rom/graphics/getsprite.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Graphics function GetSprite()
   6     Lang: english
   7 */
   8 #include <graphics/gfxbase.h>
   9 #include <graphics/sprite.h>
  10 #include <proto/exec.h>
  11 #include "graphics_intern.h"
  12
  13 /*****************************************************************************
  14
  15     NAME */
  16 #include <proto/graphics.h>
  17
  18         AROS_LH2(WORD, GetSprite,
  19
  20 /*  SYNOPSIS */
  21         AROS_LHA(struct SimpleSprite *, sprite, A0),
  22         AROS_LHA(WORD                 , pick  , D0),
  23
  24 /*  LOCATION */
  25         struct GfxBase *, GfxBase, 68, Graphics)
  26
  27 /*  FUNCTION
  28         Try to get a hardware sprite for the simple sprite manager.
  29         There are eight sprites available in the system and by calling
  30         this function you can allocate one for yourself. You have to
  31         call this function before talking to other sprite routines.
  32         If you want a 15 color sprite, you must allocate both sprites
  33         (see the manual!) and set the SPRITE_ATTACHED bit in the
  34         odd sprite's posctldata array.
  35
  36
  37     INPUTS
  38         sprite - pointer to a SimpleSprite structure
  39         pick   - number of the sprite (0-7) of -1 if you just want
  40                  the next available sprite
  41
  42     RESULT
  43         -1 - if the selected sprite is not available (pick was 0-7) or
  44              no further sprites are available (pick was -1). -1 will
  45              also be found in the SimpleSprite structure.
  46         0-7: The sprite number of your allocated sprite. The number will
  47              also be found in the SimpleSprite structure.
  48
  49     NOTES
  50
  51     EXAMPLE
  52
  53     BUGS
  54         On some machines this will never return anything else than -1!
  55
  56     SEE ALSO
  57         FreeSprite(), ChangeSprite(), MoveSprite(), GetSprite(), graphics/sprite.h
  58
  59     INTERNALS
  60
  61     HISTORY
  62
  63 *****************************************************************************/
  64 {
  65   AROS_LIBFUNC_INIT
  66
  67   UBYTE SearchMask;
  68
  69   if (pick > 7 && pick != -1) {
  70     pick = -1;
  71   } else {
  72     /*  let nobody else interrupt us while we're looking for a free
  73      *  sprite
  74      */
  75     Disable();
  76
  77     if (-1 == pick) {
  78       LONG Count = 0;
  79       /* user just wants the next available sprite */
  80       SearchMask = 0x01;
  81
  82       /* look for the first not allocated sprite */
  83       while (0 != (GfxBase->SpriteReserved & SearchMask)  &&  Count < 8) {
  84         SearchMask <<= 1;
  85         Count++;
  86       }
  87
  88       if (8 != Count) {
  89         /* we were able to allocated a free sprite */
  90         /* mark the sprite as reserved for the user */
  91         GfxBase->SpriteReserved |= SearchMask;
  92         pick = Count;
  93       } else {
  94         /* no sprite was available for the user */
  95         pick = -1;
  96       }
  97
  98     } else {
  99       /* user wants one specific sprite */
 100       SearchMask = 0x01 << pick;
 101
 102       /* is that sprite still available? */
 103       if (0 == (GfxBase->SpriteReserved & SearchMask) ) {
 104         /* yes -> mark it as reserved for the user */
 105         GfxBase->SpriteReserved |= SearchMask;
 106       } else {
 107         /* no, it's not available any more */
 108         pick = -1;
 109       }
 110     }
 111     Enable();
 112   }
 113
 114   sprite->num = pick;
 115
 116   return pick;
 117   AROS_LIBFUNC_EXIT
 118 } /* GetSprite */