几何本身的阴影效果
首先我们要确认几何的材质是否能产生阴影、比如基础网格材质(MeshBasicMaterial)没有阴影效果,建议使用Lambert网格材质(MeshLambertMaterial)
在three.js添加光源和阴影,我们需要先创建一个聚光灯,可以理解为一个小太阳
//创建一个聚光灯
var spotLight = new THREE.SpotLight(0xFFFFFF);
然后我们需要设置小太阳的位置、设置 小太阳是否能产生阴影、小太阳产生阴影的精细程度、阴影的投射远点和投射近点在后在场景中添加小太阳
//设置小太阳的位置
spotLight.position.set(-50, 50, 20);
//设置小太阳是否能产生阴影
spotLight.castShadow = true;
//设置小太阳的阴影精细程度
spotLight.shadow.mapSize = new THREE.Vector2(5000, 5000);
//设置物体阴影的远点
spotLight.shadow.camera.far = 120;
//设置物体阴影的近点
spotLight.shadow.camera.near = 40;
scene.add(spotLight);
我们还可以通过设置AmbientLight来生成环境光
环境光会均匀的照亮场景中的所有物体。环境光不能用来投射阴影,因为它没有方向。
//创建一个环境光并添加到场景中
var ambienLight = new THREE.AmbientLight(0x353535);
scene.add(ambienLight);
然后我们需要让第一节我们所创建的每一个几何物体都会生成阴影
//开启立方体、圆、平面开启阴影效果
cube.castShadow = true;
sphere.castShadow = true;
plane.receiveShadow = true;
由于渲染阴影需要耗费大量的计算资源,所以渲染器默认是不渲染的,我们需要手动开启renderer的阴影效果
//开启renderer的阴影效果
renderer.shadowMap.enabled = true;
全部代码
function init() {
// create a scene, that will hold all our elements such as objects, cameras and lights.
var scene = new THREE.Scene();
const axesHelper = new THREE.AxesHelper( 200 );
scene.add( axesHelper );
// create a camera, which defines where we're looking at.
var camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);
// create a render and configure it with shadows
var renderer = new THREE.WebGLRenderer();
renderer.setClearColor(new THREE.Color(0x000000));
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.shadowMap.enabled = true;
// create a cube
var cubeGeometry = new THREE.BoxGeometry(4, 4, 4);
var cubeMaterial = new THREE.MeshLambertMaterial({
color: 0xFF0000
});
var cube = new THREE.Mesh(cubeGeometry, cubeMaterial);
cube.castShadow = true;
// position the cube
cube.position.x = -4;
cube.position.y = 2;
cube.position.z = 0;
// add the cube to the scene
var sphereGeometry = new THREE.SphereGeometry(4, 20, 20);
var sphereMaterial = new THREE.MeshLambertMaterial({
color: 0x7777ff
});
var sphere = new THREE.Mesh(sphereGeometry, sphereMaterial);
// position the sphere
sphere.position.x = 20;
sphere.position.y = 4;
sphere.position.z = 2;
sphere.castShadow = true;
// create the ground plane
var planeGeometry = new THREE.PlaneGeometry(60, 20);
var planeMaterial = new THREE.MeshLambertMaterial({
color: 0xAAAAAA
});
var plane = new THREE.Mesh(planeGeometry, planeMaterial);
// rotate and position the plane
plane.rotation.x = -0.5 * Math.PI;
plane.position.set(15, 0, 0);
plane.receiveShadow = true;
// add the objects
scene.add(cube);
scene.add(sphere);
scene.add(plane);
// position and point the camera to the center of the scene
camera.position.x = 0;
camera.position.y = 70;
camera.position.z = 20;
camera.lookAt(scene.position);
// add spotlight for the shadows
var spotLight = new THREE.SpotLight(0xFFFFFF);
spotLight.position.set(-50, 50, 20);
spotLight.castShadow = true;
spotLight.shadow.mapSize = new THREE.Vector2(5000, 5000);
spotLight.shadow.camera.far = 120;
spotLight.shadow.camera.near = 40;
scene.add(spotLight);
var ambienLight = new THREE.AmbientLight(0x353535);
scene.add(ambienLight);
// add the output of the renderer to the html element
document.getElementById("webgl-output").appendChild(renderer.domElement);
// call the render function
renderer.render(scene, camera);
}