glPolygonMode(3)

NAME

       glPolygonMode - select a polygon rasterization mode

C SPECIFICATION

       void glPolygonMode( GLenum face,
                           GLenum mode )

PARAMETERS

       face  Specifies  the  polygons  that mode applies to.  Must be GL_FRONT
             for front-facing polygons, GL_BACK for back-facing  polygons,  or
             GL_FRONT_AND_BACK for front- and back-facing polygons.

       mode  Specifies  how  polygons will be rasterized.  Accepted values are
             GL_POINT, GL_LINE, and GL_FILL.  The initial value is GL_FILL for
             both front- and back-facing polygons.

DESCRIPTION

       glPolygonMode  controls  the  interpretation of polygons for rasteriza-
       tion.  face describes which  polygons  mode  applies  to:  front-facing
       polygons   (GL_FRONT),  back-facing  polygons  (GL_BACK),  or  both  (-
       GL_FRONT_AND_BACK).  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:

       GL_POINT      Polygon vertices that are marked as the start of a bound-
                     ary edge are drawn as points.  Point attributes  such  as
                     GL_POINT_SIZE  and GL_POINT_SMOOTH control the rasteriza-
                     tion of the  points.   Polygon  rasterization  attributes
                     other than GL_POLYGON_MODE have no effect.

       GL_LINE       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 GL_LINE_WIDTH and GL_LINE_SMOOTH con-
                     trol the rasterization of the lines.  Polygon  rasteriza-
                     tion   attributes  other  than  GL_POLYGON_MODE  have  no
                     effect.

       GL_FILL       The  interior  of  the  polygon   is   filled.    Polygon
                     attributes     such     as     GL_POLYGON_STIPPLE     and
                     GL_POLYGON_SMOOTH control the rasterization of the  poly-
                     gon.

EXAMPLES

       To  draw a surface with filled back-facing polygons and outlined front-
       facing polygons, call glPolygonMode(GL_FRONT, GL_LINE);

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.

ERRORS

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

       GL_INVALID_OPERATION  is generated if glPolygonMode is executed between
       the execution of glBegin and the corresponding execution of glEnd.

ASSOCIATED GETS

       glGet with argument GL_POLYGON_MODE

SEE ALSO

       glBegin(3G),   glEdgeFlag(3G),   glLineStipple(3G),    glLineWidth(3G),
       glPointSize(3G), glPolygonStipple(3G)

                                                             GLPOLYGONMODE(3G)