shithub: qk1

ref: e65eec36dd5aa7223691f9557e8236ee78fbd1a9
dir: /d_polyse.c/

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#include "quakedef.h"

// !!! if this is changed, it must be changed in asm_draw.h too !!!
typedef struct {
	void			*pdest;
	uzint			*pz;
	int				count;
	byte			*ptex;
	int				sfrac, tfrac, light, zi;
} spanpackage_t;

typedef struct {
	int		isflattop;
	int		numleftedges;
	int		*pleftedgevert0;
	int		*pleftedgevert1;
	int		*pleftedgevert2;
	int		numrightedges;
	int		*prightedgevert0;
	int		*prightedgevert1;
	int		*prightedgevert2;
} edgetable;

// TODO: put in span spilling to shrink list size
// !!! if this is changed, it must be changed in d_polysa.s too !!!
static spanpackage_t a_spans[MAXHEIGHT+1];
									// 1 extra for spanpackage that marks end

static int r_p0[6], r_p1[6], r_p2[6];
static byte *d_pcolormap;
static int d_xdenom;
static edgetable *pedgetable;

static edgetable edgetables[12] = {
	{0, 1, r_p0, r_p2, nil, 2, r_p0, r_p1, r_p2 },
	{0, 2, r_p1, r_p0, r_p2,   1, r_p1, r_p2, nil},
	{1, 1, r_p0, r_p2, nil, 1, r_p1, r_p2, nil},
	{0, 1, r_p1, r_p0, nil, 2, r_p1, r_p2, r_p0 },
	{0, 2, r_p0, r_p2, r_p1,   1, r_p0, r_p1, nil},
	{0, 1, r_p2, r_p1, nil, 1, r_p2, r_p0, nil},
	{0, 1, r_p2, r_p1, nil, 2, r_p2, r_p0, r_p1 },
	{0, 2, r_p2, r_p1, r_p0,   1, r_p2, r_p0, nil},
	{0, 1, r_p1, r_p0, nil, 1, r_p1, r_p2, nil},
	{1, 1, r_p2, r_p1, nil, 1, r_p0, r_p1, nil},
	{1, 1, r_p1, r_p0, nil, 1, r_p2, r_p0, nil},
	{0, 1, r_p0, r_p2, nil, 1, r_p0, r_p1, nil},
};

// FIXME: some of these can become statics
static int a_sstepxfrac, a_tstepxfrac, r_lstepx, a_ststepxwhole;
static int r_sstepx, r_tstepx, r_lstepy, r_sstepy, r_tstepy;
static int r_zistepx, r_zistepy;
static int d_aspancount, d_countextrastep;

static spanpackage_t *d_pedgespanpackage;
static int ystart;
static byte *d_pdest, *d_ptex;
static uzint *d_pz;
static int d_sfrac, d_tfrac, d_light, d_zi;
static int d_ptexextrastep, d_sfracextrastep;
static int d_tfracextrastep, d_lightextrastep, d_pdestextrastep;
static int d_lightbasestep, d_pdestbasestep, d_ptexbasestep;
static int d_sfracbasestep, d_tfracbasestep;
static int d_ziextrastep, d_zibasestep;
static int d_pzextrastep, d_pzbasestep;
static int ubasestep, errorterm, erroradjustup, erroradjustdown;

typedef struct {
	int		quotient;
	int		remainder;
} adivtab_t;

static const adivtab_t adivtab[32*32] = {
#include "adivtab.h"
};

static byte *skintable[MAX_LBM_HEIGHT];
static byte *skinstart;
int skinwidth;

void D_PolysetDrawSpans8 (spanpackage_t *pspanpackage, byte *colormap, byte alpha);
void D_PolysetCalcGradients (int skinwidth);
void D_DrawSubdiv (byte *colormap);
void D_DrawNonSubdiv (void);
void D_PolysetRecursiveTriangle (int *p1, int *p2, int *p3, byte alpha);
void D_PolysetSetEdgeTable (void);
void D_RasterizeAliasPolySmooth (void);
void D_PolysetScanLeftEdge (int height);

/*
================
D_PolysetDraw
================
*/
void D_PolysetDraw (byte *colormap)
{
	if (r_affinetridesc.drawtype)
	{
		D_DrawSubdiv (colormap);
	}
	else
	{
		D_DrawNonSubdiv ();
	}
}


