gluTessVertex
gluTessVertex
NAME
gluTessVertex -- specify a vertex on a polygon
C SPECIFICATION
void gluTessVertex(GLUtriangulatorObj *tobj,
GLdouble v[3],
void *data)
PARAMETERS
tobj
Specifies the tessellation object (created with gluNewTess).
v
Specifies the location of the vertex.
data
Specifies an opaque pointer passed back to the user with the vertex callback (as specified by gluTessCallback).
DESCRIPTION
gluTessVertex describes a vertex on a polygon that the user is defining. Successive gluTessVertex calls describe a closed contour. For example, if the user wants to describe a quadrilateral, then gluTessVertex should be called four times. gluTessVertex can only be called between gluBeginPolygon and gluEndPolygon.
data normally points to a structure containing the vertex location, as well as other per-vertex attributes such as color and normal. This pointer is passed back to the user through the GLU_VERTEX callback after tessellation (see gluTessCallback).
EXAMPLE
A quadrilateral with a triangular hole in it can be described as follows:
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);