GLGETMAP(3G) UNIX Programmer's Manual GLGETMAP(3G)
NAME
glGetMapdv, glGetMapfv, glGetMapiv - return evaluator param-
eters
C SPECIFICATION
void glGetMapdv( GLenum target,
GLenum query,
GLdouble *v )
void glGetMapfv( GLenum target,
GLenum query,
GLfloat *v )
void glGetMapiv( GLenum target,
GLenum query,
GLint *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
glMap1 and glMap2 define evaluators. glGetMap 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 glMap1 and glMap2 reference pages.
query can assume the following values:
GL_COEFF v returns the control points for the evalua-
tor 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
MirBSD #10-current Printed 2021-12-07 1
GLGETMAP(3G) UNIX Programmer's Manual GLGETMAP(3G)
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.
GL_ORDER v returns the order of the evaluator func-
tion. 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 parame-
ters. One-dimensional evaluators return two
values, u1 and u2, as specified by glMap1.
Two-dimensional evaluators return four values
(u1, u2, v1, and v2) as specified by glMap2.
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 glGetMap is executed
between the execution of glBegin and the corresponding exe-
cution of glEnd.
SEE ALSO
glEvalCoord(3G), glMap1(3G), glMap2(3G)
MirBSD #10-current Printed 2021-12-07 2