点到圆心的距离

Mathf.Sqrt(p.x * p.x + p.y * p.y);

极坐标的角度

float a = (Mathf.Atan2(p.y, p.x) + Mathf.PI) / (Mathf.PI * 2);

笛卡尔坐标系转极坐标

float r = Mathf.Sqrt(p.x * p.x + p.y * p.y);
float a = (Mathf.Atan2(p.y, p.x) + Mathf.PI) / (Mathf.PI * 2);
return new Vector2(r, a);

极坐标转笛卡尔坐标系

float x = Mathf.Sqrt(r) * Mathf.Cos(a * Mathf.PI);
float y = Mathf.Sqrt(r) * Mathf.Sin(a * Mathf.PI);
return new Vector2(x, y);