using UnityEngine;
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public struct Line2D
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{
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public Vector2 start;
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public Vector2 end;
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public float slope
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{
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get
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{
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if (end.x == start.x)
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return 0;
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return (end.y - start.y) / (end.x - start.x);
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}
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}
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public float perpSlope
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{
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get
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{
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return -1 / slope;
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}
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}
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/// <summary>
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/// 计算给定点是否在线的左边
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/// </summary>
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/// <param name="point">给定点</param>
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/// <param name="line">线</param>
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/// <returns>是否在左边</returns>
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public static bool PointAtLineLeft(Vector2 point, Line2D line)
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{
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return PointRelation(line, point) > 0;
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}
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/// <summary>
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/// 计算给定点是否在线的右边
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/// </summary>
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/// <param name="point">给定点</param>
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/// <param name="line">线</param>
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/// <returns>是否在右边</returns>
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public static bool PointAtLineRight(Vector2 point, Line2D line)
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{
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return PointRelation(line, point) < 0;
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}
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/// <summary>
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/// 计算两个斜率是否垂直
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/// </summary>
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/// <param name="slope1">斜率1</param>
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/// <param name="slope2">斜率2</param>
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/// <returns>是否垂直</returns>
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public static bool IsPerp(float slope1, float slope2)
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{
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return (slope1 * slope2 == -1);
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}
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/// <summary>
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/// 计算两条线的交点
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/// </summary>
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/// <param name="line1">给定的线1</param>
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/// <param name="line2">给定的线2</param>
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/// <returns>交点</returns>
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public static Vector2 Line2DIntersect(Line2D line1, Line2D line2)
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{
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Vector2 _intersectPoint;
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_intersectPoint.x = (line1.slope * line1.start.x - line2.slope * line2.start.x + line2.start.y - line1.start.y) / (line1.slope - line2.slope);
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_intersectPoint.y = line1.slope * (_intersectPoint.x - line1.start.x) + line1.start.y;
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return _intersectPoint;
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}
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private static float PointRelation(Line2D line, Vector2 pt)
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{
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return (pt.y - line.start.y) * (line.end.x - line.start.x) - (pt.x - line.start.x) * (line.end.y - line.start.y);
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}
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public void DebugDraw(Color color)
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{
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Debug.DrawLine(new Vector3(start.x, 0, start.y), new Vector3(end.x, 0, end.y), color);
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}
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}
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