/*
================
D_PolysetDrawFinalVerts
================
*/
void D_PolysetDrawFinalVerts (finalvert_t *fv, int numverts, byte *colormap, byte alpha)
{
	int		i, z;
	uzint	*zbuf;

	for (i=0 ; i<numverts ; i++, fv++)
	{
		// valid triangle coordinates for filling can include the bottom and
		// right clip edges, due to the fill rule; these shouldn't be drawn
		if ((fv->v[0] < r_refdef.vrectright) &&
			(fv->v[1] < r_refdef.vrectbottom))
		{
			z = fv->v[5]>>16;
			zbuf = zspantable[fv->v[1]] + fv->v[0];
			if (z >= *zbuf){
				if(r_drawflags & DRAW_BLEND){
					int n = d_scantable[fv->v[1]] + fv->v[0];
					int pix = skintable[fv->v[3]>>16][fv->v[2]>>16];
					pix = colormap[pix + (fv->v[4] & 0xFF00) ];
					d_viewbuffer[n] = blendalpha(pix, d_viewbuffer[n], alpha);
				}else{
					int		pix;
					*zbuf = z;
					pix = skintable[fv->v[3]>>16][fv->v[2]>>16];
					pix = colormap[pix + (fv->v[4] & 0xFF00) ];
					d_viewbuffer[d_scantable[fv->v[1]] + fv->v[0]] = pix;
				}
			}
		}
	}
}


/*
================
D_DrawSubdiv
================
*/
void D_DrawSubdiv (byte *colormap)
{
	mtriangle_t		*ptri;
	finalvert_t		*pfv, *index0, *index1, *index2;
	int				i;
	int				lnumtriangles;

	pfv = r_affinetridesc.pfinalverts;
	ptri = r_affinetridesc.ptriangles;
	lnumtriangles = r_affinetridesc.numtriangles;

	for (i=0 ; i<lnumtriangles ; i++)
	{
		index0 = pfv + ptri[i].vertindex[0];
		index1 = pfv + ptri[i].vertindex[1];
		index2 = pfv + ptri[i].vertindex[2];

		if (((index0->v[1]-index1->v[1]) *
			 (index0->v[0]-index2->v[0]) -
			 (index0->v[0]-index1->v[0]) *
			 (index0->v[1]-index2->v[1])) >= 0)
		{
			continue;
		}

		d_pcolormap = colormap + (index0->v[4] & 0xFF00);

		if (ptri[i].facesfront)
		{
			D_PolysetRecursiveTriangle(index0->v, index1->v, index2->v, currententity->alpha);
		}
		else
		{
			int		s0, s1, s2;

			s0 = index0->v[2];
			s1 = index1->v[2];
			s2 = index2->v[2];

			if (index0->flags & ALIAS_ONSEAM)
				index0->v[2] += r_affinetridesc.seamfixupX16;
			if (index1->flags & ALIAS_ONSEAM)
				index1->v[2] += r_affinetridesc.seamfixupX16;
			if (index2->flags & ALIAS_ONSEAM)
				index2->v[2] += r_affinetridesc.seamfixupX16;

			D_PolysetRecursiveTriangle(index0->v, index1->v, index2->v, currententity->alpha);

			index0->v[2] = s0;
			index1->v[2] = s1;
			index2->v[2] = s2;
		}
	}
}


/*
================
D_DrawNonSubdiv
================
*/
void D_DrawNonSubdiv (void)
{
	mtriangle_t		*ptri;
	finalvert_t		*pfv, *index0, *index1, *index2;
	int				i;
	int				lnumtriangles;

	pfv = r_affinetridesc.pfinalverts;
	ptri = r_affinetridesc.ptriangles;
	lnumtriangles = r_affinetridesc.numtriangles;

	for (i=0 ; i<lnumtriangles ; i++, ptri++)
	{
		index0 = pfv + ptri->vertindex[0];
		index1 = pfv + ptri->vertindex[1];
		index2 = pfv + ptri->vertindex[2];

		d_xdenom = (index0->v[1]-index1->v[1]) *
				(index0->v[0]-index2->v[0]) -
				(index0->v[0]-index1->v[0])*(index0->v[1]-index2->v[1]);

		if (d_xdenom >= 0)
		{
			continue;
		}

		r_p0[0] = index0->v[0];		// u
		r_p0[1] = index0->v[1];		// v
		r_p0[2] = index0->v[2];		// s
		r_p0[3] = index0->v[3];		// t
		r_p0[4] = index0->v[4];		// light
		r_p0[5] = index0->v[5];		// iz

