r_poly.c

Quake 2 Source code for students by Theerthan You can also download from idsoftwares.com

/*
Copyright (C) 1997-2001 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.

*/
#include <assert.h>
#include "r_local.h"

#define AFFINE_SPANLET_SIZE      16
#define AFFINE_SPANLET_SIZE_BITS 4

typedef struct
{
	byte     *pbase, *pdest;
	short	 *pz;
	fixed16_t s, t;
	fixed16_t sstep, tstep;
	int       izi, izistep, izistep_times_2;
	int       spancount;
	unsigned  u, v;
} spanletvars_t;

spanletvars_t s_spanletvars;

static int r_polyblendcolor;

static espan_t	*s_polygon_spans;

polydesc_t	r_polydesc;

msurface_t *r_alpha_surfaces;

extern int *r_turb_turb;

static int		clip_current;
vec5_t	r_clip_verts[2][MAXWORKINGVERTS+2];

static int		s_minindex, s_maxindex;

static void R_DrawPoly( int iswater );

/*
** R_DrawSpanletOpaque
*/
void R_DrawSpanletOpaque( void )
{
	unsigned btemp;

	do
	{
		unsigned ts, tt;

		ts = s_spanletvars.s >> 16;
		tt = s_spanletvars.t >> 16;

		btemp = *(s_spanletvars.pbase + (ts) + (tt) * cachewidth);
		if (btemp != 255)
		{
			if (*s_spanletvars.pz <= (s_spanletvars.izi >> 16))
			{
				*s_spanletvars.pz    = s_spanletvars.izi >> 16;
				*s_spanletvars.pdest = btemp;
			}
		}

		s_spanletvars.izi += s_spanletvars.izistep;
		s_spanletvars.pdest++;
		s_spanletvars.pz++;
		s_spanletvars.s += s_spanletvars.sstep;
		s_spanletvars.t += s_spanletvars.tstep;
	} while (--s_spanletvars.spancount > 0);
}

/*
** R_DrawSpanletTurbulentStipple33
*/
void R_DrawSpanletTurbulentStipple33( void )
{
	unsigned btemp;
	int	     sturb, tturb;
	byte    *pdest = s_spanletvars.pdest;
	short   *pz    = s_spanletvars.pz;
	int      izi   = s_spanletvars.izi;
	
	if ( s_spanletvars.v & 1 )
	{
		s_spanletvars.pdest += s_spanletvars.spancount;
		s_spanletvars.pz    += s_spanletvars.spancount;

		if ( s_spanletvars.spancount == AFFINE_SPANLET_SIZE )
			s_spanletvars.izi += s_spanletvars.izistep << AFFINE_SPANLET_SIZE_BITS;
		else
			s_spanletvars.izi += s_spanletvars.izistep * s_spanletvars.izistep;
		
		if ( s_spanletvars.u & 1 )
		{
			izi += s_spanletvars.izistep;
			s_spanletvars.s   += s_spanletvars.sstep;
			s_spanletvars.t   += s_spanletvars.tstep;

			pdest++;
			pz++;
			s_spanletvars.spancount--;
		}

		s_spanletvars.sstep   *= 2;
		s_spanletvars.tstep   *= 2;

		while ( s_spanletvars.spancount > 0 )
		{
			sturb = ((s_spanletvars.s + r_turb_turb[(s_spanletvars.t>>16)&(CYCLE-1)])>>16)&63;
			tturb = ((s_spanletvars.t + r_turb_turb[(s_spanletvars.s>>16)&(CYCLE-1)])>>16)&63;
			
			btemp = *( s_spanletvars.pbase + ( sturb ) + ( tturb << 6 ) );
			
			if ( *pz <= ( izi >> 16 ) )
				*pdest = btemp;
			
			izi               += s_spanletvars.izistep_times_2;
			s_spanletvars.s   += s_spanletvars.sstep;
			s_spanletvars.t   += s_spanletvars.tstep;
			
			pdest += 2;
			pz    += 2;
			
			s_spanletvars.spancount -= 2;
		}
	}
}

/*
** R_DrawSpanletTurbulentStipple66
*/
void R_DrawSpanletTurbulentStipple66( void )
{
	unsigned btemp;
	int	     sturb, tturb;
	byte    *pdest = s_spanletvars.pdest;
	short   *pz    = s_spanletvars.pz;
	int      izi   = s_spanletvars.izi;
	
	if ( !( s_spanletvars.v & 1 ) )
	{
		s_spanletvars.pdest += s_spanletvars.spancount;
		s_spanletvars.pz    += s_spanletvars.spancount;

