseup" : "pointerdown,pointermove,pointercancel,pointerup").split(",");
			setTimeout(() => _startup = 0, 500);
			_coreInitted = 1;
		}
		ScrollTrigger || _setScrollTrigger(); // Observer might be initted BEFORE ScrollTrigger, so don't put this with the initting code. ScrollTrigger will call Observer.register() when it inits.
		return _coreInitted;
	};

_horizontal.op = _vertical;
_scrollers.cache = 0;