ref: 516fc276f112baf0bd4508596598aed49929bde9
dir: /src/engine.c/
/*
Copyright (C) 1994-1995 Apogee Software, Ltd.
Copyright (C) 2002-2015 icculus.org, GNU/Linux port
Copyright (C) 2017-2018 Steven LeVesque
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.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include "rt_def.h"
#include "watcom.h"
#include "engine.h"
#include "_engine.h"
#include "rt_draw.h"
#include "rt_door.h"
#include "rt_stat.h"
#include "rt_ted.h"
#include "rt_view.h"
#include <stdlib.h>
/*
=============================================================================
Global Variables GLOBAL VARIABLES
=============================================================================
*/
//wallcast_t posts[642];//bna++
wallcast_t posts[MAXSCREENWIDTH+4];//bna++
//wallcast_t posts[321];
int lasttilex;
int lasttiley;
/*
=============================================================================
Local Variables GLOBAL VARIABLES
=============================================================================
*/
static int xtilestep,ytilestep;
static int c_vx,c_vy;
void InitialCast ( void );
void Cast ( int curx );
void Interpolate (int x1, int x2)
{
int i;
int dtexture;
int frac;
int dheight;
int hfrac;
int dx;
dx=x2-x1;
dtexture=(((posts[x2].texture-posts[x1].texture)<<12)+0x800)/dx;
dheight=(((posts[x2].wallheight-posts[x1].wallheight)<<8)+0x80)/dx;
frac=dtexture+(posts[x1].texture<<12);
hfrac=dheight+(posts[x1].wallheight<<8);
for (i=x1+1; i<=x2-1; i++,frac+=dtexture,hfrac+=dheight)
{
posts[i].lump=posts[x1].lump;
posts[i].posttype=posts[x1].posttype;
posts[i].offset=posts[x1].offset;
posts[i].alttile=posts[x1].alttile;
posts[i].texture=(frac>>12);
posts[i].wallheight=hfrac>>8;
}
}
void Refresh ( void )
{
int x;
// Cast Initial comb filter
InitialCast();
for (x=0; x<=viewwidth-4; x+=4)
{
if NOTSAMETILE(x,x+4)
{
Cast(x+2);
if NOTSAMETILE(x,x+2)
{
Cast(x+1);
}
else
Interpolate (x,x+2);
if NOTSAMETILE(x+2,x+4)
{
Cast(x+3);
}
else
Interpolate (x+2,x+4);
}
else
Interpolate(x,x+4);
}
}
void HitWall(int curx, int vertical, int xtile, int ytile)
{
int num;
posts[curx].offset=(xtile<<7)+ytile;
posts[curx].lump = tilemap[xtile][ytile];
posts[curx].alttile=0;
posts[curx].posttype=0;
if (vertical<0)
{
xintercept=xtile<<16;
if (xtilestep<0)
xintercept+=0xffff;
yintercept=FixedScale(xintercept-viewx,c_vy,c_vx)+viewy;
if (posts[curx].lump & 0x4000)
{
if (tilemap[xtile-(xtilestep>>7)][ytile]&0x8000)
{
num=tilemap[xtile-(xtilestep>>7)][ytile];
if (num&0x4000)
{
if (maskobjlist[num&0x3ff]->sidepic)
posts[curx].lump = maskobjlist[num&0x3ff]->sidepic;
else
posts[curx].lump &= 0x3ff;
}
else
posts[curx].lump = doorobjlist[num&0x3ff]->sidepic;
}
else
{
if (posts[curx].lump&0x1000)
posts[curx].lump=animwalls[posts[curx].lump&0x3ff].texture;
else
posts[curx].lump &= 0x3ff;
}
}
else if (posts[curx].lump & 0x2000)
{
if (IsWindow(xtile,ytile))
posts[curx].alttile=-1;
else
posts[curx].alttile=(MAPSPOT(xtile,ytile,2))+1;
posts[curx].lump &= 0x3ff;
}
else if (posts[curx].lump & 0x1000)
posts[curx].lump=animwalls[posts[curx].lump&0x3ff].texture;
else if (posts[curx].lump & 0x800)
{
posts[curx].lump &= 0x3ff;
posts[curx].posttype=2;
}
posts[curx].texture=yintercept-(ytile<<16);
// posts[curx].texture&=0xffff;
if (posts[curx].texture<0)
posts[curx].texture=0;
if (posts[curx].texture>65535)
posts[curx].texture=65535;
if (xtilestep<0)
posts[curx].texture^=0xffff;
posts[curx].posttype+=1;
// posts[curx].texture=(posts[curx].texture+firstcoloffset)&65535;
}
else
{
yintercept=ytile<<16;
if (ytilestep<0)
yintercept+=0xffff;
xintercept=FixedScale(yintercept-viewy,c_vx,c_vy)+viewx;
