ref: 4fa31de5c586b93ad54ce9cbd2ddd0ddb2e839b2
dir: /src/heretic/p_maputl.c/
// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 1993-2008 Raven Software
// Copyright(C) 2008 Simon Howard
//
// 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.
//
//-----------------------------------------------------------------------------
// P_maputl.c
#include <stdlib.h>
#include "doomdef.h"
#include "m_bbox.h"
#include "p_local.h"
/*
===================
=
= P_AproxDistance
=
= Gives an estimation of distance (not exact)
=
===================
*/
fixed_t P_AproxDistance(fixed_t dx, fixed_t dy)
{
dx = abs(dx);
dy = abs(dy);
if (dx < dy)
return dx + dy - (dx >> 1);
return dx + dy - (dy >> 1);
}
/*
==================
=
= P_PointOnLineSide
=
= Returns 0 or 1
==================
*/
int P_PointOnLineSide(fixed_t x, fixed_t y, line_t * line)
{
fixed_t dx, dy;
fixed_t left, right;
if (!line->dx)
{
if (x <= line->v1->x)
return line->dy > 0;
return line->dy < 0;
}
if (!line->dy)
{
if (y <= line->v1->y)
return line->dx < 0;
return line->dx > 0;
}
dx = (x - line->v1->x);
dy = (y - line->v1->y);
left = FixedMul(line->dy >> FRACBITS, dx);
right = FixedMul(dy, line->dx >> FRACBITS);
if (right < left)
return 0; // front side
return 1; // back side
}
/*
=================
=
= P_BoxOnLineSide
=
= Considers the line to be infinite
= Returns side 0 or 1, -1 if box crosses the line
=================
*/
int P_BoxOnLineSide(fixed_t * tmbox, line_t * ld)
{
int p1 = 0, p2 = 0;
switch (ld->slopetype)
{
case ST_HORIZONTAL:
p1 = tmbox[BOXTOP] > ld->v1->y;
p2 = tmbox[BOXBOTTOM] > ld->v1->y;
if (ld->dx < 0)
{
p1 ^= 1;
p2 ^= 1;
}
break;
case ST_VERTICAL:
p1 = tmbox[BOXRIGHT] < ld->v1->x;
p2 = tmbox[BOXLEFT] < ld->v1->x;
if (ld->dy < 0)
{
p1 ^= 1;
p2 ^= 1;
}
break;
case ST_POSITIVE:
p1 = P_PointOnLineSide(tmbox[BOXLEFT], tmbox[BOXTOP], ld);
p2 = P_PointOnLineSide(tmbox[BOXRIGHT], tmbox[BOXBOTTOM], ld);
break;
case ST_NEGATIVE:
p1 = P_PointOnLineSide(tmbox[BOXRIGHT], tmbox[BOXTOP], ld);
p2 = P_PointOnLineSide(tmbox[BOXLEFT], tmbox[BOXBOTTOM], ld);
break;
}
if (p1 == p2)
return p1;
return -1;
}
/*
==================
=
= P_PointOnDivlineSide
=
= Returns 0 or 1
==================
*/
int P_PointOnDivlineSide(fixed_t x, fixed_t y, divline_t * line)
{
fixed_t dx, dy;
fixed_t left, right;
if (!line->dx)
{
if (x <= line->x)
return line->dy > 0;
return line->dy < 0;
}
if (!line->dy)
{
if (y <= line->y)
return line->dx < 0;
return line->dx > 0;
}
dx = (x - line->x);
dy = (y - line->y);
// try to quickly decide by looking at sign bits
if ((line->dy ^ line->dx ^ dx ^ dy) & 0x80000000)
{
if ((line->dy ^ dx) & 0x80000000)
return 1; // (left is negative)
return 0;
}
left = FixedMul(line->dy >> 8, dx >> 8);
right = FixedMul(dy >> 8, line->dx >> 8);
if (right < left)
return 0; // front side
return 1; // back side
}
/*
==============
=
= P_MakeDivline
=
==============
*/
void P_MakeDivline(line_t * li, divline_t * dl)
{
dl->x = li->v1->x;
dl->y = li->v1->y;
dl->dx = li->dx;
dl->dy = li->dy;
}
/*
===============
=
= P_InterceptVector
=
= Returns the fractional intercept point along the first divline
=
= This is only called by the addthings and addlines traversers
===============
*/
fixed_t P_InterceptVector(divline_t * v2, divline_t * v1)
{
#if 1
fixed_t frac, num, den;
den = FixedMul(v1->dy >> 8, v2->dx) - FixedMul(v1->dx >> 8, v2->dy);
if (den == 0)
return 0;
// I_Error ("P_InterceptVector: parallel");
num = FixedMul((v1->x - v2->x) >> 8, v1->dy) +
FixedMul((v2->y - v1->y) >> 8, v1->dx);
frac = FixedDiv(num, den);
return frac;
#else
float frac, num, den, v1x, v1y, v1dx, v1dy, v2x, v2y, v2dx, v2dy;
