d_scan.c

/*
Copyright (C) 1996-1997 Id Software, Inc.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// d_scan.c
//
// Portable C scan-level rasterization code, all pixel depths.

#include "quakedef.h"
//#include "r_local.h"
#include "d_local.h"

unsigned char	*r_turb_pbase, *r_turb_pdest;
fixed16_t		r_turb_s, r_turb_t, r_turb_sstep, r_turb_tstep;
int				*r_turb_turb;
int				r_turb_spancount;

void D_DrawTurbulent8Span (void);


/*
=============
D_WarpScreen

// this performs a slight compression of the screen at the same time as
// the sine warp, to keep the edges from wrapping
=============
*/
void D_WarpScreen (void)
{
	int		w, h;
	int		u,v;
	byte	*dest;
	int		*turb;
	int		*col;
	byte	**row;
	byte	*rowptr[MAXHEIGHT+(AMP2*2)];
	int		column[MAXWIDTH+(AMP2*2)];
	float	wratio, hratio;

	w = r_refdef.vrect.width;
	h = r_refdef.vrect.height;

	wratio = w / (float)scr_vrect.width;
	hratio = h / (float)scr_vrect.height;

	for (v=0 ; v<scr_vrect.height+AMP2*2 ; v++)
		rowptr[v] = d_viewbuffer + (r_refdef.vrect.y * screenwidth) + (screenwidth * (int)((float)v * hratio * h / (h + AMP2 * 2)));

	for (u=0 ; u<scr_vrect.width+AMP2*2 ; u++)
		column[u] = r_refdef.vrect.x + (int)((float)u * wratio * w / (w + AMP2 * 2));

	turb = intsintable + ((int)(cl.time*SPEED)&(CYCLE-1));
	dest = vid.buffer + scr_vrect.y * vid.rowbytes + scr_vrect.x;

	for (v=0 ; v<scr_vrect.height ; v++, dest += vid.rowbytes)
	{
		col = &column[turb[v]];
		row = &rowptr[v];

		for (u=0 ; u<scr_vrect.width ; u+=4)
		{
			dest[u+0] = row[turb[u+0]][col[u+0]];
			dest[u+1] = row[turb[u+1]][col[u+1]];
			dest[u+2] = row[turb[u+2]][col[u+2]];
			dest[u+3] = row[turb[u+3]][col[u+3]];
		}
	}
}


#ifdef SUPPORTS_SW_WATERALPHA
/*
=============
D_DrawTurbulent8SpanC
=============
*/
void D_DrawTurbulent8SpanC (void)
{
//	int		sturb, tturb;

	do
	{
#define sturb (((r_turb_s + r_turb_turb[(r_turb_t>>16)&(CYCLE-1)])>>16)&63) // Manoel Kasimier - edited
#define tturb (((r_turb_t + r_turb_turb[(r_turb_s>>16)&(CYCLE-1)])>>16)&63) // Manoel Kasimier - edited
		*r_turb_pdest++ = *(r_turb_pbase + (tturb<<6) + sturb);
		r_turb_s += r_turb_sstep;
		r_turb_t += r_turb_tstep;
	} while (--r_turb_spancount > 0);
#undef sturb
#undef tturb
}

#else
#if	!id386

/*
=============
D_DrawTurbulent8SpanC
=============
*/
void D_DrawTurbulent8SpanC (void)
{
	int		sturb, tturb;

	do
	{
		sturb = ((r_turb_s + r_turb_turb[(r_turb_t>>16)&(CYCLE-1)])>>16)&63;
		tturb = ((r_turb_t + r_turb_turb[(r_turb_s>>16)&(CYCLE-1)])>>16)&63;
		*r_turb_pdest++ = *(r_turb_pbase + (tturb<<6) + sturb);
		r_turb_s += r_turb_sstep;
		r_turb_t += r_turb_tstep;
	} while (--r_turb_spancount > 0);
}

