samien
/
three.js
oglindă de https://github.com/mrdoob/three.js.git


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js webgl - gimbal lock</title>
		<meta charset="utf-8" />
		<meta
			name="viewport"
			content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0"
		/>
		<style>
			body {
				color: #000;
				font-family: Monospace;
				font-size: 13px;
				text-align: center;
				font-weight: bold;

				background-color: #fff;
				margin: 0px;
				overflow: hidden;
			}

			#info {
				color: #000;
				position: absolute;
				top: 0px;
				width: 100%;
				padding: 5px;
			}

			a {
				color: red;
			}
		</style>
	</head>

	<body>
		<div id="container"></div>
		<div id="info">
			<a href="http://threejs.org" target="_blank">three.js</a> - gimbal lock
			example
			<p>
				The object slowly rotates back and forth; one of its Euler angle
				components is close to pi/2.
			</p>
			<p>
				Every frame, with probability 0.5, the orientation is transformed into a
				quaternion then back into Euler angles.
			</p>
			<p>
				This causes an observable glitch when the calculation is imprecise due
				to gimbal lock.
			</p>
		</div>

		<script src="../build/three.js"></script>

		<script src="js/controls/OrbitControls.js"></script>

		<script src="js/libs/stats.min.js"></script>

		<script>
			var stats;

			var camera, controls, scene, renderer, mesh;

			init();
			render(); // remove when using next line for animation loop (requestAnimationFrame)
			animate();

			function init() {
				scene = new THREE.Scene();
				scene.fog = new THREE.FogExp2(0xcccccc, 0.002);

				renderer = new THREE.WebGLRenderer();
				renderer.setClearColor(scene.fog.color);
				renderer.setPixelRatio(window.devicePixelRatio);
				renderer.setSize(window.innerWidth, window.innerHeight);

				var container = document.getElementById('container');
				container.appendChild(renderer.domElement);

				camera = new THREE.PerspectiveCamera(
					60,
					window.innerWidth / window.innerHeight,
					1,
					1000
				);
				camera.position.copy(new THREE.Vector3(-10, -22, 17));
				camera.rotation.copy(new THREE.Euler(0.9, -0.3, 0.4, 'XYZ'));

				controls = new THREE.OrbitControls(camera, renderer.domElement);
				controls.addEventListener('change', render); // remove when using animation loop
				// enable animation loop when using damping or autorotation
				//controls.enableDamping = true;
				//controls.dampingFactor = 0.25;
				controls.enableZoom = false;

				// world

				var geometry = new THREE.CylinderGeometry(0, 10, 30, 16, 10);
				var material = new THREE.MeshPhongMaterial({
					color: 0xffffff,
					shading: THREE.FlatShading,
				});

				mesh = new THREE.Mesh(geometry, material);
				scene.add(mesh);

				// lights

				light = new THREE.DirectionalLight(0xffffff);
				light.position.set(1, 1, 1);
				scene.add(light);

				light = new THREE.DirectionalLight(0x002288);
				light.position.set(-1, -1, -1);
				scene.add(light);

				light = new THREE.AmbientLight(0x222222);
				scene.add(light);

				//

				stats = new Stats();
				container.appendChild(stats.dom);

				//

				window.addEventListener('resize', onWindowResize, false);
			}

			function onWindowResize() {
				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize(window.innerWidth, window.innerHeight);
			}

			function animate() {
				requestAnimationFrame(animate);

				controls.update(); // required if controls.enableDamping = true, or if controls.autoRotate = true

				stats.update();

				render();
			}

			var startTime = Date.now();

			function render() {
				var timer = (Date.now() - startTime) * 0.00025;
				var theta = Math.PI / 2 + Math.sin(timer) * 0.1;
				// var theta = 1.575;

				var euler = new THREE.Euler(0.7, theta, 0.5, 'ZYX');

				if (Math.random() < 0.5) {
					let quat = new THREE.Quaternion().setFromEuler(euler);
					let matrix = new THREE.Matrix4().makeRotationFromQuaternion(quat);
					var newEuler = new THREE.Euler().setFromRotationMatrix(matrix, 'ZYX');

					euler = newEuler;
				}
				mesh.setRotationFromEuler(euler);

				renderer.render(scene, camera);
			}
		</script>
	</body>
</html>