samien
/
three.js
зеркало из https://github.com/mrdoob/three.js.git


			
				
					
						
						
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		<h1>[name]</h1>

		<p class="desc">
			This class is an alternative to [page:Clock] with a different API design and behavior.
			The goal is to avoid the conceptual flaws that became apparent in [page:Clock] over time.

			<ul>
				<li>[name] has an [page:.update]() method that updates its internal state. That makes it possible to call [page:.getDelta]() and [page:.getElapsed]() multiple times per simulation step without getting different values.</li>
				<li>The class uses the Page Visibility API to avoid large time delta values when the app is inactive (e.g. tab switched or browser hidden).</li>
			</ul>
		</p>

		<h2>Import</h2>

		<p>
			[name] is an add-on, and must be imported explicitly.
			See [link:#manual/introduction/Installation Installation / Addons].
		</p>

		<code>
			import { Timer } from 'three/addons/misc/Timer.js';
		</code>

		<h2>Code Example</h2>

		<code>
		const timer = new Timer();

		function animate( timestamp ) {

			requestAnimationFrame( animate );

			// timestamp is optional
			timer.update( timestamp );

			const delta = timer.getDelta();

			// do something with delta

			renderer.render( scene, camera );

		}
		</code>

		<h2>Examples</h2>

		<p>
			[example:webgl_morphtargets_sphere WebGL / morphtargets / sphere]
		</p>

		<h2>Constructor</h2>

		<h3>Timer( [param:Boolean usePageVisibilityAPI] )</h3>
		<p>
			[page:Boolean usePageVisibilityAPI] - (optional) Whether to use the Page Visibility API to avoid large time delta values in inactive tabs or not. Default is `true`. 
		</p>

		<h2>Methods</h2>

		<h3>[method:Number getDelta]()</h3>
		<p>
			Returns the time delta in seconds.
		</p>

		<h3>[method:Number getElapsed]()</h3>
		<p>
			Returns the elapsed time in seconds.
		</p>

		<h3>[method:this setTimescale]( [param:Number timescale] )</h3>
		<p>
			Sets a time scale that scales the time delta in [page:.update]().
		</p>

		<h3>[method:this reset]()</h3>
		<p>
			Resets the time computation for the current simulation step.
		</p>

		<h3>[method:this dispose]()</h3>
		<p>
			Can be used to free all internal resources. Usually called when the timer instance isn't required anymore.
		</p>

		<h3>[method:this update]( [param:Number timestamp] )</h3>
		<p>
			timestamp -- (optional) The current time in milliseconds. Can be obtained from the
			[link:https://developer.mozilla.org/en-US/docs/Web/API/window/requestAnimationFrame requestAnimationFrame]
			callback argument. If not provided, the current time will be determined with
			[link:https://developer.mozilla.org/en-US/docs/Web/API/Performance/now performance.now].<br /><br />

			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 [page:.getDelta]()).
		</p>

		<h2>Source</h2>

		<p>
			[link:https://github.com/mrdoob/three.js/blob/master/examples/jsm/misc/Timer.js examples/jsm/misc/Timer.js]
		</p>
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