fglPolygonMode(3G)

NAME
     fglPolygonMode - select a polygon rasterization mode


FORTRAN SPECIFICATION
     SUBROUTINE fglPolygonMode( INTEGER*4 face,
                                INTEGER*4 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
     fglPolygonMode controls the interpretation of polygons for rasterization.
     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 rasterization 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 boundary
                   edge are drawn as points.  Point attributes such as
                   GL_POINT_SIZE and GL_POINT_SMOOTH control the rasterization
                   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 fglLineStipple).  Line
                   attributes such as GL_LINE_WIDTH and GL_LINE_SMOOTH control
                   the rasterization of the lines.  Polygon rasterization
                   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 polygon.

EXAMPLES
     To draw a surface with filled back-facing polygons and outlined front-
     facing polygons, call

          fglPolygonMode(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 fglEdgeFlag.

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

     GL_INVALID_OPERATION is generated if fglPolygonMode is executed between
     the execution of fglBegin and the corresponding execution of fglEnd.


ASSOCIATED GETS
     fglGet with argument GL_POLYGON_MODE

SEE ALSO
     fglBegin, fglEdgeFlag, fglLineStipple, fglLineWidth, fglPointSize,
     fglPolygonStipple