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)
       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(3G)