		r_p1[0] = index1->v[0];
		r_p1[1] = index1->v[1];
		r_p1[2] = index1->v[2];
		r_p1[3] = index1->v[3];
		r_p1[4] = index1->v[4];
		r_p1[5] = index1->v[5];

		r_p2[0] = index2->v[0];
		r_p2[1] = index2->v[1];
		r_p2[2] = index2->v[2];
		r_p2[3] = index2->v[3];
		r_p2[4] = index2->v[4];
		r_p2[5] = index2->v[5];

		if (!ptri->facesfront)
		{
			if (index0->flags & ALIAS_ONSEAM)
				r_p0[2] += r_affinetridesc.seamfixupX16;
			if (index1->flags & ALIAS_ONSEAM)
				r_p1[2] += r_affinetridesc.seamfixupX16;
			if (index2->flags & ALIAS_ONSEAM)
				r_p2[2] += r_affinetridesc.seamfixupX16;
		}

		D_PolysetSetEdgeTable ();
		D_RasterizeAliasPolySmooth ();
	}
}


/*
================
D_PolysetRecursiveTriangle
================
*/
void D_PolysetRecursiveTriangle (int *lp1, int *lp2, int *lp3, byte alpha)
{
	int		*temp;
	int		d;
	int		new[6];
	int		z;
	uzint	*zbuf;

	d = lp2[0] - lp1[0];
	if (d < -1 || d > 1)
		goto split;
	d = lp2[1] - lp1[1];
	if (d < -1 || d > 1)
		goto split;

	d = lp3[0] - lp2[0];
	if (d < -1 || d > 1)
		goto split2;
	d = lp3[1] - lp2[1];
	if (d < -1 || d > 1)
		goto split2;

	d = lp1[0] - lp3[0];
	if (d < -1 || d > 1)
		goto split3;
	d = lp1[1] - lp3[1];
	if (d < -1 || d > 1)
	{
split3:
		temp = lp1;
		lp1 = lp3;
		lp3 = lp2;
		lp2 = temp;

		goto split;
	}

	return;			// entire tri is filled

split2:
	temp = lp1;
	lp1 = lp2;
	lp2 = lp3;
	lp3 = temp;

split:
	// split this edge
	new[0] = (lp1[0] + lp2[0]) >> 1;
	new[1] = (lp1[1] + lp2[1]) >> 1;
	new[2] = (lp1[2] + lp2[2]) >> 1;
	new[3] = (lp1[3] + lp2[3]) >> 1;
	new[5] = (lp1[5] + lp2[5]) >> 1;

	// draw the point if splitting a leading edge
	if (lp2[1] > lp1[1])
		goto nodraw;
	if ((lp2[1] == lp1[1]) && (lp2[0] < lp1[0]))
		goto nodraw;


	z = new[5]>>16;
	zbuf = zspantable[new[1]] + new[0];
	if (z >= *zbuf){
		if(r_drawflags & DRAW_BLEND){
			int n = d_scantable[new[1]] + new[0];
			int pix = d_pcolormap[skintable[new[3]>>16][new[2]>>16]];
			d_viewbuffer[n] = blendalpha(pix, d_viewbuffer[n], alpha);
		}else{
			int		pix;
			*zbuf = z;
			pix = d_pcolormap[skintable[new[3]>>16][new[2]>>16]];
			d_viewbuffer[d_scantable[new[1]] + new[0]] = pix;
		}
	}

nodraw:
	// recursively continue
	D_PolysetRecursiveTriangle (lp3, lp1, new, alpha);
	D_PolysetRecursiveTriangle (lp3, new, lp2, alpha);
}


/*
================
D_PolysetUpdateTables
================
*/
void D_PolysetUpdateTables (void)
{
	int		i;
	byte	*s;

	if (r_affinetridesc.skinwidth != skinwidth ||
		r_affinetridesc.pskin != skinstart)
	{
		skinwidth = r_affinetridesc.skinwidth;
		skinstart = r_affinetridesc.pskin;
		s = skinstart;
		for (i=0 ; i<MAX_LBM_HEIGHT ; i++, s+=skinwidth)
			skintable[i] = s;
	}
}

