_C_ License Applicability. Except to the extent portions of this file are
_C_ made subject to an alternative license as permitted in the SGI Free
_C_ Software License B, Version 1.1 (the "License"), the contents of this
_C_ file are subject only to the provisions of the License. You may not use
_C_ this file except in compliance with the License. You may obtain a copy
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_C_ 
_C_ http://oss.sgi.com/projects/FreeB
_C_ 
_C_ Note that, as provided in the License, the Software is distributed on an
_C_ "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
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_C_ PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
_C_ 
_C_ Original Code. The Original Code is: OpenGL Sample Implementation,
_C_ Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
_C_ Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
_C_ Copyright in any portions created by third parties is as indicated
_C_ elsewhere herein. All Rights Reserved.
_C_ 
_C_ Additional Notice Provisions: The application programming interfaces
_C_ established by SGI in conjunction with the Original Code are The
_C_ OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
_C_ April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
_C_ 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
_C_ Window System(R) (Version 1.3), released October 19, 1998. This software
_C_ was created using the OpenGL(R) version 1.2.1 Sample Implementation
_C_ published by SGI, but has not been independently verified as being
_C_ compliant with the OpenGL(R) version 1.2.1 Specification.
_C_
_C_ The first character in this file must be an '_'!
_C_ Anything on a line after _C_ is ignored
_define(_filters,tbl|eqn)_C_
_C_      eqn is automatically replaced with neqn for nroff
_header(GetMap,return evaluator parameters)
_names(GetMap,[dfi]v)
.EQ
delim $$
.EN
.SH PARAMETERS
_phead(_param1)
Specifies the symbolic name of a map.
Accepted values are
_const(MAP1_COLOR_4),
_const(MAP1_INDEX),
_const(MAP1_NORMAL),
_const(MAP1_TEXTURE_COORD_1),
_const(MAP1_TEXTURE_COORD_2),
_const(MAP1_TEXTURE_COORD_3),
_const(MAP1_TEXTURE_COORD_4),
_const(MAP1_VERTEX_3),
_const(MAP1_VERTEX_4),
_const(MAP2_COLOR_4),
_const(MAP2_INDEX),
_const(MAP2_NORMAL),
_const(MAP2_TEXTURE_COORD_1),
_const(MAP2_TEXTURE_COORD_2),
_const(MAP2_TEXTURE_COORD_3),
_const(MAP2_TEXTURE_COORD_4),
_const(MAP2_VERTEX_3), and
_const(MAP2_VERTEX_4).
_phead(_param2)
Specifies which parameter to return.
Symbolic names
_const(COEFF),
_const(ORDER), and
_const(DOMAIN) are accepted.
_phead(_param3)
Returns the requested data.
.SH DESCRIPTION
_cmnd(Map1) and _cmnd(Map2) define evaluators.
_cmnd returns evaluator parameters.
_param1 chooses a map,
_param2 selects a specific parameter,
and _param3 points to storage where the values will be returned.
.P
The acceptable values for the _param1 parameter are described
in the _cmnd(Map1) and _cmnd(Map2) reference pages.
.P
_param2 can assume the following values:
.TP 15
_const(COEFF)
_param3 returns the control points for the evaluator function.
One-dimensional evaluators return $order$ control points,
and two-dimensional evaluators return $uorder ~times~ vorder$ control points.
Each control point consists of one, two, three, or four integer,
single-precision floating-point,
or double-precision floating-point values,
depending on the type of the evaluator.
The GL returns two-dimensional control points in row-major order,
incrementing the $uorder$ index quickly
and the $vorder$ index after each row.
Integer values,
when requested,
are computed by rounding the internal floating-point values to the
nearest integer values. 
.TP
_const(ORDER)
_param3 returns the order of the evaluator function.
One-dimensional evaluators return a single value,
$order$. The initial value is 1.
Two-dimensional evaluators return two values,
$uorder$ and $vorder$. The initial value is 1,1. 
.TP
_const(DOMAIN)
_param3 returns the linear $u$ and $v$ mapping parameters.
One-dimensional evaluators return two values,
$u1$ and $u2$,
as specified by _cmnd(Map1).
Two-dimensional evaluators return four values
($u1$, $u2$, $v1$, and $v2$)
as specified by _cmnd(Map2).
Integer values,
when requested,
are computed by rounding the internal floating-point values to the
nearest integer values.
.SH NOTES
If an error is generated,
no change is made to the contents of _param3.
.SH ERRORS
_const(INVALID_ENUM) is generated if either _param1 or _param2 is not
an accepted value.
.P
_const(INVALID_OPERATION) is generated if _cmnd
is executed between the execution of _cmnd(Begin)
and the corresponding execution of _cmnd(End).
.SH SEE ALSO
_cmnd(EvalCoord),
_cmnd(Map1),
_cmnd(Map2)