Function enablePointerEvent

packages/melonjs/src/input/pointerevent.ts:139–231

* enable pointer event (Pointer/Mouse/Touch) * @ignore

()

 * @ignore
 */
function enablePointerEvent(): void {
	if (!pointerInitialized) {
		if (!_app) {
			throw new Error("Pointer events require an initialized Application");
		}
		// the current pointer area
		currentPointer = new Rect(0, 0, 1, 1);

		// instantiate a pool of pointer catched
		for (let v = 0; v < device.maxTouchPoints; v++) {
			T_POINTERS.push(new Pointer());
		}

		if (pointerEventTarget === null || pointerEventTarget === undefined) {
			// default pointer event target
			pointerEventTarget = _app.renderer.getCanvas();
		}

		if (device.pointerEvent) {
			// standard Pointer Events
			activeEventList = pointerEventList;
		} else {
			// Regular Mouse events
			activeEventList = mouseEventList;
		}
		if (device.touch && !device.pointerEvent) {
			// touch event on mobile devices
			activeEventList = activeEventList.concat(touchEventList);
		}
		registerEventListener(activeEventList, onPointerEvent);

		// set the PointerMove/touchMove/MouseMove event
		if (typeof throttlingInterval === "undefined") {
			// set the default value
			throttlingInterval = ~~(1000 / timer.maxfps);
		}

		if (device.autoFocus) {
			device.focus();
			pointerEventTarget.addEventListener(
				activeEventList[2], // MOUSE/POINTER DOWN
				() => {
					device.focus();
				},
				{ passive: !preventDefault },
			);
		}

		// if time interval <= 16, disable the feature
		const events = findAllActiveEvents(activeEventList, POINTER_MOVE);
		if (throttlingInterval < 17) {
			for (let i = 0; i < events.length; i++) {
				if (activeEventList.indexOf(events[i]) !== -1) {
					pointerEventTarget.addEventListener(
						events[i],
						onMoveEvent,
						{ passive: true }, // do not preventDefault on Move events
					);