/*
===================
D_PolysetScanLeftEdge
====================
*/
void D_PolysetScanLeftEdge (int height)
{

	do
	{
		d_pedgespanpackage->pdest = d_pdest;
		d_pedgespanpackage->pz = d_pz;
		d_pedgespanpackage->count = d_aspancount;
		d_pedgespanpackage->ptex = d_ptex;

		d_pedgespanpackage->sfrac = d_sfrac;
		d_pedgespanpackage->tfrac = d_tfrac;

		// FIXME: need to clamp l, s, t, at both ends?
		d_pedgespanpackage->light = d_light;
		d_pedgespanpackage->zi = d_zi;

		d_pedgespanpackage++;

		errorterm += erroradjustup;
		if (errorterm >= 0)
		{
			d_pdest += d_pdestextrastep;
			d_pz += d_pzextrastep;
			d_aspancount += d_countextrastep;
			d_ptex += d_ptexextrastep;
			d_sfrac += d_sfracextrastep;
			d_ptex += d_sfrac >> 16;

			d_sfrac &= 0xFFFF;
			d_tfrac += d_tfracextrastep;
			if (d_tfrac & 0x10000)
			{
				d_ptex += r_affinetridesc.skinwidth;
				d_tfrac &= 0xFFFF;
			}
			d_light += d_lightextrastep;
			d_zi += d_ziextrastep;
			errorterm -= erroradjustdown;
		}
		else
		{
			d_pdest += d_pdestbasestep;
			d_pz += d_pzbasestep;
			d_aspancount += ubasestep;
			d_ptex += d_ptexbasestep;
			d_sfrac += d_sfracbasestep;
			d_ptex += d_sfrac >> 16;
			d_sfrac &= 0xFFFF;
			d_tfrac += d_tfracbasestep;
			if (d_tfrac & 0x10000)
			{
				d_ptex += r_affinetridesc.skinwidth;
				d_tfrac &= 0xFFFF;
			}
			d_light += d_lightbasestep;
			d_zi += d_zibasestep;
		}
	} while (--height);
}


/*
===================
D_PolysetSetUpForLineScan
====================
*/
void D_PolysetSetUpForLineScan(fixed8_t startvertu, fixed8_t startvertv,
		fixed8_t endvertu, fixed8_t endvertv)
{
	double		dm, dn;
	int			tm, tn, n;

	// TODO: implement x86 version

	errorterm = -1;

	tm = endvertu - startvertu;
	tn = endvertv - startvertv;

	if (((tm <= 16) && (tm >= -15)) &&
		((tn <= 16) && (tn >= -15)))
	{
		n = ((tm+15) << 5) + (tn+15);
		ubasestep = adivtab[n].quotient;
		erroradjustup = adivtab[n].remainder;
		erroradjustdown = tn;
	}
	else
	{
		dm = (double)tm;
		dn = (double)tn;

		FloorDivMod (dm, dn, &ubasestep, &erroradjustup);

		erroradjustdown = dn;
	}
}


/*
================
D_PolysetCalcGradients
================
*/
void D_PolysetCalcGradients (int skinwidth)
{
	float	xstepdenominv, ystepdenominv, t0, t1;
	float	p01_minus_p21, p11_minus_p21, p00_minus_p20, p10_minus_p20;

	p00_minus_p20 = r_p0[0] - r_p2[0];
	p01_minus_p21 = r_p0[1] - r_p2[1];
	p10_minus_p20 = r_p1[0] - r_p2[0];
	p11_minus_p21 = r_p1[1] - r_p2[1];

	xstepdenominv = 1.0 / (float)d_xdenom;

	ystepdenominv = -xstepdenominv;

	// ceil () for light so positive steps are exaggerated, negative steps
	// diminished,  pushing us away from underflow toward overflow. Underflow is
	// very visible, overflow is very unlikely, because of ambient lighting
	t0 = r_p0[4] - r_p2[4];
	t1 = r_p1[4] - r_p2[4];
	r_lstepx = (int)
			ceil((t1 * p01_minus_p21 - t0 * p11_minus_p21) * xstepdenominv);
	r_lstepy = (int)
			ceil((t1 * p00_minus_p20 - t0 * p10_minus_p20) * ystepdenominv);

	t0 = r_p0[2] - r_p2[2];
	t1 = r_p1[2] - r_p2[2];
	r_sstepx = (int)((t1 * p01_minus_p21 - t0 * p11_minus_p21) *
			xstepdenominv);
	r_sstepy = (int)((t1 * p00_minus_p20 - t0* p10_minus_p20) *
			ystepdenominv);

