glMapGrid2f

GLMAPGRID(3G)							GLMAPGRID(3G)



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)  float-
       ing-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	coor-
       dinates 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(3G),	   glEvalMesh(3G),    glEvalPoint(3G),	  glMap1(3G),
       glMap2(3G)



								GLMAPGRID(3G)