engine.c

小型游戏引擎

	if (ynice) tsizy = (picsiz[globalpicnum]>>4);

	fpalookup = (long)FP_OFF(palookup[globalpal]);

	setupvlineasm(globalshiftval);

	x = x1;
	while ((umost[x] > dmost[x]) && (x <= x2)) x++;

	for(;(x<=x2)&&((x+frameoffset)&3);x++)
	{
		y1ve[0] = max(uwal[x],umost[x]);
		y2ve[0] = min(dwal[x],dmost[x]);
		if (y2ve[0] <= y1ve[0]) continue;

		palookupoffse[0] = fpalookup+(getpalookup((long)mulscale16(swal[x],globvis),globalshade)<<8);

		bufplce[0] = lwal[x] + globalxpanning;
		if (bufplce[0] >= tsizx) { if (xnice == 0) bufplce[0] %= tsizx; else bufplce[0] &= tsizx; }
		if (ynice == 0) bufplce[0] *= tsizy; else bufplce[0] <<= tsizy;

		vince[0] = swal[x]*globalyscale;
		vplce[0] = globalzd + vince[0]*(y1ve[0]-globalhoriz+1);

		vlineasm1(vince[0],palookupoffse[0],y2ve[0]-y1ve[0]-1,vplce[0],bufplce[0]+waloff[globalpicnum],x+frameoffset+ylookup[y1ve[0]]);
	}
	for(;x<=x2-3;x+=4)
	{
		bad = 0;
		for(z=3;z>=0;z--)
		{
			y1ve[z] = max(uwal[x+z],umost[x+z]);
			y2ve[z] = min(dwal[x+z],dmost[x+z])-1;
			if (y2ve[z] < y1ve[z]) { bad += pow2char[z]; continue; }

			i = lwal[x+z] + globalxpanning;
			if (i >= tsizx) { if (xnice == 0) i %= tsizx; else i &= tsizx; }
			if (ynice == 0) i *= tsizy; else i <<= tsizy;
			bufplce[z] = waloff[globalpicnum]+i;

			vince[z] = swal[x+z]*globalyscale;
			vplce[z] = globalzd + vince[z]*(y1ve[z]-globalhoriz+1);
		}
		if (bad == 15) continue;

		palookupoffse[0] = fpalookup+(getpalookup((long)mulscale16(swal[x],globvis),globalshade)<<8);
		palookupoffse[3] = fpalookup+(getpalookup((long)mulscale16(swal[x+3],globvis),globalshade)<<8);

		if ((palookupoffse[0] == palookupoffse[3]) && ((bad&0x9) == 0))
		{
			palookupoffse[1] = palookupoffse[0];
			palookupoffse[2] = palookupoffse[0];
		}
		else
		{
			palookupoffse[1] = fpalookup+(getpalookup((long)mulscale16(swal[x+1],globvis),globalshade)<<8);
			palookupoffse[2] = fpalookup+(getpalookup((long)mulscale16(swal[x+2],globvis),globalshade)<<8);
		}

		u4 = max(max(y1ve[0],y1ve[1]),max(y1ve[2],y1ve[3]));
		d4 = min(min(y2ve[0],y2ve[1]),min(y2ve[2],y2ve[3]));

		if ((bad != 0) || (u4 >= d4))
		{
			if (!(bad&1)) prevlineasm1(vince[0],palookupoffse[0],y2ve[0]-y1ve[0],vplce[0],bufplce[0],ylookup[y1ve[0]]+x+frameoffset+0);
			if (!(bad&2)) prevlineasm1(vince[1],palookupoffse[1],y2ve[1]-y1ve[1],vplce[1],bufplce[1],ylookup[y1ve[1]]+x+frameoffset+1);
			if (!(bad&4)) prevlineasm1(vince[2],palookupoffse[2],y2ve[2]-y1ve[2],vplce[2],bufplce[2],ylookup[y1ve[2]]+x+frameoffset+2);
			if (!(bad&8)) prevlineasm1(vince[3],palookupoffse[3],y2ve[3]-y1ve[3],vplce[3],bufplce[3],ylookup[y1ve[3]]+x+frameoffset+3);
			continue;
		}

