GLPOLYGONMODE(3G)GLPOLYGONMODE(3G)NAMEglPolygonMode - 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.
DESCRIPTIONglPolygonMode 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.
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 polygons;
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 ALSOglBegin(3G), glEdgeFlag(3G), glLineStipple(3G), glLineWidth(3G),
glPointSize(3G), glPolygonStipple(3G)
March 1, 2011
