rom/graphics/sortglist.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Graphics function SortGList()
   6     Lang: english
   7 */
   8 #include <graphics/gels.h>
   9 #include <graphics/rastport.h>
  10 #include "graphics_intern.h"
  11
  12 /*****************************************************************************
  13
  14     NAME */
  15 #include <proto/graphics.h>
  16
  17         AROS_LH1(void, SortGList,
  18
  19 /*  SYNOPSIS */
  20         AROS_LHA(struct RastPort *, rp, A1),
  21
  22 /*  LOCATION */
  23         struct GfxBase *, GfxBase, 25, Graphics)
  24
  25 /*  FUNCTION
  26         Sort the current gel list by the y and x coordinates of it's
  27         elements.
  28         You have to call this routine prior to calling DoCollision()
  29         of DrawGList or make sure that the list is sorted!
  30
  31     INPUTS
  32         rp  = pointer to RastPort that has an GelsInfo linked to it
  33
  34     RESULT
  35
  36     NOTES
  37
  38     EXAMPLE
  39
  40     BUGS
  41
  42     SEE ALSO
  43         InitGels() DrawGList() DoCollision() graphics/rastport.h
  44
  45     INTERNALS
  46
  47     HISTORY
  48
  49 *****************************************************************************/
  50 {
  51         AROS_LIBFUNC_INIT
  52         AROS_LIBBASE_EXT_DECL(struct GfxBase *,GfxBase)
  53
  54         struct VSprite * CorrectVSprite = rp -> GelsInfo -> gelHead;
  55         struct VSprite * CurVSprite = CorrectVSprite -> NextVSprite;
  56
  57         LONG Coord = JOIN_XY_COORDS( CorrectVSprite -> X, CorrectVSprite -> Y );
  58
  59         while ( NULL != CurVSprite ) {
  60                 LONG NewCoord =  JOIN_XY_COORDS( CurVSprite -> X, CurVSprite -> Y );
  61
  62                 if (0 != CurVSprite->VSBob)
  63                         CurVSprite->VSBob->Flags &= ~BDRAWN;
  64
  65                 if (Coord <= NewCoord) {
  66                         /* sorting is not necessary for this VSprite */
  67                         CorrectVSprite = CurVSprite;
  68                         CurVSprite     = CurVSprite -> NextVSprite;
  69
  70                         Coord = NewCoord;
  71                 } else {
  72                         struct VSprite * tmpVSprite = CorrectVSprite->PrevVSprite;
  73                         /*
  74                            The CurVSprite is at the wrong position. It has to appear
  75                            somewhere earlier in the list.
  76                          */
  77
  78                         /* unlink it from it's current position */
  79                         CorrectVSprite -> NextVSprite = CurVSprite -> NextVSprite;
  80                         if (NULL != CurVSprite -> NextVSprite)
  81                                 CurVSprite -> NextVSprite -> PrevVSprite = CorrectVSprite;
  82
  83                         /* insert CurVSprite at some previous place */
  84
  85                         while ( ( NULL != tmpVSprite ) &&
  86                                  ( JOIN_XY_COORDS(tmpVSprite -> X, tmpVSprite -> Y) > NewCoord ) )
  87                                 tmpVSprite = tmpVSprite -> PrevVSprite;
  88
  89                         if (NULL == tmpVSprite) {
  90                                 /* our CurVSprite becomes the fist one in the list */
  91                                 /* Due to the head VSprite this should never happen!!! */
  92                                 rp->GelsInfo->gelHead->PrevVSprite = CurVSprite;
  93                                 CurVSprite->NextVSprite = rp->GelsInfo->gelHead;
  94                                 CurVSprite->PrevVSprite = NULL;
  95                                 rp->GelsInfo->gelHead   = CurVSprite;
  96                         } else {
  97                                 /* link it into the list *after* the tmpVSprite */
  98                                 CurVSprite->PrevVSprite = tmpVSprite;
  99                                 CurVSprite->NextVSprite = tmpVSprite->NextVSprite;
 100
 101                                 if (NULL != tmpVSprite->NextVSprite)
 102                                         tmpVSprite->NextVSprite->PrevVSprite = CurVSprite;
 103
 104                                 tmpVSprite->NextVSprite = CurVSprite;
 105                         }
 106
 107                         /* set the new CurVSprite */
 108                         CurVSprite = CorrectVSprite -> NextVSprite;
 109                 }
 110         } /* while ( NULL != CurVSprite ) */
 111
 112         rp->GelsInfo->gelTail = CorrectVSprite;
 113
 114         AROS_LIBFUNC_EXIT
 115
 116 } /* SortGList */