esengine/source/src/Math/Rectangle.ts

class Rectangle {
    public x: number;
    public y: number;
    public width: number;
    public height: number;

    private _tempMat: Matrix2D;
    private _transformMat: Matrix2D;

    /**
     * 获取矩形的最大点，即右下角
     */
    public get max(){
        return new Vector2(this.right, this.bottom);
    }

    public get left() {
        return this.x;
    }

    public get right() {
        return this.x + this.width;
    }

    public get top() {
        return this.y;
    }

    public get bottom() {
        return this.y + this.height;
    }

    public get center() {
        return new Vector2(this.x + (this.width / 2), this.y + (this.height / 2));
    }

    public get location() {
        return new Vector2(this.x, this.y);
    }

    public set location(value: Vector2) {
        this.x = value.x;
        this.y = value.y;
    }

    public get size() {
        return new Vector2(this.width, this.height);
    }

    public set size(value: Vector2) {
        this.width = value.x;
        this.height = value.y;
    }

    constructor(x?: number, y?: number, width?: number, height?: number) {
        this.x = x ? x : 0;
        this.y = y ? y : 0;
        this.width = width ? width : 0;
        this.height = height ? height : 0;
    }

    public intersects(value: Rectangle) {
        return value.left < this.right &&
            this.left < value.right &&
            value.top < this.bottom &&
            this.top < value.bottom;
    }

    public contains(value: Vector2) {
        return ((((this.x <= value.x) && (value.x < (this.x + this.width))) &&
            (this.y <= value.y)) &&
            (value.y < (this.y + this.height)));
    }

    public containsRect(value: Rectangle) {
        return ((((this.x <= value.x) && (value.x < (this.x + this.width))) &&
            (this.y <= value.y)) &&
            (value.y < (this.y + this.height)));
    }

    public getHalfSize(){
        return new Vector2(this.width * 0.5, this.height * 0.5);
    }

    public static fromMinMax(minX: number, minY: number, maxX: number, maxY: number) {
        return new Rectangle(minX, minY, maxX - minX, maxY - minY);
    }

    public getClosestPointOnRectangleBorderToPoint(point: Point): { res: Vector2, edgeNormal: Vector2 } {
        let edgeNormal = new Vector2(0, 0);

        let res = new Vector2(0, 0);
        res.x = MathHelper.clamp(point.x, this.left, this.right);
        res.y = MathHelper.clamp(point.y, this.top, this.bottom);

        if (this.contains(res)) {
            let dl = res.x - this.left;
            let dr = this.right - res.x;
            let dt = res.y - this.top;
            let db = this.bottom - res.y;

            let min = Math.min(dl, dr, dt, db);
            if (min == dt) {
                res.y = this.top;
                edgeNormal.y = -1;
            } else if (min == db) {
                res.y = this.bottom;
                edgeNormal.y = 1;
            } else if (min == dl) {
                res.x = this.left;
                edgeNormal.x = -1;
            } else {
                res.x = this.right;
                edgeNormal.x = 1;
            }
        } else {
            if (res.x == this.left) {
                edgeNormal.x = -1;
            }
            if (res.x == this.right) {
                edgeNormal.x = 1;
            }
            if (res.y == this.top) {
                edgeNormal.y = -1;
            }
            if (res.y == this.bottom) {
                edgeNormal.y = 1;
            }
        }

        return { res: res, edgeNormal: edgeNormal };
    }

    public getClosestPointOnBoundsToOrigin(){
        let max = this.max;
        let minDist = Math.abs(this.location.x);
        let boundsPoint = new Vector2(this.location.x, 0);

        if (Math.abs(max.x) < minDist){
            minDist = Math.abs(max.x);
            boundsPoint.x = max.x;
            boundsPoint.y = 0;
        }
        
        if (Math.abs(max.y) < minDist){
            minDist = Math.abs(max.y);
            boundsPoint.x = 0;
            boundsPoint.y = max.y;
        }

        if (Math.abs(this.location.y) < minDist){
            minDist = Math.abs(this.location.y);
            boundsPoint.x = 0;
            boundsPoint.y = this.location.y;
        }

        return boundsPoint;
    }

    public calculateBounds(parentPosition: Vector2, position: Vector2, origin: Vector2, scale: Vector2,
        rotation: number, width: number, height: number) {
        if (rotation == 0) {
            this.x = parentPosition.x + position.x - origin.x * scale.x;
            this.y = parentPosition.y + position.y - origin.y * scale.y;
            this.width = width * scale.x;
            this.height = height * scale.y;
        } else {
            let worldPosX = parentPosition.x + position.x;
            let worldPosY = parentPosition.y + position.y;

            this._transformMat = Matrix2D.createTranslation(-worldPosX - origin.x, -worldPosY - origin.y);
            this._tempMat = Matrix2D.createScale(scale.x, scale.y);
            this._transformMat = Matrix2D.multiply(this._transformMat, this._tempMat);
            this._tempMat = Matrix2D.createRotation(rotation);
            this._transformMat = Matrix2D.multiply(this._transformMat, this._tempMat);
            this._tempMat = Matrix2D.createTranslation(worldPosX, worldPosY);
            this._transformMat = Matrix2D.multiply(this._transformMat, this._tempMat);

            let topLeft = new Vector2(worldPosX, worldPosY);
            let topRight = new Vector2(worldPosX + width, worldPosY);
            let bottomLeft = new Vector2(worldPosX, worldPosY + height);
            let bottomRight = new Vector2(worldPosX + width, worldPosY + height);

            topLeft = Vector2Ext.transformR(topLeft, this._transformMat);
            topRight = Vector2Ext.transformR(topRight, this._transformMat);
            bottomLeft = Vector2Ext.transformR(bottomLeft, this._transformMat);
            bottomRight = Vector2Ext.transformR(bottomRight, this._transformMat);

            let minX = Math.min(topLeft.x, bottomRight.x, topRight.x, bottomLeft.x);
            let maxX = Math.max(topLeft.x, bottomRight.x, topRight.x, bottomLeft.x);
            let minY = Math.min(topLeft.y, bottomRight.y, topRight.y, bottomLeft.y);
            let maxY = Math.max(topLeft.y, bottomRight.y, topRight.y, bottomLeft.y);

            this.location = new Vector2(minX, minY);
            this.width = maxX - minX;
            this.height = maxY - minY;
        }
    }

    /**
     * 给定多边形的点，计算边界
     * @param points 
     */
    public static rectEncompassingPoints(points: Vector2[]) {
        let minX = Number.POSITIVE_INFINITY;
        let minY = Number.POSITIVE_INFINITY;
        let maxX = Number.NEGATIVE_INFINITY;
        let maxY = Number.NEGATIVE_INFINITY;

        for (let i = 0; i < points.length; i++) {
            let pt = points[i];

            if (pt.x < minX) {
                minX = pt.x;
            }
            if (pt.x > maxX) {
                maxX = pt.x;
            }

            if (pt.y < minY) {
                minY = pt.y;
            }
            if (pt.y > maxY) {
                maxY = pt.y;
            }
        }

        return this.fromMinMax(minX, minY, maxX, maxY);
    }
}