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(3plplot), but differs
       from that function in that plpoly3(3plplot) attempts to determine if the polygon is viewable depending on
       the order of the points within the vector 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(3plplot) 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(3plplot), input)
              Number of points defining line.

       x (PLFLT_VECTOR(3plplot), input)
              A vector containing n x coordinates of points.

       y (PLFLT_VECTOR(3plplot), input)
              A vector containing n y coordinates of points.

       z (PLFLT_VECTOR(3plplot), input)
              A vector containing n z coordinates of points.

       draw (PLBOOL_VECTOR(3plplot), input)
              A  vector  containing  n-1  Boolean  values which control 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(3plplot), 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

       Many developers (who are credited at http://plplot.org/credits.php) have contributed to PLplot  over  its
       long history.

SEE ALSO

       PLplot documentation at http://plplot.org/documentation.php.

                                                   March, 2025                                  PLPOLY3(3plplot)