threejs-效果合成器（EffectComposer）

文章目录

• 前言
• EffectComposer 使用流程
• EffectComposer 使用示例
• 总结

---

前言

threejs中的效果合成器 EffectComposer 可以在场景渲染完毕后再增加一些特效，如：让场景再某些情况下变得更加模糊或者更加鲜艳，增加滤镜或者闪烁效果，使用扫描线添加老旧电视屏幕上的效果等等。本文介绍 EffectComposer的基本使用，并使用 OutlinePass 这个通道为地球添加闪烁效果

---

EffectComposer 使用流程

场景初始化：自转的地球

在正式使用效果合成器前，首先创建一个基本场景作为对比，在场景中通过贴图添加一个旋转的地球

import { useRef, useEffect, useCallback, useState } from 'react'
import * as THREE from 'three'
import OrbitControls from 'three-orbitcontrols';
import Earth from '../../assets/textures/earth/Earth.png'
import EarthNormal from '../../assets/textures/earth/EarthNormal.png'
import EarthSpec from '../../assets/textures/earth/EarthSpec.png'
import './index.scss'

const View = () => {
  const page = useRef(); // useRef不会导致重新渲染

  /**
   * 场景、相机、渲染器作为threejs的基本结构，需要在页面进入时渲染完毕
   */
  const scene = useRef(new THREE.Scene()).current; //场景
  const camera = useRef(new THREE.PerspectiveCamera()).current; //摄像机（透视投影）
  const render = useRef(new THREE.WebGLRenderer()).current; //渲染器
  const controls = new OrbitControls(camera, render.domElement);//创建控件对象
  const timer = useRef(null) // 定义定时器

  const earthRef = useRef()

  useEffect(() => {
    page.current.appendChild(render.domElement);
    init();
    initLight();
    addEarth();
    renderScene();
  }, [])

  // 初始化场景
  const init = useCallback(() => {
    render.setSize(page.current.offsetWidth, page.current.offsetHeight); // 渲染器设置尺寸
    // 设置背景颜色
    render.setClearColor(new THREE.Color(0x000000)); // 设置背景颜色和透明度
    render.shadowMap.enabled = true; // 渲染器允许渲染阴影⭐

    /**
     * 设置摄像机的属性
     */
    camera.aspect = (page.current.offsetWidth / page.current.offsetHeight) // 摄像机设置屏幕宽高比
    camera.fov = 45; // 摄像机的视角
    camera.near = 0.01; // 近面距离
    camera.far = 1001; // 远面距离
    camera.position.set(30, 40, 30) // 设置摄像机在threejs坐标系中的位置
    camera.lookAt(0, 0, 0) // 摄像机的指向
    camera.updateProjectionMatrix(); // 更新摄像机投影矩阵,在任何参数被改变以后必须被调用
  }, [render, scene])

  // 初始化环境光
  const initLight = () => {
    const ambientLight = new THREE.AmbientLight(0x343434) // 基本光源

    const spotLight = new THREE.SpotLight(0xFFFFFF); // 聚光灯
    spotLight.position.set(-10, 30, 40);
    spotLight.castShadow = true; // 只有该属性为true时，该点光源允许产生阴影，并且下列属性可用
    spotLight.shadow.mapSize.width = 2048;
    spotLight.shadow.mapSize.height = 2048;
    spotLight.shadow.camera.fov = 15;
    spotLight.castShadow = true;
    spotLight.decay = 2;
    spotLight.penumbra = 0.05;

    scene.add(ambientLight, spotLight); // 向场景中添加光源
  }

  // 添加地球
  function addEarth() {
    const textureLoader = new THREE.TextureLoader();
    const planetMaterial = new THREE.MeshPhongMaterial({
      map: textureLoader.load(Earth),
      normalMap: textureLoader.load(EarthNormal),
      specularMap: textureLoader.load(EarthSpec),
      specular: new THREE.Color(0x4444aa),
      normalScale: new THREE.Vector2(6, 6),
      shininess: 0.5
    });

    earthRef.current = new THREE.Mesh(new THREE.SphereGeometry(15, 40, 40), planetMaterial);
    scene.add(earthRef.current);
  }

