Unity GL 画圆

Unity下GL没有画圆的函数，只能自己来了。

如果能帮到大家，我也很高兴。

虽然没有画圆的函数，但是能画直线，利用这一点，配合微积分什么的，就可以画出来了。反正就是花很多连在一起的直线，每条直线足够短的时候，就足够圆了

 void DrawCircle(float x, float y, float z, float r, float accuracy)
 {
     GL.PushMatrix ();
     //绘制2D图像
     GL.LoadOrtho ();

     float stride = r * accuracy;
     float size =  / accuracy;
     float x1 = x, x2 = x, y1 = , y2 = ;
     float x3 = x, x4 = x, y3 = , y4 = ;

     double squareDe;
     squareDe = r * r - Math.Pow (x - x1, );
     squareDe = squareDe >  ? squareDe : ;
     y1 = (float)(y + Math.Sqrt (squareDe));
     squareDe = r * r - Math.Pow (x - x1, );
     squareDe = squareDe >  ? squareDe : ;
         y2 = (float)(y - Math.Sqrt (squareDe));
     for (int i = ; i < size; i++) {
         x3 = x1 + stride;
         x4 = x2 - stride;
         squareDe = r * r - Math.Pow (x - x3, );
         squareDe = squareDe >  ? squareDe : ;
                 y3 = (float)(y + Math.Sqrt (squareDe));
         squareDe = r * r - Math.Pow (x - x4, );
         squareDe = squareDe >  ? squareDe : ;
         y4 = (float)(y - Math.Sqrt (squareDe));

         //绘制线段
                 GL.Begin (GL.LINES);
         GL.Color (Color.blue);
         GL.Vertex (new Vector3 (x1 / Screen.width, y1 / Screen.height, z));
         GL.Vertex (new Vector3 (x3 / Screen.width, y3 / Screen.height, z));
         GL.End ();
 GL.Begin (GL.LINES);
         GL.Color (Color.blue);
         GL.Vertex (new Vector3 (x2 / Screen.width, y1 / Screen.height, z));
         GL.Vertex (new Vector3 (x4 / Screen.width, y3 / Screen.height, z));
         GL.End ();
                 GL.Begin (GL.LINES);
         GL.Color (Color.blue);
         GL.Vertex (new Vector3 (x1 / Screen.width, y2 / Screen.height, z));
         GL.Vertex (new Vector3 (x3 / Screen.width, y4 / Screen.height, z));
         GL.End ();
                 GL.Begin (GL.LINES);
         GL.Color (Color.blue);
         GL.Vertex (new Vector3 (x2 / Screen.width, y2 / Screen.height, z));
         GL.Vertex (new Vector3 (x4 / Screen.width, y4 / Screen.height, z));
         GL.End ();

         x1 = x3;
         x2 = x4;
         y1 = y3;
         y2 = y4;
     }
     GL.PopMatrix ();
 }

参数分别为: x,y,z 中心点三维坐标, r 圆的半径, accuracy 精度,精度越小,越圆

如有错误，请不吝指教