Provided by: plplot-doc_5.9.9-2ubuntu2_all #### 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
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(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, 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.

```

#### SEEALSO

```       PLplot documentation at http://plplot.sourceforge.net/resources.

February, 2012                         PLPOLY3(3plplot)
```