GLGETMAP(3G)                                                      GLGETMAP(3G)



NAME
       glGetapdv,, glGetapfv,, glGetapiv - return evaluator parameters


C SPECIFICATION
       void glGetapdv( GLenum target,
                        GLenum query,
                        GLdouble *v )
       void glGetapfv( GLenum target,
                        GLenum query,
                        GLfloat *v )
       void glGetapiv( GLenum target,
                        GLenum query,
                        GLint *v )


PARAMETERS
       target  Specifies  the  symbolic  name  of  a map.  Accepted values are
               GLMAP1COLOR4,         GLMAP1INDEX,         GLMAP1NORMAL,
               GLMAP1TEXTURECORD1,               GLMAP1TEXTURECORD2,
               GLMAP1TEXTURECORD3,               GLMAP1TEXTURECORD4,
               GLMAP1VERTEX3,       GLMAP1VERTEX4,      GLMAP2COLOR4,
               GLMAP2INDEX,     GLMAP2NORMAL,     GLMAP2TEXTURECORD1,
               GLMAP2TEXTURECORD2,               GLMAP2TEXTURECORD3,
               GLMAP2TEXTURECORD4,         GLMAP2VERTEX3,          and
               GLMAP2VERTEX4.

       query   Specifies  which parameter to return.  Symbolic names GLCOEF,
               GLORDER, and GLDOMAIN are accepted.

       v       Returns the requested data.

DESCRIPTION
       glap1 and glap2 define evaluators.  glGetap returns evaluator param-
       eters.  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
       glap1 and glap2 reference pages.

       query can assume the following values:

       GLCOEF       v returns the control points for the evaluator function.
                      One-dimensional evaluators return order control  points,
                      and  two-dimensional  evaluators  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 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.

       GLORDER       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.

       GLDOMAIN      v returns the linear u and v mapping  parameters.   One-
                      dimensional  evaluators return two values, u1 and u2, as
                      specified by glap1.  Two-dimensional evaluators  return
                      four values (u1, u2, v1, and v2) as specified by glap2.
                      Integer values, when requested, are computed by rounding
                      the  internal floating-point values to the nearest inte-
                      ger values.

NOTES
       If an error is generated, no change is made to the contents of v.

ERORS
       GLINVALIDENUM is generated if  either  target  or  query  is  not  an
       accepted value.

       GLINVALIDOPERATION  is  generated if glGetap is executed between the
       execution of glBegin and the corresponding execution of glEnd.

SEE ALSO
       glEvalCoord, glap1, glap2



                                                                  GLGETMAP(3G)