P
glPolygonMode
Chapter 14
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glPolygonMode
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 polygons (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 rasterization of the polygon.
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