first app vibe

app/node_modules/three/examples/jsm/misc/Timer.js

@@ -0,0 +1,222 @@
+/**
+ * This class is an alternative to {@link Clock} with a different API design and behavior.
+ * The goal is to avoid the conceptual flaws that became apparent in `Clock` over time.
+ *
+ * - `Timer` has an `update()` method that updates its internal state. That makes it possible to
+ * call `getDelta()` and `getElapsed()` multiple times per simulation step without getting different values.
+ * - The class can make use of the Page Visibility API to avoid large time delta values when the app
+ * is inactive (e.g. tab switched or browser hidden).
+ *
+ * ```js
+ * const timer = new Timer();
+ * timer.connect( document ); // use Page Visibility API
+ * ```
+ *
+ * @three_import import { Timer } from 'three/addons/misc/Timer.js';
+ */
+class Timer {
+
+	/**
+	 * Constructs a new timer.
+	 */
+	constructor() {
+
+		this._previousTime = 0;
+		this._currentTime = 0;
+		this._startTime = now();
+
+		this._delta = 0;
+		this._elapsed = 0;
+
+		this._timescale = 1;
+
+		this._document = null;
+		this._pageVisibilityHandler = null;
+
+	}
+
+	/**
+	 * Connect the timer to the given document.Calling this method is not mandatory to
+	 * use the timer but enables the usage of the Page Visibility API to avoid large time
+	 * delta values.
+	 *
+	 * @param {Document} document - The document.
+	 */
+	connect( document ) {
+
+		this._document = document;
+
+		// use Page Visibility API to avoid large time delta values
+
+		if ( document.hidden !== undefined ) {
+
+			this._pageVisibilityHandler = handleVisibilityChange.bind( this );
+
+			document.addEventListener( 'visibilitychange', this._pageVisibilityHandler, false );
+
+		}
+
+	}
+
+	/**
+	 * Disconnects the timer from the DOM and also disables the usage of the Page Visibility API.
+	 */
+	disconnect() {
+
+		if ( this._pageVisibilityHandler !== null ) {
+
+			this._document.removeEventListener( 'visibilitychange', this._pageVisibilityHandler );
+			this._pageVisibilityHandler = null;
+
+		}
+
+		this._document = null;
+
+	}
+
+	/**
+	 * Returns the time delta in seconds.
+	 *
+	 * @return {number} The time delta in second.
+	 */
+	getDelta() {
+
+		return this._delta / 1000;
+
+	}
+
+	/**
+	 * Returns the elapsed time in seconds.
+	 *
+	 * @return {number} The elapsed time in second.
+	 */
+	getElapsed() {
+
+		return this._elapsed / 1000;
+
+	}
+
+	/**
+	 * Returns the timescale.
+	 *
+	 * @return {number} The timescale.
+	 */
+	getTimescale() {
+
+		return this._timescale;
+
+	}
+
+	/**
+	 * Sets the given timescale which scale the time delta computation
+	 * in `update()`.
+	 *
+	 * @param {number} timescale - The timescale to set.
+	 * @return {Timer} A reference to this timer.
+	 */
+	setTimescale( timescale ) {
+
+		this._timescale = timescale;
+
+		return this;
+
+	}
+
+	/**
+	 * Resets the time computation for the current simulation step.
+	 *
+	 * @return {Timer} A reference to this timer.
+	 */
+	reset() {
+
+		this._currentTime = now() - this._startTime;
+
+		return this;
+
+	}
+
+	/**
+	 * Can be used to free all internal resources. Usually called when
+	 * the timer instance isn't required anymore.
+	 */
+	dispose() {
+
+		this.disconnect();
+
+	}
+
+	/**
+	 * Updates the internal state of the timer. This method should be called
+	 * once per simulation step and before you perform queries against the timer
+	 * (e.g. via `getDelta()`).
+	 *
+	 * @param {number} timestamp - The current time in milliseconds. Can be obtained
+	 * from the `requestAnimationFrame` callback argument. If not provided, the current
+	 * time will be determined with `performance.now`.
+	 * @return {Timer} A reference to this timer.
+	 */
+	update( timestamp ) {
+
+		if ( this._pageVisibilityHandler !== null && this._document.hidden === true ) {
+
+			this._delta = 0;
+
+		} else {
+
+			this._previousTime = this._currentTime;
+			this._currentTime = ( timestamp !== undefined ? timestamp : now() ) - this._startTime;
+
+			this._delta = ( this._currentTime - this._previousTime ) * this._timescale;
+			this._elapsed += this._delta; // _elapsed is the accumulation of all previous deltas
+
+		}
+
+		return this;
+
+	}
+
+}
+
+/**
+ * A special version of a timer with a fixed time delta value.
+ * Can be useful for testing and debugging purposes.
+ *
+ * @augments Timer
+ */
+class FixedTimer extends Timer {
+
+	/**
+	 * Constructs a new timer.
+	 *
+	 * @param {number} [fps=60] - The fixed FPS of this timer.
+	 */
+	constructor( fps = 60 ) {
+
+		super();
+		this._delta = ( 1 / fps ) * 1000;
+
+	}
+
+	update() {
+
+		this._elapsed += ( this._delta * this._timescale ); // _elapsed is the accumulation of all previous deltas
+
+		return this;
+
+	}
+
+}
+
+function now() {
+
+	return performance.now();
+
+}
+
+function handleVisibilityChange() {
+
+	if ( this._document.hidden === false ) this.reset();
+
+}
+
+export { Timer, FixedTimer };