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.

                                          February, 2023                         PLPOLY3(3plplot)