	t0 = r_p0[3] - r_p2[3];
	t1 = r_p1[3] - r_p2[3];
	r_tstepx = (int)((t1 * p01_minus_p21 - t0 * p11_minus_p21) *
			xstepdenominv);
	r_tstepy = (int)((t1 * p00_minus_p20 - t0 * p10_minus_p20) *
			ystepdenominv);

	t0 = r_p0[5] - r_p2[5];
	t1 = r_p1[5] - r_p2[5];
	r_zistepx = (int)((t1 * p01_minus_p21 - t0 * p11_minus_p21) *
			xstepdenominv);
	r_zistepy = (int)((t1 * p00_minus_p20 - t0 * p10_minus_p20) *
			ystepdenominv);

	a_sstepxfrac = r_sstepx & 0xFFFF;
	a_tstepxfrac = r_tstepx & 0xFFFF;
	a_ststepxwhole = skinwidth * (r_tstepx >> 16) + (r_sstepx >> 16);
}

/*
================
D_PolysetDrawSpans8
================
*/
void D_PolysetDrawSpans8 (spanpackage_t *pspanpackage, byte *colormap, byte alpha)
{
	int		lcount;
	byte	*lpdest;
	byte	*lptex;
	int		lsfrac, ltfrac;
	int		llight;
	int		lzi;
	uzint	*lpz;

	do
	{
		lcount = d_aspancount - pspanpackage->count;

		errorterm += erroradjustup;
		if (errorterm >= 0)
		{
			d_aspancount += d_countextrastep;
			errorterm -= erroradjustdown;
		}
		else
		{
			d_aspancount += ubasestep;
		}

		if (lcount)
		{
			lpdest = pspanpackage->pdest;
			lptex = pspanpackage->ptex;
			lpz = pspanpackage->pz;
			lsfrac = pspanpackage->sfrac;
			ltfrac = pspanpackage->tfrac;
			llight = pspanpackage->light;
			lzi = pspanpackage->zi;

			do
			{
				if ((lzi >> 16) >= *lpz){
					if(r_drawflags & DRAW_BLEND){
						*lpdest = blendalpha(
							colormap[*lptex + (llight & 0xFF00)],
							*lpdest,
							alpha
						);
					}else{
						*lpdest = colormap[*lptex + (llight & 0xFF00)];
						// gel mapping	*lpdest = gelmap[*lpdest];
						*lpz = lzi >> 16;
					}
				}
				lpdest++;
				lzi += r_zistepx;
				lpz++;
				llight += r_lstepx;
				lptex += a_ststepxwhole;
				lsfrac += a_sstepxfrac;
				lptex += lsfrac >> 16;
				lsfrac &= 0xFFFF;
				ltfrac += a_tstepxfrac;
				if (ltfrac & 0x10000)
				{
					lptex += r_affinetridesc.skinwidth;
					ltfrac &= 0xFFFF;
				}
			} while (--lcount);
		}

		pspanpackage++;
	} while (pspanpackage->count != Q_MININT);
}

/*
================
D_RasterizeAliasPolySmooth
================
*/
void D_RasterizeAliasPolySmooth (void)
{
	int				initialleftheight, initialrightheight;
	int				*plefttop, *prighttop, *pleftbottom, *prightbottom;
	int				working_lstepx, originalcount;

	plefttop = pedgetable->pleftedgevert0;
	prighttop = pedgetable->prightedgevert0;

	pleftbottom = pedgetable->pleftedgevert1;
	prightbottom = pedgetable->prightedgevert1;

	initialleftheight = pleftbottom[1] - plefttop[1];
	initialrightheight = prightbottom[1] - prighttop[1];

	// set the s, t, and light gradients, which are consistent across the triangle
	// because being a triangle, things are affine
	D_PolysetCalcGradients (r_affinetridesc.skinwidth);

