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qzdoom/src/p_trace.cpp

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/*
** p_trace.cpp
** Generalized trace function, like most 3D games have
**
**---------------------------------------------------------------------------
** Copyright 1998-2006 Randy Heit
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in the
** documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
** derived from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
*/
#include "p_trace.h"
#include "p_local.h"
#include "i_system.h"
#include "r_sky.h"
#include "doomstat.h"
struct FTraceInfo
{
fixed_t StartX, StartY, StartZ;
fixed_t Vx, Vy, Vz;
DWORD ActorMask, WallMask;
AActor *IgnoreThis;
FTraceResults *Results;
sector_t *CurSector;
fixed_t MaxDist;
fixed_t EnterDist;
bool (*TraceCallback)(FTraceResults &res);
DWORD TraceFlags;
int inshootthrough;
// These are required for 3D-floor checking
// to create a fake sector with a floor
// or ceiling plane coming from a 3D-floor
sector_t DummySector[2];
int sectorsel;
bool TraceTraverse (int ptflags);
bool CheckSectorPlane (const sector_t *sector, bool checkFloor);
};
static bool EditTraceResult (DWORD flags, FTraceResults &res);
bool Trace (fixed_t x, fixed_t y, fixed_t z, sector_t *sector,
fixed_t vx, fixed_t vy, fixed_t vz, fixed_t maxDist,
DWORD actorMask, DWORD wallMask, AActor *ignore,
FTraceResults &res,
DWORD flags, bool (*callback)(FTraceResults &res))
{
int ptflags;
FTraceInfo inf;
ptflags = actorMask ? PT_ADDLINES|PT_ADDTHINGS|PT_COMPATIBLE : PT_ADDLINES;
inf.StartX = x;
inf.StartY = y;
inf.StartZ = z;
inf.Vx = vx;
inf.Vy = vy;
inf.Vz = vz;
inf.ActorMask = actorMask;
inf.WallMask = wallMask;
inf.IgnoreThis = ignore;
inf.CurSector = sector;
inf.MaxDist = maxDist;
inf.EnterDist = 0;
inf.TraceCallback = callback;
inf.TraceFlags = flags;
res.CrossedWater = NULL;
inf.Results = &res;
inf.inshootthrough = true;
res.HitType = TRACE_HitNone;
// Do a 3D floor check in the starting sector
memset(&res, 0, sizeof(res));
inf.sectorsel=0;
#ifdef _3DFLOORS
TDeletingArray<F3DFloor*> &ff = sector->e->XFloor.ffloors;
if (ff.Size())
{
memcpy(&inf.DummySector[0],sector,sizeof(sector_t));
inf.CurSector=sector=&inf.DummySector[0];
inf.sectorsel=1;
fixed_t bf = sector->floorplane.ZatPoint (x, y);
fixed_t bc = sector->ceilingplane.ZatPoint (x, y);
for(unsigned int i=0;i<ff.Size();i++)
{
F3DFloor * rover=ff[i];
if (!(rover->flags&FF_SHOOTTHROUGH) && rover->flags&FF_EXISTS)
{
fixed_t ff_bottom=rover->bottom.plane->ZatPoint(x, y);
fixed_t ff_top=rover->top.plane->ZatPoint(x, y);
// clip to the part of the sector we are in
if (z>ff_top)
{
// above
if (bf<ff_top)
{
sector->floorplane=*rover->top.plane;
sector->SetTexture(sector_t::floor, *rover->top.texture, false);
bf=ff_top;
}
}
else if (z<ff_bottom)
{
//below
if (bc>ff_bottom)
{
sector->ceilingplane=*rover->bottom.plane;
sector->SetTexture(sector_t::ceiling, *rover->bottom.texture, false);
bc=ff_bottom;
}
}
else
{
// inside
if (bf<ff_bottom)
{
sector->floorplane=*rover->bottom.plane;
