简介
此光源可以创建出更加贴近自然的户外光照效果。就是为了模拟在户外场景中的反光效果。
光源简单的创建
首先实例化函数：
var hemiLight = new THREE.HemisphereLight(天空的反光颜色,地面的反光颜色,光的强度);然后设置光的位置
hemiLight.position.set(0,500,0);最后添加到场景当中去
scene.add(hemiLight);相关属性
| 属性 | 描述 |
|---|---|
| groundColor | 从地面发出的光线的颜色 |
| color | 从天空发出的光线的颜色 |
| intensity | 光线照射的强度 |
案例代码
这个案例是通过three.js上一节的代码修改而成，可以调节相关属性：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style type="text/css">
html, body {
margin: 0;
height: 100%;
}
canvas {
display: block;
}
</style>
</head>
<body onload="draw();">
</body>
<script src="build/three.js"></script>
<script src="examples/js/controls/OrbitControls.js"></script>
<script src="examples/js/libs/stats.min.js"></script>
<script src="examples/js/libs/dat.gui.min.js"></script>
<script>
var renderer;
function initRender() {
renderer = new THREE.WebGLRenderer({antialias: true});
renderer.setSize(window.innerWidth, window.innerHeight);
//告诉渲染器需要阴影效果
renderer.shadowMap.enabled = true;
renderer.shadowMap.type = THREE.PCFSoftShadowMap; // 默认的是，没有设置的这个清晰 THREE.PCFShadowMap
document.body.appendChild(renderer.domElement);
}
var camera;
function initCamera() {
camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);
camera.position.set(0, 40, 100);
camera.lookAt(new THREE.Vector3(0, 0, 0));
}
var scene;
function initScene() {
scene = new THREE.Scene();
}
//初始化dat.GUI简化试验流程
var gui;
function initGui() {
//声明一个保存需求修改的相关数据的对象
gui = {
directionalLight:"#ffffff", //点光源
directionalLightIntensity:1, //灯光强度
visible:true, //是否可见
castShadow:true,
exponent:30,
target:"plane",
debug:false,
groundColor:"#00ff00",
skyColor:"#0000ff",
hemiLightIntensity:0.3
};
var datGui = new dat.GUI();
//将设置属性添加到gui当中，gui.add(对象，属性，最小值，最大值）
datGui.addColor(gui,"skyColor").onChange(function (e) {
hemiLight.color = new THREE.Color(e);
});
datGui.addColor(gui,"groundColor").onChange(function (e) {
hemiLight.groundColor = new THREE.Color(e);
});
datGui.add(gui,"hemiLightIntensity",0,1).onChange(function (e) {
hemiLight.intensity = e;
});
datGui.addColor(gui,"directionalLight").onChange(function (e) {
directionalLight.color = new THREE.Color(e);
});
datGui.add(gui,"directionalLightIntensity",0,5).onChange(function (e) {
directionalLight.intensity = e;
});
datGui.add(gui,"visible").onChange(function (e) {
directionalLight.visible = e;
});
datGui.add(gui,"castShadow").onChange(function (e) {
directionalLight.castShadow = e;
});
datGui.add(gui,"debug").onChange(function (e) {
if(e){
var debug = new THREE.CameraHelper(directionalLight.shadow.camera);
debug.name = "debug";
scene.add(debug);
}
else{
var debug = scene.getObjectByName("debug");
scene.remove(debug);
}
});
}
var hemiLight,directionalLight;
function initLight() {
hemiLight = new THREE.HemisphereLight(0x0000ff,0x00ff00,0.3);
hemiLight.position.set(0,500,0);
scene.add(hemiLight);
directionalLight = new THREE.DirectionalLight("#ffffff");
directionalLight.position.set(-40, 60, -10);
directionalLight.shadow.camera.near = 20; //产生阴影的最近距离
directionalLight.shadow.camera.far = 200; //产生阴影的最远距离
directionalLight.shadow.camera.left = -50; //产生阴影距离位置的最左边位置
directionalLight.shadow.camera.right = 50; //最右边
directionalLight.shadow.camera.top = 50; //最上边
directionalLight.shadow.camera.bottom = -50; //最下面
//这两个值决定使用多少像素生成阴影 默认512
directionalLight.shadow.mapSize.height = 1024;
directionalLight.shadow.mapSize.width = 1024;
console.log(directionalLight);
//告诉平行光需要开启阴影投射
directionalLight.castShadow = true;
scene.add(directionalLight);
}
var cube,plane;
function initModel() {
//辅助工具
var helper = new THREE.AxisHelper(10);
scene.add(helper);
//球体
var sphereGeometry = new THREE.SphereGeometry(10,30,30);
var sphereMaterial = new THREE.MeshStandardMaterial({color:0xeeeeee});
var sphere = new THREE.Mesh(sphereGeometry,sphereMaterial);
sphere.position.set(-20,20,0);
sphere.castShadow = true;
scene.add(sphere);
//立方体
var cubeGeometry = new THREE.CubeGeometry(10,10,10);
var cubeMaterial = new THREE.MeshLambertMaterial({color: 0x00ffff});
cube = new THREE.Mesh(cubeGeometry, cubeMaterial);
cube.position.x = 30;
cube.position.y = 5;
cube.position.z = -5;
//告诉立方体需要投射阴影
cube.castShadow = true;
scene.add(cube);
//底部平面
var planeGeometry = new THREE.PlaneGeometry(5000, 5000, 20, 20);
var planeMaterial = new THREE.MeshLambertMaterial({color: 0xaaaaaa});
plane = new THREE.Mesh(planeGeometry, planeMaterial);
plane.rotation.x = -0.5 * Math.PI;
plane.position.y = -0;
//告诉底部平面需要接收阴影
plane.receiveShadow = true;
scene.add(plane);
}
//初始化性能插件
var stats;
function initStats() {
stats = new Stats();
document.body.appendChild(stats.dom);
}
//用户交互插件 鼠标左键按住旋转，右键按住平移，滚轮缩放
var controls;
function initControls() {
controls = new THREE.OrbitControls(camera, renderer.domElement);
// 如果使用animate方法时，将此函数删除
//controls.addEventListener( 'change', render );
// 使动画循环使用时阻尼或自转 意思是否有惯性
controls.enableDamping = true;
//动态阻尼系数 就是鼠标拖拽旋转灵敏度
//controls.dampingFactor = 0.25;
//是否可以缩放
controls.enableZoom = true;
//是否自动旋转
controls.autoRotate = false;
//设置相机距离原点的最远距离
controls.minDistance = 50;
//设置相机距离原点的最远距离
controls.maxDistance = 200;
//是否开启右键拖拽
controls.enablePan = true;
}
function render() {
renderer.render(scene, camera);
}
//窗口变动触发的函数
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
render();
renderer.setSize(window.innerWidth, window.innerHeight);
}
function animate() {
//更新控制器
render();
//更新性能插件
stats.update();
controls.update();
requestAnimationFrame(animate);
}
function draw() {
initGui();
initRender();
initScene();
initCamera();
initLight();
initModel();
initControls();
initStats();
animate();
window.onresize = onWindowResize;
}
</script>
</html>