glgetmap
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glGetMap(3G) OpenGL Reference glGetMap(3G)
NAME
glGetMapdv, glGetMapfv, glGetMapiv - return evaluator parameters
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 evaluator map.
One-dimensional maps return order control points, and
two-dimensional maps return uorder*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 map. Two-dimensional
control points are returned in row-major order,
incrementing the uorder index quickly, and the vorder
index after each row. Integer values, when requested,
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glGetMap(3G) OpenGL Reference glGetMap(3G)
are computed by rounding the internal floating-point
values to the nearest integer values.
GL_ORDER v returns the order of the map. One-dimensional maps
return a single value, order. Two-dimensional maps
return two values, uorder and vorder.
GL_DOMAIN v returns the linear u and v mapping parameters. One-
dimensional maps return two values, u1 and u2, as
specified by glMap1. Two-dimensional maps 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 execution of glEnd.
SEE ALSO
glEvalCoord, glMap1, glMap2
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