		if ( s_spanletvars.spancount == AFFINE_SPANLET_SIZE )
			s_spanletvars.izi += s_spanletvars.izistep << AFFINE_SPANLET_SIZE_BITS;
		else
			s_spanletvars.izi += s_spanletvars.izistep * s_spanletvars.izistep;
		
		if ( s_spanletvars.u & 1 )
		{
			izi += s_spanletvars.izistep;
			s_spanletvars.s   += s_spanletvars.sstep;
			s_spanletvars.t   += s_spanletvars.tstep;

			pdest++;
			pz++;
			s_spanletvars.spancount--;
		}

		s_spanletvars.sstep   *= 2;
		s_spanletvars.tstep   *= 2;

		while ( s_spanletvars.spancount > 0 )
		{
			sturb = ((s_spanletvars.s + r_turb_turb[(s_spanletvars.t>>16)&(CYCLE-1)])>>16)&63;
			tturb = ((s_spanletvars.t + r_turb_turb[(s_spanletvars.s>>16)&(CYCLE-1)])>>16)&63;
			
			btemp = *( s_spanletvars.pbase + ( sturb ) + ( tturb << 6 ) );
			
			if ( *pz <= ( izi >> 16 ) )
				*pdest = btemp;
			
			izi               += s_spanletvars.izistep_times_2;
			s_spanletvars.s   += s_spanletvars.sstep;
			s_spanletvars.t   += s_spanletvars.tstep;
			
			pdest += 2;
			pz    += 2;
			
			s_spanletvars.spancount -= 2;
		}
	}
	else
	{
		s_spanletvars.pdest += s_spanletvars.spancount;
		s_spanletvars.pz    += s_spanletvars.spancount;

		if ( s_spanletvars.spancount == AFFINE_SPANLET_SIZE )
			s_spanletvars.izi += s_spanletvars.izistep << AFFINE_SPANLET_SIZE_BITS;
		else
			s_spanletvars.izi += s_spanletvars.izistep * s_spanletvars.izistep;
		
		while ( s_spanletvars.spancount > 0 )
		{
			sturb = ((s_spanletvars.s + r_turb_turb[(s_spanletvars.t>>16)&(CYCLE-1)])>>16)&63;
			tturb = ((s_spanletvars.t + r_turb_turb[(s_spanletvars.s>>16)&(CYCLE-1)])>>16)&63;
			
			btemp = *( s_spanletvars.pbase + ( sturb ) + ( tturb << 6 ) );
			
			if ( *pz <= ( izi >> 16 ) )
				*pdest = btemp;
			
			izi               += s_spanletvars.izistep;
			s_spanletvars.s   += s_spanletvars.sstep;
			s_spanletvars.t   += s_spanletvars.tstep;
			
			pdest++;
			pz++;
			
			s_spanletvars.spancount--;
		}
	}
}

/*
** R_DrawSpanletTurbulentBlended
*/
void R_DrawSpanletTurbulentBlended66( void )
{
	unsigned btemp;
	int	     sturb, tturb;

	do
	{
		sturb = ((s_spanletvars.s + r_turb_turb[(s_spanletvars.t>>16)&(CYCLE-1)])>>16)&63;
		tturb = ((s_spanletvars.t + r_turb_turb[(s_spanletvars.s>>16)&(CYCLE-1)])>>16)&63;

		btemp = *( s_spanletvars.pbase + ( sturb ) + ( tturb << 6 ) );

		if ( *s_spanletvars.pz <= ( s_spanletvars.izi >> 16 ) )
			*s_spanletvars.pdest = vid.alphamap[btemp*256+*s_spanletvars.pdest];

		s_spanletvars.izi += s_spanletvars.izistep;
		s_spanletvars.pdest++;
		s_spanletvars.pz++;
		s_spanletvars.s += s_spanletvars.sstep;
		s_spanletvars.t += s_spanletvars.tstep;

	} while ( --s_spanletvars.spancount > 0 );
}

void R_DrawSpanletTurbulentBlended33( void )
{
	unsigned btemp;
	int	     sturb, tturb;

	do
	{
		sturb = ((s_spanletvars.s + r_turb_turb[(s_spanletvars.t>>16)&(CYCLE-1)])>>16)&63;
		tturb = ((s_spanletvars.t + r_turb_turb[(s_spanletvars.s>>16)&(CYCLE-1)])>>16)&63;

		btemp = *( s_spanletvars.pbase + ( sturb ) + ( tturb << 6 ) );

		if ( *s_spanletvars.pz <= ( s_spanletvars.izi >> 16 ) )
			*s_spanletvars.pdest = vid.alphamap[btemp+*s_spanletvars.pdest*256];

		s_spanletvars.izi += s_spanletvars.izistep;
		s_spanletvars.pdest++;
		s_spanletvars.pz++;
		s_spanletvars.s += s_spanletvars.sstep;
		s_spanletvars.t += s_spanletvars.tstep;

