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 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

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 Permission is hereby granted, free of charge, to any person obtaining a copy
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 Xiamen Yaji Software Co., Ltd. reserves all rights not expressly granted to you.

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/**
 * !#en Intersection helper class
 * !#zh 辅助类，用于测试形状与形状是否相交
 * @class Intersection
 * @static
 */
var Intersection = {};
/**
 * !#en Test line and line
 * !#zh 测试线段与线段是否相交
 * @method lineLine
 * @param {Vec2} a1 - The start point of the first line
 * @param {Vec2} a2 - The end point of the first line
 * @param {Vec2} b1 - The start point of the second line
 * @param {Vec2} b2 - The end point of the second line
 * @return {boolean}
 */

function lineLine(a1, a2, b1, b2) {
  // jshint camelcase:false
  var ua_t = (b2.x - b1.x) * (a1.y - b1.y) - (b2.y - b1.y) * (a1.x - b1.x);
  var ub_t = (a2.x - a1.x) * (a1.y - b1.y) - (a2.y - a1.y) * (a1.x - b1.x);
  var u_b = (b2.y - b1.y) * (a2.x - a1.x) - (b2.x - b1.x) * (a2.y - a1.y);

  if (u_b !== 0) {
    var ua = ua_t / u_b;
    var ub = ub_t / u_b;

    if (0 <= ua && ua <= 1 && 0 <= ub && ub <= 1) {
      return true;
    }
  }

  return false;
}

Intersection.lineLine = lineLine;
/**
 * !#en Test line and rect
 * !#zh 测试线段与矩形是否相交
 * @method lineRect
 * @param {Vec2} a1 - The start point of the line
 * @param {Vec2} a2 - The end point of the line
 * @param {Rect} b - The rect
 * @return {boolean}
 */

function lineRect(a1, a2, b) {
  var r0 = new cc.Vec2(b.x, b.y);
  var r1 = new cc.Vec2(b.x, b.yMax);
  var r2 = new cc.Vec2(b.xMax, b.yMax);
  var r3 = new cc.Vec2(b.xMax, b.y);
  if (lineLine(a1, a2, r0, r1)) return true;
  if (lineLine(a1, a2, r1, r2)) return true;
  if (lineLine(a1, a2, r2, r3)) return true;
  if (lineLine(a1, a2, r3, r0)) return true;
  return false;
}

Intersection.lineRect = lineRect;
/**
 * !#en Test line and polygon
 * !#zh 测试线段与多边形是否相交
 * @method linePolygon
 * @param {Vec2} a1 - The start point of the line
 * @param {Vec2} a2 - The end point of the line
 * @param {Vec2[]} b - The polygon, a set of points
 * @return {boolean}
 */

function linePolygon(a1, a2, b) {
  var length = b.length;

  for (var i = 0; i < length; ++i) {
    var b1 = b[i];
    var b2 = b[(i + 1) % length];
    if (lineLine(a1, a2, b1, b2)) return true;
  }

  return false;
}

Intersection.linePolygon = linePolygon;
/**
 * !#en Test rect and rect
 * !#zh 测试矩形与矩形是否相交
 * @method rectRect
 * @param {Rect} a - The first rect
 * @param {Rect} b - The second rect
 * @return {boolean}
 */

function rectRect(a, b) {
  // jshint camelcase:false
  var a_min_x = a.x;
  var a_min_y = a.y;
  var a_max_x = a.x + a.width;
  var a_max_y = a.y + a.height;
  var b_min_x = b.x;
  var b_min_y = b.y;
  var b_max_x = b.x + b.width;
  var b_max_y = b.y + b.height;
  return a_min_x <= b_max_x && a_max_x >= b_min_x && a_min_y <= b_max_y && a_max_y >= b_min_y;
}

Intersection.rectRect = rectRect;
/**
 * !#en Test rect and polygon
 * !#zh 测试矩形与多边形是否相交
 * @method rectPolygon
 * @param {Rect} a - The rect
 * @param {Vec2[]} b - The polygon, a set of points
 * @return {boolean}
 */

function rectPolygon(a, b) {
  var i, l;
  var r0 = new cc.Vec2(a.x, a.y);
  var r1 = new cc.Vec2(a.x, a.yMax);
  var r2 = new cc.Vec2(a.xMax, a.yMax);
  var r3 = new cc.Vec2(a.xMax, a.y); // intersection check

  if (linePolygon(r0, r1, b)) return true;
  if (linePolygon(r1, r2, b)) return true;
  if (linePolygon(r2, r3, b)) return true;
  if (linePolygon(r3, r0, b)) return true; // check if a contains b

  for (i = 0, l = b.length; i < l; ++i) {
    if (pointInPolygon(b[i], a)) return true;
  } // check if b contains a


  if (pointInPolygon(r0, b)) return true;
  if (pointInPolygon(r1, b)) return true;
  if (pointInPolygon(r2, b)) return true;
  if (pointInPolygon(r3, b)) return true;
  return false;
}

