rom/graphics/setrgb4cm.c

   1 /*
   2     Copyright © 1995-2012, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Graphics function SetRGB4CM()
   6     Lang: english
   7 */
   8 #include <graphics/view.h>
   9 #include "graphics_intern.h"
  10
  11 /*****************************************************************************
  12
  13     NAME */
  14 #include <proto/graphics.h>
  15
  16         AROS_LH5(void, SetRGB4CM,
  17
  18 /*  SYNOPSIS */
  19         AROS_LHA(struct ColorMap *, cm, A0),
  20         AROS_LHA(WORD             , n , D0),
  21         AROS_LHA(UBYTE            , r , D1),
  22         AROS_LHA(UBYTE            , g , D2),
  23         AROS_LHA(UBYTE            , b , D3),
  24
  25 /*  LOCATION */
  26         struct GfxBase *, GfxBase, 105, Graphics)
  27
  28 /*  FUNCTION
  29         Set one color in the ColorMap.
  30
  31     INPUTS
  32         cm - ColorMap structure obtained via GetColorMap()
  33         n  - the number of the color register to set
  34         r  - red level   (0-15)
  35         g  - green level (0-15)
  36         b  - blue level  (0-15)
  37
  38     RESULT
  39         Store the (r,g,b) triplet at index n in the ColorMap structure.
  40         The changes will not be immediately displayed. Use this function
  41         before linking the ColorMap to a ViewPort.
  42
  43     NOTES
  44
  45     EXAMPLE
  46
  47     BUGS
  48
  49     SEE ALSO
  50         GetColorMap(), SetRGB4(), GetRGB4(), graphics/view.h
  51
  52     INTERNALS
  53         This function depends on the ColorMap->ColorTable structure
  54
  55     HISTORY
  56
  57 *****************************************************************************/
  58 {
  59     AROS_LIBFUNC_INIT
  60
  61     if (NULL != cm && n < cm->Count)
  62     {
  63         /* Preserve the highest nibble. Needed for interoperability
  64            with m68k graphics.library. Exact purpose is currently
  65            unknown - sonic */
  66         UWORD a = cm->ColorTable[n] & 0xF000;
  67
  68         cm->ColorTable[n] = a | (r << 8) | (g <<  4) | b;
  69
  70         if (cm->Type > COLORMAP_TYPE_V1_2)
  71             cm->LowColorBits[n] = 0;
  72     }
  73
  74     AROS_LIBFUNC_EXIT
  75
  76 } /* SetRGB4CM */