enabled one- and two-dimensional maps

C SPECIFICATION

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

PARAMETERS

       u  Specifies a value that is the domain coordinate u to the basis func-
          tion defined in a previous glMap1 or glMap2 command.

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

C SPECIFICATION

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

PARAMETERS

       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.

DESCRIPTION

       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
       rides 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

                                       m=_<I>u_x_<I>v_

       Then the generated normal n is
                                       n=_____

       If  automatic  normal  generation is disabled, the corresponding normal
       map GL_MAP2_NORMAL, if enabled, is used to produce a normal.   If  nei-
       ther automatic normal generation nor a normal map is enabled, no normal
       is generated for glEvalCoord2 commands.

ASSOCIATED GETS

       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

SEE ALSO

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



                                                               GLEVALCOORD(3G)