gluTessVertex Subroutine

OpenGL 1.1 for AIX: Reference Manual

gluTessVertex Subroutine

Purpose

Specifies a vertex on a polygon.

Library

OpenGL C bindings library: libGL.a

C Syntax

void gluTessVertex(GLUtriangulator Obj *tobj, 
   GLdouble Vertex[3], 
   void *Data)

Description

The gluTessVertex subroutine describes a vertex on a polygon that the user is defining. Successive gluTessVertex calls describe a closed contour. For example, to describe a quadrilateral, the gluTessVertex subroutine must be called four times.

This subroutine can only be called between gluBeginPolygon and gluEndPolygon.

The Data parameter normally points to a structure containing the vertex location, as well as other vertex-specific attributes (such as color and normal). This pointer is passed back to the user through the GLU_VERTEX callback after tessellation. (See the gluTessCallback subroutine for details on defining callbacks for a tessellation object.)

Parameters

tobj	Specifies the tessellation object created with the gluNewTess subroutine.
Vertex	Specifies the location of the vertex.
Data	Specifies an opaque pointer that is passed back to the user with the vertex callback (as specified by the gluTessCallback subroutine).

Files

/usr/include/GL/gl.h

Contains C language constraints, variable type definitions, and ANSI function prototypes for OpenGL.

Examples

A quadrilateral with a triangle 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);

Related Information

The gluBeginPolygon subroutine, gluNewTess subroutine, gluNextContour subroutine, gluTessCallback subroutine.

OpenGL Overview.