使用 Three.js 创建管道流动效果，使用 GSAP 动画和纹理偏移实现管道内液体流动效果。

class DemoPipe extends THREE.Mesh {
    flowAnimation;
    flowTexture;
    
    constructor(name, options) {
        const defaultOptions = {
            radius: 70,
            color: 0x777777,
            radiusSegments: 16,
            tubularSegments: 100,
            curve: new THREE.CatmullRomCurve3(),
        };
        const finalOptions = Object.assign({}, defaultOptions, options);
        
        const flowTexture = new THREE.TextureLoader().load(FILE_HOST + "threeExamples/application/flow.png");
        flowTexture.colorSpace = THREE.SRGBColorSpace;
        flowTexture.wrapS = flowTexture.wrapT = THREE.RepeatWrapping;
        flowTexture.repeat.set(finalOptions.curve.getLength() / 1000, 1);
        flowTexture.needsUpdate = true;
        
        const mat = new THREE.MeshPhongMaterial({
            color: finalOptions.color,
            transparent: true,
            side: THREE.DoubleSide,
            specular: finalOptions.color,
            shininess: 15,
        });
        
        const geo = new THREE.TubeGeometry(finalOptions.curve, finalOptions.tubularSegments, finalOptions.radius, finalOptions.radiusSegments);
        super(name, geo, mat);
        
        this.flowTexture = flowTexture;
        this.flowAnimation = this.createFlowAnimation();
    }
    
    createFlowAnimation() {
        return gsap.to(this.flowTexture.offset, {
            x: -3,
            duration: 1,
            ease: "none",
            repeat: -1,
            paused: true
        });
    }
}

const curve = new THREE.CatmullRomCurve3([
    new THREE.Vector3(-10, 0, 0),
    new THREE.Vector3(-5, 5, 5),
    new THREE.Vector3(0, 0, 10),
    new THREE.Vector3(5, -5, 5),
    new THREE.Vector3(10, 0, 0)
]);

const pipe = new DemoPipe("flowPipe", {
    radius: 1,
    color: 0x777777,
    curve: curve
});

scene.add(pipe);

function startFlow() {
    pipe.flowAnimation.play();
}

function stopFlow() {
    pipe.flowAnimation.pause();
}

function setFlowSpeed(speed) {
    pipe.flowAnimation.timeScale(speed);
}