GLPOLYGONMODE(3G)                                            GLPOLYGONMODE(3G)



NAME
       glPolygonode - select a polygon rasterization mode


C SPECIFICATION
       void glPolygonode( GLenum face,
                           GLenum mode )


PARAMETERS
       face  Specifies  the  polygons  that mode applies to.  Must be GLFRONT
             for front-facing polygons, GLBACK for back-facing  polygons,  or
             GLFRONTANDBACK for front- and back-facing polygons.

       mode  Specifies  how  polygons will be rasterized.  Accepted values are
             GLPOINT, GLINE, and GLFIL.  The initial value is GLFIL for
             both front- and back-facing polygons.

DESCRIPTION
       glPolygonode  controls  the  interpretation of polygons for rasteriza-
       tion.  face describes which  polygons  mode  applies  to:  front-facing
       polygons   (GLFRONT),  back-facing  polygons  (GLBACK),  or  both  (-
       GLFRONTANDBACK).  The polygon mode affects only the final rasteriza-
       tion  of polygons.  In particular, a polygon's vertices are lit and the
       polygon is clipped and possibly culled before these modes are  applied.

       Three modes are defined and can be specified in mode:

       GLPOINT      Polygon vertices that are marked as the start of a bound-
                     ary edge are drawn as points.  Point attributes  such  as
                     GLPOINTSIZE  and GLPOINTSMOTH control the rasteriza-
                     tion of the  points.   Polygon  rasterization  attributes
                     other than GLPOLYGONMODE have no effect.

       GLINE       Boundary edges of the polygon are drawn as line segments.
                     They are treated as  connected  line  segments  for  line
                     stippling;  the  line stipple counter and pattern are not
                     reset  between  segments   (see   glLineStipple).    Line
                     attributes  such as GLINEWIDTH and GLINESMOTH con-
                     trol the rasterization of the lines.  Polygon  rasteriza-
                     tion   attributes  other  than  GLPOLYGONMODE  have  no
                     effect.

       GLFIL       The  interior  of  the  polygon   is   filled.    Polygon
                     attributes     such     as     GLPOLYGONSTIPLE     and
                     GLPOLYGONSMOTH control the rasterization of the  poly-
                     gon.

EXAMPLES
       To  draw a surface with filled back-facing polygons and outlined front-
       facing polygons, call glPolygonMode(GLFRONT, GLINE);

NOTES
       Vertices are marked as boundary or nonboundary with an edge flag.  Edge
       flags  are  generated internally by the GL when it decomposes polygons;
       they can be set explicitly using glEdgeFlag.

ERORS
       GLINVALIDENUM is generated if either face or mode is not an  accepted
       value.

       GLINVALIDOPERATION  is generated if glPolygonode is executed between
       the execution of glBegin and the corresponding execution of glEnd.

ASOCIATED GETS
       glGet with argument GLPOLYGONMODE

SEE ALSO
       glBegin,   glEdgeFlag,   glLineStipple,    glLineWidth,    glPointSize,
       glPolygonStipple



                                                             GLPOLYGONMODE(3G)