三角函數必備，角度轉孤度、孤度轉角度

/** Degrees to Radian **/
#define DEGREES_TO_RADIANS( degrees ) ( ( degrees ) / 180.0 * M_PI )

/** Radians to Degrees **/
#define RADIANS_TO_DEGREES( radians ) ( ( radians ) * ( 180.0 / M_PI ) )