#endif // NO_ASSEMBLY (formerly !id386)
#endif // NO SW_WATERALPHA

/*
=============
Turbulent8
=============
*/
void Turbulent8 (espan_t *pspan)
{
	int				count;
	int				izi, izistep, izistep2, sturb, tturb, teste; // Manoel Kasimier - translucent water
	short			*pz; // Manoel Kasimier - translucent water
	fixed16_t		snext, tnext;
	float			sdivz, tdivz, zi, z, du, dv, spancountminus1;
	float			sdivz16stepu, tdivz16stepu, zi16stepu;

	r_turb_turb = sintable + ((int)(cl.time*SPEED)&(CYCLE-1));

	r_turb_sstep = 0;	// keep compiler happy
	r_turb_tstep = 0;	// ditto

	r_turb_pbase = (unsigned char *)cacheblock;

	sdivz16stepu = d_sdivzstepu * 16;
	tdivz16stepu = d_tdivzstepu * 16;
	zi16stepu = d_zistepu * 16;

#ifdef SUPPORTS_SW_WATERALPHA
	// Manoel Kasimier - translucent water - begin
// we count on FP exceptions being turned off to avoid range problems
	izistep = (int)(d_zistepu * 0x8000 * 0x10000);
#if 1
	izistep2 = izistep*2;
#else
	izistep2 = izistep*4;
#endif
	// Manoel Kasimier - translucent water - end
#endif
	do
	{
		r_turb_pdest = (unsigned char *)((byte *)d_viewbuffer + (screenwidth * pspan->v) + pspan->u);
#ifdef SUPPORTS_SW_WATERALPHA
		pz = d_pzbuffer + (d_zwidth * pspan->v) + pspan->u; // Manoel Kasimier - translucent water
#endif

		count = pspan->count;

	// calculate the initial s/z, t/z, 1/z, s, and t and clamp
		du = (float)pspan->u;
		dv = (float)pspan->v;

		sdivz = d_sdivzorigin + dv*d_sdivzstepv + du*d_sdivzstepu;
		tdivz = d_tdivzorigin + dv*d_tdivzstepv + du*d_tdivzstepu;
		zi = d_ziorigin + dv*d_zistepv + du*d_zistepu;
		z = (float)0x10000 / zi;	// prescale to 16.16 fixed-point
#ifdef SUPPORTS_SW_WATERALPHA
	// we count on FP exceptions being turned off to avoid range problems // Manoel Kasimier - translucent water
		izi = (int)(zi * 0x8000 * 0x10000); // Manoel Kasimier - translucent water
#endif

		r_turb_s = (int)(sdivz * z) + sadjust;
		if (r_turb_s > bbextents)
			r_turb_s = bbextents;
		else if (r_turb_s < 0)
			r_turb_s = 0;

		r_turb_t = (int)(tdivz * z) + tadjust;
		if (r_turb_t > bbextentt)
			r_turb_t = bbextentt;
		else if (r_turb_t < 0)
			r_turb_t = 0;

		do
		{
		// calculate s and t at the far end of the span
			if (count >= 16)
				r_turb_spancount = 16;
			else
				r_turb_spancount = count;

			count -= r_turb_spancount;

			if (count)
			{
			// calculate s/z, t/z, zi->fixed s and t at far end of span,
			// calculate s and t steps across span by shifting
				sdivz += sdivz16stepu;
				tdivz += tdivz16stepu;
				zi += zi16stepu;
				z = (float)0x10000 / zi;	// prescale to 16.16 fixed-point

				snext = (int)(sdivz * z) + sadjust;
				if (snext > bbextents)
					snext = bbextents;
				else if (snext < 16)
					snext = 16;	// prevent round-off error on <0 steps from
								//  from causing overstepping & running off the
								//  edge of the texture

				tnext = (int)(tdivz * z) + tadjust;
				if (tnext > bbextentt)
					tnext = bbextentt;
				else if (tnext < 16)
					tnext = 16;	// guard against round-off error on <0 steps

