examples/webgl_lights_hemisphere.html

<!DOCTYPE html>
<html lang="en">
	<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">
		<style>
			body {
				background-color: #fff;
				color: #111;
				margin: 0px;
				overflow: hidden;
				font-family: Monospace;
				font-size: 13px;
			}

			#info {
				position: absolute;
				top: 0px; 
				width: 100%;
				padding: 5px;
				text-align: center;
			}
			
			#status {
				position: absolute;
				top: 25px;
				width: 100%;
				text-align: center;
				color: purple;
				font-size: 18px;
				font-weight: bold;
			}

			/*
			未访问		a:link    {color:blue;}
			已访问		a:visited {color:blue;}
			鼠标悬停	a:hover   {color:red;}
			鼠标按下	a:active  {color:yellow;}
			*/
			a {
				color: #0080ff;
				text-decoration: none;
			}

			a:hover {
				color: #f00;
			}

			/*
			任意浏览器的默认字体高都是16px。所有未经调整的浏览器都符合: 1em=16px。那么12px=0.75em,10px=0.625em。
			为了简化font-size的换算，需要在css中的body选择器中声明 font-size=62.5%，这就使em值变为 16px*62.5%=10px, 这样12px=1.2em, 10px=1em, 也就是说只需要将你的原来的px数值除以10，然后换上em作为单位就行了。
			em会继承父级元素的字体大小。
			*/
			#footer { width: 100%; margin: 2em auto; text-align: center; position: absolute; bottom: 0 }
			strong { color: red }
		</style>
	</head>
	<body>

		<div id="container"></div>
		<div id="info">
			<a href="http://threejs.org" target="_blank">three.js</a> - webgl hemisphere light example -
			flamingo by <a href="http://mirada.com/">mirada</a> from <a href="http://ro.me">rome</a><br/>
		</div>
		<div id="status">
		</div>
		<div id="footer">
			press <strong>h</strong> to toggle hemisphere light, <strong>d</strong> to toggle directional light
		</div>

		<script src="../build/three.js"></script>
		<!--
		检测支持(canvas，webgl，workers，fileApi)
		-->
		<script src="js/Detector.js"></script>
		
		<!--
		统计插件(FPS，渲染时间，chrome内存使用率)，min表示js代码经过压缩
		-->
		<script src="js/libs/stats.min.js"></script>

		<!--
		GLSL顶点着色器
		-->
		<script type="x-shader/x-vertex" id="vertexShader">
			/*
			varying: 顶点着色器的输出。例如颜色或者纹理坐标，(插值后的数据)作为片段着色器的只读输入数据。
			必须是全局范围声明的全局变量。可以是浮点数类型的标量，向量，矩阵。不能是数组或者结构体。
			*/
			varying vec3 vWorldPosition;

			void main() {
				vec4 worldPosition = modelMatrix * vec4( position, 1.0 );
				vWorldPosition = worldPosition.xyz;
				//gl_Position: 输出属性-变换后的顶点的位置，用于后面的固定的裁剪等操作。所有的顶点着色器都必须写这个值。
				gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
			}
		</script>

		<!--
		GLSL片元着色器
		-->
		<script type="x-shader/x-fragment" id="fragmentShader">
			/*
			一致变量。在着色器执行期间一致变量的值是不变的。
			与const常量不同的是，这个值在编译时期是未知的是由着色器外部初始化的。
			一致变量在顶点着色器和片段着色器之间是共享的。它也只能在全局范围进行声明。
			*/
			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: 输出的颜色用于随后的像素操作
				mix(color1, color2, r)是将color1和color2 两种颜色，按照bg = color1*(1-r)+r*color2的方式混合
				*/
				gl_FragColor = vec4( mix( bottomColor, topColor, max( pow( max( h , 0.0), exponent ), 0.0 ) ), 1.0 );
			}
		</script>

		<script>
			//如果不支持webgl，则会在当前的父布局上添加一个不支持的提示信息DIV
			if ( ! Detector.webgl ) Detector.addGetWebGLMessage();

			var camera, scene, renderer, dirLight, hemiLight;
			var mixers = [];
			var stats;

			//three.js定义的一种计时器，内部也是使用Date.now()来进行计时的
			var clock = new THREE.Clock();

			init();
			animate();

			function init() {
				var container = document.getElementById( 'container' );

