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);
  } void main() { vec2 _uv = vec2(vUv.xiResolution.x, vUv.yiResolution.y); vec3 finalColor; vec2 uv = _uv; //center of the image vec2 c = vec2(iResolution.x / 2.0, iResolution.y / 2.0); finalColor = vec3( 0.3*_cross(uv, c, 240.0) ); finalColor += ( circle(uv, c, 100.0, 1.0)
  circle(uv, c, 165.0, 1.0) ) * blue1;
  finalColor += (circle(uv, c, 240.0, 2.0) );//+ dots(uv,c,240.0)) * blue4; finalColor += circle3(uv, c, 313.0, 4.0) * blue1; finalColor += triangles(uv, c, 315.0 + 30.0sin(iTime))blue2; finalColor += movingLine(uv, c, 240.0) * blue3; finalColor += circle(uv, c, 10.0, 1.0) * blue3; finalColor += 0.7circle2(uv, c, 262.0, 1.0, 0.5+0.2cos(iTime)) * blue3; if( length(uv-c) < 240.0 ) { //animate some bips with random movements vec2 p = 130.0MOV(1.3,1.0,1.0,1.4,3.0+0.1iTime); finalColor += bip1(uv, c+p) * vec3(1,1,1); p = 130.0MOV(0.9,-1.1,1.7,0.8,-2.0+sin(0.1iTime)+0.15*iTime); finalColor += bip1(uv, c+p) * vec3(1,1,1); p = 50.0MOV(1.54,1.7,1.37,1.8,sin(0.1iTime+7.0)+0.2*iTime); finalColor += bip2(uv,c+p) * red; }
  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