	// rasterize the polygon
	// scan out the top (and possibly only) part of the left edge
	d_pedgespanpackage = a_spans;

	ystart = plefttop[1];
	d_aspancount = plefttop[0] - prighttop[0];

	d_ptex = (byte *)r_affinetridesc.pskin + (plefttop[2] >> 16) +
			(plefttop[3] >> 16) * r_affinetridesc.skinwidth;
	d_sfrac = plefttop[2] & 0xFFFF;
	d_tfrac = plefttop[3] & 0xFFFF;
	d_light = plefttop[4];
	d_zi = plefttop[5];

	d_pdest = (byte *)d_viewbuffer +
			ystart * screenwidth + plefttop[0];
	d_pz = d_pzbuffer + ystart * d_zwidth + plefttop[0];

	if (initialleftheight == 1)
	{
		d_pedgespanpackage->pdest = d_pdest;
		d_pedgespanpackage->pz = d_pz;
		d_pedgespanpackage->count = d_aspancount;
		d_pedgespanpackage->ptex = d_ptex;

		d_pedgespanpackage->sfrac = d_sfrac;
		d_pedgespanpackage->tfrac = d_tfrac;

		// FIXME: need to clamp l, s, t, at both ends?
		d_pedgespanpackage->light = d_light;
		d_pedgespanpackage->zi = d_zi;

		d_pedgespanpackage++;
	}
	else
	{
		D_PolysetSetUpForLineScan(plefttop[0], plefttop[1],
							  pleftbottom[0], pleftbottom[1]);

		d_pzbasestep = d_zwidth + ubasestep;
		d_pzextrastep = d_pzbasestep + 1;
		d_pdestbasestep = screenwidth + ubasestep;
		d_pdestextrastep = d_pdestbasestep + 1;

		// TODO: can reuse partial expressions here

		// for negative steps in x along left edge, bias toward overflow rather than
		// underflow (sort of turning the floor () we did in the gradient calcs into
		// ceil (), but plus a little bit)
		if (ubasestep < 0)
			working_lstepx = r_lstepx - 1;
		else
			working_lstepx = r_lstepx;

		d_countextrastep = ubasestep + 1;
		d_ptexbasestep = ((r_sstepy + r_sstepx * ubasestep) >> 16) +
				((r_tstepy + r_tstepx * ubasestep) >> 16) *
				r_affinetridesc.skinwidth;
		d_sfracbasestep = (r_sstepy + r_sstepx * ubasestep) & 0xFFFF;
		d_tfracbasestep = (r_tstepy + r_tstepx * ubasestep) & 0xFFFF;
		d_lightbasestep = r_lstepy + working_lstepx * ubasestep;
		d_zibasestep = r_zistepy + r_zistepx * ubasestep;

		d_ptexextrastep = ((r_sstepy + r_sstepx * d_countextrastep) >> 16) +
				((r_tstepy + r_tstepx * d_countextrastep) >> 16) *
				r_affinetridesc.skinwidth;
		d_sfracextrastep = (r_sstepy + r_sstepx*d_countextrastep) & 0xFFFF;
		d_tfracextrastep = (r_tstepy + r_tstepx*d_countextrastep) & 0xFFFF;
		d_lightextrastep = d_lightbasestep + working_lstepx;
		d_ziextrastep = d_zibasestep + r_zistepx;

		D_PolysetScanLeftEdge (initialleftheight);
	}

	// scan out the bottom part of the left edge, if it exists
	if (pedgetable->numleftedges == 2)
	{
		int		height;

		plefttop = pleftbottom;
		pleftbottom = pedgetable->pleftedgevert2;

		height = pleftbottom[1] - plefttop[1];

		// TODO: make this a function; modularize this function in general

		ystart = plefttop[1];
		d_aspancount = plefttop[0] - prighttop[0];
		d_ptex = (byte *)r_affinetridesc.pskin + (plefttop[2] >> 16) +
				(plefttop[3] >> 16) * r_affinetridesc.skinwidth;
		d_sfrac = 0;
		d_tfrac = 0;
		d_light = plefttop[4];
		d_zi = plefttop[5];

		d_pdest = (byte *)d_viewbuffer + ystart * screenwidth + plefttop[0];
		d_pz = d_pzbuffer + ystart * d_zwidth + plefttop[0];

		if (height == 1)
		{
			d_pedgespanpackage->pdest = d_pdest;
			d_pedgespanpackage->pz = d_pz;
			d_pedgespanpackage->count = d_aspancount;
			d_pedgespanpackage->ptex = d_ptex;

			d_pedgespanpackage->sfrac = d_sfrac;
			d_pedgespanpackage->tfrac = d_tfrac;

