examples/12_graphs_custom_functions.html

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	<head>
		<title>Tween.js / graphs for custom easing functions</title>
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		<style>
			body {
				margin: 0px;
			}

			#target {
				font-size: 13px;
				padding: 0px 32px;
			}
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		<div id="info" style="position: relative">
			<h1><a href="http://github.com/tweenjs/tween.js">tween.js</a></h1>
			<h2>12 _ graphs for custom easing functions</h2>
			<p>
				A version of the <a href="03_graphs.html">graphs</a> example, but using custom easing functions (not included in
				<a href="https://github.com/tween.js/tween.js">tween.js</a> by default).
			</p>
		</div>

		<div id="target"></div>

		<script type="module">
			import {createGraph} from './js/createGraph.js'
			import * as TWEEN from '../dist/tween.esm.js'

			const group = new TWEEN.Group()

			window.addEventListener('load', function () {
				init()
				animate()
			})

			function init() {
				const target = document.getElementById('target')

				target.appendChild(createGraph(group, 'Ten Steps', tenStepsEasing))

				target.appendChild(document.createElement('br'))

				for (let i = 0; i < 4; i++) {
					const numSteps = (i + 1) * 4
					target.appendChild(createGraph(group, numSteps + ' steps', createStepFunction(numSteps)))
				}

				target.appendChild(document.createElement('br'))

				target.appendChild(createGraph(group, 'Random', randomEasing))

				target.appendChild(document.createElement('br'))

				target.appendChild(
					createGraph(group, 'Noisy Exponential.InOut', createNoisyEasing(0.1, TWEEN.Easing.Exponential.InOut)),
				)
				target.appendChild(
					createGraph(group, 'Noisy Elastic.InOut', createNoisyEasing(0.1, TWEEN.Easing.Elastic.InOut)),
				)
				target.appendChild(
					createGraph(group, 'Noisy Circular.InOut', createNoisyEasing(0.1, TWEEN.Easing.Circular.InOut)),
				)
			}

			function animate() {
				requestAnimationFrame(animate)

				group.update()
			}

			function tenStepsEasing(k) {
				return Math.floor(k * 10) / 10
			}

			// This is where we get very meta and write a function for
			// generating functions! The returned function is similar to
			// the tenStepsEasing function above, but the number of steps
			// is passed as a parameter
			function createStepFunction(numSteps) {
				return function (k) {
					return Math.floor(k * numSteps) / numSteps
				}
			}

			function randomEasing(k) {
				return Math.random()
			}

			// Getting meta again: why not use existing functions as the
			// base for new easing functions?
			function createNoisyEasing(randomProportion, easingFunction) {
				const normalProportion = 1.0 - randomProportion
				return function (k) {
					return randomProportion * Math.random() + normalProportion * easingFunction(k)
				}
			}
		</script>
	</body>
</html>