Index Page dskz02_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 dskz02_c ( SpiceInt               handle,
                       ConstSpiceDLADescr   * dladsc,
                       SpiceInt             * nv,
                       SpiceInt             * np     )

#### Abstract

       Return plate model size parameters---plate count and
       vertex count---for 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.
       nv         O   Number of vertices.
       np         O   Number of 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.

#### Detailed_Output

       nv             is the number of vertices belonging to
                      the specified plate model.

       np             is the number of plates belonging to the
                      specified plate model.

#### 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.

#### Files

       See input argument `handle'.

#### Particulars

       This routine enables SPICE-based user applications to
       conveniently fetch the plate and vertex counts of a type 2 DSK
       segment.

       See the routine DSKB02 (DSK, fetch type 2 bookkeeping data)
       for an interface that returns all type 2 DSK segment
       bookkeeping data in a single call.

#### 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/32bit
       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, 27-JAN-2016 (NJB)

          Removed references to old header files. Updated
          example program.

       -DSKLIB_C Version 1.0.0, 03-JUN-2010 (NJB)

#### Index_Entries

       fetch model size parameters from a type 2 dsk segment

#### Link to routine dskz02_c source file dskz02_c.c

    Wed Apr  5 17:54:32 2017