				r_turb_sstep = (snext - r_turb_s) >> 4;
				r_turb_tstep = (tnext - r_turb_t) >> 4;
			}
			else
			{
			// calculate s/z, t/z, zi->fixed s and t at last pixel in span (so
			// can't step off polygon), clamp, calculate s and t steps across
			// span by division, biasing steps low so we don't run off the
			// texture
				spancountminus1 = (float)(r_turb_spancount - 1);
				sdivz += d_sdivzstepu * spancountminus1;
				tdivz += d_tdivzstepu * spancountminus1;
				zi += d_zistepu * spancountminus1;
				z = (float)0x10000 / zi;	// prescale to 16.16 fixed-point
				snext = (int)(sdivz * z) + sadjust;
				if (snext > bbextents)
					snext = bbextents;
				else if (snext < 16)
					snext = 16;	// prevent round-off error on <0 steps from
								//  from causing overstepping & running off the
								//  edge of the texture

				tnext = (int)(tdivz * z) + tadjust;
				if (tnext > bbextentt)
					tnext = bbextentt;
				else if (tnext < 16)
					tnext = 16;	// guard against round-off error on <0 steps

				if (r_turb_spancount > 1)
				{
					r_turb_sstep = (snext - r_turb_s) / (r_turb_spancount - 1);
					r_turb_tstep = (tnext - r_turb_t) / (r_turb_spancount - 1);
				}
			}

			r_turb_s = r_turb_s & ((CYCLE<<16)-1);
			r_turb_t = r_turb_t & ((CYCLE<<16)-1);

#ifdef SUPPORTS_SW_WATERALPHA
			// Manoel Kasimier - translucent water - begin
			if (r_drawwater)
			{
				// r_wateralpha*10: 1&2=25% 3&4=33% 5&6=50% 7&8&9=66%
				if (r_wateralpha.value <= 0.25) // 25%
				{
					teste = ((((int)r_turb_pdest-(int)d_viewbuffer) / screenwidth)+1) & 1;
					if (teste) // 25% transparency
					{
#if 1
stipple:
						if (!(((int)r_turb_pdest + teste) & 1)) // if we are in the wrong pixel,
						{
							if (r_turb_spancount == 1)
								goto end_of_loop;
							// this is not working the way it should. it's drawing 1 pixel outside of the screen.
							// advance one pixel
							*r_turb_pdest++;
							izi += izistep;
							pz++;
							r_turb_s += r_turb_sstep;
							r_turb_t += r_turb_tstep;
							r_turb_spancount = (r_turb_spancount/2); // -1
						}
						else
							r_turb_spancount = (r_turb_spancount+1)/2;
						// multiply steps by 2
						r_turb_sstep*=2;
						r_turb_tstep*=2;
						do
						{
							#define sturb2 (((r_turb_s + r_turb_turb[(r_turb_t>>16)&(CYCLE-1)])>>16)&63)
							#define tturb2 (((r_turb_t + r_turb_turb[(r_turb_s>>16)&(CYCLE-1)])>>16)&63)
							if (*pz <= (izi >> 16))
								*r_turb_pdest = *(r_turb_pbase + (tturb2<<6) + sturb2);
							// advance two pixels
							r_turb_pdest += 2;
							pz += 2;
							izi += izistep2;
							r_turb_s += r_turb_sstep;
							r_turb_t += r_turb_tstep;
						}
						while (--r_turb_spancount > 0);
#else
						stipple:
						if (!(((int)r_turb_pdest + teste) & 1)) // if we are in the wrong pixel,
						{
							if (r_turb_spancount == 1)
								goto end_of_loop;
							// this is not working the way it should. it's drawing 1 pixel outside of the screen.
							// advance one pixel
							*r_turb_pdest++;
							izi += izistep;
							pz++;
							r_turb_s += r_turb_sstep;
							r_turb_t += r_turb_tstep;
							r_turb_spancount = (r_turb_spancount/4); // -1
						}
						else
							r_turb_spancount = (r_turb_spancount+1)/4;
						// multiply steps by 4
						r_turb_sstep*=4;
						r_turb_tstep*=4;
						do
						{
							#define sturb2 (((r_turb_s + r_turb_turb[(r_turb_t>>16)&(CYCLE-1)])>>16)&63)
							#define tturb2 (((r_turb_t + r_turb_turb[(r_turb_s>>16)&(CYCLE-1)])>>16)&63)
							if (*pz <= (izi >> 16))
								*r_turb_pdest = *(r_turb_pbase + (tturb2<<6) + sturb2);
							// advance four pixels
							r_turb_pdest += 4;
							pz += 4;
							izi += izistep2;
							r_turb_s += r_turb_sstep;
							r_turb_t += r_turb_tstep;
						}
						while (--r_turb_spancount > 0);
#endif
					}