v1x = (float) v1->x / FRACUNIT;
v1y = (float) v1->y / FRACUNIT;
v1dx = (float) v1->dx / FRACUNIT;
v1dy = (float) v1->dy / FRACUNIT;
v2x = (float) v2->x / FRACUNIT;
v2y = (float) v2->y / FRACUNIT;
v2dx = (float) v2->dx / FRACUNIT;
v2dy = (float) v2->dy / FRACUNIT;
den = v1dy * v2dx - v1dx * v2dy;
if (den == 0)
return 0; // parallel
num = (v1x - v2x) * v1dy + (v2y - v1y) * v1dx;
frac = num / den;
return frac * FRACUNIT;
#endif
}
/*
==================
=
= P_LineOpening
=
= Sets opentop and openbottom to the window through a two sided line
= OPTIMIZE: keep this precalculated
==================
*/
fixed_t opentop, openbottom, openrange;
fixed_t lowfloor;
void P_LineOpening(line_t * linedef)
{
sector_t *front, *back;
if (linedef->sidenum[1] == -1)
{ // single sided line
openrange = 0;
return;
}
front = linedef->frontsector;
back = linedef->backsector;
if (front->ceilingheight < back->ceilingheight)
opentop = front->ceilingheight;
else
opentop = back->ceilingheight;
if (front->floorheight > back->floorheight)
{
openbottom = front->floorheight;
lowfloor = back->floorheight;
}
else
{
openbottom = back->floorheight;
lowfloor = front->floorheight;
}
openrange = opentop - openbottom;
}
/*
===============================================================================
THING POSITION SETTING
===============================================================================
*/
/*
===================
=
= P_UnsetThingPosition
=
= Unlinks a thing from block map and sectors
=
===================
*/
void P_UnsetThingPosition(mobj_t * thing)
{
int blockx, blocky;
if (!(thing->flags & MF_NOSECTOR))
{ // inert things don't need to be in blockmap
// unlink from subsector
if (thing->snext)
thing->snext->sprev = thing->sprev;
if (thing->sprev)
thing->sprev->snext = thing->snext;
else
thing->subsector->sector->thinglist = thing->snext;
}
if (!(thing->flags & MF_NOBLOCKMAP))
{ // inert things don't need to be in blockmap
// unlink from block map
if (thing->bnext)
thing->bnext->bprev = thing->bprev;
if (thing->bprev)
thing->bprev->bnext = thing->bnext;
else
{
blockx = (thing->x - bmaporgx) >> MAPBLOCKSHIFT;
blocky = (thing->y - bmaporgy) >> MAPBLOCKSHIFT;
if (blockx >= 0 && blockx < bmapwidth
&& blocky >= 0 && blocky < bmapheight)
blocklinks[blocky * bmapwidth + blockx] = thing->bnext;
}
}
}
/*
===================
=
= P_SetThingPosition
=
= Links a thing into both a block and a subsector based on it's x y
= Sets thing->subsector properly
=
===================
*/
void P_SetThingPosition(mobj_t * thing)
{
subsector_t *ss;
sector_t *sec;
int blockx, blocky;
mobj_t **link;
//
// link into subsector
//
ss = R_PointInSubsector(thing->x, thing->y);
thing->subsector = ss;
if (!(thing->flags & MF_NOSECTOR))
{ // invisible things don't go into the sector links
sec = ss->sector;
thing->sprev = NULL;
thing->snext = sec->thinglist;
if (sec->thinglist)
sec->thinglist->sprev = thing;
sec->thinglist = thing;
}
//
// link into blockmap
//
if (!(thing->flags & MF_NOBLOCKMAP))
{ // inert things don't need to be in blockmap
blockx = (thing->x - bmaporgx) >> MAPBLOCKSHIFT;
blocky = (thing->y - bmaporgy) >> MAPBLOCKSHIFT;
if (blockx >= 0 && blockx < bmapwidth && blocky >= 0
&& blocky < bmapheight)
{
link = &blocklinks[blocky * bmapwidth + blockx];
thing->bprev = NULL;
thing->bnext = *link;
if (*link)
(*link)->bprev = thing;
*link = thing;
}
else
{ // thing is off the map
thing->bnext = thing->bprev = NULL;
}
}
}
/*
===============================================================================
BLOCK MAP ITERATORS
For each line/thing in the given mapblock, call the passed function.