  // 渲染器执行渲染
  const renderScene = useCallback(() => {
    console.log('renderScene')
    timer.current = window.requestAnimationFrame(() => renderScene())
    controls.update();
    earthRef.current.rotation.y += 0.001; 
    render.render(scene, camera);
  }, [render])

  return (

    <div className='page' ref={page} />

  )
};

export default View

创建THREE.EffectComposer

首先要创建一个 THREE.EffectComposer 对象，传入的参数是WebGLRenderer：

  const renderer = new THREE.WebGLRenderer();
  const composer = new THREE.EffectComposer(renderer);

添加后期处理通道并更新渲染

• RenderPass： 渲染场景，但是不会添加至屏幕上
• FilmPass：添加扫描线。可以设置添加到屏幕
• addPass()：将通道添加至组合器中

  const renderPass = new THREE.RenderPass(scene, camera);
  const effectFilm = new THREE.FilmPass(0.8, 0.325, 256, false);
  effectFilm.renderToScreen = true;

  const composer = new THREE.EffectComposer(renderer);
  
  composer.addPass(renderPass);
  composer.addPass(effectFilm);

在场景进行render时，使用 composer 而不是 renderer 进行渲染：

  const renderScene = useCallback(() => {
    console.log('renderScene')
    const delta = clock.current.getDelta();
    window.requestAnimationFrame(() => renderScene())
    controls.update();
    earthRef.current.rotation.y += 0.001; 
    // render.render(scene,camera);
    composer.current.render(delta);
  }, [render])

EffectComposer 使用示例

示例一：FilmPass 添加电视效果

修改后代码如下👇

import { useRef, useEffect, useCallback, useState } from 'react'
import * as THREE from 'three'
import OrbitControls from 'three-orbitcontrols';
import { EffectComposer } from "three/examples/jsm/postprocessing/EffectComposer.js";

//后处理通道包
import {RenderPass} from "three/examples/jsm/postprocessing/RenderPass.js";
import {FilmPass} from "three/examples/jsm/postprocessing/FilmPass.js";

import Earth from '../../assets/textures/earth/Earth.png'
import EarthNormal from '../../assets/textures/earth/EarthNormal.png'
import EarthSpec from '../../assets/textures/earth/EarthSpec.png'
import './index.scss'

const View = () => {
  const page = useRef(); // useRef不会导致重新渲染

  /**
   * 场景、相机、渲染器作为threejs的基本结构，需要在页面进入时渲染完毕
   */
  const scene = useRef(new THREE.Scene()).current; //场景
  const camera = useRef(new THREE.PerspectiveCamera()).current; //摄像机（透视投影）
  const render = useRef(new THREE.WebGLRenderer()).current; //渲染器
  const composer = useRef(); //渲染器
  const controls = new OrbitControls(camera, render.domElement);//创建控件对象
  const clock = useRef(new THREE.Clock());

  const earthRef = useRef()

  useEffect(() => {
    page.current.appendChild(render.domElement);
    init();
    initLight();
    addEarth();
    renderScene();
  }, [])

  // 初始化场景
  const init = useCallback(() => {
    render.setSize(page.current.offsetWidth, page.current.offsetHeight); // 渲染器设置尺寸
    // 设置背景颜色
    render.shadowMap.enabled = true;
    render.shadowMapSoft = true;
    render.shadowMap.type = THREE.PCFSoftShadowMap;

    render.setClearColor(new THREE.Color(0x000000)); // 设置背景颜色和透明度
    render.shadowMap.enabled = true; // 渲染器允许渲染阴影⭐
    
    // 配置通道
    const renderPass = new RenderPass(scene, camera);
    const effectFilm = new FilmPass(0.8, 0.325, 256, false);
    effectFilm.renderToScreen = true;
    
    composer.current = new EffectComposer(render);
    composer.current.addPass(renderPass);
    composer.current.addPass(effectFilm);

