The swf_perspective() function
defines a perspective projection transformation. The fovy parameter is field-of-view
angle in the y direction. The
aspect parameter should be set to the aspect ratio
of the viewport that is being drawn onto. The near parameter is the near clipping
plane and the far parameter
is the far clipping plane.
注: Various distortion artifacts may appear when performing a perspective projection, this is because Flash players only have a two dimensional matrix. Some are not to pretty.