centos man page for glutessnormal

GLUTESSNORMAL(3G)						   OpenGL Manual						 GLUTESSNORMAL(3G)

NAME
       gluTessNormal - specify a normal for a polygon

C SPECIFICATION
       void gluTessNormal(GLUtesselator* tess, GLdouble valueX, GLdouble valueY, GLdouble valueZ);

PARAMETERS
       tess
	   Specifies the tessellation object (created with gluNewTess()).

       valueX
	   Specifies the first component of the normal.

       valueY
	   Specifies the second component of the normal.

       valueZ
	   Specifies the third component of the normal.

DESCRIPTION
       gluTessNormal describes a normal for a polygon that the program is defining. All input data will be projected onto a plane perpendicular to
       one of the three coordinate axes before tessellation and all output triangles will be oriented CCW with respect to the normal (CW
       orientation can be obtained by reversing the sign of the supplied normal). For example, if you know that all polygons lie in the x-y plane,
       call gluTessNormal(tess, 0.0, 0.0, 1.0) before rendering any polygons.

       If the supplied normal is (0.0, 0.0, 0.0) (the initial value), the normal is determined as follows. The direction of the normal, up to its
       sign, is found by fitting a plane to the vertices, without regard to how the vertices are connected. It is expected that the input data
       lies approximately in the plane; otherwise, projection perpendicular to one of the three coordinate axes may substantially change the
       geometry. The sign of the normal is chosen so that the sum of the signed areas of all input contours is nonnegative (where a CCW contour
       has positive area).

       The supplied normal persists until it is changed by another call to gluTessNormal.

SEE ALSO
       gluTessBeginPolygon(), gluTessEndPolygon()

COPYRIGHT
       Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see
       http://oss.sgi.com/projects/FreeB/.

AUTHORS
       opengl.org

opengl.org							    06/10/2014							 GLUTESSNORMAL(3G)