    /**
     * 设置摄像机的属性
     */
    camera.aspect = (page.current.offsetWidth / page.current.offsetHeight) // 摄像机设置屏幕宽高比
    camera.fov = 45; // 摄像机的视角
    camera.near = 0.1; // 近面距离
    camera.far = 1001; // 远面距离
    camera.position.set(-30, 40, 30) // 设置摄像机在threejs坐标系中的位置
    camera.lookAt(0, 0, 0) // 摄像机的指向
    camera.updateProjectionMatrix(); // 更新摄像机投影矩阵,在任何参数被改变以后必须被调用
  }, [render, scene])

  // 初始化环境光
  const initLight = () => {
    const ambientLight = new THREE.AmbientLight(0x343434) // 基本光源

    const spotLight = new THREE.SpotLight(0xFFFFFF); // 聚光灯
    spotLight.position.set(-10, 30, 40);
    spotLight.castShadow = true; // 只有该属性为true时，该点光源允许产生阴影，并且下列属性可用
    spotLight.shadow.mapSize.width = 2048;
    spotLight.shadow.mapSize.height = 2048;
    spotLight.shadow.camera.fov = 15;
    spotLight.castShadow = true;
    spotLight.decay = 2;
    spotLight.penumbra = 0.05;

    scene.add(ambientLight, spotLight); // 向场景中添加光源
  }

  // 添加地球
  function addEarth() {
    const textureLoader = new THREE.TextureLoader();
    const planetMaterial = new THREE.MeshPhongMaterial({
      map: textureLoader.load(Earth),
      normalMap: textureLoader.load(EarthNormal),
      specularMap: textureLoader.load(EarthSpec),
      specular: new THREE.Color(0x4444aa),
      normalScale: new THREE.Vector2(6, 6),
      shininess: 0.5
    });

    earthRef.current = new THREE.Mesh(new THREE.SphereGeometry(15, 40, 40), planetMaterial);
    scene.add(earthRef.current);
  }


  // 渲染器执行渲染
  const renderScene = useCallback(() => {
    console.log('renderScene')
    const delta = clock.current.getDelta();
    window.requestAnimationFrame(() => renderScene())
    controls.update();
    earthRef.current.rotation.y += 0.001; 
    // render.render(scene,camera);
    composer.current.render(delta);
  }, [render])

  return (

    <div className='page' ref={page} />

  )
};

export default View

示例二：OutlinePass 添加闪烁效果

import { useRef, useEffect, useCallback, useState } from 'react'
import * as THREE from 'three'
import OrbitControls from 'three-orbitcontrols';
import { EffectComposer } from "three/examples/jsm/postprocessing/EffectComposer.js";

//后处理通道包
import { RenderPass } from "three/examples/jsm/postprocessing/RenderPass.js";
import { OutlinePass } from "three/examples/jsm/postprocessing/OutlinePass.js";

import Earth from '../../assets/textures/earth/Earth.png'
import EarthNormal from '../../assets/textures/earth/EarthNormal.png'
import EarthSpec from '../../assets/textures/earth/EarthSpec.png'
import './index.scss'

const View = () => {
  const page = useRef(); // useRef不会导致重新渲染

  /**
   * 场景、相机、渲染器作为threejs的基本结构，需要在页面进入时渲染完毕
   */
  const scene = useRef(new THREE.Scene()).current; //场景
  const camera = useRef(new THREE.PerspectiveCamera()).current; //摄像机（透视投影）
  const render = useRef(new THREE.WebGLRenderer()).current; //渲染器
  const composer = useRef(); //渲染器
  const controls = new OrbitControls(camera, render.domElement);//创建控件对象
  const clock = useRef(new THREE.Clock());

  const earthRef = useRef()

  useEffect(() => {
    page.current.appendChild(render.domElement);
    addEarth();
    init();
    initLight();
    renderScene();
  }, [])

