/* 功能：判断线段和矩形是否相交 先判断线段的俩个端点是否在矩形的内部，在就必然相交 其次判断线段的包围盒是否和矩形相交，不相交的话线段和矩形肯定也不相交 最后判断，矩形的四个顶点是否位于线段的两侧，是则必然相交，否则就不相交*/
using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace ConsoleApplication1{ class LineConverttoRectangleClass { public class Point { public Point(float xx,float yy) { x = xx; y = yy; } public float x,y; } public class Line { public Line(Point pp1, Point pp2) { p1 = pp1; p2 = pp2; } public Point p1; public Point p2; } public class Rectangle { public Rectangle(Point pp1, Point pp2) { p1 = pp1; p2 = pp2; } public Point p1; public Point p2; public float MinX { get { return p1.x < p2.x ? p1.x : p2.x; } } public float MaxX { get { return p1.x > p2.x ? p1.x : p2.x; } } public float MinY { get { return p1.y < p2.y ? p1.y : p2.y; } } public float MaxY { get { return p1.y > p2.y ? p1.y : p2.y; } } }; public static bool PointInsideRectangle(Point point,Rectangle rect) { if (point.x >= rect.MinX && point.x <= rect.MaxX) if (point.y >= rect.MinY && point.y <= rect.MaxY) return true; return false; } // -1 点位于线段的左侧，0 点位于线段上面 ，1 点位于线段右侧 public static int PointAtLineLeftRight(Point point,Line line) { Point vect1 = new Point((line.p1.x - point.x),(line.p1.y - point.y)); Point vect2 = new Point((line.p2.x - point.x), (line.p2.y - point.y)); float nRet = vect1.x * vect2.y - vect1.y * vect2.x; if (nRet == 0) return 0; else if (nRet > 0) return 1; else if (nRet < 0) return -1; return 0; } public static bool IsTwoLineIntersect(Line line1,Line line2) { int a = PointAtLineLeftRight(line1.p1,line2); int b = PointAtLineLeftRight(line1.p2,line2); if (a * b > 0) return false; a = PointAtLineLeftRight(line2.p1, line1); b = PointAtLineLeftRight(line2.p2, line1); if (a * b > 0) return false; return true; } public static bool IsLineIntersectRect(Line line,Rectangle rect) { if (PointInsideRectangle(line.p1, rect) || PointInsideRectangle(line.p2, rect)) return true; if (PointInsideRectangle(new Point(line.p1.x, line.p2.y), rect) || PointInsideRectangle(new Point(line.p2.x, line.p1.y), rect)) return true; if (IsTwoLineIntersect(line, new Line(rect.p1, new Point(rect.p1.x, rect.p2.y)))) return true; if (IsTwoLineIntersect(line, new Line(rect.p1, new Point(rect.p2.x, rect.p1.y)))) return true; if (IsTwoLineIntersect(line, new Line(rect.p2, new Point(rect.p1.x, rect.p2.y)))) return true; if (IsTwoLineIntersect(line, new Line(rect.p2, new Point(rect.p2.x, rect.p1.y)))) return true; return false; } public static bool LineConverttoRectangle(Line line,Rectangle rect) { if (PointInsideRectangle(line.p1, rect) || PointInsideRectangle(line.p2, rect)) return true; if (!IsLineIntersectRect(line,rect)) return false; int b1 = PointAtLineLeftRight(rect.p1,line); int b2 = PointAtLineLeftRight(rect.p2, line); int b3 = PointAtLineLeftRight(new Point(rect.p1.x, rect.p2.y), line); int b4 = PointAtLineLeftRight(new Point(rect.p2.x, rect.p1.y), line); if (b1 + b2 + b3 + b4 == 4) return false; if (b1 + b2 + b3 + b4 == -4) return false; return true; } public static void Main() { Console.WriteLine(LineConverttoRectangle(new Line(new Point(5.0f, 1.8f), new Point(5.0f, -15f)), new Rectangle(new Point(4.7f, -0.7f), new Point(6.7f, 1.4f)))); } }} public bool RectCrossRect(Rect r1, Rect r2, ref Vector2 start, ref Vector2 end) { float x, y, z, w; ; x = Mathf.Max(r1.xMin, r2.xMin); y = Mathf.Max(r1.yMin, r2.yMin); w = Mathf.Min(r1.xMax, r2.xMax); z = Mathf.Min(r1.yMax, r2.yMax); if (x >= w || y >= z) return false; start = new Vector2(x, y); end = new Vector2(w, z); return true; }