	} while ( --s_spanletvars.spancount > 0 );
}

/*
** R_DrawSpanlet33
*/
void R_DrawSpanlet33( void )
{
	unsigned btemp;

	do
	{
		unsigned ts, tt;

		ts = s_spanletvars.s >> 16;
		tt = s_spanletvars.t >> 16;

		btemp = *(s_spanletvars.pbase + (ts) + (tt) * cachewidth);

		if ( btemp != 255 )
		{
			if (*s_spanletvars.pz <= (s_spanletvars.izi >> 16))
			{
				*s_spanletvars.pdest = vid.alphamap[btemp+*s_spanletvars.pdest*256];
			}
		}

		s_spanletvars.izi += s_spanletvars.izistep;
		s_spanletvars.pdest++;
		s_spanletvars.pz++;
		s_spanletvars.s += s_spanletvars.sstep;
		s_spanletvars.t += s_spanletvars.tstep;
	} while (--s_spanletvars.spancount > 0);
}

void R_DrawSpanletConstant33( void )
{
	do
	{
		if (*s_spanletvars.pz <= (s_spanletvars.izi >> 16))
		{
			*s_spanletvars.pdest = vid.alphamap[r_polyblendcolor+*s_spanletvars.pdest*256];
		}

		s_spanletvars.izi += s_spanletvars.izistep;
		s_spanletvars.pdest++;
		s_spanletvars.pz++;
	} while (--s_spanletvars.spancount > 0);
}

/*
** R_DrawSpanlet66
*/
void R_DrawSpanlet66( void )
{
	unsigned btemp;

	do
	{
		unsigned ts, tt;

		ts = s_spanletvars.s >> 16;
		tt = s_spanletvars.t >> 16;

		btemp = *(s_spanletvars.pbase + (ts) + (tt) * cachewidth);

		if ( btemp != 255 )
		{
			if (*s_spanletvars.pz <= (s_spanletvars.izi >> 16))
			{
				*s_spanletvars.pdest = vid.alphamap[btemp*256+*s_spanletvars.pdest];
			}
		}

		s_spanletvars.izi += s_spanletvars.izistep;
		s_spanletvars.pdest++;
		s_spanletvars.pz++;
		s_spanletvars.s += s_spanletvars.sstep;
		s_spanletvars.t += s_spanletvars.tstep;
	} while (--s_spanletvars.spancount > 0);
}

/*
** R_DrawSpanlet33Stipple
*/
void R_DrawSpanlet33Stipple( void )
{
	unsigned btemp;
	byte    *pdest = s_spanletvars.pdest;
	short   *pz    = s_spanletvars.pz;
	int      izi   = s_spanletvars.izi;
	
	if ( r_polydesc.stipple_parity ^ ( s_spanletvars.v & 1 ) )
	{
		s_spanletvars.pdest += s_spanletvars.spancount;
		s_spanletvars.pz    += s_spanletvars.spancount;

		if ( s_spanletvars.spancount == AFFINE_SPANLET_SIZE )
			s_spanletvars.izi += s_spanletvars.izistep << AFFINE_SPANLET_SIZE_BITS;
		else
			s_spanletvars.izi += s_spanletvars.izistep * s_spanletvars.izistep;
		
		if ( r_polydesc.stipple_parity ^ ( s_spanletvars.u & 1 ) )
		{
			izi += s_spanletvars.izistep;
			s_spanletvars.s   += s_spanletvars.sstep;
			s_spanletvars.t   += s_spanletvars.tstep;

			pdest++;
			pz++;
			s_spanletvars.spancount--;
		}

		s_spanletvars.sstep *= 2;
		s_spanletvars.tstep *= 2;

		while ( s_spanletvars.spancount > 0 )
		{
			unsigned s = s_spanletvars.s >> 16;
			unsigned t = s_spanletvars.t >> 16;

			btemp = *( s_spanletvars.pbase + ( s ) + ( t * cachewidth ) );
			
			if ( btemp != 255 )
			{
				if ( *pz <= ( izi >> 16 ) )
					*pdest = btemp;
			}
			
			izi               += s_spanletvars.izistep_times_2;
			s_spanletvars.s   += s_spanletvars.sstep;
			s_spanletvars.t   += s_spanletvars.tstep;
			
			pdest += 2;
			pz    += 2;
			
			s_spanletvars.spancount -= 2;
		}
	}
}

/*
** R_DrawSpanlet66Stipple