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GLMAPGRID()                                                        GLMAPGRID()

NAME
       glMapGrid1d, glMapGrid1f, glMapGrid2d, glMapGrid2f - define a one- or
       two-dimensional mesh

C SPECIFICATION
       void glMapGrid1d( GLint un,
                         GLdouble u1,
                         GLdouble u2 )
       void glMapGrid1f( GLint un,
                         GLfloat u1,
                         GLfloat u2 )
       void glMapGrid2d( GLint un,
                         GLdouble u1,
                         GLdouble u2,
                         GLint vn,
                         GLdouble v1,
                         GLdouble v2 )
       void glMapGrid2f( GLint un,
                         GLfloat u1,
                         GLfloat u2,
                         GLint vn,
                         GLfloat v1,
                         GLfloat v2 )

PARAMETERS
       un  Specifies the number of partitions in the grid range interval [u1,
           u2].  Must be positive.

       u1, u2
           Specify the mappings for integer grid domain values i = 0 and i =
           un.

       vn  Specifies the number of partitions in the grid range interval [v1,
           v2]
           (glMapGrid2 only).

       v1, v2
           Specify the mappings for integer grid domain values j = 0 and j =
           vn
           (glMapGrid2 only).

DESCRIPTION
       glMapGrid and glEvalMesh are used together to efficiently generate and
       evaluate a series of evenly-spaced map domain values.  glEvalMesh steps
       through the integer domain of a one- or two-dimensional grid, whose
       range is the domain of the evaluation maps specified by glMap1 and
       glMap2.

       glMapGrid1 and glMapGrid2 specify the linear grid mappings between the
       i (or i and j) integer grid coordinates, to the u (or u and v)
       floating-point evaluation map coordinates.  See glMap1 and glMap2 for
       details of how u and v coordinates are evaluated.

       glMapGrid1 specifies a single linear mapping such that integer grid
       coordinate 0 maps exactly to u1, and integer grid coordinate un maps
       exactly to u2.  All other integer grid coordinates i are mapped so that

       u = i (u2 - u1) / un + u1

       glMapGrid2 specifies two such linear mappings.  One maps integer grid
       coordinate i = 0 exactly to u1, and integer grid coordinate i = un
       exactly to u2.  The other maps integer grid coordinate j = 0 exactly to
       v1, and integer grid coordinate j = vn exactly to v2.  Other integer
       grid coordinates i and j are mapped such that

       u = i (u2 - u1) / un + u1

       v = j (v2 - v1) / vn + v1

       The mappings specified by glMapGrid are used identically by glEvalMesh
       and glEvalPoint.

ERRORS
       GL_INVALID_VALUE is generated if either un or vn is not positive.

       GL_INVALID_OPERATION is generated if glMapGrid is executed between the
       execution of glBegin and the corresponding execution of glEnd.

ASSOCIATED GETS
       glGet with argument GL_MAP1_GRID_DOMAIN
       glGet with argument GL_MAP2_GRID_DOMAIN
       glGet with argument GL_MAP1_GRID_SEGMENTS
       glGet with argument GL_MAP2_GRID_SEGMENTS

SEE ALSO
       glEvalCoord, glEvalMesh, glEvalPoint, glMap1, glMap2

                                                                   GLMAPGRID()