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glpolygonmode(3g) [xfree86 man page]

GLPOLYGONMODE(3G)														 GLPOLYGONMODE(3G)

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 rasterization.  face describes which polygons mode applies to: front-facing poly-
       gons (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  glLineStipple).	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  ras-
		     terization of the polygon.

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 poly-
       gons; 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)

Check Out this Related Man Page

GLFRONTFACE(3G) 						   OpenGL Manual						   GLFRONTFACE(3G)

NAME

       glFrontFace - define front- and back-facing polygons

C SPECIFICATION

       void glFrontFace(GLenum mode);

PARAMETERS

       mode
	   Specifies the orientation of front-facing polygons.	GL_CW and GL_CCW are accepted. The initial value is GL_CCW.

DESCRIPTION

       In a scene composed entirely of opaque closed surfaces, back-facing polygons are never visible. Eliminating these invisible polygons has
       the obvious benefit of speeding up the rendering of the image. To enable and disable elimination of back-facing polygons, call glEnable()
       and glDisable() with argument GL_CULL_FACE.

       The projection of a polygon to window coordinates is said to have clockwise winding if an imaginary object following the path from its
       first vertex, its second vertex, and so on, to its last vertex, and finally back to its first vertex, moves in a clockwise direction about
       the interior of the polygon. The polygon's winding is said to be counterclockwise if the imaginary object following the same path moves in
       a counterclockwise direction about the interior of the polygon.	glFrontFace specifies whether polygons with clockwise winding in window
       coordinates, or counterclockwise winding in window coordinates, are taken to be front-facing. Passing GL_CCW to mode selects
       counterclockwise polygons as front-facing; GL_CW selects clockwise polygons as front-facing. By default, counterclockwise polygons are
       taken to be front-facing.

ERRORS

       GL_INVALID_ENUM is generated if mode is not an accepted value.

ASSOCIATED GETS

       glGet() with argument GL_FRONT_FACE

SEE ALSO

       glCullFace(),

COPYRIGHT

       Copyright (C) 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/.

AUTHORS

       opengl.org

opengl.org							    06/10/2014							   GLFRONTFACE(3G)
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