				}
				else if (r_wateralpha.value < 0.66) // 50%
				{
					teste = ((((int)r_turb_pdest-(int)d_viewbuffer) / screenwidth)+1) & 1;
					goto stipple;
				}
#if 0
				else //if (r_wateralpha.value >= 0.66 && alphamap) // 66%
				{
					do
					{
						if (*pz <= (izi >> 16))
						{
							sturb = ((r_turb_s + r_turb_turb[(r_turb_t>>16)&(CYCLE-1)])>>16)&63;
							tturb = ((r_turb_t + r_turb_turb[(r_turb_s>>16)&(CYCLE-1)])>>16)&63;
							#define temp *(r_turb_pbase + (tturb<<6) + sturb)
							*r_turb_pdest = alphamap[*r_turb_pdest + temp*256];
						}
						*r_turb_pdest++;
						izi += izistep;
						pz++;
						r_turb_s += r_turb_sstep;
						r_turb_t += r_turb_tstep;
					} while (--r_turb_spancount > 0);
				}
#endif
			}

			else
			// Manoel Kasimier - translucent water - end
			D_DrawTurbulent8SpanC ();

end_of_loop: // Manoel Kasimier - translucent water
#endif
			r_turb_s = snext;
			r_turb_t = tnext;

		} while (count > 0);

	} while ((pspan = pspan->pnext) != NULL);
}


#if	!id386

/*
=============
D_DrawSpans8
=============
*/
void D_DrawSpans8 (espan_t *pspan)
{
	int				count, spancount;
	unsigned char	*pbase, *pdest;
	fixed16_t		s, t, snext, tnext, sstep, tstep;
	float			sdivz, tdivz, zi, z, du, dv, spancountminus1;
	float			sdivz8stepu, tdivz8stepu, zi8stepu;

	sstep = 0;	// keep compiler happy
	tstep = 0;	// ditto

	pbase = (unsigned char *)cacheblock;

	sdivz8stepu = d_sdivzstepu * 8;
	tdivz8stepu = d_tdivzstepu * 8;
	zi8stepu = d_zistepu * 8;

	do
	{
		pdest = (unsigned char *)((byte *)d_viewbuffer + (screenwidth * pspan->v) + pspan->u);

		count = pspan->count;

	// calculate the initial s/z, t/z, 1/z, s, and t and clamp
		du = (float)pspan->u;
		dv = (float)pspan->v;

		sdivz = d_sdivzorigin + dv*d_sdivzstepv + du*d_sdivzstepu;
		tdivz = d_tdivzorigin + dv*d_tdivzstepv + du*d_tdivzstepu;
		zi = d_ziorigin + dv*d_zistepv + du*d_zistepu;
		z = (float)0x10000 / zi;	// prescale to 16.16 fixed-point

		s = (int)(sdivz * z) + sadjust;
		if (s > bbextents)
			s = bbextents;
		else if (s < 0)
			s = 0;

		t = (int)(tdivz * z) + tadjust;
		if (t > bbextentt)
			t = bbextentt;
		else if (t < 0)
			t = 0;

