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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 )

       delim $$

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 co-
       ordinate	0 maps exactly to u1, and integer grid coordinate un maps  ex-
       actly 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()

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