Index of Functions: A B C D E F G H I J K L M N O P Q R S T U V W X
Index Page dskp02_c

Table of contents

Procedure Abstract Required_Reading Keywords Brief_I/O Detailed_Input | Detailed_Output Parameters Exceptions Files Particulars Examples | Restrictions Literature_References Author_and_Institution Version Index_Entries

#### Procedure

       dskp02_c ( DSK, fetch type 2 plate data )

       void dskp02_c ( SpiceInt              handle,
                       ConstSpiceDLADescr  * dladsc,
                       SpiceInt              start,
                       SpiceInt              room,
                       SpiceInt            * n,
                       SpiceInt              plates[][3] )

#### Abstract

       Fetch triangular plates from a type 2 DSK segment.

#### Required_Reading

       DAS
       DSK

#### Keywords

       DAS
       DSK
       FILES

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       handle     I   DSK file handle.
       dladsc     I   DLA descriptor.
       start      I   Start index.
       room       I   Amount of room in output array.
       n          O   Number of plates returned.
       plates     O   Array containing plates.

#### Detailed_Input

       handle      is the handle of a DSK file containing a type 2
                   segment from which data are to be fetched.

       dladsc      is the DLA descriptor associated with the segment
                   from which data are to be fetched.

       start       is the ID of the first plate to be fetched from the
                   segment designated by `handle' and `dladsc'. The ID
                   of a plate is its ordinal position within the
                   segment. Plate IDs range from 1 to `np', where `np' is
                   the number of plates in the segment.

                   Note that Fortran-style 1-based indexing is used for
                   plate IDs because these IDs must be consistent with
                   the IDs used in DSK files, across all languages
                   supported by SPICE.

       room        is the number of plates that can fit in the output
                   `plates' array: the output array must be large enough
                   to hold at least 3*room integer values.

#### Detailed_Output

       n           is the number of plates fetched to the output
                   array `plates'. `n' is normally in the range

                      1 : min( np, room )

                   If an error occurs on the call, `n' is undefined.

       plates      is a contiguous set of plates. The returned
                   plates are arranged in order of increasing plate
                   ID. The IDs of the returned plates range from

                      start

                   to

                      start + n - 1

                   Each plate consists of three vertex indices. The
                   correspondence of elements of `plates' with the
                   elements of the set of plates contained in the
                   segment is:

                      plates[0][0]      plate_set[start][0]
                      plates[0][1]      plate_set[start][1]
                      plates[0][2]      plate_set[start][2]
                        ...             ...
                      plates[n-1][0]    plate_set[start+n-1][0]
                      plates[n-1][1]    plate_set[start+n-1][1]
                      plates[n-1][2]    plate_set[start+n-1][2]

                   If an error occurs on the call, `plates' is
                   undefined.

#### Parameters

       See the header file

          SpiceDLA.h

       for declarations of DLA descriptor sizes and documentation of the
       contents of DLA descriptors.

       See the header file

          SpiceDSK.h

       for declarations of DSK descriptor sizes and documentation of the
       contents of DSK descriptors.

       See the header file

          SpiceDSK.h

       for declarations of DSK data type 2 (plate model) parameters.

#### Exceptions

       1)  If the input handle is invalid, an error is signaled by a
           routine in the call tree of this routine.

       2)  If a file read error occurs, the error is signaled by a
           routine in the call tree of this routine.

       3)  If the input DLA descriptor is invalid, the effect of this
           routine is undefined. The error *may* be diagnosed by
           routines in the call tree of this routine, but there are no
           guarantees.

       4)  If `room' is non-positive, the error SPICE(VALUEOUTOFRANGE)
           is signaled by a routine in the call tree of this routine.

       5)  If `start' is less than 1 or greater than the number of plates in the
           segment, the error SPICE(INDEXOUTOFRANGE) is signaled by a routine in
           the call tree of this routine.

#### Files

       See input argument `handle'.

#### Particulars

       This routine enables SPICE-based user applications to rapidly
       fetch the plate data from a specified type 2 DSK segment. Using
       a large output array generally improves efficiency.

#### Examples

       The numerical results shown for this example may differ across
       platforms. The results depend on the SPICE kernels used as
       input, the compiler and supporting libraries, and the machine
       specific arithmetic implementation.

       1) Look up all the vertices associated with each plate
          of the model contained in a specified type 2 segment. For each
          of the first 5 plates, display the plate's vertices and normal
          vector.

          For this example, we'll show the context of this look-up:
          opening the DSK file for read access, traversing a trivial,
          one-segment list to obtain the segment of interest.

          Example code begins here.

          /.
             Program dskp02_ex1
          ./
          #include <stdio.h>
          #include "SpiceUsr.h"

          int main()
          {
             /.
             Constants
             ./
             #define PBUFSIZ         10000
             #define FILSIZ          256

             /.
             Local variables
             ./
             SpiceBoolean            found;

             SpiceChar               dsk  [ FILSIZ ];

             SpiceDLADescr           dladsc;

             SpiceDouble             normal [3];
             SpiceDouble             verts  [3][3];

             SpiceInt                handle;
             SpiceInt                i;
             SpiceInt                j;
             SpiceInt                n;
             SpiceInt                np;
             SpiceInt                nread;
             SpiceInt                nv;
             SpiceInt                nvtx;
             SpiceInt                plates[PBUFSIZ][3];
             SpiceInt                plix;
             SpiceInt                remain;
             SpiceInt                start;

             /.
             Prompt for name of DSK and open file for reading.
             ./
             prompt_c ( "Enter DSK name > ", FILSIZ, dsk );

             dasopr_c ( dsk,    &handle );

             dlabfs_c ( handle, &dladsc, &found );

             if ( !found )
             {
                setmsg_c ( "No segment found in file #." );
                errch_c  ( "#",  dsk                     );
                sigerr_c ( "SPICE(NOSEGMENT)"            );
             }

