罗盘 · Compass 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 罗盘 效果：基于 WebGL 实现「罗盘」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, 0, 0.6)
const renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true, logarithmicDepthBuffer: true })
renderer.setSize(box.clientWidth, box.clientHeight)
box.appendChild(renderer.domElement)
const controls = new OrbitControls(camera, renderer.domElement)
controls.enableDamping = true
window.onresize = () => {
renderer.setSize(box.clientWidth, box.clientHeight)
camera.aspect = box.clientWidth / box.clientHeight
camera.updateProjectionMatrix()
}
const uniforms = {
iTime: {
value: 0
},
iResolution: {
value: new THREE.Vector2(box.clientWidth, box.clientHeight)
}
}
const geometry = new THREE.PlaneGeometry(1, 1)
const material = new THREE.ShaderMaterial({
uniforms,
transparent: true,
side: THREE.DoubleSide,
vertexShader: `
varying vec3 vPosition;
varying vec2 vUv;
void main() {
vUv = uv;
vec4 mvPosition = modelViewMatrix * vec4(position, 1.0);
gl_Position = projectionMatrix * mvPosition;
}
`,
fragmentShader: `
uniform float ratio;
float PI = 3.1415926;
uniform float iTime;
uniform vec2 iResolution;
varying vec2 vUv;
vec2 rotate(vec2 p, float rad) {
mat2 m = mat2(cos(rad), sin(rad), -sin(rad), cos(rad));
return m * p;
}
vec2 translate(vec2 p, vec2 diff) {
return p - diff;
}
vec2 scale(vec2 p, float r) {
return p*r;
}
float circle(float pre, vec2 p, float r1, float r2, float power) {
float leng = length(p);
float d = min(abs(leng-r1), abs(leng-r2));
if (r1<leng && leng<r2) pre /= exp(d)/r2;
float res = power / d;
return clamp(pre + res, 0.0, 1.0);
}
float rectangle(float pre, vec2 p, vec2 half1, vec2 half2, float power) {
p = abs(p);
if ((half1.x<p.x || half1.y<p.y) && (p.x<half2.x && p.y<half2.y)) {
pre = max(0.01, pre);
}
float dx1 = (p.y < half1.y) ? abs(half1.x-p.x) : length(p-half1);
float dx2 = (p.y < half2.y) ? abs(half2.x-p.x) : length(p-half2);
float dy1 = (p.x < half1.x) ? abs(half1.y-p.y) : length(p-half1);
float dy2 = (p.x < half2.x) ? abs(half2.y-p.y) : length(p-half2);
float d = min(min(dx1, dx2), min(dy1, dy2));
float res = power / d;
return clamp(pre + res, 0.0, 1.0);
}
float radiation(float pre, vec2 p, float r1, float r2, int num, float power) {
float angle = 2.0*PI/float(num);
float d = 1e10;
for(int i=0; i<360; i++) {
if (i>=num) break;
float _d = (r1<p.y && p.y<r2) ?
abs(p.x) :
min(length(p-vec2(0.0, r1)), length(p-vec2(0.0, r2)));
d = min(d, _d);
p = rotate(p, angle);
}
float res = power / d;
return clamp(pre + res, 0.0, 1.0);
}
vec3 calc(vec2 p) {
float dst = 0.0;
p = scale(p, sin(PI*iTime/1.0)*0.02+1.1);
{
vec2 q = p;
q = rotate(q, iTime * PI / 6.0);
dst = circle(dst, q, 0.85, 0.9, 0.006);
dst = radiation(dst, q, 0.87, 0.88, 36, 0.0008);
}
{
vec2 q = p;
q = rotate(q, iTime * PI / 6.0);
const int n = 6;
float angle = PI / float(n);
q = rotate(q, floor(atan(q.x, q.y)/angle + 0.5) * angle);
for(int i=0; i<n; i++) {
dst = rectangle(dst, q, vec2(0.85/sqrt(2.0)), vec2(0.85/sqrt(2.0)), 0.0015);
q = rotate(q, angle);
}
}
{
vec2 q = p;
q = rotate(q, iTime * PI / 6.0);
const int n = 12;
q = rotate(q, 2.0*PI/float(n)/2.0);
float angle = 2.0*PI / float(n);
for(int i=0; i<n; i++) {
dst = circle(dst, q-vec2(0.0, 0.875), 0.001, 0.05, 0.004);
dst = circle(dst, q-vec2(0.0, 0.875), 0.001, 0.001, 0.008);
q = rotate(q, angle);
}
}
{
vec2 q = p;
dst = circle(dst, q, 0.5, 0.55, 0.002);
}
{
vec2 q = p;
q = rotate(q, -iTime * PI / 6.0);
const int n = 3;
float angle = PI / float(n);
q = rotate(q, floor(atan(q.x, q.y)/angle + 0.5) * angle);
for(int i=0; i<n; i++) {
dst = rectangle(dst, q, vec2(0.36, 0.36), vec2(0.36, 0.36), 0.0015);
q = rotate(q, angle);
}
}
{
vec2 q = p;
q = rotate(q, -iTime * PI / 6.0);
const int n = 12;
q = rotate(q, 2.0*PI/float(n)/2.0);
float angle = 2.0*PI / float(n);
for(int i=0; i<n; i++) {
dst = circle(dst, q-vec2(0.0, 0.53), 0.001, 0.035, 0.004);
dst = circle(dst, q-vec2(0.0, 0.53), 0.001, 0.001, 0.001);
q = rotate(q, angle);
}
}
{
vec2 q = p;
q = rotate(q, iTime * PI / 6.0);
dst = radiation(dst, q, 0.25, 0.3, 12, 0.005);
}
{
vec2 q = p;
q = scale(q, sin(PI*iTime/1.0)*0.04+1.1);
q = rotate(q, -iTime * PI / 6.0);
for(float i=0.0; i<6.0; i++) {
float r = 0.13-i*0.01;
q = translate(q, vec2(0.1, 0.0));
dst = circle(dst, q, r, r, 0.002);
q = translate(q, -vec2(0.1, 0.0));
q = rotate(q, -iTime * PI / 12.0);
}
dst = circle(dst, q, 0.04, 0.04, 0.004);
}
return pow(dst, 2.5) * vec3(1.0, 0.95, 0.8);
}
void main() {
vec2 uv = (vUv - 0.5) * 2.0;
gl_FragColor = vec4(calc(uv), 1.0);;
}
`
})
const mesh = new THREE.Mesh(geometry, material)
scene.add(mesh)
animate()
function animate() {
uniforms.iTime.value += 0.01
requestAnimationFrame(animate)
controls.update()
renderer.render(scene, camera)
}
完整源码：GitHub
小结
- 本文提供 罗盘 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