'''_glPolygonMode:''' select a polygon rasterization mode


{{PageSyntax}}

  SUB _glPolygonMode (BYVAL face AS _UNSIGNED LONG, BYVAL mode AS _UNSIGNED LONG)
  void '''_glPolygonMode'''(GLenum {{Parameter|face}}, GLenum {{Parameter|mode}});


; face
: Specifies the polygons that {{Parameter|mode}} applies to. Must be {{KW|_GL_FRONT_AND_BACK}} for front- and back-facing polygons.
; mode
: Specifies how polygons will be rasterized. Accepted values are {{KW|_GL_POINT}}, {{KW|_GL_LINE}}, and {{KW|_GL_FILL}}. The initial value is {{KW|_GL_FILL}} for both front- and back-facing polygons.


{{PageDescription}}

'''_glPolygonMode''' controls the interpretation of polygons for rasterization. {{Parameter|face}} describes which polygons {{Parameter|mode}} applies to: both front and back-facing polygons ({{KW|_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 {{Parameter|mode}}:

; {{KW|_GL_POINT}}
: Polygon vertices that are marked as the start of a boundary edge are drawn as points. Point attributes such as {{KW|_GL_POINT_SIZE}} and {{KW|_GL_POINT_SMOOTH}} control the rasterization of the points. Polygon rasterization attributes other than {{KW|_GL_POLYGON_MODE}} have no effect.
; {{KW|_GL_LINE}}
: Boundary edges of the polygon are drawn as line segments. Line attributes such as {{KW|_GL_LINE_WIDTH}} and {{KW|_GL_LINE_SMOOTH}} control the rasterization of the lines. Polygon rasterization attributes other than {{KW|_GL_POLYGON_MODE}} have no effect.
; {{KW|_GL_FILL}}
: The interior of the polygon is filled. Polygon attributes such as {{KW|_GL_POLYGON_SMOOTH}} control the rasterization of the polygon.
== Examples ==

To draw a surface with outlined polygons, call 

<source lang="cpp">

glPolygonMode(, );
            
</source>


{{PageNotes}}

Vertices are marked as boundary or nonboundary with an edge flag. Edge flags are generated internally by the GL when it decomposes triangle stips and fans.


{{PageErrors}}

{{KW|_GL_INVALID_ENUM}} is generated if either {{Parameter|face}} or {{Parameter|mode}} is not an accepted value.


{{PageUseWith}}

{{KW|_glGet}} with argument {{KW|_GL_POLYGON_MODE}}


{{PageSeeAlso}}

{{KW|_GL}}
{{KW|_glLineWidth}}, {{KW|_glPointSize}}


{{PageCopyright}}

Copyright 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see [http://oss.sgi.com/projects/FreeB/ http://oss.sgi.com/projects/FreeB/].