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Assets/CoolapeFrame/Scripts/toolkit/AngleEx.cs

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+/*
+******************************************************************************** 
+  *Copyright(C),coolae.net 
+  *Author:  chenbin
+  *Version:  2.0 
+  *Date:  2017-01-09
+  *Description:  几何
+  *Others:  
+  *History:
+*********************************************************************************
+*/ 
+
+using UnityEngine;
+using System.Collections;
+
+namespace Coolape
+{
+	public static class AngleEx
+	{
+		// xy平面上的两个点A(a,b),B(c,d),求C(e,f)沿A-->B的向量方向移动一定距离h;此时求所在的位置D的xy坐标
+		// xy正切值是(d-b)/(c-a);
+		//假设D(x,y)可以得两个方程:
+		//(y-f)/(x-e) = (d-b)/(c-a);
+		//(y-f)^2 + (x-e) ^2 = h ^2;
+		//可求得x,y
+		static public Vector2 getEndVector2(Vector2 directionalFrom, Vector2 directionalTo, Vector2 from, float toDistance)
+		{
+			float x = 0f;
+			float y = 0f;
+			//取得正切值
+			float tanXY = (directionalTo.y - directionalFrom.y) / (directionalTo.x - directionalFrom.x);
+			float xx = Mathf.Pow(toDistance, 2) / (Mathf.Pow(tanXY, 2) + 1);
+			x = Mathf.Sqrt(xx) + from.x;
+			y = tanXY * (x - from.x) + from.y;
+			return new Vector2(x, y);
+		}
+	
+		//求圆心p,半径r，逆时针角度angle，所得的圆上的点的坐标
+		static public Vector2 getCirclePointV2(Vector2 p, float r, float angle)
+		{
+			//弧度
+			float radian = angle * Mathf.PI / 180;
+			float x = p.x + r * Mathf.Cos(radian);
+			float y = p.y + r * Mathf.Sin(radian);
+			return new Vector2(x, y);
+		}
+
+		static public Vector3 getCirclePointV3(Vector3 p, float r, float angle)
+		{
+			float y = p.y;
+			Vector2 pos = getCirclePointV2(new Vector2(p.x, p.z), r, angle);
+			return new Vector3(pos.x, y, pos.y);
+		}
+
+		static public Vector3 getCirclePointStartWithXV3(Vector3 p, float r, float angle)
+		{
+			return getCirclePointV3(p, r, angle);
+		}
+
+		static public Vector3 getCirclePointStartWithYV3(Vector3 p, float r, float angle)
+		{
+			return getCirclePointV3(p, r, 90 - angle);
+		}
+	}
+}