_ParkingCar/assets/module_movecar/Script/Components/RainEffect.ts

import { _decorator, Component, Node, Vec3, view, randomRangeInt, UITransform } from 'cc';
const { ccclass, property } = _decorator;

@ccclass('RainEffect')
export class RainEffect extends Component {

    @property(Vec3)
    public speed: Vec3 = new Vec3(0, -100, 0); // 雨点下落速度

    @property
    public resetY: number = 120; // 雨点重置的Y坐标

    private isRaining: boolean = false;
    private rainDrops: Node[] = [];

    start() {
        // 获取所有雨点子节点
        this.rainDrops = this.node.children;

        // 初始化雨点位置
        this.resetRainDrops();
        this.startRain();
    }

    public startRain() {
        this.isRaining = true;
    }

    public stopRain() {
        this.isRaining = false;
    }

    public clearRain() {
        this.stopRain();
        this.resetRainDrops();
    }

    private resetRainDrops() {
        const _width = this.node.getComponent(UITransform).width;
        const _height = this.node.getComponent(UITransform).height;

        // 随机初始化雨点的位置
        for (let drop of this.rainDrops) {
            const randomX = randomRangeInt(-_width / 2, _width / 2);
            const randomY = randomRangeInt(0, _height / 2);
            drop.setPosition(randomX, randomY, 0);
        }
    }

    update(dt: number) {
        if (!this.isRaining) return;

        for (let drop of this.rainDrops) {
            // 更新雨点位置
            const position = drop.position;
            position.add3f(this.speed.x * dt, this.speed.y * dt, this.speed.z * dt);
            drop.setPosition(position);

            const _width = this.node.getComponent(UITransform).width;
            const _height = this.node.getComponent(UITransform).height;

            if (drop.position.y < -_height / 2) {
                const randomX = randomRangeInt(-_width / 2, _height / 2);
                drop.setPosition(randomX, this.resetY, 0);
            }
        }
    }

    protected onDestroy(): void {
        // this.clearRain();
    }
}