109 lines
2.7 KiB
C#
109 lines
2.7 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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namespace TransportGame.Model
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{
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public struct LineSegment
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{
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public float X0 { get; private set; }
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public float Y0 { get; private set; }
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public float X1 { get; private set; }
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public float Y1 { get; private set; }
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public Vector2 P0
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{
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get
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{
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return new Vector2(X0, Y0);
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}
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}
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public Vector2 P1
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{
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get
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{
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return new Vector2(X1, Y1);
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}
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}
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public float Length
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{
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get
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{
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return (P1 - P0).Length;
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}
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}
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public float LengthSq
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{
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get
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{
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return (P1 - P0).LengthSq;
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}
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}
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public Vector2 Direction
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{
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get
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{
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return (P1 - P0).Normalized;
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}
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}
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public LineSegment(Vector2 p0, Vector2 p1)
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: this()
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{
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X0 = p0.X; Y0 = p0.Y;
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X1 = p1.X; Y1 = p1.Y;
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}
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public LineSegment(float x0, float y0, float x1, float y1)
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: this()
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{
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X0 = x0; Y0 = y0;
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X1 = x1; Y1 = y1;
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}
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public static Vector2? Intersect(LineSegment a, LineSegment b)
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{
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float s1x = a.X1 - a.X0, s1y = a.Y1 - a.Y0;
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float s2x = b.X1 - b.X0, s2y = b.Y1 - b.Y0;
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float det = (-s2x * s1y + s1x * s2y);
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// Avoid division by zero
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// Note: this is an edge case, the vectors might be parallel or colliniar
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if (det == 0) return null;
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float s = (-s1y * (a.X0 - b.X0) + s1x * (a.Y0 - b.Y0)) / det;
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float t = (s2x * (a.Y0 - b.Y0) - s2y * (a.X0 - b.X0)) / det;
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// Collision detected
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if (s >= 0 && s <= 1 && t >= 0 && t <= 1)
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return new Vector2(a.X0 + t * s1x, a.Y0 + t * s1y);
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// No collision
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return null;
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}
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/// <summary>
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/// Calculates the distance from point p to line segment
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/// </summary>
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/// <param name="line">Line</param>
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/// <param name="p">Point</param>
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/// <returns>Distance</returns>
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public static float Distance(LineSegment line, Vector2 p)
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{
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float det = (line.Y1 - line.Y0) * p.X - (line.X1 - line.X0) * p.Y
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+ line.X1 * line.Y0 - line.Y1 * line.X0;
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return Math.Abs(det) / line.Length;
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}
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public override string ToString()
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{
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return string.Format("({0}, {1})->({2}, {3})", X0, Y0, X1, Y1);
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}
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}
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}
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