sector->SetTexture(sector_t::floor, *rover->bottom.texture, false);
bf=ff_bottom;
}
if (bc>ff_top)
{
sector->ceilingplane=*rover->top.plane;
sector->SetTexture(sector_t::ceiling, *rover->top.texture, false);
bc=ff_top;
}
inf.inshootthrough = false;
}
}
}
}
#endif
// check for overflows and clip if necessary
SQWORD xd= (SQWORD)x + ( ( SQWORD(vx) * SQWORD(maxDist) )>>16);
if (xd>SQWORD(32767)*FRACUNIT)
{
maxDist = inf.MaxDist=FixedDiv(FIXED_MAX-x,vx);
}
else if (xd<-SQWORD(32767)*FRACUNIT)
{
maxDist = inf.MaxDist=FixedDiv(FIXED_MIN-x,vx);
}
SQWORD yd= (SQWORD)y + ( ( SQWORD(vy) * SQWORD(maxDist) )>>16);
if (yd>SQWORD(32767)*FRACUNIT)
{
maxDist = inf.MaxDist=FixedDiv(FIXED_MAX-y,vy);
}
else if (yd<-SQWORD(32767)*FRACUNIT)
{
maxDist = inf.MaxDist=FixedDiv(FIXED_MIN-y,vy);
}
// recalculate the trace's end points for robustness
if (inf.TraceTraverse (ptflags))
{ // check for intersection with floor/ceiling
res.Sector = &sectors[inf.CurSector->sectornum];
if (inf.CheckSectorPlane (inf.CurSector, true))
{
res.HitType = TRACE_HitFloor;
res.HitTexture = inf.CurSector->GetTexture(sector_t::floor);
if (res.CrossedWater == NULL &&
inf.CurSector->heightsec != NULL &&
inf.CurSector->heightsec->floorplane.ZatPoint (res.X, res.Y) >= res.Z)
{
res.CrossedWater = &sectors[inf.CurSector->sectornum];
}
}
else if (inf.CheckSectorPlane (inf.CurSector, false))
{
res.HitType = TRACE_HitCeiling;
res.HitTexture = inf.CurSector->GetTexture(sector_t::ceiling);
}
}
if (res.HitType != TRACE_HitNone)
{
if (flags)
{
return EditTraceResult (flags, res);
}
else
{
return true;
}
}
else
{
res.HitType = TRACE_HitNone;
res.X = x + FixedMul (vx, maxDist);
res.Y = y + FixedMul (vy, maxDist);
res.Z = z + FixedMul (vz, maxDist);
res.Distance = maxDist;
res.Fraction = FRACUNIT;
return false;
}
}
bool FTraceInfo::TraceTraverse (int ptflags)
{
FPathTraverse it(StartX, StartY, StartX + FixedMul (Vx, MaxDist), StartY + FixedMul (Vy, MaxDist), ptflags);
intercept_t *in;
while ((in = it.Next()))
{
fixed_t hitx, hity, hitz;
fixed_t dist;
if (in->isaline)
{
int lineside;
sector_t *entersector;
dist = FixedMul (MaxDist, in->frac);
hitx = StartX + FixedMul (Vx, dist);
hity = StartY + FixedMul (Vy, dist);
hitz = StartZ + FixedMul (Vz, dist);
fixed_t ff, fc, bf = 0, bc = 0;
// CurSector may be a copy so we must compare the sector number, not the index!
if (in->d.line->frontsector->sectornum == CurSector->sectornum)
{
lineside = 0;
}
else if (in->d.line->backsector && in->d.line->backsector->sectornum == CurSector->sectornum)
{
lineside = 1;
}
else
{ // Dammit. Why does Doom have to allow non-closed sectors?
if (in->d.line->backsector == NULL)
{
lineside = 0;
CurSector = in->d.line->frontsector;
}
else
{
lineside = P_PointOnLineSide (StartX, StartY, in->d.line);
CurSector = lineside ? in->d.line->backsector : in->d.line->frontsector;
}
}
if (!(in->d.line->flags & ML_TWOSIDED))
{
entersector = NULL;
}
else
{
entersector = (lineside == 0) ? in->d.line->backsector : in->d.line->frontsector;
// For backwards compatibility: Ignore lines with the same sector on both sides.
