/* resample.h */

/*
 * Vis5D system for visualizing five dimensional gridded data sets.
 * Copyright (C) 1990 - 2000 Bill Hibbard, Johan Kellum, Brian Paul,
 * Dave Santek, and Andre Battaiola.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * As a special exception to the terms of the GNU General Public
 * License, you are permitted to link Vis5D with (and distribute the
 * resulting source and executables) the LUI library (copyright by
 * Stellar Computer Inc. and licensed for distribution with Vis5D),
 * the McIDAS library, and/or the NetCDF library, where those
 * libraries are governed by the terms of their own licenses.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#ifndef RESAMPLE_H
#define RESAMPLE_H


#include "grid_i.h"


/*
 * A resampler struct carries the information needed to resample a 3-D
 * grid from one projection and VCS to a new projection and VCS.
 * We perform vertical resampling first, then horizontal resampling.
 */
struct resampler {

   struct projection *inproj;        /* Input projection */
   struct vcs *invcs;                /* Input VCS */
   struct projection *outproj;       /* Output projection */
   struct vcs *outvcs;               /* Output VCS */

   /*
    * These values indicate the size of the dynamic arrays below:
    */
   int inR, inC, inL;     /* size of input grid */
   int outR, outC, outL;  /* size of output grid */

   /*
    * For a given level in the output grid, Level indicates which
    * data values to sample in the input grid.  The Coef values are
    * the weights to use in the resampling.  The arrays are also
    * indexed by (row,col) to allow sigma coordinates (relative to
    * topography).
    */
   int DoVertical;        /* Is vertical resampling needed? */
   float *SampLev;        /* SampLev[outL][inR][inC] */

   /*
    * For a given (row,col) in the output grid, RectRow and RectCol
    * indicates which data values to sample in the input grid.  The
    * Coef_s and Coef_t values are the weights to use in the sampling.
    */
   int DoHorizontal;      /* Is horizontal resampling needed? */
   float *SampRow;        /* SampRow[outR][outC] */
   float *SampCol;        /* SampCol[outR][outC] */

   int Guard;             /* how many boundary rows & cols to discard */
};




extern struct resampler *get_resampler( struct projection *inproj,
                                        struct vcs *invcs,
                                        struct projection *outproj,
                                        struct vcs *outvcs,
                                        int outnl );


extern void free_resamplers( void );


extern void resample_vertical( struct resampler *r,
                               float *indata, float *outdata );


extern void resample_horizontal( struct resampler *r,
                                 float *indata, float *outdata );


#endif