一套奇怪、复杂的算法，
ptTemp.x = (int) (pt[i].x * cos (TWOPI * iAngle / 360) +
pt[i].y * sin (TWOPI * iAngle / 360)) ;
ptTemp.y = (int) (pt[i].y * cos (TWOPI * iAngle / 360) -
pt[i].x * sin (TWOPI * iAngle / 360)) ;
pt[i] = ptTemp ;
一套奇怪、复杂的算法，
ptTemp.x = (int) (pt[i].x * cos (TWOPI * iAngle / 360) +
pt[i].y * sin (TWOPI * iAngle / 360)) ;
ptTemp.y = (int) (pt[i].y * cos (TWOPI * iAngle / 360) -
pt[i].x * sin (TWOPI * iAngle / 360)) ;
pt[i] = ptTemp ;