The Wolfenstein 3D source as originally released.

WOLFSRC/WOLFHACK.C

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