Three.js 雷达着色器教程
雷达着色器 ·Radar Shader· ▶ 在线运行案例
- 案例合集:三维可视化功能案例(threehub.cn)
- 开源仓库github地址:https://github.com/z2586300277/three-cesium-examples
- 400个案例代码:网盘链接
你将学到什么
- ShaderMaterial 自定义着色器实现核心视觉效果
- OrbitControls 相机轨道交互
requestAnimationFrame渲染循环与resize自适应
效果说明
本案例演示雷达着色器效果:基于 WebGL 实现「雷达着色器」可视化效果,附完整可运行源码;核心用到 ShaderMaterial、OrbitControls。建议先打开文首在线案例查看动态画面,再对照下方源码逐步理解。
核心概念
- Scene / Camera / WebGLRenderer构成最小渲染闭环;大场景可开
logarithmicDepthBuffer缓解 Z-fighting。 - ShaderMaterial通过
uniforms+ 自定义 GLSL 控制逐像素/逐点效果;透明粒子常配合depthTest: false。 - OrbitControls提供轨道旋转/缩放;开启
enableDamping后需在 animate 中controls.update()。
实现步骤
- 搭建 Scene、PerspectiveCamera、WebGLRenderer,挂载 canvas 并处理
resize - 定义 uniforms / onBeforeCompile 或 ShaderMaterial,编写 GLSL 与材质参数
- 创建 OrbitControls(及 Raycaster 等交互控件,若源码包含)
- 在
requestAnimationFrame循环中更新状态并 render(Cesium 为viewer.render或自动渲染) 代码要点
import * as THREE from 'three'import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls.js'
const box = document.getElementById('box') const scene = new THREE.Scene() const camera = new THREE.PerspectiveCamera(75, box.clientWidth / box.clientHeight, 0.1, 1000) camera.position.set(0, 10, 10) const renderer = new THREE.WebGLRenderer() renderer.setSize(box.clientWidth, box.clientHeight) box.appendChild(renderer.domElement) new OrbitControls(camera, renderer.domElement) scene.add(new THREE.AxesHelper(50000)) window.onresize = () => { renderer.setSize(box.clientWidth, box.clientHeight) camera.aspect = box.clientWidth / box.clientHeight camera.updateProjectionMatrix() }
const { mesh, uniforms } = getShaderMesh() scene.add(mesh)
animate() function animate() { uniforms.iTime.value += 0.01 requestAnimationFrame(animate) renderer.render(scene, camera) }
function getShaderMesh() { const uniforms = { iTime: { value: 0 }, iResolution: { value: new THREE.Vector2(1900, 1900) }, iChannel0: { value: window.iChannel0 } } const geometry = new THREE.PlaneGeometry(20, 20); const material = new THREE.ShaderMaterial({ uniforms, side: 2, depthWrite: false, transparent: true, vertexShader:
varying vec3 vPosition; varying vec2 vUv; void main() { vUv = uv; vec4 mvPosition = modelViewMatrix * vec4(position, 1.0); gl_Position = projectionMatrix * mvPosition; }, fragmentShader:#define SMOOTH(r,R) (1.0-smoothstep(R-1.0,R+1.0, r)) #define RANGE(a,b,x) ( step(a,x)*(1.0-step(b,x)) ) #define RS(a,b,x) ( smoothstep(a-1.0,a+1.0,x)*(1.0-smoothstep(b-1.0,b+1.0,x)) ) #define M_PI 3.1415926535897932384626433832795#define blue1 vec3(0.74,0.95,1.00) #define blue2 vec3(0.87,0.98,1.00) #define blue3 vec3(0.35,0.76,0.83) #define blue4 vec3(0.953,0.969,0.89) #define red vec3(1.00,0.38,0.227)
#define MOV(a,b,c,d,t) (vec2(acos(t)+bcos(0.1(t)), csin(t)+dcos(0.1(t))))
uniform float ratio;
float PI = 3.1415926; uniform float iTime; uniform vec2 iResolution; varying vec2 vUv; float movingLine(vec2 uv, vec2 center, float radius) { //angle of the line float theta0 = 90.0 * iTime; vec2 d = uv - center; float r = sqrt( dot( d, d ) ); if(r vec2(cos(theta0M_PI/180.0), -sin(theta0*M_PI/180.0)); float l = length( d - p*clamp( dot(d,p)/dot(p,p), 0.0, 1.0) ); d = normalize(d); //compute gradient based on angle difference to theta0 float theta = mod(180.0*atan(d.y,d.x)/M_PI+theta0,360.0); float gradient = clamp(1.0-theta/90.0,0.0,1.0); return SMOOTH(l,1.0)+0.5*gradient; } else return 0.0; }
float circle(vec2 uv, vec2 center, float radius, float width) { float r = length(uv - center); return SMOOTH(r-width/2.0,radius)-SMOOTH(r+width/2.0,radius); }
float circle2(vec2 uv, vec2 center, float radius, float width, float opening) { vec2 d = uv - center; float r = sqrt( dot( d, d ) ); d = normalize(d); if( abs(d.y) > opening ) return SMOOTH(r-width/2.0,radius)-SMOOTH(r+width/2.0,radius); else return 0.0; } float circle3(vec2 uv, vec2 center, float radius, float width) { vec2 d = uv - center; float r = sqrt( dot( d, d ) ); d = normalize(d); float theta = 180.0*(atan(d.y,d.x)/M_PI); return smoothstep(2.0, 2.1, abs(mod(theta+2.0,45.0)-2.0)) * mix( 0.5, 1.0, step(45.0, abs(mod(theta, 180.0)-90.0)) ) * (SMOOTH(r-width/2.0,radius)-SMOOTH(r+width/2.0,radius)); }
float triangles(vec2 uv, vec2 center, float radius) { vec2 d = uv - center; return RS(-8.0, 0.0, d.x-radius) * (1.0-smoothstep( 7.0+d.x-radius,9.0+d.x-radius, abs(d.y)))
- RS( 0.0, 8.0, d.x+radius) * (1.0-smoothstep( 7.0-d.x-radius,9.0-d.x-radius, abs(d.y)))
- RS(-8.0, 0.0, d.y-radius) * (1.0-smoothstep( 7.0+d.y-radius,9.0+d.y-radius, abs(d.x)))
- RS( 0.0, 8.0, d.y+radius) * (1.0-smoothstep( 7.0-d.y-radius,9.0-d.y-radius, abs(d.x)));
float _cross(vec2 uv, vec2 center, float radius) { vec2 d = uv - center; int x = int(d.x); int y = int(d.y); float r = sqrt( dot( d, d ) ); if( (r = 50.0 ) && ( r < 115.0 ) ) return 0.5; else return 0.0; } float bip1(vec2 uv, vec2 center) { return SMOOTH(length(uv - center),3.0); } float bip2(vec2 uv, vec2 center) { float r = length(uv - center); float R = 8.0+mod(87.0*iTime, 80.0); return (0.5-0.5cos(30.0iTime)) * SMOOTH(r,5.0)
- SMOOTH(6.0,r)-SMOOTH(8.0,r)
- smoothstep(max(8.0,R-20.0),R,r)-SMOOTH(R,r);
- circle(uv, c, 165.0, 1.0) ) * blue1;
gl_FragColor = vec4( finalColor, 1.0 ); }}) const mesh = new THREE.Mesh(geometry, material); return { mesh, uniforms } }完整源码:GitHub
小结
- 本文提供雷达着色器完整 Three.js 源码与在线 Demo,建议先运行案例再改 uniform/参数做二次实验
- 更多 Three.js 实战案例见 three-cesium-examples 合集 与 GitHub 开源仓库