		do
		{
		// calculate s and t at the far end of the span
			if (count >= 8)
				spancount = 8;
			else
				spancount = count;

			count -= spancount;

			if (count)
			{
			// calculate s/z, t/z, zi->fixed s and t at far end of span,
			// calculate s and t steps across span by shifting
				sdivz += sdivz8stepu;
				tdivz += tdivz8stepu;
				zi += zi8stepu;
				z = (float)0x10000 / zi;	// prescale to 16.16 fixed-point

				snext = (int)(sdivz * z) + sadjust;
				if (snext > bbextents)
					snext = bbextents;
				else if (snext < 8)
					snext = 8;	// prevent round-off error on <0 steps from
								//  from causing overstepping & running off the
								//  edge of the texture

				tnext = (int)(tdivz * z) + tadjust;
				if (tnext > bbextentt)
					tnext = bbextentt;
				else if (tnext < 8)
					tnext = 8;	// guard against round-off error on <0 steps

				sstep = (snext - s) >> 3;
				tstep = (tnext - t) >> 3;
			}
			else
			{
			// calculate s/z, t/z, zi->fixed s and t at last pixel in span (so
			// can't step off polygon), clamp, calculate s and t steps across
			// span by division, biasing steps low so we don't run off the
			// texture
				spancountminus1 = (float)(spancount - 1);
				sdivz += d_sdivzstepu * spancountminus1;
				tdivz += d_tdivzstepu * spancountminus1;
				zi += d_zistepu * spancountminus1;
				z = (float)0x10000 / zi;	// prescale to 16.16 fixed-point
				snext = (int)(sdivz * z) + sadjust;
				if (snext > bbextents)
					snext = bbextents;
				else if (snext < 8)
					snext = 8;	// prevent round-off error on <0 steps from
								//  from causing overstepping & running off the
								//  edge of the texture

				tnext = (int)(tdivz * z) + tadjust;
				if (tnext > bbextentt)
					tnext = bbextentt;
				else if (tnext < 8)
					tnext = 8;	// guard against round-off error on <0 steps

				if (spancount > 1)
				{
					sstep = (snext - s) / (spancount - 1);
					tstep = (tnext - t) / (spancount - 1);
				}
			}

			do
			{
				*pdest++ = *(pbase + (s >> 16) + (t >> 16) * cachewidth);
				s += sstep;
				t += tstep;
			} while (--spancount > 0);

			s = snext;
			t = tnext;

		} while (count > 0);

	} while ((pspan = pspan->pnext) != NULL);
}

#endif


#if	!id386

/*
=============
D_DrawZSpans
=============
*/
void D_DrawZSpans (espan_t *pspan)
{
	int				count, doublecount, izistep, izi;
	short			*pdest;
	unsigned		ltemp;
	double			zi;
	float			du, dv;

// FIXME: check for clamping/range problems
// we count on FP exceptions being turned off to avoid range problems
	izistep = (int)(d_zistepu * 0x8000 * 0x10000);

	do
	{
		pdest = d_pzbuffer + (d_zwidth * pspan->v) + pspan->u;

		count = pspan->count;

	// calculate the initial 1/z
		du = (float)pspan->u;
		dv = (float)pspan->v;

		zi = d_ziorigin + dv*d_zistepv + du*d_zistepu;
	// we count on FP exceptions being turned off to avoid range problems
		izi = (int)(zi * 0x8000 * 0x10000);

		if ((long)pdest & 0x02)
		{
			*pdest++ = (short)(izi >> 16);
			izi += izistep;
			count--;
		}

		if ((doublecount = count >> 1) > 0)
		{
			do
			{
				ltemp = izi >> 16;
				izi += izistep;
				ltemp |= izi & 0xFFFF0000;
				izi += izistep;
				*(int *)pdest = ltemp;
				pdest += 2;
			} while (--doublecount > 0);
		}

		if (count & 1)
			*pdest = (short)(izi >> 16);

	} while ((pspan = pspan->pnext) != NULL);
}

#endif