glEvalCoord1d, glEvalCoord1f,	glEvalCoord2d, glEvalCoord2f,
	  glEvalCoord1dv, glEvalCoord1fv, glEvalCoord2dv,
	  glEvalCoord2fv - evaluate enabled one- and two-dimensional

	  void glEvalCoord1d( GLdouble u )
	  void glEvalCoord1f( GLfloat u	)
	  void glEvalCoord2d( GLdouble u,
			      GLdouble v )
	  void glEvalCoord2f( GLfloat u,
			      GLfloat v	)

	  u  Specifies a value that is the domain coordinate u to the
	     basis function defined in a previous glMap1 or glMap2

	  v  Specifies a value that is the domain coordinate v to the
	     basis function defined in a previous glMap2 command.
	     This argument is not present in a glEvalCoord1 command.

	  void glEvalCoord1dv( const GLdouble *u )
	  void glEvalCoord1fv( const GLfloat *u	)
	  void glEvalCoord2dv( const GLdouble *u )
	  void glEvalCoord2fv( const GLfloat *u	)

	  u    Specifies a pointer to an array containing either one
	       or two domain coordinates.  The first coordinate	is u.
	       The second coordinate is	v, which is present only in
	       glEvalCoord2 versions.

	  glEvalCoord1 evaluates enabled one-dimensional maps at
	  argument u.  glEvalCoord2 does the same for two-dimensional
	  maps using two domain	values,	u and v.  To define a map,
	  call glMap1 and glMap2; to enable and	disable	it, call
	  glEnable and glDisable.

	  When one of the glEvalCoord commands is issued, all
	  currently enabled maps of the	indicated dimension are
	  evaluated.  Then, for	each enabled map, it is	as if the
	  corresponding	GL command had been issued with	the computed
	  value.  That is, if GL_MAP1_INDEX or GL_MAP2_INDEX is
	  enabled, a glIndex command is	simulated.  If GL_MAP1_COLOR_4
	  or GL_MAP2_COLOR_4 is	enabled, a glColor command is
	  simulated.  If GL_MAP1_NORMAL	or GL_MAP2_NORMAL is enabled,
	  a normal vector is produced, and if any of
	  enabled, then	an appropriate glTexCoord command is

	  For color, color index, normal, and texture coordinates the
	  GL uses evaluated values instead of current values for those
	  evaluations that are enabled,	and current values otherwise,
	  However, the evaluated values	do not update the current
	  values.  Thus, if glVertex commands are interspersed with
	  glEvalCoord commands,	the color, normal, and texture
	  coordinates associated with the glVertex commands are	not
	  affected by the values generated by the glEvalCoord
	  commands, but	only by	the most recent	glColor, glIndex,
	  glNormal, and	glTexCoord commands.

	  No commands are issued for maps that are not enabled.	 If
	  more than one	texture	evaluation is enabled for a particular
	  dimension (for example, GL_MAP2_TEXTURE_COORD_1 and
	  GL_MAP2_TEXTURE_COORD_2), then only the evaluation of	the
	  map that produces the	larger number of coordinates (in this
	  case,	GL_MAP2_TEXTURE_COORD_2) is carried out.
	  GL_MAP1_VERTEX_4 overrides GL_MAP1_VERTEX_3, and
	  GL_MAP2_VERTEX_4 overrides GL_MAP2_VERTEX_3, in the same
	  manner.  If neither a	three- nor a four-component vertex map
	  is enabled for the specified dimension, the glEvalCoord
	  command is ignored.

	  If you have enabled automatic	normal generation, by calling
	  glEnable with	argument GL_AUTO_NORMAL, glEvalCoord2
	  generates surface normals analytically, regardless of	the
	  contents or enabling of the GL_MAP2_NORMAL map.  Let

	      Pp   Pp
	  m = -- X --
	      Pu   Pv

	  Then the generated normal n is


	  If automatic normal generation is disabled, the
	  corresponding	normal map GL_MAP2_NORMAL, if enabled, is used
	  to produce a normal.	If neither automatic normal generation
	  nor a	normal map is enabled, no normal is generated for
	  glEvalCoord2 commands.
	  glIsEnabled with argument GL_MAP1_VERTEX_3
	  glIsEnabled with argument GL_MAP1_VERTEX_4
	  glIsEnabled with argument GL_MAP1_INDEX
	  glIsEnabled with argument GL_MAP1_COLOR_4
	  glIsEnabled with argument GL_MAP1_NORMAL
	  glIsEnabled with argument GL_MAP1_TEXTURE_COORD_1
	  glIsEnabled with argument GL_MAP1_TEXTURE_COORD_2
	  glIsEnabled with argument GL_MAP1_TEXTURE_COORD_3
	  glIsEnabled with argument GL_MAP1_TEXTURE_COORD_4
	  glIsEnabled with argument GL_MAP2_VERTEX_3
	  glIsEnabled with argument GL_MAP2_VERTEX_4
	  glIsEnabled with argument GL_MAP2_INDEX
	  glIsEnabled with argument GL_MAP2_COLOR_4
	  glIsEnabled with argument GL_MAP2_NORMAL
	  glIsEnabled with argument GL_MAP2_TEXTURE_COORD_1
	  glIsEnabled with argument GL_MAP2_TEXTURE_COORD_2
	  glIsEnabled with argument GL_MAP2_TEXTURE_COORD_3
	  glIsEnabled with argument GL_MAP2_TEXTURE_COORD_4
	  glIsEnabled with argument GL_AUTO_NORMAL

	  glBegin, glColor, glEnable, glEvalMesh, glEvalPoint,
	  glIndex, glMap1, glMap2, glMapGrid, glNormal,	glTexCoord,