// This is the way Doom.exe did it and some WADs (e.g. Alien Vendetta MAP15 need it.
if (i_compatflags & COMPATF_TRACE && in->d.line->backsector == in->d.line->frontsector)
{
// We must check special activation here because the code below is never reached.
if (TraceFlags & TRACE_PCross)
{
P_ActivateLine (in->d.line, IgnoreThis, lineside, SPAC_PCross);
}
if (TraceFlags & TRACE_Impact)
{
P_ActivateLine (in->d.line, IgnoreThis, lineside, SPAC_Impact);
}
continue;
}
}
ff = CurSector->floorplane.ZatPoint (hitx, hity);
fc = CurSector->ceilingplane.ZatPoint (hitx, hity);
if (entersector != NULL)
{
bf = entersector->floorplane.ZatPoint (hitx, hity);
bc = entersector->ceilingplane.ZatPoint (hitx, hity);
}
sector_t *hsec = CurSector->GetHeightSec();
if (Results->CrossedWater == NULL &&
hsec != NULL &&
//CurSector->heightsec->waterzone &&
hitz <= hsec->floorplane.ZatPoint (hitx, hity))
{
// hit crossed a water plane
Results->CrossedWater = &sectors[CurSector->sectornum];
}
if (hitz <= ff)
{ // hit floor in front of wall
Results->HitType = TRACE_HitFloor;
Results->HitTexture = CurSector->GetTexture(sector_t::floor);
}
else if (hitz >= fc)
{ // hit ceiling in front of wall
Results->HitType = TRACE_HitCeiling;
Results->HitTexture = CurSector->GetTexture(sector_t::ceiling);
}
else if (entersector == NULL ||
hitz <= bf || hitz >= bc ||
in->d.line->flags & WallMask)
{ // hit the wall
Results->HitType = TRACE_HitWall;
Results->Tier =
entersector == NULL ? TIER_Middle :
hitz <= bf ? TIER_Lower :
hitz >= bc ? TIER_Upper : TIER_Middle;
if (TraceFlags & TRACE_Impact)
{
P_ActivateLine (in->d.line, IgnoreThis, lineside, SPAC_Impact);
}
}
else
{ // made it past the wall
#ifdef _3DFLOORS
// check for 3D floors first
if (entersector->e->XFloor.ffloors.Size())
{
memcpy(&DummySector[sectorsel],entersector,sizeof(sector_t));
entersector=&DummySector[sectorsel];
sectorsel^=1;
for(unsigned int i=0;i<entersector->e->XFloor.ffloors.Size();i++)
{
F3DFloor * rover=entersector->e->XFloor.ffloors[i];
int entershootthrough = !!(rover->flags&FF_SHOOTTHROUGH);
if (entershootthrough != inshootthrough && rover->flags&FF_EXISTS)
{
fixed_t ff_bottom=rover->bottom.plane->ZatPoint(hitx, hity);
fixed_t ff_top=rover->top.plane->ZatPoint(hitx, hity);
// clip to the part of the sector we are in
if (hitz>ff_top)
{
// above
if (bf<ff_top)
{
entersector->floorplane=*rover->top.plane;
entersector->SetTexture(sector_t::floor, *rover->top.texture, false);
bf=ff_top;
}
}
else if (hitz<ff_bottom)
{
//below
if (bc>ff_bottom)
{
entersector->ceilingplane=*rover->bottom.plane;
entersector->SetTexture(sector_t::ceiling, *rover->bottom.texture, false);
bc=ff_bottom;
}
}
else
{
//hit the edge - equivalent to hitting the wall
Results->HitType = TRACE_HitWall;
Results->Tier = TIER_FFloor;
Results->ffloor = rover;
if ((TraceFlags & TRACE_Impact) && in->d.line->special)
{
P_ActivateLine (in->d.line, IgnoreThis, lineside, SPAC_Impact);
}
goto cont;
}
}
}
}
#endif
Results->HitType = TRACE_HitNone;
if (TraceFlags & TRACE_PCross)
{
P_ActivateLine (in->d.line, IgnoreThis, lineside, SPAC_PCross);
}
if (TraceFlags & TRACE_Impact)
{ // This is incorrect for "impact", but Hexen did this, so
// we need to as well, for compatibility
P_ActivateLine (in->d.line, IgnoreThis, lineside, SPAC_Impact);
}
}
#ifdef _3DFLOORS
cont:
#endif
if (Results->HitType != TRACE_HitNone)
{
// We hit something, so figure out where exactly
Results->Sector = &sectors[CurSector->sectornum];
if (Results->HitType != TRACE_HitWall &&