If the function returns false, exit with false without checking anything else.
===============================================================================
*/
/*
==================
=
= P_BlockLinesIterator
=
= The validcount flags are used to avoid checking lines
= that are marked in multiple mapblocks, so increment validcount before
= the first call to P_BlockLinesIterator, then make one or more calls to it
===================
*/
boolean P_BlockLinesIterator(int x, int y, boolean(*func) (line_t *))
{
int offset;
short *list;
line_t *ld;
if (x < 0 || y < 0 || x >= bmapwidth || y >= bmapheight)
return true;
offset = y * bmapwidth + x;
offset = *(blockmap + offset);
for (list = blockmaplump + offset; *list != -1; list++)
{
ld = &lines[*list];
if (ld->validcount == validcount)
continue; // line has already been checked
ld->validcount = validcount;
if (!func(ld))
return false;
}
return true; // everything was checked
}
/*
==================
=
= P_BlockThingsIterator
=
==================
*/
boolean P_BlockThingsIterator(int x, int y, boolean(*func) (mobj_t *))
{
mobj_t *mobj;
if (x < 0 || y < 0 || x >= bmapwidth || y >= bmapheight)
return true;
for (mobj = blocklinks[y * bmapwidth + x]; mobj; mobj = mobj->bnext)
if (!func(mobj))
return false;
return true;
}
/*
===============================================================================
INTERCEPT ROUTINES
===============================================================================
*/
intercept_t intercepts[MAXINTERCEPTS], *intercept_p;
divline_t trace;
boolean earlyout;
int ptflags;
/*
==================
=
= PIT_AddLineIntercepts
=
= Looks for lines in the given block that intercept the given trace
= to add to the intercepts list
= A line is crossed if its endpoints are on opposite sides of the trace
= Returns true if earlyout and a solid line hit
==================
*/
boolean PIT_AddLineIntercepts(line_t * ld)
{
int s1, s2;
fixed_t frac;
divline_t dl;
// avoid precision problems with two routines
if (trace.dx > FRACUNIT * 16 || trace.dy > FRACUNIT * 16
|| trace.dx < -FRACUNIT * 16 || trace.dy < -FRACUNIT * 16)
{
s1 = P_PointOnDivlineSide(ld->v1->x, ld->v1->y, &trace);
s2 = P_PointOnDivlineSide(ld->v2->x, ld->v2->y, &trace);
}
else
{
s1 = P_PointOnLineSide(trace.x, trace.y, ld);
s2 = P_PointOnLineSide(trace.x + trace.dx, trace.y + trace.dy, ld);
}
if (s1 == s2)
return true; // line isn't crossed
//
// hit the line
//
P_MakeDivline(ld, &dl);
frac = P_InterceptVector(&trace, &dl);
if (frac < 0)
return true; // behind source
// try to early out the check
if (earlyout && frac < FRACUNIT && !ld->backsector)
return false; // stop checking
intercept_p->frac = frac;
intercept_p->isaline = true;
intercept_p->d.line = ld;
intercept_p++;
return true; // continue
}
/*
==================
=
= PIT_AddThingIntercepts
=
==================
*/
boolean PIT_AddThingIntercepts(mobj_t * thing)
{
fixed_t x1, y1, x2, y2;
int s1, s2;
boolean tracepositive;
divline_t dl;
fixed_t frac;
tracepositive = (trace.dx ^ trace.dy) > 0;
// check a corner to corner crossection for hit
if (tracepositive)
{
x1 = thing->x - thing->radius;
y1 = thing->y + thing->radius;
x2 = thing->x + thing->radius;
y2 = thing->y - thing->radius;
}
else
{
x1 = thing->x - thing->radius;
y1 = thing->y - thing->radius;
x2 = thing->x + thing->radius;
y2 = thing->y + thing->radius;
}
s1 = P_PointOnDivlineSide(x1, y1, &trace);
s2 = P_PointOnDivlineSide(x2, y2, &trace);
if (s1 == s2)
return true; // line isn't crossed
dl.x = x1;
dl.y = y1;
dl.dx = x2 - x1;
dl.dy = y2 - y1;
