( double view_x, double view_y, double view_z, double reference_x, double reference_y, double reference_z, double twist )
The swf_lookat() function defines a viewing
transformation by giving the viewing position (the parameters
view_x, view_y, and
view_z) and the coordinates of a reference
point in the scene, the reference point is defined by the
, and reference_z parameters.
The twist controls the rotation along
with viewer's z axis.