		if (u4 > y1ve[0]) vplce[0] = prevlineasm1(vince[0],palookupoffse[0],u4-y1ve[0]-1,vplce[0],bufplce[0],ylookup[y1ve[0]]+x+frameoffset+0);
		if (u4 > y1ve[1]) vplce[1] = prevlineasm1(vince[1],palookupoffse[1],u4-y1ve[1]-1,vplce[1],bufplce[1],ylookup[y1ve[1]]+x+frameoffset+1);
		if (u4 > y1ve[2]) vplce[2] = prevlineasm1(vince[2],palookupoffse[2],u4-y1ve[2]-1,vplce[2],bufplce[2],ylookup[y1ve[2]]+x+frameoffset+2);
		if (u4 > y1ve[3]) vplce[3] = prevlineasm1(vince[3],palookupoffse[3],u4-y1ve[3]-1,vplce[3],bufplce[3],ylookup[y1ve[3]]+x+frameoffset+3);

		if (d4 >= u4) vlineasm4(d4-u4+1,ylookup[u4]+x+frameoffset);

		i = x+frameoffset+ylookup[d4+1];
		if (y2ve[0] > d4) prevlineasm1(vince[0],palookupoffse[0],y2ve[0]-d4-1,vplce[0],bufplce[0],i+0);
		if (y2ve[1] > d4) prevlineasm1(vince[1],palookupoffse[1],y2ve[1]-d4-1,vplce[1],bufplce[1],i+1);
		if (y2ve[2] > d4) prevlineasm1(vince[2],palookupoffse[2],y2ve[2]-d4-1,vplce[2],bufplce[2],i+2);
		if (y2ve[3] > d4) prevlineasm1(vince[3],palookupoffse[3],y2ve[3]-d4-1,vplce[3],bufplce[3],i+3);
	}
	for(;x<=x2;x++)
	{
		y1ve[0] = max(uwal[x],umost[x]);
		y2ve[0] = min(dwal[x],dmost[x]);
		if (y2ve[0] <= y1ve[0]) continue;

		palookupoffse[0] = fpalookup+(getpalookup((long)mulscale16(swal[x],globvis),globalshade)<<8);

		bufplce[0] = lwal[x] + globalxpanning;
		if (bufplce[0] >= tsizx) { if (xnice == 0) bufplce[0] %= tsizx; else bufplce[0] &= tsizx; }
		if (ynice == 0) bufplce[0] *= tsizy; else bufplce[0] <<= tsizy;

		vince[0] = swal[x]*globalyscale;
		vplce[0] = globalzd + vince[0]*(y1ve[0]-globalhoriz+1);

		vlineasm1(vince[0],palookupoffse[0],y2ve[0]-y1ve[0]-1,vplce[0],bufplce[0]+waloff[globalpicnum],x+frameoffset+ylookup[y1ve[0]]);
	}
	faketimerhandler();
}


/* this renders masking sprites. See wallscan(). --ryan. */
static void maskwallscan(long x1, long x2,
                         short *uwal, short *dwal,
                         long *swal, long *lwal)
{
	long i, x, startx, xnice, ynice, fpalookup;
	long y1ve[4], y2ve[4], u4, d4, dax, z, p, tsizx, tsizy;
	char bad;

	tsizx = tilesizx[globalpicnum];
	tsizy = tilesizy[globalpicnum];
	setgotpic(globalpicnum);
	if ((tsizx <= 0) || (tsizy <= 0)) return;
	if ((uwal[x1] > ydimen) && (uwal[x2] > ydimen)) return;
	if ((dwal[x1] < 0) && (dwal[x2] < 0)) return;

	if (waloff[globalpicnum] == 0) loadtile(globalpicnum);

	startx = x1;

	xnice = (pow2long[picsiz[globalpicnum]&15] == tsizx);
	if (xnice) tsizx = (tsizx-1);
	ynice = (pow2long[picsiz[globalpicnum]>>4] == tsizy);
	if (ynice) tsizy = (picsiz[globalpicnum]>>4);

	fpalookup = (long)FP_OFF(palookup[globalpal]);

	setupmvlineasm(globalshiftval);

	x = startx;
	while ((startumost[x+windowx1] > startdmost[x+windowx1]) && (x <= x2)) x++;

	p = x+frameoffset;

	for(;(x<=x2)&&(p&3);x++,p++)
	{
		y1ve[0] = max(uwal[x],startumost[x+windowx1]-windowy1);
		y2ve[0] = min(dwal[x],startdmost[x+windowx1]-windowy1);
		if (y2ve[0] <= y1ve[0]) continue;

		palookupoffse[0] = fpalookup+(getpalookup((long)mulscale16(swal[x],globvis),globalshade)<<8);