				/*
				透视相机
				PerspectiveCamera(fov, aspect, near, far)
                    fov(视场)：从相机位置能够看到的部分场景。推荐默认值45
                    aspect(长宽比)：渲染结果输出区域的横向长度和纵向长度的比值。推荐默认值window.innerWidth/window.innerHeight
                    near(近面)：定义从距离相机多近的地方开始渲染场景。推荐默认值0.1
                    far(远面)：定义相机可以从它所处的位置看多远。默认值1000
                */
				camera = new THREE.PerspectiveCamera( 30, window.innerWidth / window.innerHeight, 1, 5000 );
				camera.position.set( 0, 0, 250 );

				scene = new THREE.Scene();

				//添加雾化效果
				
				//设置雾化浓度在near和far浓度渐变
				scene.fog = new THREE.Fog( 0xffffff, 1, 5000 );
				//设置场景中统一的雾化浓度
				//scene.fog = new THREE.FogExp2(0xffffff, 0.015);
				//设置雾的颜色，色相(Hue)、饱和度(Siguation)、明度(Lightness)
				scene.fog.color.setHSL( 0.6, 0, 1 );

				// LIGHTS

				hemiLight = new THREE.HemisphereLight( 0xffffff, 0xffffff, 0.6 );
				hemiLight.color.setHSL( 0.6, 1, 0.6 );
				hemiLight.groundColor.setHSL( 0.095, 1, 0.75 );
				hemiLight.position.set( 0, 500, 0 );
				scene.add( hemiLight );

				//平行光
				dirLight = new THREE.DirectionalLight( 0xffffff, 1 );
				dirLight.color.setHSL( 0.1, 1, 0.95 );
				dirLight.position.set( -1, 1.75, 1 );
				dirLight.position.multiplyScalar( 50 );
				scene.add( dirLight );

				dirLight.castShadow = true;

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

				var 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;

				// GROUND

				var groundGeo = new THREE.PlaneBufferGeometry( 10000, 10000 );
				var groundMat = new THREE.MeshPhongMaterial( { color: 0xffffff, specular: 0x050505 } );
				groundMat.color.setHSL( 0.095, 1, 0.75 );

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

				ground.receiveShadow = true;

				// SKYDOME

				var vertexShader = document.getElementById( 'vertexShader' ).textContent;
				var fragmentShader = document.getElementById( 'fragmentShader' ).textContent;
				var 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 );

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

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

				// MODEL

				var loader = new THREE.JSONLoader();

				loader.load( 'models/animated/flamingo.js', function( geometry ) {

					var material = new THREE.MeshPhongMaterial( { color: 0xffffff, specular: 0xffffff, shininess: 20, morphTargets: true, vertexColors: THREE.FaceColors, shading: THREE.FlatShading } );
					var mesh = new THREE.Mesh( geometry, material );

					var 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 );

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

				} );

				// RENDERER

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

				renderer.gammaInput = true;
				renderer.gammaOutput = true;

				renderer.shadowMap.enabled = true;
				renderer.shadowMap.renderReverseSided = false;

				// STATS

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

				window.addEventListener( 'resize', onWindowResize, false );
				document.addEventListener( 'keydown', onKeyDown, false );

			}

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

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

			function onKeyDown ( event ) {
				//keyCode是字母和数字键的键码值
				switch ( event.keyCode ) {
					case 72: // h
						hemiLight.visible = !hemiLight.visible;
						resetStatus();
						break;
					case 68: // d
						dirLight.visible = !dirLight.visible;
						resetStatus();
						break;
				}
			}

			function animate() {
				requestAnimationFrame( animate );

				render();
				//这里可以在render前后使用stats.begin和stats.end，也可以在每次渲染的时候调用一次stats.update
				stats.update();
			}

			function render() {
				//获取两次getDelta()的时间差，单位:秒
				var delta = clock.getDelta();

				for ( var i = 0; i < mixers.length; i ++ ) {
					mixers[ i ].update( delta );
				}
				
				renderer.render( scene, camera );
			}
			function resetStatus() {
				document.getElementById("status").innerHTML = "hemiLight.visible = " + hemiLight.visible + ", dirLight.visible = " + dirLight.visible;
			}
		</script>
	</body>
</html>