Intersection.rectPolygon = rectPolygon;
/**
 * !#en Test polygon and polygon
 * !#zh 测试多边形与多边形是否相交
 * @method polygonPolygon
 * @param {Vec2[]} a - The first polygon, a set of points
 * @param {Vec2[]} b - The second polygon, a set of points
 * @return {boolean}
 */

function polygonPolygon(a, b) {
  var i, l; // check if a intersects b

  for (i = 0, l = a.length; i < l; ++i) {
    var a1 = a[i];
    var a2 = a[(i + 1) % l];
    if (linePolygon(a1, a2, b)) return true;
  } // check if a contains b


  for (i = 0, l = b.length; i < l; ++i) {
    if (pointInPolygon(b[i], a)) return true;
  } // check if b contains a


  for (i = 0, l = a.length; i < l; ++i) {
    if (pointInPolygon(a[i], b)) return true;
  }

  return false;
}

Intersection.polygonPolygon = polygonPolygon;
/**
 * !#en Test circle and circle
 * !#zh 测试圆形与圆形是否相交
 * @method circleCircle
 * @param {Object} a - Object contains position and radius
 * @param {Object} b - Object contains position and radius
 * @return {boolean}
 * @typescript circleCircle(a: {position: Vec2, radius: number}, b: {position: Vec2, radius: number}): boolean
 */

function circleCircle(a, b) {
  var distance = a.position.sub(b.position).mag();
  return distance < a.radius + b.radius;
}

Intersection.circleCircle = circleCircle;
/**
 * !#en Test polygon and circle
 * !#zh 测试矩形与圆形是否相交
 * @method polygonCircle
 * @param {Vec2[]} polygon - The Polygon, a set of points
 * @param {Object} circle - Object contains position and radius
 * @return {boolean}
 * @typescript polygonCircle(polygon: Vec2[], circle: {position: Vec2, radius: number}): boolean
 */

function polygonCircle(polygon, circle) {
  var position = circle.position;

  if (pointInPolygon(position, polygon)) {
    return true;
  }

  for (var i = 0, l = polygon.length; i < l; i++) {
    var start = i === 0 ? polygon[polygon.length - 1] : polygon[i - 1];
    var end = polygon[i];

    if (pointLineDistance(position, start, end, true) < circle.radius) {
      return true;
    }
  }

  return false;
}

Intersection.polygonCircle = polygonCircle;
/**
 * !#en Test whether the point is in the polygon
 * !#zh 测试一个点是否在一个多边形中
 * @method pointInPolygon
 * @param {Vec2} point - The point
 * @param {Vec2[]} polygon - The polygon, a set of points
 * @return {boolean}
 */

function pointInPolygon(point, polygon) {
  var inside = false;
  var x = point.x;
  var y = point.y; // use some raycasting to test hits
  // https://github.com/substack/point-in-polygon/blob/master/index.js

  var length = polygon.length;

  for (var i = 0, j = length - 1; i < length; j = i++) {
    var xi = polygon[i].x,
        yi = polygon[i].y,
        xj = polygon[j].x,
        yj = polygon[j].y,
        intersect = yi > y !== yj > y && x < (xj - xi) * (y - yi) / (yj - yi) + xi;
    if (intersect) inside = !inside;
  }

  return inside;
}

Intersection.pointInPolygon = pointInPolygon;
/**
 * !#en Calculate the distance of point to line.
 * !#zh 计算点到直线的距离。如果这是一条线段并且垂足不在线段内，则会计算点到线段端点的距离。
 * @method pointLineDistance
 * @param {Vec2} point - The point
 * @param {Vec2} start - The start point of line
 * @param {Vec2} end - The end point of line
 * @param {boolean} isSegment - whether this line is a segment
 * @return {number}
 */

function pointLineDistance(point, start, end, isSegment) {
  var dx = end.x - start.x;
  var dy = end.y - start.y;
  var d = dx * dx + dy * dy;
  var t = ((point.x - start.x) * dx + (point.y - start.y) * dy) / d;
  var p;

  if (!isSegment) {
    p = cc.v2(start.x + t * dx, start.y + t * dy);
  } else {
    if (d) {
      if (t < 0) p = start;else if (t > 1) p = end;else p = cc.v2(start.x + t * dx, start.y + t * dy);
    } else {
      p = start;
    }
  }

  dx = point.x - p.x;
  dy = point.y - p.y;
  return Math.sqrt(dx * dx + dy * dy);
}