		bufplce[0] = lwal[x] + globalxpanning;
		if (bufplce[0] >= tsizx) { if (xnice == 0) bufplce[0] %= tsizx; else bufplce[0] &= tsizx; }
		if (ynice == 0) bufplce[0] *= tsizy; else bufplce[0] <<= tsizy;

		vince[0] = swal[x]*globalyscale;
		vplce[0] = globalzd + vince[0]*(y1ve[0]-globalhoriz+1);

		mvlineasm1(vince[0],palookupoffse[0],y2ve[0]-y1ve[0]-1,vplce[0],bufplce[0]+waloff[globalpicnum],p+ylookup[y1ve[0]]);
	}
	for(;x<=x2-3;x+=4,p+=4)
	{
		bad = 0;
		for(z=3,dax=x+3;z>=0;z--,dax--)
		{
			y1ve[z] = max(uwal[dax],startumost[dax+windowx1]-windowy1);
			y2ve[z] = min(dwal[dax],startdmost[dax+windowx1]-windowy1)-1;
			if (y2ve[z] < y1ve[z]) { bad += pow2char[z]; continue; }

			i = lwal[dax] + globalxpanning;
			if (i >= tsizx) { if (xnice == 0) i %= tsizx; else i &= tsizx; }
			if (ynice == 0) i *= tsizy; else i <<= tsizy;
			bufplce[z] = waloff[globalpicnum]+i;

			vince[z] = swal[dax]*globalyscale;
			vplce[z] = globalzd + vince[z]*(y1ve[z]-globalhoriz+1);
		}
		if (bad == 15) continue;

		palookupoffse[0] = fpalookup+(getpalookup((long)mulscale16(swal[x],globvis),globalshade)<<8);
		palookupoffse[3] = fpalookup+(getpalookup((long)mulscale16(swal[x+3],globvis),globalshade)<<8);

		if ((palookupoffse[0] == palookupoffse[3]) && ((bad&0x9) == 0))
		{
			palookupoffse[1] = palookupoffse[0];
			palookupoffse[2] = palookupoffse[0];
		}
		else
		{
			palookupoffse[1] = fpalookup+(getpalookup((long)mulscale16(swal[x+1],globvis),globalshade)<<8);
			palookupoffse[2] = fpalookup+(getpalookup((long)mulscale16(swal[x+2],globvis),globalshade)<<8);
		}

		u4 = max(max(y1ve[0],y1ve[1]),max(y1ve[2],y1ve[3]));
		d4 = min(min(y2ve[0],y2ve[1]),min(y2ve[2],y2ve[3]));

		if ((bad > 0) || (u4 >= d4))
		{
			if (!(bad&1)) mvlineasm1(vince[0],palookupoffse[0],y2ve[0]-y1ve[0],vplce[0],bufplce[0],ylookup[y1ve[0]]+p+0);
			if (!(bad&2)) mvlineasm1(vince[1],palookupoffse[1],y2ve[1]-y1ve[1],vplce[1],bufplce[1],ylookup[y1ve[1]]+p+1);
			if (!(bad&4)) mvlineasm1(vince[2],palookupoffse[2],y2ve[2]-y1ve[2],vplce[2],bufplce[2],ylookup[y1ve[2]]+p+2);
			if (!(bad&8)) mvlineasm1(vince[3],palookupoffse[3],y2ve[3]-y1ve[3],vplce[3],bufplce[3],ylookup[y1ve[3]]+p+3);
			continue;
		}

		if (u4 > y1ve[0]) vplce[0] = mvlineasm1(vince[0],palookupoffse[0],u4-y1ve[0]-1,vplce[0],bufplce[0],ylookup[y1ve[0]]+p+0);
		if (u4 > y1ve[1]) vplce[1] = mvlineasm1(vince[1],palookupoffse[1],u4-y1ve[1]-1,vplce[1],bufplce[1],ylookup[y1ve[1]]+p+1);
		if (u4 > y1ve[2]) vplce[2] = mvlineasm1(vince[2],palookupoffse[2],u4-y1ve[2]-1,vplce[2],bufplce[2],ylookup[y1ve[2]]+p+2);
		if (u4 > y1ve[3]) vplce[3] = mvlineasm1(vince[3],palookupoffse[3],u4-y1ve[3]-1,vplce[3],bufplce[3],ylookup[y1ve[3]]+p+3);

		if (d4 >= u4) mvlineasm4(d4-u4+1,ylookup[u4]+p);

