StarRacingClient/assets/script/engines/utils/MathUtils.ts

export default class MathUtils{

    /**
     * 环形映射
     * @param value 
     * @param min 
     * @param max 
     */
    static CircularMapping(value:number,max:number,min:number=0):number{
        value=value-min;
        let dis:number=max-min;
        if(value<0){
            return dis+value%dis;
        }
        return value%dis;
    }
    
    /**
     * 绕点旋转
     * @param angle 
     * @param point 
     * @param origin 
     * @param out 
     */
    static RotationFormOrigin(angle:number,point:cc.Vec3,origin:cc.Vec3,out:cc.Vec3):void{
        //旋转
        let q:cc.Quat=new cc.Quat();
        cc.Quat.fromEuler(q,0,0,angle);
        let m:cc.Mat4=new cc.Mat4();
        cc.Mat4.fromRTSOrigin(m,q,cc.Vec3.ZERO,new cc.Vec3(1,1,1),origin);
        //应用矩阵
        cc.Vec3.transformMat4(out,point,m);
    }
    /**
     * 求圆内多边形的中心点的高度
     * @param l     边长
     * @param n     内角
     */
    static InCirclePolygonCentre(l:number,n:number):number{
        let hl:number=l*0.5;
        let angle:number=n*0.5;
        //角度转弧度
        let radian:number=this.angle2Radian(angle);
        let value:number=hl/Math.tanh(radian);
        return value;
    }

    static InCircle

    /**
     * 随机范围值
     * @param min 
     * @param max 
     */
    static RandomRange(min:number,max:number):number{
        return min+Math.random()*(max-min);
    }
    /**
     * 获取速度分量 从2个点及速度计算
     * @param currentPoint 
     * @param targetPoint 
     * @param speed 
     * @param result 
     */
    static getSpeed2dByPoint(currentPoint:cc.Vec2,targetPoint:cc.Vec2,speed:number,result?:cc.Vec2):cc.Vec2{
        if(result==null){
            result=new cc.Vec2();
        }
        let angle:number=this.getRadian(targetPoint.x,targetPoint.y,currentPoint.x,currentPoint.y);
        this.getSpeed2DR(angle,speed,result);
        return result;
    }
    /**
     * 速度转2维速度
     * @param angle         角度
     * @param speed         速度
     * @param result        结果
     */
    public static getSpeed2D(angle:number,speed:number,result:cc.Vec2=null):cc.Vec2{
        //角度转弧度
        let radian:number= angle * (Math.PI /180);
        return this.getSpeed2DR(radian,speed,result);
    }

    public static getSpeed2DR(radian:number,speed:number,result:cc.Vec2=null):cc.Vec2{
        if(result==null){
            result=new cc.Vec2();
        }
        result.x=Math.cos(radian)*speed;
        result.y=Math.sin(radian)*speed;
        return result;
    }

    /**
     * 根据角度和X轴计算Y轴速度
     * @param angle 
     * @param speedX 
     * @param result 
     */
    public static getSpeed2DByX(angle:number,speedX:number,result:cc.Vec2=null):cc.Vec2{
        if(result==null){
            result=new cc.Vec2();
        }
        //角度转弧度
        let radian:number= angle * (Math.PI /180);
        //求出斜边的长度
        let leg:number=speedX/Math.cos(radian);
        result.x=speedX;
        result.y=Math.sin(radian)*leg;
        return result;
    }
    /**
     * 求旋转后的点坐标
     * @param angle         角度
     * @param point         旋转前的坐标点
     * @param result        
     */
    public static rotationPoint(angle:number,point:{x:number,y:number},result:{x:number,y:number}):void{
        //角度转弧度
        angle=angle*(Math.PI/180);
        result.x = Math.cos(angle) * point.x - Math.sin(angle) * point.y;
        result.y = Math.cos(angle) * point.y + Math.sin(angle) * point.x;
    }

    
    public static getAngle(a:cc.Vec2,b:cc.Vec2):number{
        return  this.getRadianByPoint(a,b)*(180/Math.PI);
    }

    public static getRadianByPoint(a:cc.Vec2,b:cc.Vec2):number{
        return Math.atan2((a.y-b.y), (a.x-b.x));
    }

    public static getRadian(ax:number,ay:number,bx:number,by:number):number{
        return Math.atan2(ay-by, ax-bx);
    }

    static angle2Radian(angle:number):number{
        return angle*(Math.PI/180);
    }

    static radian2Angle(radian:number):number{
        return radian*(180/Math.PI);
    }

    /**
     * 计算两线段相交点坐标
     * @param line1Point1
     * @param line1Point2
     * @param line2Point1
     * @param line2Point2
     * @return 返回该点
     */
    static getIntersectionPoint(line1Point1:cc.Vec2, line1Point2:cc.Vec2, line2Point1:cc.Vec2, line2Point2:cc.Vec2,result?:cc.Vec2):cc.Vec2{
        if(!result){
            result=new cc.Vec2();
        }
        let  x1:number,y1:number,x2:number,y2:number,x3:number,y3:number,x4:number,y4:number;
        x1 = line1Point1.x;
        y1 = line1Point1.y;
        x2 = line1Point2.x;
        y2 = line1Point2.y;
        x3 = line2Point1.x;
        y3 = line2Point1.y;
        x4 = line2Point2.x;
        y4 = line2Point2.y;

        result.x=Math.ceil((x1 - x2) * (x3 * y4 - x4 * y3) - (x3 - x4) * (x1 * y2 - x2 * y1)) / ((x3 - x4) * (y1 - y2) - (x1 - x2) * (y3 - y4));
        result.y=Math.ceil((y1 - y2) * (x3 * y4 - x4 * y3) - (x1 * y2 - x2 * y1) * (y3 - y4)) / ((y1 - y2) * (x3 - x4) - (x1 - x2) * (y3 - y4));
        return  result;
    }

    /**
     * 判断点是否在线段内
     * @param Pi 
     * @param Pj 
     * @param Q 
     */
    static onSegment(Pi:cc.Vec2 , Pj:cc.Vec2 , Q:cc.Vec2):boolean
    {
        Q.x=Math.round(Q.x);
        Q.y=Math.round(Q.y);
        let xValue:number=(Q.x - Pi.x) * (Pj.y - Pi.y) - (Pj.x - Pi.x) * (Q.y - Pi.y);
        if(Math.floor(xValue)==0 
        //保证Q点坐标在pi,pj之间 
        && Math.min(Pi.x , Pj.x) <= Q.x && Q.x <= Math.max(Pi.x , Pj.x)    
        && Math.min(Pi.y , Pj.y) <= Q.y && Q.y <= Math.max(Pi.y , Pj.y)){
            return true;
        }
        return false;
    }

    /**
     * 求两个向量之间的夹角
     * @param av        单位向量
     * @param bv        单位向量
     */
    static calculateAngle(av:cc.Vec3,bv:cc.Vec3):number{
        //cos=a.b/(|a||b|);
        return Math.acos(cc.Vec3.dot(av,bv)/(av.len()*bv.len()));
    }

    static calculateAngleByPoints(a:cc.Vec3,b:cc.Vec3,c:cc.Vec3){
        let av:cc.Vec3=new cc.Vec3();
        let bv:cc.Vec3=new cc.Vec3();
        cc.Vec3.subtract(b,a,av);
        cc.Vec3.subtract(b,c,bv);
        return this.calculateAngle(av,bv);
    }
}