/* 
   ======================================================================
   Header for N-way out-of-core merge sort of precomputed photon
   contributions.
   
   Roland Schregle (roland.schregle@{hslu.ch, gmail.com})
   (c) Lucerne University of Applied Sciences and Arts,
       supported by the Swiss National Science Foundation 
       (SNSF #179067, "Light Fields for Spatio-Temporal Glare Assessment")   
   ======================================================================   
   
   $Id$
*/


#ifndef _PMAPCONTRIB_SORT_H
   #define _PMAPCONTRIB_SORT_H
   
   #include "pmapdata.h"


   int contribPhotonSort (
      const PhotonMap *pmap, FILE *leafFile, FVECT bbOrg, RREAL bbSize, 
      unsigned numBlk, unsigned long blkSize, unsigned numProc
   );
   /* Sort photons and their corresponding binned contributions by
    * subdividing input files into small blocks, sorting these in-core, and
    * merging them out-of-core via a priority queue.  This code is adapted
    * from oocsort.{h,c}
    *
    * The sort is implemented as a recursive (numBlk)-way sort; the input
    * files are successively split into numBlk smaller blocks until these
    * are of size <= blkSize, i.e.  small enough for in-core sorting, then
    * merging the sorted blocks as the stack unwinds.  The in-core sort is
    * parallelised over numProc processes.
    *
    * Parameters are as follows:
    * pmap        Photon Map with opened photon heap and precomputed 
    *             contributions
    * leafFile    Opened output file for sorted photons (=OOC octree leaves)
    * numBlk      Number of blocks to divide into / merge from 
    * blkSize     Max block size and size of in-core sort buffer, in bytes 
    * numProc     Number of parallel processes for in-core sort 
    * bbOrg       Origin of bounding box containing photons
    * bbSize      Extent of bounding box containing photons
    */
#endif