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	<head>
		<title>three.js webgl - lights - hemisphere light</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<link type="text/css" rel="stylesheet" href="main.css">
		<style>
			body {
				color: #444;
			}
			a {
				color: #08f;
			}
		</style>
	</head>
	<body>

		<div id="container"></div>
		<div id="info">
			<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - webgl hemisphere light example<br/>
			flamingo by <a href="https://mirada.com/" target="_blank" rel="noopener">mirada</a> from <a href="http://www.ro.me" target="_blank" rel="noopener">ro.me</a>
		</div>

		<script type="x-shader/x-vertex" id="vertexShader">

			varying vec3 vWorldPosition;

			void main() {

				vec4 worldPosition = modelMatrix * vec4( position, 1.0 );
				vWorldPosition = worldPosition.xyz;

				gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );

			}

		</script>

		<script type="x-shader/x-fragment" id="fragmentShader">

			uniform vec3 topColor;
			uniform vec3 bottomColor;
			uniform float offset;
			uniform float exponent;

			varying vec3 vWorldPosition;

			void main() {

				float h = normalize( vWorldPosition + offset ).y;
				gl_FragColor = vec4( mix( bottomColor, topColor, max( pow( max( h , 0.0), exponent ), 0.0 ) ), 1.0 );

			}

		</script>

		<!-- Import maps polyfill -->
		<!-- Remove this when import maps will be widely supported -->
		<script async src="https://unpkg.com/es-module-shims@1.8.0/dist/es-module-shims.js"></script>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.module.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three';

			import Stats from 'three/addons/libs/stats.module.js';
			import { GUI } from 'three/addons/libs/lil-gui.module.min.js';

			import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';

			let camera, scene, renderer;
			const mixers = [];
			let stats;

			const clock = new THREE.Clock();

			init();
			animate();

			function init() {

				const container = document.getElementById( 'container' );

				camera = new THREE.PerspectiveCamera( 30, window.innerWidth / window.innerHeight, 1, 5000 );
				camera.position.set( 0, 0, 250 );

				scene = new THREE.Scene();
				scene.background = new THREE.Color().setHSL( 0.6, 0, 1 );
				scene.fog = new THREE.Fog( scene.background, 1, 5000 );

				// LIGHTS

				const hemiLight = new THREE.HemisphereLight( 0xffffff, 0xffffff, 2 );
				hemiLight.color.setHSL( 0.6, 1, 0.6 );
				hemiLight.groundColor.setHSL( 0.095, 1, 0.75 );
				hemiLight.position.set( 0, 50, 0 );
				scene.add( hemiLight );

				const hemiLightHelper = new THREE.HemisphereLightHelper( hemiLight, 10 );
				scene.add( hemiLightHelper );

				//

				const dirLight = new THREE.DirectionalLight( 0xffffff, 3 );
				dirLight.color.setHSL( 0.1, 1, 0.95 );
				dirLight.position.set( - 1, 1.75, 1 );
				dirLight.position.multiplyScalar( 30 );
				scene.add( dirLight );

				dirLight.castShadow = true;

				dirLight.shadow.mapSize.width = 2048;
				dirLight.shadow.mapSize.height = 2048;

				const d = 50;

				dirLight.shadow.camera.left = - d;
				dirLight.shadow.camera.right = d;
				dirLight.shadow.camera.top = d;
				dirLight.shadow.camera.bottom = - d;

				dirLight.shadow.camera.far = 3500;
				dirLight.shadow.bias = - 0.0001;

				const dirLightHelper = new THREE.DirectionalLightHelper( dirLight, 10 );
				scene.add( dirLightHelper );

				// GROUND

				const groundGeo = new THREE.PlaneGeometry( 10000, 10000 );
				const groundMat = new THREE.MeshLambertMaterial( { color: 0xffffff } );
				groundMat.color.setHSL( 0.095, 1, 0.75 );

				const ground = new THREE.Mesh( groundGeo, groundMat );
				ground.position.y = - 33;
				ground.rotation.x = - Math.PI / 2;
				ground.receiveShadow = true;
				scene.add( ground );

				// SKYDOME

				const vertexShader = document.getElementById( 'vertexShader' ).textContent;
				const fragmentShader = document.getElementById( 'fragmentShader' ).textContent;
				const uniforms = {
					'topColor': { value: new THREE.Color( 0x0077ff ) },
					'bottomColor': { value: new THREE.Color( 0xffffff ) },
					'offset': { value: 33 },
					'exponent': { value: 0.6 }
				};
				uniforms[ 'topColor' ].value.copy( hemiLight.color );

				scene.fog.color.copy( uniforms[ 'bottomColor' ].value );

				const skyGeo = new THREE.SphereGeometry( 4000, 32, 15 );
				const skyMat = new THREE.ShaderMaterial( {
					uniforms: uniforms,
					vertexShader: vertexShader,
					fragmentShader: fragmentShader,
					side: THREE.BackSide
				} );

				const sky = new THREE.Mesh( skyGeo, skyMat );
				scene.add( sky );

				// MODEL

				const loader = new GLTFLoader();

				loader.load( 'models/gltf/Flamingo.glb', function ( gltf ) {

					const mesh = gltf.scene.children[ 0 ];

					const s = 0.35;
					mesh.scale.set( s, s, s );
					mesh.position.y = 15;
					mesh.rotation.y = - 1;

					mesh.castShadow = true;
					mesh.receiveShadow = true;

					scene.add( mesh );

					const mixer = new THREE.AnimationMixer( mesh );
					mixer.clipAction( gltf.animations[ 0 ] ).setDuration( 1 ).play();
					mixers.push( mixer );

				} );

				// RENDERER

				renderer = new THREE.WebGLRenderer( { antialias: true } );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				container.appendChild( renderer.domElement );
				renderer.shadowMap.enabled = true;

				// STATS

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

				//

				const params = {
					toggleHemisphereLight: function () {

						hemiLight.visible = ! hemiLight.visible;
						hemiLightHelper.visible = ! hemiLightHelper.visible;

					},
					toggleDirectionalLight: function () {

						dirLight.visible = ! dirLight.visible;
						dirLightHelper.visible = ! dirLightHelper.visible;

					}
				};

				const gui = new GUI();

				gui.add( params, 'toggleHemisphereLight' ).name( 'toggle hemisphere light' );
				gui.add( params, 'toggleDirectionalLight' ).name( 'toggle directional light' );
				gui.open();

				//

				window.addEventListener( 'resize', onWindowResize );

			}

			function onWindowResize() {

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

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

			}

			//

			function animate() {

				requestAnimationFrame( animate );

				render();
				stats.update();

			}

			function render() {

				const delta = clock.getDelta();

				for ( let i = 0; i < mixers.length; i ++ ) {

					mixers[ i ].update( delta );

				}

				renderer.render( scene, camera );

			}

		</script>
	</body>
</html>