fglGetMap(3G) OpenGL Reference fglGetMap(3G)NAME
fglGetMapdv, fglGetMapfv, fglGetMapiv - return evaluator parameters
FORTRAN SPECIFICATION
SUBROUTINE fglGetMapdv( INTEGER*4 target,
INTEGER*4 query,
CHARACTER*8 v )
SUBROUTINE fglGetMapfv( INTEGER*4 target,
INTEGER*4 query,
CHARACTER*8 v )
SUBROUTINE fglGetMapiv( INTEGER*4 target,
INTEGER*4 query,
CHARACTER*8 v )
PARAMETERS
target Specifies the symbolic name of a map. Accepted values are
GL_MAP1_COLOR_4, GL_MAP1_INDEX, GL_MAP1_NORMAL,
GL_MAP1_TEXTURE_COORD_1, GL_MAP1_TEXTURE_COORD_2,
GL_MAP1_TEXTURE_COORD_3, GL_MAP1_TEXTURE_COORD_4,
GL_MAP1_VERTEX_3, GL_MAP1_VERTEX_4, GL_MAP2_COLOR_4,
GL_MAP2_INDEX, GL_MAP2_NORMAL, GL_MAP2_TEXTURE_COORD_1,
GL_MAP2_TEXTURE_COORD_2, GL_MAP2_TEXTURE_COORD_3,
GL_MAP2_TEXTURE_COORD_4, GL_MAP2_VERTEX_3, and GL_MAP2_VERTEX_4.
query Specifies which parameter to return. Symbolic names GL_COEFF,
GL_ORDER, and GL_DOMAIN are accepted.
v Returns the requested data.
DESCRIPTION
fglMap1 and fglMap2 define evaluators. fglGetMap returns evaluator
parameters. target chooses a map, query selects a specific parameter,
and v points to storage where the values will be returned.
The acceptable values for the target parameter are described in the
fglMap1 and fglMap2 reference pages.
query can assume the following values:
GL_COEFF v returns the control points for the evaluator function.
One-dimensional evaluators return order control points,
and two-dimensional evaluators return uorder x 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
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fglGetMap(3G) OpenGL Reference fglGetMap(3G)
values.
GL_ORDER v 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.
GL_DOMAIN v returns the linear u and v mapping parameters. One-
dimensional evaluators return two values, u1 and u2, as
specified by fglMap1. Two-dimensional evaluators return
four values (u1, u2, v1, and v2) as specified by fglMap2.
Integer values, when requested, are computed by rounding
the internal floating-point values to the nearest integer
values.
NOTES
If an error is generated, no change is made to the contents of v.
ERRORS
GL_INVALID_ENUM is generated if either target or query is not an accepted
value.
GL_INVALID_OPERATION is generated if fglGetMap is executed between the
execution of fglBegin and the corresponding execution of fglEnd.
SEE ALSO
fglEvalCoord, fglMap1, fglMap2
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