import { Vec3 } from "cc";

class Shake {
    private intensity:number;
    private duration:number;
    private shakePos:Vec3=new Vec3(0,0,0);
    constructor(public startPos:Vec3=new Vec3(0,0,0)) {
        this.duration=0;
        this.intensity = 0;
    }
    /**改变初起点*/
    setStartPos(x:number,y:number):void{
        this.startPos.x=x;
        this.startPos.y=y;
    }
    /**开始抖动
    * duration 时间
    * intensity 强度
    */
    start(duration:number=0.3,intensity:number=3.8):void{
        this.duration=duration;
        this.intensity = intensity;
    }
    /**停止抖动*/
    stop():Vec3 {
        this.shakePos.x = this.startPos.x;
        this.shakePos.y = this.startPos.y;
        this.duration=0;
        return this.shakePos;
    }
    getShakePos():Vec3{
        return this.shakePos;
    }
    action(dt: number):Vec3 {
        if (this.duration>0) {
            this.duration-=dt;
            if(this.duration<=0){
                return this.stop();
            }else{
                const randomX = Math.random() * this.intensity - this.intensity* 0.5;
                const randomY = Math.random() * this.intensity - this.intensity *0.5;
                this.shakePos.x = this.startPos.x+randomX;
                this.shakePos.y = this.startPos.y+randomY;
                return this.shakePos;
            }
        }
        return null;
    }
}
export default function get_new_shake(startPos:Vec3=new Vec3(0,0,0)):Shake { return new Shake(startPos);}