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glpolygonmode(3g) [osx man page]


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

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

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 AUTHORS 06/10/2014 GLFRONTFACE(3G)
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