if (posts[curx].lump & 0x4000)
{ // check for adjacent doors
if (tilemap[xtile][ytile-ytilestep]&0x8000)
{
num=tilemap[xtile][ytile-ytilestep];
if (num&0x4000)
{
if (maskobjlist[num&0x3ff]->sidepic)
posts[curx].lump = maskobjlist[num&0x3ff]->sidepic;
else
posts[curx].lump &= 0x3ff;
}
else
posts[curx].lump = doorobjlist[num&0x3ff]->sidepic;
}
else
{
if (posts[curx].lump&0x1000)
posts[curx].lump=animwalls[posts[curx].lump&0x3ff].texture;
else
posts[curx].lump &= 0x3ff;
}
}
else if (posts[curx].lump & 0x2000)
{
if (IsWindow(xtile,ytile))
posts[curx].alttile=-1;
else
posts[curx].alttile=(MAPSPOT(xtile,ytile,2))+1;
posts[curx].lump &= 0x3ff;
}
else if (posts[curx].lump & 0x1000)
posts[curx].lump=animwalls[posts[curx].lump&0x3ff].texture;
else if (posts[curx].lump & 0x800)
{
posts[curx].lump &= 0x3ff;
posts[curx].posttype=2;
}
posts[curx].texture=xintercept-(xtile<<16);
// posts[curx].texture&=0xffff;
if (posts[curx].texture<0)
posts[curx].texture=0;
if (posts[curx].texture>65535)
posts[curx].texture=65535;
if (ytilestep>0)
posts[curx].texture^=0xffff;
// posts[curx].posttype+=0;
// posts[curx].texture=(posts[curx].texture+firstcoloffset)&65535;
}
posts[curx].wallheight=CalcHeight();
}
void InitialCast ( void )
{
int snx,sny;
int incr[2];
int thedir[2];
int cnt;
int grid[2];
int index;
int curx;
c_vx=c_startx;
c_vy=c_starty;
for (curx=0; curx<=viewwidth; curx+=4)
{
snx=viewx&0xffff;
sny=viewy&0xffff;
if (c_vx>0)
{
thedir[0]=1;
xtilestep=0x80;
snx^=0xffff;
incr[1]=-c_vx;
}
else
{
thedir[0]=-1;
xtilestep=-0x80;
incr[1]=c_vx;
}
if (c_vy>0)
{
thedir[1]=1;
ytilestep=1;
sny^=0xffff;
incr[0]=c_vy;
}
else
{
thedir[1]=-1;
ytilestep=-1;
incr[0]=-c_vy;
}
cnt=FixedMul(snx,incr[0])+FixedMul(sny,incr[1]);
grid[0]=viewx>>16;
grid[1]=viewy>>16;
do
{
int tile;
index=(cnt>=0);
cnt+=incr[index];
spotvis[grid[0]][grid[1]]=1;
grid[index]+=thedir[index];
if ((tile=tilemap[grid[0]][grid[1]])!=0)
{
if (tile&0x8000)
{
if ( (!(tile&0x4000)) && (doorobjlist[tile&0x3ff]->action==dr_closed))
{
spotvis[grid[0]][grid[1]]=1;
if (doorobjlist[tile&0x3ff]->flags&DF_MULTI)
MakeWideDoorVisible(tile&0x3ff);
do
{
index=(cnt>=0);
cnt+=incr[index];
grid[index]+=thedir[index];
if ((tilemap[grid[0]][grid[1]]!=0) &&
(!(tilemap[grid[0]][grid[1]]&0x8000)) )
break;
}
while (1);
break;
}
else
continue;
}
else
{
mapseen[grid[0]][grid[1]]=1;
break;
}
}
}
while (1);
HitWall(curx, cnt-incr[index], grid[0], grid[1]);
c_vx+=viewsin<<2;
c_vy+=viewcos<<2;
}
}
void Cast ( int curx )
{
int snx,sny;
int incr[2];
int thedir[2];
int cnt;
int grid[2];
int index;
c_vx=c_startx+(curx*viewsin);
c_vy=c_starty+(curx*viewcos);
snx=viewx&0xffff;
sny=viewy&0xffff;
if (c_vx>0)
{
thedir[0]=1;
xtilestep=0x80;
snx^=0xffff;
incr[1]=-c_vx;
}
else
{
thedir[0]=-1;
xtilestep=-0x80;
incr[1]=c_vx;
}
if (c_vy>0)
{
thedir[1]=1;
ytilestep=1;
sny^=0xffff;
incr[0]=c_vy;
}
else
{
thedir[1]=-1;
ytilestep=-1;
incr[0]=-c_vy;
}
cnt=FixedMul(snx,incr[0])+FixedMul(sny,incr[1]);
grid[0]=viewx>>16;
grid[1]=viewy>>16;
do
{
int tile;
index=(cnt>=0);
cnt+=incr[index];
spotvis[grid[0]][grid[1]]=1;
grid[index]+=thedir[index];
if ((tile=tilemap[grid[0]][grid[1]])!=0)
{
if (tile&0x8000)
{
if ( (!(tile&0x4000)) && (doorobjlist[tile&0x3ff]->action==dr_closed))
{
spotvis[grid[0]][grid[1]]=1;
if (doorobjlist[tile&0x3ff]->flags&DF_MULTI)
MakeWideDoorVisible(tile&0x3ff);
do
{
index=(cnt>=0);
cnt+=incr[index];
grid[index]+=thedir[index];
if ((tilemap[grid[0]][grid[1]]!=0) &&
(!(tilemap[grid[0]][grid[1]]&0x8000)) )
break;
}
while (1);
break;
}
else
continue;
}
else
{
mapseen[grid[0]][grid[1]]=1;
break;
}
}
}
while (1);
HitWall(curx, cnt-incr[index], grid[0], grid[1]);
}