  // 初始化场景
  const init = useCallback(() => {
    render.setSize(page.current.offsetWidth, page.current.offsetHeight); // 渲染器设置尺寸
    // 设置背景颜色
    render.shadowMap.enabled = true;
    render.shadowMapSoft = true;
    render.shadowMap.type = THREE.PCFSoftShadowMap;

    render.setClearColor(new THREE.Color(0x000000)); // 设置背景颜色和透明度
    render.shadowMap.enabled = true; // 渲染器允许渲染阴影⭐


    // OutLine
    const outlinePass = new OutlinePass(
      new THREE.Vector2(window.innerWidth, window.innerHeight),
      scene,
      camera,
      [earthRef.current]);
    const renderPass = new RenderPass(scene, camera);


    outlinePass.edgeStrength = 2; // 边缘强度
    outlinePass.edgeGlow = 2; // 光晕强度
    outlinePass.edgeThickness = 3; // 光晕尺寸
    outlinePass.pulsePeriod = 1;// 闪烁频率
    outlinePass.visibleEdgeColor.set('red'); // 光晕颜色

    composer.current = new EffectComposer(render);
    composer.current.addPass(renderPass);
    composer.current.addPass(outlinePass);


    /**
     * 设置摄像机的属性
     */
    camera.aspect = (page.current.offsetWidth / page.current.offsetHeight) // 摄像机设置屏幕宽高比
    camera.fov = 45; // 摄像机的视角
    camera.near = 0.1; // 近面距离
    camera.far = 1001; // 远面距离
    camera.position.set(-30, 40, 30) // 设置摄像机在threejs坐标系中的位置
    camera.lookAt(0, 0, 0) // 摄像机的指向
    camera.updateProjectionMatrix(); // 更新摄像机投影矩阵,在任何参数被改变以后必须被调用
  }, [render, scene])

  // 初始化环境光
  const initLight = () => {
    const ambientLight = new THREE.AmbientLight(0x343434) // 基本光源

    const spotLight = new THREE.SpotLight(0xFFFFFF); // 聚光灯
    spotLight.position.set(-10, 30, 40);
    spotLight.castShadow = true; // 只有该属性为true时，该点光源允许产生阴影，并且下列属性可用
    spotLight.shadow.mapSize.width = 2048;
    spotLight.shadow.mapSize.height = 2048;
    spotLight.shadow.camera.fov = 15;
    spotLight.castShadow = true;
    spotLight.decay = 2;
    spotLight.penumbra = 0.05;

    scene.add(ambientLight, spotLight); // 向场景中添加光源
  }

  // 添加地球
  function addEarth() {
    const textureLoader = new THREE.TextureLoader();
    const planetMaterial = new THREE.MeshPhongMaterial({
      map: textureLoader.load(Earth),
      normalMap: textureLoader.load(EarthNormal),
      specularMap: textureLoader.load(EarthSpec),
      specular: new THREE.Color(0x4444aa),
      normalScale: new THREE.Vector2(6, 6),
      shininess: 0.5
    });

    earthRef.current = new THREE.Mesh(new THREE.SphereGeometry(15, 40, 40), planetMaterial);
    scene.add(earthRef.current);



  // 渲染器执行渲染
  const renderScene = useCallback(() => {
    console.log('renderScene')
    const delta = clock.current.getDelta();
    window.requestAnimationFrame(() => renderScene())
    controls.update();
    earthRef.current.rotation.y += 0.001;
    render.autoClear = false;
    render.clear();
    // render.render(scene,camera);
    composer.current.render(delta);
  }, [render])

  return (

    <div className='page' ref={page} />

  )
};

export default View

总结

EffectComposer 使用流程

• 场景初始化：自转的地球
• 创建THREE.EffectComposer
• 添加后期处理通道并更新渲染

EffectComposer 使用示例

• 示例一：FilmPass 添加电视效果
• 示例二：OutlinePass 添加闪烁效果