GLAPI/glPolygonMode: Difference between revisions
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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/]. | 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/]. | ||
[[Category:Core API Ref Rasterization|PolygonMode]] | [[Category:Core API Ref Rasterization|PolygonMode]] | ||
[[Category:Core API Reference|PolygonMode]] | |||
Revision as of 07:51, 26 February 2012
| Core in version | 4.6 | |
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| Core since version | 1.0 | |
glPolygonMode: select a polygon rasterization mode
Function Definition
void glPolygonMode(GLenum face, GLenum mode);
- face
- Specifies the polygons that mode applies to. Must be 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: both front and back-facing polygons (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. 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_SMOOTH control the rasterization of the polygon.
Examples
To draw a surface with outlined polygons, call
glPolygonMode(, );
Notes
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.
Errors
GL_INVALID_ENUM is generated if either face or mode is not an accepted value.
Associated Gets
glGet with argument GL_POLYGON_MODE
See Also
Copyright
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/.