			// FIXME: need to clamp l, s, t, at both ends?
			d_pedgespanpackage->light = d_light;
			d_pedgespanpackage->zi = d_zi;
		}
		else
		{
			D_PolysetSetUpForLineScan(plefttop[0], plefttop[1],
								  pleftbottom[0], pleftbottom[1]);

			d_pdestbasestep = screenwidth + ubasestep;
			d_pdestextrastep = d_pdestbasestep + 1;
			d_pzbasestep = d_zwidth + ubasestep;
			d_pzextrastep = d_pzbasestep + 1;

			if (ubasestep < 0)
				working_lstepx = r_lstepx - 1;
			else
				working_lstepx = r_lstepx;

			d_countextrastep = ubasestep + 1;
			d_ptexbasestep = ((r_sstepy + r_sstepx * ubasestep) >> 16) +
					((r_tstepy + r_tstepx * ubasestep) >> 16) *
					r_affinetridesc.skinwidth;
			d_sfracbasestep = (r_sstepy + r_sstepx * ubasestep) & 0xFFFF;
			d_tfracbasestep = (r_tstepy + r_tstepx * ubasestep) & 0xFFFF;
			d_lightbasestep = r_lstepy + working_lstepx * ubasestep;
			d_zibasestep = r_zistepy + r_zistepx * ubasestep;

			d_ptexextrastep = ((r_sstepy + r_sstepx * d_countextrastep) >> 16) +
					((r_tstepy + r_tstepx * d_countextrastep) >> 16) *
					r_affinetridesc.skinwidth;
			d_sfracextrastep = (r_sstepy+r_sstepx*d_countextrastep) & 0xFFFF;
			d_tfracextrastep = (r_tstepy+r_tstepx*d_countextrastep) & 0xFFFF;
			d_lightextrastep = d_lightbasestep + working_lstepx;
			d_ziextrastep = d_zibasestep + r_zistepx;

			D_PolysetScanLeftEdge (height);
		}
	}

	// scan out the top (and possibly only) part of the right edge, updating the
	// count field
	d_pedgespanpackage = a_spans;

	D_PolysetSetUpForLineScan(prighttop[0], prighttop[1],
						  prightbottom[0], prightbottom[1]);
	d_aspancount = 0;
	d_countextrastep = ubasestep + 1;
	originalcount = a_spans[initialrightheight].count;
	a_spans[initialrightheight].count = Q_MININT; // mark end of the spanpackages
	D_PolysetDrawSpans8 (a_spans, currententity->colormap, currententity->alpha);

	// scan out the bottom part of the right edge, if it exists
	if (pedgetable->numrightedges == 2)
	{
		int				height;
		spanpackage_t	*pstart;

		pstart = a_spans + initialrightheight;
		pstart->count = originalcount;

		d_aspancount = prightbottom[0] - prighttop[0];

		prighttop = prightbottom;
		prightbottom = pedgetable->prightedgevert2;

		height = prightbottom[1] - prighttop[1];

		D_PolysetSetUpForLineScan(prighttop[0], prighttop[1],
							  prightbottom[0], prightbottom[1]);

		d_countextrastep = ubasestep + 1;
		a_spans[initialrightheight + height].count = Q_MININT;
											// mark end of the spanpackages
		D_PolysetDrawSpans8 (pstart, currententity->colormap, currententity->alpha);
	}
}


/*
================
D_PolysetSetEdgeTable
================
*/
void D_PolysetSetEdgeTable (void)
{
	int			edgetableindex;

	edgetableindex = 0;	// assume the vertices are already in
						//  top to bottom order

	// determine which edges are right & left, and the order in which
	// to rasterize them
	if (r_p0[1] >= r_p1[1])
	{
		if (r_p0[1] == r_p1[1])
		{
			if (r_p0[1] < r_p2[1])
				pedgetable = &edgetables[2];
			else
				pedgetable = &edgetables[5];

			return;
		}
		else
		{
			edgetableindex = 1;
		}
	}

	if (r_p0[1] == r_p2[1])
	{
		if (edgetableindex)
			pedgetable = &edgetables[8];
		else
			pedgetable = &edgetables[9];

		return;
	}
	else if (r_p1[1] == r_p2[1])
	{
		if (edgetableindex)
			pedgetable = &edgetables[10];
		else
			pedgetable = &edgetables[11];

		return;
	}

	if (r_p0[1] > r_p2[1])
		edgetableindex += 2;

	if (r_p1[1] > r_p2[1])
		edgetableindex += 4;

	pedgetable = &edgetables[edgetableindex];
}