gluBeginPolygon, gluEndPolygon
NAME
gluBeginPolygon, gluEndPolygon -- delimit a polygon description
C SPECIFICATION
void gluBeginPolygon(GLUtriangulatorObj *tobj)
void gluEndPolygon(GLUtriangulatorObj *tobj)
PARAMETERS
- tobj
-
Specifies the tessellation object (created with
gluNewTess).
DESCRIPTION
gluBeginPolygon and gluEndPolygon delimit the definition of a
nonconvex polygon. To define such a polygon, first call gluBeginPolygon.
Then define the contours of the polygon by calling
gluTessVertex for each vertex and
gluNextContour to start each
new contour. Finally, call gluEndPolygon to signal the end of the
definition. See the gluTessVertex
and gluNextContour reference
pages for more details.
Once gluEndPolygon is called, the polygon is tessellated, and the
resulting triangles are described through callbacks. See
gluTessCallback for descriptions
of the callback functions.
EXAMPLE
A quadrilateral with a triangular hole in it can be described like this:
gluBeginPolygon(tobj);
gluTessVertex(tobj, v1, v1);
gluTessVertex(tobj, v2, v2);
gluTessVertex(tobj, v3, v3);
gluTessVertex(tobj, v4, v4);
gluNextContour(tobj, GLU_INTERIOR);
gluTessVertex(tobj, v5, v5);
gluTessVertex(tobj, v6, v6);
gluTessVertex(tobj, v7, v7);
gluEndPolygon(tobj);
SEE ALSO
gluNewTess,
gluNextContour,
gluTessCallback,
gluTessVertex
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© 1995 Uwe Behrens All rights reserved