NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

       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    [Toc]    [Back]

       Specifies the number  of  partitions  in  the  grid  range
       interval [u1, u2]. Must be positive.  Specify the mappings
       for integer grid domain values i=0 and i="un".   Specifies
       the  number  of partitions in the grid range interval [v1,
       v2] (glMapGrid2() only).  Specify the mappings for integer
       grid domain values j=0 and j="vn" (glMapGrid2() only).

DESCRIPTION    [Toc]    [Back]

       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 + uv1

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

ERRORS    [Toc]    [Back]

       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    [Toc]    [Back]

       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    [Toc]    [Back]

       glEvalCoord(3),  glEvalMesh(3), glEvalPoint(3), glMap1(3),
       glMap2(3)



                                                    glMapGrid(3G)