             /.
             Get segment vertex and plate counts.
             ./
             dskz02_c ( handle, &dladsc, &nv, &np );

             printf ( "\n"
                      "Number of vertices:  %d\n"
                      "Number of plates:    %d\n",
                      (int)nv,
                      (int)np                      );

             /.
             Display the vertices of each of the first 5 plates.
             ./
             remain = mini_c ( 2, 5, np );
             start  = 1;

             while ( remain > 0 )
             {
                /.
                `nread' is the number of plates we"ll read on this
                loop pass.
                ./
                nread  = mini_c ( 2, PBUFSIZ, remain );

                dskp02_c ( handle, &dladsc, start, nread, &n, plates );

                for ( i = 0; i < nread; i++ )
                {
                   plix = start + i;

                   /.
                   Read the vertices of the current plate.
                   ./
                   for ( j = 0;  j < 3;  j++ )
                   {
                      dskv02_c ( handle, &dladsc, plates[i][j],
                                 1,      &nvtx,
                                 ( SpiceDouble(*)[3] )(verts[j])  );
                   }

                   /.
                   Display the vertices of the current plate:
                   ./
                   printf ( "\n"
                            " Plate number: %d\n"
                            "    Vertex 1: ( %16.8e %16.8e %16.8e )\n"
                            "    Vertex 2: ( %16.8e %16.8e %16.8e )\n"
                            "    Vertex 3: ( %16.8e %16.8e %16.8e )\n",
                            (int)plix,
                            verts[0][0],  verts[0][1],  verts[0][2],
                            verts[1][0],  verts[1][1],  verts[1][2],
                            verts[2][0],  verts[2][1],  verts[2][2]   );

                   /.
                   Display the normal vector of the current plate:
                   ./
                   dskn02_c ( handle, &dladsc, plix, normal );

                   printf( "    Normal:   ( %16.8e %16.8e %16.8e )\n",
                           normal[0], normal[1], normal[2]           );
                }

                start  = start  + nread;
                remain = remain - nread;
             }

             /.
             Close the kernel.  This isn't necessary in a stand-
             alone program, but it's good practice in subroutines
             because it frees program and system resources.
             ./
             dascls_c ( handle );

             return ( 0 );
          }

          When this program was executed on a Mac/Intel/cc/64-bit
          platform, using the DSK file named phobos512.bds, the output
          was:

          Enter DSK name > phobos512.bds

          Number of vertices:  1579014
          Number of plates:    3145728

           Plate number: 1
              Vertex 1: (  -6.77444000e+00   6.26815000e+00   6.01149000e+00 )
              Vertex 2: (  -6.76238000e+00   6.25728000e+00   6.02556000e+00 )
              Vertex 3: (  -6.75710000e+00   6.27754000e+00   6.02096000e+00 )
              Normal:   (  -5.81973770e-01   3.21285613e-01   7.47048918e-01 )

           Plate number: 2
              Vertex 1: (  -6.77444000e+00   6.26815000e+00   6.01149000e+00 )
              Vertex 2: (  -6.77973000e+00   6.24790000e+00   6.01610000e+00 )
              Vertex 3: (  -6.76238000e+00   6.25728000e+00   6.02556000e+00 )
              Normal:   (  -5.81456950e-01   3.21988310e-01   7.47148809e-01 )

           Plate number: 3
              Vertex 1: (  -6.77973000e+00   6.24790000e+00   6.01610000e+00 )
              Vertex 2: (  -6.76768000e+00   6.23701000e+00   6.03019000e+00 )
              Vertex 3: (  -6.76238000e+00   6.25728000e+00   6.02556000e+00 )
              Normal:   (  -5.81597068e-01   3.22641957e-01   7.46757671e-01 )

           Plate number: 4
              Vertex 1: (  -6.77973000e+00   6.24790000e+00   6.01610000e+00 )
              Vertex 2: (  -6.78499000e+00   6.22762000e+00   6.02070000e+00 )
              Vertex 3: (  -6.76768000e+00   6.23701000e+00   6.03019000e+00 )
              Normal:   (  -5.83129010e-01   3.20560704e-01   7.46459237e-01 )

           Plate number: 5
              Vertex 1: (  -6.78499000e+00   6.22762000e+00   6.02070000e+00 )
              Vertex 2: (  -6.77299000e+00   6.21674000e+00   6.03482000e+00 )
              Vertex 3: (  -6.76768000e+00   6.23701000e+00   6.03019000e+00 )
              Normal:   (  -5.83664048e-01   3.23060196e-01   7.44962005e-01 )

#### Restrictions

       None.

#### Literature_References

       None.

#### Author_and_Institution

       N.J. Bachman        (JPL)
       J. Diaz del Rio     (ODC Space)

#### Version

       -CSPICE Version 1.0.1, 10-AUG-2021 (JDR)

           Edited the header to comply with NAIF standard. Updated
           code example to reduce the number of plates whose vertices are
           shown on output.

       -CSPICE Version 1.0.0, 04-APR-2017 (NJB)

           Removed references to old header files. Updated
           example program.

           DSKLIB_C Version 1.0.1, 22-APR-2014 (NJB)

              The diagram in the -Detailed_Output header section showing the
              contents of the output `plates' array has been corrected.

           DSKLIB_C Version 1.0.0, 04-JUN-2010 (NJB)

#### Index_Entries

       fetch plate data from a type 2 DSK segment

#### Link to routine dskp02_c source file dskp02_c.c

    Fri Dec 31 18:41:05 2021