		i = p+ylookup[d4+1];
		if (y2ve[0] > d4) mvlineasm1(vince[0],palookupoffse[0],y2ve[0]-d4-1,vplce[0],bufplce[0],i+0);
		if (y2ve[1] > d4) mvlineasm1(vince[1],palookupoffse[1],y2ve[1]-d4-1,vplce[1],bufplce[1],i+1);
		if (y2ve[2] > d4) mvlineasm1(vince[2],palookupoffse[2],y2ve[2]-d4-1,vplce[2],bufplce[2],i+2);
		if (y2ve[3] > d4) mvlineasm1(vince[3],palookupoffse[3],y2ve[3]-d4-1,vplce[3],bufplce[3],i+3);
	}
	for(;x<=x2;x++,p++)
	{
		y1ve[0] = max(uwal[x],startumost[x+windowx1]-windowy1);
		y2ve[0] = min(dwal[x],startdmost[x+windowx1]-windowy1);
		if (y2ve[0] <= y1ve[0]) continue;

		palookupoffse[0] = fpalookup+(getpalookup((long)mulscale16(swal[x],globvis),globalshade)<<8);

		bufplce[0] = lwal[x] + globalxpanning;
		if (bufplce[0] >= tsizx) { if (xnice == 0) bufplce[0] %= tsizx; else bufplce[0] &= tsizx; }
		if (ynice == 0) bufplce[0] *= tsizy; else bufplce[0] <<= tsizy;

		vince[0] = swal[x]*globalyscale;
		vplce[0] = globalzd + vince[0]*(y1ve[0]-globalhoriz+1);

		mvlineasm1(vince[0],palookupoffse[0],y2ve[0]-y1ve[0]-1,vplce[0],bufplce[0]+waloff[globalpicnum],p+ylookup[y1ve[0]]);
	}
	faketimerhandler();
}

/* renders parallaxed skies/floors  --ryan. */
static void parascan(long dax1, long dax2, long sectnum,
                     char dastat, long bunch)
{
	sectortype *sec;
	long j, k, l, m, n, x, z, wallnum, nextsectnum, globalhorizbak;
	short *topptr, *botptr;

	sectnum = thesector[bunchfirst[bunch]]; sec = &sector[sectnum];

	globalhorizbak = globalhoriz;
	if (parallaxyscale != 65536)
		globalhoriz = mulscale16(globalhoriz-(ydimen>>1),parallaxyscale) + (ydimen>>1);
	globvis = globalpisibility;
	/* globalorientation = 0L; */
	if (sec->visibility != 0) globvis = mulscale4(globvis,(long)((unsigned char)(sec->visibility+16)));

	if (dastat == 0)
	{
		globalpal = sec->ceilingpal;
		globalpicnum = sec->ceilingpicnum;
		globalshade = (long)sec->ceilingshade;
		globalxpanning = (long)sec->ceilingxpanning;
		globalypanning = (long)sec->ceilingypanning;
		topptr = umost;
		botptr = uplc;
	}
	else
	{
		globalpal = sec->floorpal;
		globalpicnum = sec->floorpicnum;
		globalshade = (long)sec->floorshade;
		globalxpanning = (long)sec->floorxpanning;
		globalypanning = (long)sec->floorypanning;
		topptr = dplc;
		botptr = dmost;
	}

	if ((unsigned)globalpicnum >= (unsigned)MAXTILES) globalpicnum = 0;
	if (picanm[globalpicnum]&192) globalpicnum += animateoffs(globalpicnum,(short)sectnum);
	globalshiftval = (picsiz[globalpicnum]>>4);
	if (pow2long[globalshiftval] != tilesizy[globalpicnum]) globalshiftval++;
	globalshiftval = 32-globalshiftval;
	globalzd = (((tilesizy[globalpicnum]>>1)+parallaxyoffs)<<globalshiftval)+(globalypanning<<24);
	globalyscale = (8<<(globalshiftval-19));
	/*if (globalorientation&256) globalyscale = -globalyscale, globalzd = -globalzd;*/

	k = 11 - (picsiz[globalpicnum]&15) - pskybits;
	x = -1;

	for(z=bunchfirst[bunch];z>=0;z=p2[z])
	{
		wallnum = thewall[z]; nextsectnum = wall[wallnum].nextsector;

		if (dastat == 0) j = sector[nextsectnum].ceilingstat;
						else j = sector[nextsectnum].floorstat;

		if ((nextsectnum < 0) || (wall[wallnum].cstat&32) || ((j&1) == 0))
		{
			if (x == -1) x = xb1[z];

