/// <summary>
/// 找出离给定点最近的线段
/// </summary>
/// <param name="pos">指定点的坐标</param>
/// <param name="sqrDistance">距离的平方</param>
/// <returns>找到线段在列表中的索引值，或-1表示未找到</returns>
private int FindNearestLine(XYGridPos pos, out float sqrDistance)
{
sqrDistance = float.MaxValue;
int index = -1;
for (int i = 0; i < list_.Count; ++i)
{
XYObstacleLine line = list_[i];
Vector2 v = new Vector2(line.End.x - line.Begin.x, line.End.y - line.Begin.y);
Vector2 v2 = new Vector2(pos.x - line.Begin.x, pos.y - line.Begin.y);
float t = Vector2.Dot(v, v2) / v.sqrMagnitude;
if (t >= 0 && t <= 1)
{
Vector2 v3 = v * t;
v3.x += line.Begin.x;
v3.y += line.Begin.y;
v3.x = pos.x - v3.x;
v3.y = pos.y - v3.y;
float dist = v3.sqrMagnitude;
if (dist < sqrDistance)
{
sqrDistance = dist;
index = i;
}
}
}
return(index);
}
private int FindWithPos(XYGridPos pos)
{
for (int i = list_.Count - 1; i >= 0; --i)
{
XYObstacleLine line = list_[i];
if (line.Begin == pos || line.End == pos)
{
return(i);
}
if (0 == XYGridPos.RelativeCCW(line.Begin, line.End, pos))
{
return(i);
}
}
// 找离该点最近的线
float sqrDistance;
int index = FindNearestLine(pos, out sqrDistance);
if (index >= 0 && sqrDistance <= 1)
{
return(index);
}
else
{
return(-1);
}
}
public static XYObstacleLine Read(BinaryReader reader)
{
XYGridPos p1 = XYGridPos.Read(reader);
XYGridPos p2 = XYGridPos.Read(reader);
return(new XYObstacleLine(p1, p2));
}
public bool RemoveWithPos(XYGridPos pos, out XYObstacleLine line)
{
int index = FindWithPos(pos);
if (index >= 0)
{
line = list_[index];
//计算奇数点
if (PointList.ContainsKey(line.Begin))
{
PointList[line.Begin].RemoveBegin();
}
if (PointList.ContainsKey(line.End))
{
PointList[line.End].RemoveEnd();
}
list_.RemoveAt(index);
return(true);
}
else
{
Debug.LogWarning("remove 失败");
line = new XYObstacleLine();
return(false);
}
}
// 判断两线是否相交
private static bool LinesIntersect(XYGridPos p1, XYGridPos p2, XYGridPos p3, XYGridPos p4)
{
return(
(XYGridPos.RelativeCCW(p1, p2, p3) * XYGridPos.RelativeCCW(p1, p2, p4) <= 0)
&&
(XYGridPos.RelativeCCW(p3, p4, p1) * XYGridPos.RelativeCCW(p3, p4, p2) <= 0)
);
}
public XYObstacleLine(XYGridPos begin, XYGridPos end)
{
if (begin == end)
{
throw new EInvalidLine(begin, end);
}
begin_ = begin;
end_ = end;
}
private static int GetPointIndex(List <XYGridPos> pointList, XYGridPos point)
{
int index = pointList.IndexOf(point);
if (index >= 0)
{
return(index);
}
else
{
pointList.Add(point);
return(pointList.Count - 1);
}
}
// 判断点是不是在线上（不包含端点）
public bool IsPosInLineAndNotAtEndPoint(XYGridPos pos)
{
for (int i = 0; i < list_.Count; ++i)
{
XYObstacleLine line = list_[i];
if (line.Begin != pos && line.End != pos)
{
if (0 == XYGridPos.RelativeCCW(line.Begin, line.End, pos))
{
return(true);
}
}
}
return(false);
}
public override bool Equals(object obj)
{
if (obj == null)
{
return(false);
}
if (object.ReferenceEquals(this, obj))
{
return(true);
}
if (this.GetType() != obj.GetType())
{
return(false);
}
XYGridPos pos = (XYGridPos)obj;
return(pos.x == x && pos.y == y);
}
// 判断一个点是否在线内
public bool PosInLine(XYGridPos pos)
{
return(XYGridPos.RelativeCCW(begin_, end_, pos) == 0);
}
public EInvalidLine(XYGridPos p1, XYGridPos p2)
: base(string.Format("Invalid line (({0},{1}) - ({2},{3}))", p1.x, p1.y, p2.x, p2.y))
{
}
//public static bool operator <(XYGridPos p1, XYGridPos p2) {
// return (p1.x < p2.x)
// || ((p1.x == p2.x) && (p1.y < p2.y));
//}
//public static bool operator >(XYGridPos p1, XYGridPos p2) {
// return (p1.x > p2.x)
// || ((p1.x == p2.x) && (p1.y > p2.y));
//}
//public static bool operator >=(XYGridPos p1, XYGridPos p2) {
// return p1.x >= p2.x && p1.y >= p2.y;
//}
//public static bool operator <=(XYGridPos p1, XYGridPos p2) {
// return p1.x <= p2.x && p1.y <= p2.y;
//}
public static int RelativeCCW(XYGridPos p1, XYGridPos p2, XYGridPos p3)
{
return(RelativeCCW(p1.x, p1.y, p2.x, p2.y, p3.x, p3.y));
}
