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

glEvalCoord
	glEvalCoordd(u[, v]) | glEvalCoordd((u[, v])) -> None
glEvalCoord1
	glEvalCoordd(u[, v]) | glEvalCoordd((u[, v])) -> None
glEvalCoord1d
	glEvalCoord1d(u) -> None
glEvalCoord1dv
	glEvalCoord1dv(v) -> None
glEvalCoord1f
	glEvalCoord1f(u) -> None
glEvalCoord1fv
	glEvalCoord1fv(v) -> None
glEvalCoord2
	glEvalCoordd(u[, v]) | glEvalCoordd((u[, v])) -> None
glEvalCoord2d
	glEvalCoord2d(u, v) -> None
glEvalCoord2dv
	glEvalCoord2dv(v) -> None
glEvalCoord2f
	glEvalCoord2f(u, v) -> None
glEvalCoord2fv
	glEvalCoord2fv(v) -> None
glEvalCoordd
	glEvalCoordd(u[, v]) | glEvalCoordd((u[, v])) -> None
glEvalCoordf
	glEvalCoordf(u[, v]) | glEvalCoordf((u[, v])) -> None

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
   command.

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
GL_MAP1_TEXTURE_COORD_1, GL_MAP1_TEXTURE_COORD_2,
GL_MAP1_TEXTURE_COORD_3, GL_MAP1_TEXTURE_COORD_4,
GL_MAP2_TEXTURE_COORD_1, GL_MAP2_TEXTURE_COORD_2,
GL_MAP2_TEXTURE_COORD_3, or GL_MAP2_TEXTURE_COORD_4 is
enabled, then	an appropriate glTexCoord command is
simulated.

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

    _
n=_____
  ||m||

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
glGetMap

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