update：雨案例代码的修改

src/examples/weather/rain/rain-function.js

-export function addRain() {
-    const script = document.createElement('script');
-    script.src = 'https://cesium.com/downloads/cesiumjs/releases/1.99/Build/Cesium/Cesium.js';
-    script.onload = () => {
-        window.Cesium.Ion.defaultAccessToken = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJqdGkiOiI3Njg4ZWU5Yi1iZDhiLTRhYmUtOTRiYS04YjM5NmUwNjVmMDMiLCJpZCI6MjI3MzQ3LCJpYXQiOjE3MjA1MjA4Mjh9.E5XW4LnwgfVAaBC-znaYr61m4yK0-j2qEQhi9qwFFPE'
-
-        const viewer = new window.Cesium.Viewer('cesiumContainer', {
-            infoBox: false,
-        });
-
-        viewer.scene.postProcessStages.add(new Cesium.PostProcessStage({
-            fragmentShader: `
-                    uniform sampler2D colorTexture;
-                    varying vec2 v_textureCoordinates;
-                    uniform float tiltAngle;
-                    uniform float rainSize;
-                    uniform float rainSpeed;
-                    float hash(float x) {
-                        return fract(sin(x * 133.3) * 13.13);
-                    }
-                    varying vec4 fragColor;
-                    void main(void) {
-                        float time = czm_frameNumber / rainSpeed;
-                        vec2 resolution = czm_viewport.zw;
-                        vec2 uv = (gl_FragCoord.xy * 2. - resolution.xy) / min(resolution.x, resolution.y);
-                        vec3 c = vec3(.6, .7, .8);
-                        float a = tiltAngle;
-                        float si = sin(a), co = cos(a);
-                        uv *= mat2(co, -si, si, co);
-                        uv *= length(uv + vec2(0, 4.9)) * rainSize + 1.;
-                        float v = 1. - sin(hash(floor(uv.x * 100.)) * 2.);
-                        float b = clamp(abs(sin(20. * time * v + uv.y * (5. / (2. + v)))) - .95, 0., 1.) * 20.;
-                        c *= v * b;
-                        gl_FragColor = mix(texture2D(colorTexture, v_textureCoordinates), vec4(c, 1.0), 0.5);
-                    }
-                    `,
-            uniforms: {
-                tiltAngle: -0.2, //倾斜角度
-                rainSize: 0.8, // 雨大小
-                rainSpeed: 200.0, // 雨速
-            },
-        }));
-    };
-    document.head.appendChild(script);
-
-    const link = document.createElement('link');
-    link.rel = 'stylesheet';
-    link.href = 'https://cesium.com/downloads/cesiumjs/releases/1.119/Build/Cesium/Widgets/widgets.css';
-    document.head.appendChild(link);
+export function addRain(viewer) {
+    viewer.scene.postProcessStages.add(new Cesium.PostProcessStage({
+        fragmentShader: `
+                uniform sampler2D colorTexture;
+                varying vec2 v_textureCoordinates;
+                uniform float tiltAngle;
+                uniform float rainSize;
+                uniform float rainSpeed;
+                float hash(float x) {
+                    return fract(sin(x * 133.3) * 13.13);
+                }
+                varying vec4 fragColor;
+                void main(void) {
+                    float time = czm_frameNumber / rainSpeed;
+                    vec2 resolution = czm_viewport.zw;
+                    vec2 uv = (gl_FragCoord.xy * 2. - resolution.xy) / min(resolution.x, resolution.y);
+                    vec3 c = vec3(.6, .7, .8);
+                    float a = tiltAngle;
+                    float si = sin(a), co = cos(a);
+                    uv *= mat2(co, -si, si, co);
+                    uv *= length(uv + vec2(0, 4.9)) * rainSize + 1.;
+                    float v = 1. - sin(hash(floor(uv.x * 100.)) * 2.);
+                    float b = clamp(abs(sin(20. * time * v + uv.y * (5. / (2. + v)))) - .95, 0., 1.) * 20.;
+                    c *= v * b;
+                    gl_FragColor = mix(texture2D(colorTexture, v_textureCoordinates), vec4(c, 1.0), 0.5);
+                }
+                `,
+        uniforms: {
+            tiltAngle: -0.2, //倾斜角度
+            rainSize: 0.8, // 雨大小
+            rainSpeed: 200.0, // 雨速
+        },
+    }));
 }

src/examples/weather/rain/rain.vue

 <template>
     <div id="cesiumContainer" class="cesium-container"></div>
 </template>
+
 <script setup>
 import { onMounted } from 'vue';
 import { addRain } from './function';
+
+let viewer;
+
 onMounted(() => {
-    addRain()
+    const script = document.createElement('script');
+    script.src = 'https://cesium.com/downloads/cesiumjs/releases/1.99/Build/Cesium/Cesium.js';
+    script.onload = () => {
+        window.Cesium.Ion.defaultAccessToken = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJqdGkiOiI3Njg4ZWU5Yi1iZDhiLTRhYmUtOTRiYS04YjM5NmUwNjVmMDMiLCJpZCI6MjI3MzQ3LCJpYXQiOjE3MjA1MjA4Mjh9.E5XW4LnwgfVAaBC-znaYr61m4yK0-j2qEQhi9qwFFPE'
+
+        viewer = new window.Cesium.Viewer('cesiumContainer', {
+            infoBox: false,
+        });
+
+        addRain(viewer)
+
+    };
+    document.head.appendChild(script);
+    const link = document.createElement('link');
+    link.rel = 'stylesheet';
+    link.href = 'https://cesium.com/downloads/cesiumjs/releases/1.119/Build/Cesium/Widgets/widgets.css';
+    document.head.appendChild(link);
 });
 </script>
 
 <style>
 .cesium-container {
-width: 100%;
-height: 100vh;
+    width: 100%;
+    height: 100vh;
 }
 </style>
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