Index Page dskp02_c
A B C D E F G H I J K L M N O P Q R S T U V W X
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
       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
#### Exceptions
       1) If the input handle is invalid, the error will be diagnosed by
          routines in the call tree of this routine.

       2) If a file read error occurs, the error will be diagnosed by
          routines 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.

       5) If `start' is less than 1 or greater than the number of plates
          in the segment, the error SPICE(INDEXOUTOFRANGE) is signaled.
#### 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
          plate, 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.

             #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 plate.
                ./
                remain = 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 PC/Linux/gcc/64bit
       platform, using a DSK file representing a regular icosahedron,
       the output was:

          Number of vertices:  12
          Number of plates:    20

           Plate number: 1
              Vertex 1: (   0.00000000e+00   0.00000000e+00   1.17557000e+00 )
              Vertex 2: (   1.05146000e+00   0.00000000e+00   5.25731000e-01 )
              Vertex 3: (   3.24920000e-01   1.00000000e+00   5.25731000e-01 )
              Normal:   (   4.91124160e-01   3.56821347e-01   7.94654382e-01 )

           Plate number: 2
              Vertex 1: (   0.00000000e+00   0.00000000e+00   1.17557000e+00 )
              Vertex 2: (   3.24920000e-01   1.00000000e+00   5.25731000e-01 )
              Vertex 3: (  -8.50651000e-01   6.18034000e-01   5.25731000e-01 )
              Normal:   (  -1.87592328e-01   5.77350079e-01   7.94654645e-01 )

              ...

           Plate number: 20
              Vertex 1: (   8.50651000e-01  -6.18034000e-01  -5.25731000e-01 )
              Vertex 2: (   0.00000000e+00   0.00000000e+00  -1.17557000e+00 )
              Vertex 3: (   8.50651000e-01   6.18034000e-01  -5.25731000e-01 )
              Normal:   (   6.07061680e-01   0.00000000e+00  -7.94654715e-01 )
#### Restrictions
       None.
#### Literature_References
       None.
#### Author_and_Institution
       N.J. Bachman    (JPL)
#### Version
       -CSPICE Version 1.1.0, APR-04-2017 (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

    Wed Apr  5 17:54:32 2017