frac = P_InterceptVector(&trace, &dl);
if (frac < 0)
return true; // behind source
intercept_p->frac = frac;
intercept_p->isaline = false;
intercept_p->d.thing = thing;
intercept_p++;
return true; // keep going
}
/*
====================
=
= P_TraverseIntercepts
=
= Returns true if the traverser function returns true for all lines
====================
*/
boolean P_TraverseIntercepts(traverser_t func, fixed_t maxfrac)
{
int count;
fixed_t dist;
intercept_t *scan, *in;
count = intercept_p - intercepts;
in = 0; // shut up compiler warning
while (count--)
{
dist = INT_MAX;
for (scan = intercepts; scan < intercept_p; scan++)
if (scan->frac < dist)
{
dist = scan->frac;
in = scan;
}
if (dist > maxfrac)
return true; // checked everything in range
#if 0
{ // don't check these yet, ther may be others inserted
in = scan = intercepts;
for (scan = intercepts; scan < intercept_p; scan++)
if (scan->frac > maxfrac)
*in++ = *scan;
intercept_p = in;
return false;
}
#endif
if (!func(in))
return false; // don't bother going farther
in->frac = INT_MAX;
}
return true; // everything was traversed
}
/*
==================
=
= P_PathTraverse
=
= Traces a line from x1,y1 to x2,y2, calling the traverser function for each
= Returns true if the traverser function returns true for all lines
==================
*/
boolean P_PathTraverse(fixed_t x1, fixed_t y1, fixed_t x2, fixed_t y2,
int flags, boolean(*trav) (intercept_t *))
{
fixed_t xt1, yt1, xt2, yt2;
fixed_t xstep, ystep;
fixed_t partial;
fixed_t xintercept, yintercept;
int mapx, mapy, mapxstep, mapystep;
int count;
earlyout = flags & PT_EARLYOUT;
validcount++;
intercept_p = intercepts;
if (((x1 - bmaporgx) & (MAPBLOCKSIZE - 1)) == 0)
x1 += FRACUNIT; // don't side exactly on a line
if (((y1 - bmaporgy) & (MAPBLOCKSIZE - 1)) == 0)
y1 += FRACUNIT; // don't side exactly on a line
trace.x = x1;
trace.y = y1;
trace.dx = x2 - x1;
trace.dy = y2 - y1;
x1 -= bmaporgx;
y1 -= bmaporgy;
xt1 = x1 >> MAPBLOCKSHIFT;
yt1 = y1 >> MAPBLOCKSHIFT;
x2 -= bmaporgx;
y2 -= bmaporgy;
xt2 = x2 >> MAPBLOCKSHIFT;
yt2 = y2 >> MAPBLOCKSHIFT;
if (xt2 > xt1)
{
mapxstep = 1;
partial = FRACUNIT - ((x1 >> MAPBTOFRAC) & (FRACUNIT - 1));
ystep = FixedDiv(y2 - y1, abs(x2 - x1));
}
else if (xt2 < xt1)
{
mapxstep = -1;
partial = (x1 >> MAPBTOFRAC) & (FRACUNIT - 1);
ystep = FixedDiv(y2 - y1, abs(x2 - x1));
}
else
{
mapxstep = 0;
partial = FRACUNIT;
ystep = 256 * FRACUNIT;
}
yintercept = (y1 >> MAPBTOFRAC) + FixedMul(partial, ystep);
if (yt2 > yt1)
{
mapystep = 1;
partial = FRACUNIT - ((y1 >> MAPBTOFRAC) & (FRACUNIT - 1));
xstep = FixedDiv(x2 - x1, abs(y2 - y1));
}
else if (yt2 < yt1)
{
mapystep = -1;
partial = (y1 >> MAPBTOFRAC) & (FRACUNIT - 1);
xstep = FixedDiv(x2 - x1, abs(y2 - y1));
}
else
{
mapystep = 0;
partial = FRACUNIT;
xstep = 256 * FRACUNIT;
}
xintercept = (x1 >> MAPBTOFRAC) + FixedMul(partial, xstep);
//
// step through map blocks
// Count is present to prevent a round off error from skipping the break
mapx = xt1;
mapy = yt1;
for (count = 0; count < 64; count++)
{
if (flags & PT_ADDLINES)
{
if (!P_BlockLinesIterator(mapx, mapy, PIT_AddLineIntercepts))
return false; // early out
}
if (flags & PT_ADDTHINGS)
{
if (!P_BlockThingsIterator(mapx, mapy, PIT_AddThingIntercepts))
return false; // early out
}
if (mapx == xt2 && mapy == yt2)
break;
if ((yintercept >> FRACBITS) == mapy)
{
yintercept += ystep;
mapx += mapxstep;
}
else if ((xintercept >> FRACBITS) == mapx)
{
xintercept += xstep;
mapy += mapystep;
}
}
//
// go through the sorted list
//
return P_TraverseIntercepts(trav, FRACUNIT);
}