圈 - 线的交点不正常？ [英] Circle - Line Intersection not working properly?

问题描述

我写了这个圈子线相交检测之后 http://mathworld.wolfram.com/Circle -LineIntersection.html ，但它似乎喜欢还是我失去了一些东西。

 公共静态布尔相交
（Vector2f CirclePos，浮CircleRad，Vector2f点1，Vector2f点2）
 {
 Vector2f P1 = Vector2f.MemCpy（点1）; 
 Vector2f P2 = Vector2f.MemCpy（点2）; 
 
 //正常化点
 p1.X  -  = CirclePos.X; 
 p1.Y  -  = CirclePos.Y; 
 p2.X  -  = CirclePos.X; 
 p2.Y  -  = CirclePos.Y; 
 
浮动DX = p2.X  -  p1.X; 
浮动DY = p2.Y  -  p1.Y; 
浮动博士=（浮点）的Math.sqrt（（双）（DX * DX）+（双）（DY * DY））; 
浮动D = p1.X * p2.Y * p2.X  -  p1.Y; 
 
浮动DI =（CircleRad * CircleRad）*（*博士DR） - （D * D）; 
 
如果（DI℃下）返回false; 
，否则真正的回报; 
} 
  

返回true唯一的一次是当点2 是withing圆。我在做什么错了？

解决方案

 浮D = p1.X * p2.Y * p2.X  -  p1.Y; 
  

您已经混了你的运营商在这条线。

I wrote this circle-line intersection detection after http://mathworld.wolfram.com/Circle-LineIntersection.html, but it appears like it or I am missing something.

    public static bool Intersect
    (Vector2f CirclePos, float CircleRad, Vector2f Point1, Vector2f Point2)
    {
        Vector2f p1 = Vector2f.MemCpy(Point1);
        Vector2f p2 = Vector2f.MemCpy(Point2);

        // Normalize points
        p1.X -= CirclePos.X;
        p1.Y -= CirclePos.Y;
        p2.X -= CirclePos.X;
        p2.Y -= CirclePos.Y;

        float dx = p2.X - p1.X;
        float dy = p2.Y - p1.Y;
        float dr = (float)Math.Sqrt((double)(dx * dx) + (double)(dy * dy));
        float D = p1.X * p2.Y * p2.X - p1.Y;

        float di = (CircleRad * CircleRad) * (dr * dr) - (D * D);

        if (di < 0) return false;
        else return true;
    }

The only occasion it returns true is when Point2 is withing the circle. What am I doing wrong?

解决方案

float D = p1.X * p2.Y * p2.X - p1.Y;

You've mixed up your operators on this line.

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