fish/surf/mapimgpix.c

   1 #include <aros/oldprograms.h>
   2 #include <stdio.h>
   3 #include "mytypes.h"
   4 #include "readilbm.h"
   5
   6 void OutErr(char *);
   7
   8 #define DefRes 2
   9 int MapImageV = DefRes*DefRepV,
  10     MapImageH= DefRes*DefRepH; /* virtual screen size */
  11 static int PixV=DefRes,
  12            PixH=DefRes;  /* true ilbm size in pixels */
  13 short MapRepV = DefRepV,
  14       MapRepH = DefRepH;
  15 static short BytesPerLine;
  16 static unsigned char *Raster= null;
  17 static long MaxShade;
  18 static bool AxisFlipped = DefXYFlip;
  19 /*
  20  * Update the MapImageH and MapImageV variables
  21  */
  22 void PrepImgPix()
  23 {
  24     MapImageV = PixV * MapRepV;
  25     MapImageH = PixH * MapRepH;
  26     if( AxisFlipped ) {
  27         int temp;
  28         temp = MapImageV;
  29         MapImageV = MapImageH;
  30         MapImageH = temp;
  31     }
  32 }
  33 /*
  34  * free up any memory holding mapping image
  35  */
  36 void CloseImgPix()
  37 {
  38         if( Raster) free(Raster);
  39         Raster = null;
  40         PixV = 0xff; PixH = 0xff;
  41         PrepImgPix();
  42 }
  43
  44 /*
  45  * cause x and y axises to be reversed
  46  */
  47 void FlipImgPix( flip )
  48     bool flip;
  49 {
  50     AxisFlipped = flip;
  51     PrepImgPix();
  52 }
  53
  54 /*
  55  * 4 bits per pixel means 2 pixels per byte
  56  */
  57 bool OpenImgPix(sizex, sizey, maxshade)
  58     int sizex, sizey;
  59     short maxshade;
  60 {
  61     CloseImgPix();
  62     if( maxshade == 0 ) {
  63         OutErr("OpenImgPix: got max shade = 0\n");
  64         maxshade = 1;
  65      }
  66     MaxShade = maxshade;
  67     BytesPerLine = (sizex +1)/2;
  68     Raster = (unsigned char *) malloc( BytesPerLine * sizey);
  69     if( !Raster ) {
  70         printf("OpenImgPix: not enough memory\n");
  71         return(false); /* no memory err */
  72     }
  73
  74     PixV = sizey;
  75     PixH = sizex;
  76     PrepImgPix();
  77     return(true);
  78 }
  79
  80 #define CalcByte(cbx,cby) (Raster + ( BytesPerLine * cby ) + (cbx >> 1))
  81
  82
  83 void SetImgPix(x, y, val)
  84     int x, y; /* location */
  85     int val;
  86 {
  87     unsigned char *bite;
  88     unsigned char shade;
  89
  90     if( x > PixH || x < 0 || y > PixV || y < 0 ) {
  91         printf("SetImgPix(%d,%d,%d) out of range\n",x,y,val);
  92         return;
  93     }
  94
  95     if( !Raster) return;
  96     shade = ( (val<< 4)-val)/MaxShade;
  97     bite = CalcByte(x,y);
  98     if( x & 1) {
  99         *bite = (*bite & 0xf) | ( shade <<4 );
 100     }
 101     else {
 102         *bite = (*bite & 0xf0) | shade;
 103     }
 104 }
 105
 106
 107 short GetImgPix(x,y)
 108     int x, y;
 109 {
 110     unsigned char *bite;
 111
 112     if( AxisFlipped ) {
 113         int temp;
 114         temp = x; x = y; y = temp;
 115     }
 116
 117     x %= PixH;
 118     y %= PixV;
 119
 120     if( !Raster ) {
 121         return( (short)(((x ^ y)& 0x10) ? 0xff: 0));
 122     }
 123     bite = CalcByte(x,y);
 124
 125     if( x & 1) {
 126         return((short)(*bite & 0xf0));
 127     }
 128     else {
 129         return( (short)((*bite & 0x0f) <<4));
 130     }
 131 }