anim3D/src/PolygonGO.i3

 Copyright (C) 1993, Digital Equipment Corporation                         
 All rights reserved.                                                      
 See the file COPYRIGHT for a full description.                            
                                                                           
 Created by Marc Najork                                                    
 Last modified on Thu Aug  4 10:39:24 PDT 1994 by najork                   




 A PolygonGO.T is a geometric object that describes a polygon. 


INTERFACE PolygonGO;

IMPORT GO, Point3, PointProp, SurfaceGO;

TYPE T <: SurfaceGO.T;

PROCEDURE NewStatic (READONLY pts : ARRAY OF Point3.T;
                     s := GO.Shape.Unknown) : T;

 Creates a new polygon pg and returns it. pg is defined by the array of
   points pts. s is a ``shape hint'', i.e.\ a hint whether the polygon is
   convex, non-convex, or complex. Refer to the \interface{GO} interface
   for details on shape hints. 

PROCEDURE New (READONLY pts : ARRAY OF PointProp.Val;
               s := GO.Shape.Unknown) : T;

 Creates a new polygon pg and returns it. The point property values in
   pts are used as the corner points of the polygon. The optional argument
   s indicates the shape of the polygon. 
 {\sl
     Note: Things would be even more general if we could dynamically add
     points to a polygon or remove them. One idea would be to introduce
     a new property value PointSequenceProp.Val, which contains an array
     of PointProp.Val's. PointSequence should be non-animatable, but
     provide methods to access its elements. For QuadMeshGO.T's, there
     should be similar types PointField and ColorField.
   } 


END PolygonGO.