16/sod8086/wolfhack.c

   1 // WOLFHACK.C\r
   2 \r
   3 #include "WL_DEF.H"\r
   4 \r
   5 #define MAXVIEWHEIGHT   200\r
   6 \r
   7 int             spanstart[MAXVIEWHEIGHT/2];\r
   8 \r
   9 fixed   stepscale[MAXVIEWHEIGHT/2];\r
  10 fixed   basedist[MAXVIEWHEIGHT/2];\r
  11 \r
  12 extern  char    far     planepics[8192];        // 4k of ceiling, 4k of floor\r
  13 \r
  14 int             halfheight = 0;\r
  15 \r
  16 byte    far *planeylookup[MAXVIEWHEIGHT/2];\r
  17 unsigned        mirrorofs[MAXVIEWHEIGHT/2];\r
  18 \r
  19 fixed   psin, pcos;\r
  20 \r
  21 fixed FixedMul (fixed a, fixed b)\r
  22 {\r
  23         return (a>>8)*(b>>8);\r
  24 }\r
  25 \r
  26 \r
  27 int             mr_rowofs;\r
  28 int             mr_count;\r
  29 int             mr_xstep;\r
  30 int             mr_ystep;\r
  31 int             mr_xfrac;\r
  32 int             mr_yfrac;\r
  33 int             mr_dest;\r
  34 \r
  35 \r
  36 /*\r
  37 ==============\r
  38 =\r
  39 = DrawSpans\r
  40 =\r
  41 = Height ranges from 0 (infinity) to viewheight/2 (nearest)\r
  42 ==============\r
  43 */\r
  44 \r
  45 void DrawSpans (int x1, int x2, int height)\r
  46 {\r
  47         fixed           length;\r
  48         int                     ofs;\r
  49         int                     prestep;\r
  50         fixed           startxfrac, startyfrac;\r
  51 \r
  52         int                     x, startx, count, plane, startplane;\r
  53         byte            far     *toprow, far *dest;\r
  54 \r
  55         toprow = planeylookup[height]+bufferofs;\r
  56         mr_rowofs = mirrorofs[height];\r
  57 \r
  58         mr_xstep = (psin<<1)/height;\r
  59         mr_ystep = (pcos<<1)/height;\r
  60 \r
  61         length = basedist[height];\r
  62         startxfrac = (viewx + FixedMul(length,pcos));\r
  63         startyfrac = (viewy - FixedMul(length,psin));\r
  64 \r
  65 // draw two spans simultaniously\r
  66 \r
  67         plane = startplane = x1&3;\r
  68         prestep = viewwidth/2 - x1;\r
  69         do\r
  70         {\r
  71                 outportb (SC_INDEX+1,1<<plane);\r
  72                 mr_xfrac = startxfrac - (mr_xstep>>2)*prestep;\r
  73                 mr_yfrac = startyfrac - (mr_ystep>>2)*prestep;\r
  74 \r
  75                 startx = x1>>2;\r
  76                 mr_dest = (unsigned)toprow + startx;\r
  77                 mr_count = ((x2-plane)>>2) - startx + 1;\r
  78                 x1++;\r
  79                 prestep--;\r
  80                 if (mr_count)\r
  81                         MapRow ();\r
  82                 plane = (plane+1)&3;\r
  83         } while (plane != startplane);\r
  84 \r
  85 }\r
  86 \r
  87 \r
  88 \r
  89 \r
  90 /*\r
  91 ===================\r
  92 =\r
  93 = SetPlaneViewSize\r
  94 =\r
  95 ===================\r
  96 */\r
  97 \r
  98 void SetPlaneViewSize (void)\r
  99 {\r
 100         int             x,y;\r
 101         byte    far *dest, far *src;\r
 102 \r
 103         halfheight = viewheight>>1;\r
 104 \r
 105 \r
 106         for (y=0 ; y<halfheight ; y++)\r
 107         {\r
 108                 planeylookup[y] = (byte far *)0xa0000000l + (halfheight-1-y)*SCREENBWIDE;;\r
 109                 mirrorofs[y] = (y*2+1)*SCREENBWIDE;\r
 110 \r
 111                 stepscale[y] = y*GLOBAL1/32;\r
 112                 if (y>0)\r
 113                         basedist[y] = GLOBAL1/2*scale/y;\r
 114         }\r
 115 \r
 116         src = PM_GetPage(0);\r
 117         dest = planepics;\r
 118         for (x=0 ; x<4096 ; x++)\r
 119         {\r
 120                 *dest = *src++;\r
 121                 dest += 2;\r
 122         }\r
 123         src = PM_GetPage(1);\r
 124         dest = planepics+1;\r
 125         for (x=0 ; x<4096 ; x++)\r
 126         {\r
 127                 *dest = *src++;\r
 128                 dest += 2;\r
 129         }\r
 130 \r
 131 }\r
 132 \r
 133 \r
 134 /*\r
 135 ===================\r
 136 =\r
 137 = DrawPlanes\r
 138 =\r
 139 ===================\r
 140 */\r
 141 \r
 142 void DrawPlanes (void)\r
 143 {\r
 144         int             height, lastheight;\r
 145         int             x;\r
 146 \r
 147         if (viewheight>>1 != halfheight)\r
 148                 SetPlaneViewSize ();            // screen size has changed\r
 149 \r
 150 \r
 151         psin = viewsin;\r
 152         if (psin < 0)\r
 153                 psin = -(psin&0xffff);\r
 154         pcos = viewcos;\r
 155         if (pcos < 0)\r
 156                 pcos = -(pcos&0xffff);\r
 157 \r
 158 //\r
 159 // loop over all columns\r
 160 //\r
 161         lastheight = halfheight;\r
 162 \r
 163         for (x=0 ; x<viewwidth ; x++)\r
 164         {\r
 165                 height = wallheight[x]>>3;\r
 166                 if (height < lastheight)\r
 167                 {       // more starts\r
 168                         do\r
 169                         {\r
 170                                 spanstart[--lastheight] = x;\r
 171                         } while (lastheight > height);\r
 172                 }\r
 173                 else if (height > lastheight)\r
 174                 {       // draw spans\r
 175                         if (height > halfheight)\r
 176                                 height = halfheight;\r
 177                         for ( ; lastheight < height ; lastheight++)\r
 178                                 DrawSpans (spanstart[lastheight], x-1, lastheight);\r
 179                 }\r
 180         }\r
 181 \r
 182         height = halfheight;\r
 183         for ( ; lastheight < height ; lastheight++)\r
 184                 DrawSpans (spanstart[lastheight], x-1, lastheight);\r
 185 }\r
 186 \r