PLPOLY3(3)                        PLplot API                        PLPOLY3(3)



NAME
       plpoly3 - Draw a polygon in 3 space

SYNOPSIS
       plpoly3(n, x, y, z, draw, ifcc)

DESCRIPTION
       Draws a polygon in 3 space defined by n points in x, y, and z. Setup
       like plline3(3), but differs from that function in that plpoly3(3)
       attempts to determine if the polygon is viewable depending on the order
       of the points within the arrays and the value of ifcc.  If the back of
       polygon is facing the viewer, then it isn't drawn.  If this isn't what
       you want, then use plline3(3) instead.

       The points are assumed to be in a plane, and the directionality of the
       plane is determined from the first three points.  Additional points do
       not have to lie on the plane defined by the first three, but if they do
       not, then the determination of visibility obviously can't be 100%
       accurate... So if you're 3 space polygons are too far from planar,
       consider breaking them into smaller polygons.  3 points define a plane
       :-).

       Bugs:  If one of the first two segments is of zero length, or if they
       are co-linear, the calculation of visibility has a 50/50 chance of
       being correct.  Avoid such situations :-).  See x18c.c for an example
       of this problem. (Search for 20.1).

       Redacted form: plpoly3(x, y, z, code)

       This function is used in example 18.

ARGUMENTS
       n (PLINT, input)
              Number of points defining line.

       x (PLFLT *, input)
              Pointer to array with x coordinates of points.

       y (PLFLT *, input)
              Pointer to array with y coordinates of points.

       z (PLFLT *, input)
              Pointer to array with z coordinates of points.

       draw (PLBOOL *, input)
              Pointer to array which controls drawing the segments of the
              polygon.  If draw[i] is true, then the polygon segment from
              index [i] to [i+1] is drawn, otherwise, not.

       ifcc (PLBOOL, input)
              If ifcc is true the directionality of the polygon is determined
              by assuming the points are laid out in a counter-clockwise
              order.  Otherwise, the directionality of the polygon is
              determined by assuming the points are laid out in a clockwise
              order.


AUTHORS
       Geoffrey Furnish and Maurice LeBrun wrote and maintain PLplot.  This
       man page was automatically generated from the DocBook source of the
       PLplot documentation, maintained by Alan W. Irwin and Rafael
       Laboissiere.

SEE ALSO
       PLplot documentation at http://plplot.sourceforge.net/resources.



                                November, 2007                      PLPOLY3(3)
