_glPolygonMode: select a polygon rasterization mode
SUB _glPolygonMode (BYVAL face AS _UNSIGNED LONG, BYVAL mode AS _UNSIGNED LONG) void _glPolygonMode(GLenum face, GLenum mode);
- Specifies the polygons that mode applies to. Must be _GL_FRONT_AND_BACK for front- and back-facing polygons.
- 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.
_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:
- 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.
- 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.
- The interior of the polygon is filled. Polygon attributes such as _GL_POLYGON_SMOOTH control the rasterization of the polygon.
To draw a surface with outlined polygons, call
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.
_GL_INVALID_ENUM is generated if either face or mode is not an accepted value.
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/.