			if (parallaxtype == 0)
			{
				n = mulscale16(xdimenrecip,viewingrange);
				for(j=xb1[z];j<=xb2[z];j++)
					lplc[j] = (((mulscale23(j-halfxdimen,n)+globalang)&2047)>>k);
			}
			else
			{
				for(j=xb1[z];j<=xb2[z];j++)
					lplc[j] = ((((long)radarang2[j]+globalang)&2047)>>k);
			}
			if (parallaxtype == 2)
			{
				n = mulscale16(xdimscale,viewingrange);
				for(j=xb1[z];j<=xb2[z];j++)
					swplc[j] = mulscale14(sintable[((long)radarang2[j]+512)&2047],n);
			}
			else
				clearbuf(&swplc[xb1[z]],xb2[z]-xb1[z]+1,mulscale16(xdimscale,viewingrange));
		}
		else if (x >= 0)
		{
			l = globalpicnum; m = (picsiz[globalpicnum]&15);
			globalpicnum = l+pskyoff[lplc[x]>>m];

			if (((lplc[x]^lplc[xb1[z]-1])>>m) == 0)
				wallscan(x,xb1[z]-1,topptr,botptr,swplc,lplc);
			else
			{
				j = x;
				while (x < xb1[z])
				{
					n = l+pskyoff[lplc[x]>>m];
					if (n != globalpicnum)
					{
						wallscan(j,x-1,topptr,botptr,swplc,lplc);
						j = x;
						globalpicnum = n;
					}
					x++;
				}
				if (j < x)
					wallscan(j,x-1,topptr,botptr,swplc,lplc);
			}

			globalpicnum = l;
			x = -1;
		}
	}

	if (x >= 0)
	{
		l = globalpicnum; m = (picsiz[globalpicnum]&15);
		globalpicnum = l+pskyoff[lplc[x]>>m];

		if (((lplc[x]^lplc[xb2[bunchlast[bunch]]])>>m) == 0)
			wallscan(x,xb2[bunchlast[bunch]],topptr,botptr,swplc,lplc);
		else
		{
			j = x;
			while (x <= xb2[bunchlast[bunch]])
			{
				n = l+pskyoff[lplc[x]>>m];
				if (n != globalpicnum)
				{
					wallscan(j,x-1,topptr,botptr,swplc,lplc);
					j = x;
					globalpicnum = n;
				}
				x++;
			}
			if (j <= x)
				wallscan(j,x,topptr,botptr,swplc,lplc);
		}
		globalpicnum = l;
	}
	globalhoriz = globalhorizbak;
}


#define BITSOFPRECISION 3  /* Don't forget to change this in A.ASM also! */
static void grouscan (long dax1, long dax2, long sectnum, char dastat)
{
	long i, j, l, x, y, dx, dy, wx, wy, y1, y2, daz;
	long daslope, dasqr;
	long shoffs, shinc, m1, m2, *mptr1, *mptr2, *nptr1, *nptr2;
	walltype *wal;
	sectortype *sec;

	sec = &sector[sectnum];

	if (dastat == 0)
	{
		if (globalposz <= getceilzofslope(sectnum,globalposx,globalposy))
			return;  /* Back-face culling */
		globalorientation = sec->ceilingstat;
		globalpicnum = sec->ceilingpicnum;
		globalshade = sec->ceilingshade;
		globalpal = sec->ceilingpal;
		daslope = sec->ceilingheinum;
		daz = sec->ceilingz;
	}
	else
	{
		if (globalposz >= getflorzofslope(sectnum,globalposx,globalposy))
			return;  /* Back-face culling */
		globalorientation = sec->floorstat;
		globalpicnum = sec->floorpicnum;
		globalshade = sec->floorshade;
		globalpal = sec->floorpal;
		daslope = sec->floorheinum;
		daz = sec->floorz;
	}

	if ((picanm[globalpicnum]&192) != 0) globalpicnum += animateoffs(globalpicnum,sectnum);
	setgotpic(globalpicnum);
	if ((tilesizx[globalpicnum] <= 0) || (tilesizy[globalpicnum] <= 0)) return;
	if (waloff[globalpicnum] == 0) loadtile(globalpicnum);

	wal = &wall[sec->wallptr];
	wx = wall[wal->point2].x - wal->x;
	wy = wall[wal->point2].y - wal->y;
	dasqr = krecipasm(nsqrtasm(wx*wx+wy*wy));
	i = mulscale21(daslope,dasqr);
	wx *= i; wy *= i;

	globalx = -mulscale19(singlobalang,xdimenrecip);