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.
Note: 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.