EffectComposer + ShaderPass 实现分区特效
一、实现步骤
在EffectComposer + Layers 实现分区特效中，EffectComposer更像是渲染出一张有辉光特效的“背景图”，renderer在这张“背景图”上渲染正常方块，以至于无论相机在哪个角度，都看到正常方块绘制在发光方块之上。针对这个问题，参考threejs提供的案例，使用ShaderPass实现分区辉光效果。步骤如下：
1、创建两个效果组合器bloomComposer和finalComposer，其中bloomComposer用来生成辉光效果，并将其渲染的结果作为着色器材质的输入，传递给finalComposer。finalComposer则用来渲染整个场景，在材质通道ShaderPass中将辉光效果整合到scene内。
const initComposer = () => {
bloomComposer = new EffectComposer(renderer);
bloomComposer.renderToScreen = false;
const renderScene = new RenderPass(scene, camera);
// 光晕
const bloomPass = new UnrealBloomPass(
new THREE.Vector2(window.innerWidth, window.innerHeight),
1.5,
0.4,
0.85
);
bloomPass.threshold = params.bloomThreshold;
bloomPass.strength = params.bloomStrength;
bloomPass.radius = params.bloomRadius;
bloomComposer.addPass(renderScene);
bloomComposer.addPass(bloomPass);
finalComposer = new EffectComposer(renderer);
const finalShader = new THREE.ShaderMaterial({
uniforms: {
baseTexture: { value: null },
bloomTexture: { value: bloomComposer.renderTarget2.texture }
},
vertexShader: `
varying vec2 vUv;
void main() {
vUv = uv;
gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
}
`,
fragmentShader: `
uniform sampler2D baseTexture;
uniform sampler2D bloomTexture;
varying vec2 vUv;
void main() {
gl_FragColor = ( texture2D( baseTexture, vUv ) + vec4( 1.0 ) * texture2D( bloomTexture, vUv ) );
}
`,
defines: {}
});
const finalPass = new ShaderPass(finalShader, "baseTexture");
finalPass.needsSwap = true;
finalComposer.addPass(renderScene);
finalComposer.addPass(finalPass);
};
2、创建正常方块和发光方块，并为它们设置不同的渲染图层，在渲染的过程钟将相机设置到对应图层进行渲染。
也可以像threejs案例中那样，在渲染发光物体时将非发光物体设置为黑色，这种方式对辉光效果有作用，因为黑色的物体不会产生辉光效果。对其他后处理效果就不一定适用了。
3、先用bloomComposer渲染出辉光效果，再使用finalComposer渲染场景。
const render = () => {
renderer.autoClear = false;
renderer.clear();
camera.layers.set(1);
bloomComposer.render();
renderer.clearDepth(); // 清除深度缓存
camera.layers.set(0);
finalComposer.render(scene, camera);
requestAnimationFrame(render);
};
二、效果
三、完整代码
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
}
</style>
</head>
<body>
<script src="./src/index.js"></script>
</body>
</html>
index.js
import * as THREE from "../node_modules/three/build/three.module.js";
import { OrbitControls } from "../node_modules/three/examples/jsm/controls/OrbitControls.js";
import { EffectComposer } from "../node_modules/three/examples/jsm/postprocessing/EffectComposer.js";
import { UnrealBloomPass } from "../node_modules/three/examples/jsm/postprocessing/UnrealBloomPass.js";
import { RenderPass } from "../node_modules/three/examples/jsm/postprocessing/RenderPass.js";
import { ShaderPass } from "../node_modules/three/examples/jsm/postprocessing/ShaderPass.js";
let scene, camera, renderer, bloomComposer, finalComposer;
const params = {
exposure: 0,
bloomStrength: 1.5,
bloomThreshold: 0,
bloomRadius: 0,
};
const init = () => {
// 场景
scene = new THREE.Scene();
// 相机
camera = new THREE.PerspectiveCamera(
70,
window.innerWidth / window.innerHeight,
1,
100000
);
camera.position.set(50, 50, 50);
camera.position.y = 50;
// 渲染器
renderer = new THREE.WebGLRenderer({
antialias: true,
});
renderer.setPixelRatio(window.devicePixelRatio);
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
// 环境光
const light = new THREE.AmbientLight(0xffffff, 0.6);
light.layers.enable(0);
light.layers.enable(1);
scene.add(light);
// 控制器
const controls = new OrbitControls(camera, renderer.domElement);
scene.add(new THREE.AxesHelper(100));
window.onresize = () => {
renderer.setSize(window.innerWidth, window.innerHeight);
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
};
};
const initComposer = () => {
bloomComposer = new EffectComposer(renderer);
bloomComposer.renderToScreen = false;
const renderScene = new RenderPass(scene, camera);
// 光晕
const bloomPass = new UnrealBloomPass(
new THREE.Vector2(window.innerWidth, window.innerHeight),
1.5,
0.4,
0.85
);
bloomPass.threshold = params.bloomThreshold;
bloomPass.strength = params.bloomStrength;
bloomPass.radius = params.bloomRadius;
bloomComposer.addPass(renderScene);
bloomComposer.addPass(bloomPass);
finalComposer = new EffectComposer(renderer);
const finalShader = new THREE.ShaderMaterial({
uniforms: {
baseTexture: { value: null },
bloomTexture: { value: bloomComposer.renderTarget2.texture }
},
vertexShader: `
varying vec2 vUv;
void main() {
vUv = uv;
gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
}
`,
fragmentShader: `
uniform sampler2D baseTexture;
uniform sampler2D bloomTexture;
varying vec2 vUv;
void main() {
gl_FragColor = ( texture2D( baseTexture, vUv ) + vec4( 1.0 ) * texture2D( bloomTexture, vUv ) );
}
`,
defines: {}
});
const finalPass = new ShaderPass(finalShader, "baseTexture");
finalPass.needsSwap = true;
finalComposer.addPass(renderScene);
finalComposer.addPass(finalPass);
};
const main = () => {
const geometry = new THREE.BoxGeometry(20, 20, 10);
// 正常方块
const normalMtl = new THREE.MeshLambertMaterial({ color: 0x00ffff });
const normalBox = new THREE.Mesh(geometry, normalMtl);
normalBox.position.z = -5;
normalBox.layers.set(0);
scene.add(normalBox);
// 发光方块
const bloomMtl = new THREE.MeshLambertMaterial({ color: 0xff5500 });
const bloomBox = new THREE.Mesh(geometry, bloomMtl);
bloomBox.position.z = 5;
bloomBox.layers.set(1);
scene.add(bloomBox);
};
const render = () => {
renderer.autoClear = false;
renderer.clear();
camera.layers.set(1);
bloomComposer.render();
renderer.clearDepth(); // 清除深度缓存
camera.layers.set(0);
finalComposer.render(scene, camera);
requestAnimationFrame(render);
};
init();
initComposer();
main();
render();
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