feedba(3G)

NAME
     feedba, endfee - control feedback mode

FORTRAN 77 SPECIFICATION
Personal Iris, Iris Entry, Indy, XL,
     subroutine feedba(buffer, size)
     real buffer(size)
     integer*4 size

     integer*4 function endfee(buffer)
     real buffer(*)

Other models:
     subroutine feedba(buffer, size)
     integer*2 buffer(size)
     integer*4 size

     integer*4 function endfee(buffer)
     integer*2 buffer(*)

PARAMETERS
     buffer   expects a buffer into which the system writes the feedback
              output from the Geometry Pipeline. On the Personal Iris, Iris
              Entry, Indy, XL, XS, XS24, Elan, Extreme, and VGX, the output
              consists of 32-bit floating point values; on the other IRIS-4D
              models, the output consists of 16-bit integer values.  Be sure
              you declare your buffer appropriately.

     size     expects the maximum number of buffer elements into which the
              system will write feedback output. This must not exceed the
              number of elements in buffer.

FUNCTION RETURN VALUE
     The return value of endfee is the actual number of elements of buffer
     that were written.  The system will not write more than size elements,
     even when the amount of feedback exceeds it.  You should assume that
     overflow has occurred whenever the return value is size.

DESCRIPTION
     feedba puts the system in feedback mode.  In feedback mode, the system
     retains the output of the Geometry Pipeline rather than sending it to the
     rendering subsystem.  endfee turns off feedback mode and returns the
     feedback output in buffer.  This information is typically a description
     of a vertex, and is machine specific.  For information for interpreting
     the returned buffer, see the ``Feedback'' chapter of the Graphics Library
     Programming Guide.

NOTES
     These routines are available only in immediate mode.
     On the IRIS-4D G, GT, and GTX models the size of the buffer should never
     exceed 0x10000 bytes.  On the IRIS-4D VGX model the size of the buffer
     should never exceed 0x80000 bytes.  On the IRIS-4D RealityEngine models
     the size of the buffer is limited by the amount of memory that can be
     locked down by the system.