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