186 lines
3.2 KiB
C
186 lines
3.2 KiB
C
// WOLFHACK.C
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#include "WL_DEF.H"
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#define MAXVIEWHEIGHT 200
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int spanstart[MAXVIEWHEIGHT/2];
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fixed stepscale[MAXVIEWHEIGHT/2];
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fixed basedist[MAXVIEWHEIGHT/2];
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extern char far planepics[8192]; // 4k of ceiling, 4k of floor
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int halfheight = 0;
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byte far *planeylookup[MAXVIEWHEIGHT/2];
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unsigned mirrorofs[MAXVIEWHEIGHT/2];
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fixed psin, pcos;
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fixed FixedMul (fixed a, fixed b)
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{
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return (a>>8)*(b>>8);
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}
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int mr_rowofs;
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int mr_count;
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int mr_xstep;
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int mr_ystep;
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int mr_xfrac;
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int mr_yfrac;
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int mr_dest;
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/*
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==============
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=
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= DrawSpans
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=
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= Height ranges from 0 (infinity) to viewheight/2 (nearest)
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==============
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*/
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void DrawSpans (int x1, int x2, int height)
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{
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fixed length;
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int ofs;
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int prestep;
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fixed startxfrac, startyfrac;
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int x, startx, count, plane, startplane;
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byte far *toprow, far *dest;
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toprow = planeylookup[height]+bufferofs;
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mr_rowofs = mirrorofs[height];
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mr_xstep = (psin<<1)/height;
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mr_ystep = (pcos<<1)/height;
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length = basedist[height];
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startxfrac = (viewx + FixedMul(length,pcos));
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startyfrac = (viewy - FixedMul(length,psin));
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// draw two spans simultaniously
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plane = startplane = x1&3;
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prestep = viewwidth/2 - x1;
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do
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{
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outportb (SC_INDEX+1,1<<plane);
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mr_xfrac = startxfrac - (mr_xstep>>2)*prestep;
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mr_yfrac = startyfrac - (mr_ystep>>2)*prestep;
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startx = x1>>2;
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mr_dest = (unsigned)toprow + startx;
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mr_count = ((x2-plane)>>2) - startx + 1;
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x1++;
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prestep--;
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if (mr_count)
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MapRow ();
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plane = (plane+1)&3;
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} while (plane != startplane);
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}
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/*
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===================
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=
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= SetPlaneViewSize
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=
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===================
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*/
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void SetPlaneViewSize (void)
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{
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int x,y;
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byte far *dest, far *src;
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halfheight = viewheight>>1;
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for (y=0 ; y<halfheight ; y++)
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{
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planeylookup[y] = (byte far *)0xa0000000l + (halfheight-1-y)*SCREENBWIDE;;
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mirrorofs[y] = (y*2+1)*SCREENBWIDE;
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stepscale[y] = y*GLOBAL1/32;
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if (y>0)
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basedist[y] = GLOBAL1/2*scale/y;
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}
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src = PM_GetPage(0);
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dest = planepics;
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for (x=0 ; x<4096 ; x++)
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{
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*dest = *src++;
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dest += 2;
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}
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src = PM_GetPage(1);
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dest = planepics+1;
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for (x=0 ; x<4096 ; x++)
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{
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*dest = *src++;
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dest += 2;
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}
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}
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/*
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===================
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=
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= DrawPlanes
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=
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===================
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*/
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void DrawPlanes (void)
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{
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int height, lastheight;
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int x;
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if (viewheight>>1 != halfheight)
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SetPlaneViewSize (); // screen size has changed
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psin = viewsin;
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if (psin < 0)
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psin = -(psin&0xffff);
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pcos = viewcos;
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if (pcos < 0)
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pcos = -(pcos&0xffff);
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//
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// loop over all columns
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//
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lastheight = halfheight;
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for (x=0 ; x<viewwidth ; x++)
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{
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height = wallheight[x]>>3;
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if (height < lastheight)
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{ // more starts
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do
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{
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spanstart[--lastheight] = x;
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} while (lastheight > height);
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}
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else if (height > lastheight)
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{ // draw spans
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if (height > halfheight)
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height = halfheight;
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for ( ; lastheight < height ; lastheight++)
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DrawSpans (spanstart[lastheight], x-1, lastheight);
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}
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}
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height = halfheight;
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for ( ; lastheight < height ; lastheight++)
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DrawSpans (spanstart[lastheight], x-1, lastheight);
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}
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