!CheckSectorPlane (CurSector, Results->HitType == TRACE_HitFloor))
{ // trace is parallel to the plane (or right on it)
if (entersector == NULL)
{
Results->HitType = TRACE_HitWall;
Results->Tier = TIER_Middle;
}
else
{
if (hitz <= bf || hitz >= bc)
{
Results->HitType = TRACE_HitWall;
Results->Tier =
hitz <= bf ? TIER_Lower :
hitz >= bc ? TIER_Upper : TIER_Middle;
}
else
{
Results->HitType = TRACE_HitNone;
}
}
if (Results->HitType == TRACE_HitWall && TraceFlags & TRACE_Impact)
{
P_ActivateLine (in->d.line, IgnoreThis, lineside, SPAC_Impact);
}
}
if (Results->HitType == TRACE_HitWall)
{
Results->X = hitx;
Results->Y = hity;
Results->Z = hitz;
Results->Distance = dist;
Results->Fraction = in->frac;
Results->Line = in->d.line;
Results->Side = lineside;
}
}
if (Results->HitType == TRACE_HitNone)
{
CurSector = entersector;
EnterDist = dist;
continue;
}
if (TraceCallback != NULL)
{
if (!TraceCallback (*Results)) return false;
}
else
{
return false;
}
}
// Encountered an actor
if (!(in->d.thing->flags & ActorMask) ||
in->d.thing == IgnoreThis)
{
continue;
}
dist = FixedMul (MaxDist, in->frac);
hitx = StartX + FixedMul (Vx, dist);
hity = StartY + FixedMul (Vy, dist);
hitz = StartZ + FixedMul (Vz, dist);
if (hitz > in->d.thing->z + in->d.thing->height)
{ // trace enters above actor
if (Vz >= 0) continue; // Going up: can't hit
// Does it hit the top of the actor?
dist = FixedDiv(in->d.thing->z + in->d.thing->height - StartZ, Vz);
if (dist > MaxDist) continue;
in->frac = FixedDiv(dist, MaxDist);
hitx = StartX + FixedMul (Vx, dist);
hity = StartY + FixedMul (Vy, dist);
hitz = StartZ + FixedMul (Vz, dist);
// calculated coordinate is outside the actor's bounding box
if (abs(hitx - in->d.thing->x) > in->d.thing->radius ||
abs(hity - in->d.thing->y) > in->d.thing->radius) continue;
}
else if (hitz < in->d.thing->z)
{ // trace enters below actor
if (Vz <= 0) continue; // Going down: can't hit
// Does it hit the bottom of the actor?
dist = FixedDiv(in->d.thing->z - StartZ, Vz);
if (dist > MaxDist) continue;
in->frac = FixedDiv(dist, MaxDist);
hitx = StartX + FixedMul (Vx, dist);
hity = StartY + FixedMul (Vy, dist);
hitz = StartZ + FixedMul (Vz, dist);
// calculated coordinate is outside the actor's bounding box
if (abs(hitx - in->d.thing->x) > in->d.thing->radius ||
abs(hity - in->d.thing->y) > in->d.thing->radius) continue;
}
// check for extrafloors first
if (CurSector->e->XFloor.ffloors.Size())
{
fixed_t ff_floor=CurSector->floorplane.ZatPoint(hitx, hity);
fixed_t ff_ceiling=CurSector->ceilingplane.ZatPoint(hitx, hity);
if (hitz>ff_ceiling) // actor is hit above the current ceiling
{
Results->HitType=TRACE_HitCeiling;
Results->HitTexture = CurSector->GetTexture(sector_t::ceiling);
}
else if (hitz<ff_floor) // actor is hit below the current floor
{
Results->HitType=TRACE_HitFloor;
Results->HitTexture = CurSector->GetTexture(sector_t::floor);
}
else goto cont1;
// the trace hit a 3D-floor before the thing.
// Calculate an intersection and abort.
Results->Sector = &sectors[CurSector->sectornum];
if (!CheckSectorPlane(CurSector, Results->HitType==TRACE_HitFloor))
{
Results->HitType=TRACE_HitNone;
}
if (TraceCallback != NULL)
{
return TraceCallback (*Results);
}
else
{
return false;
}
}
cont1:
Results->HitType = TRACE_HitActor;
Results->X = hitx;
Results->Y = hity;
Results->Z = hitz;
Results->Distance = dist;
Results->Fraction = in->frac;
Results->Actor = in->d.thing;
if (TraceCallback != NULL)
{
if (!TraceCallback (*Results)) return false;
}
else
{
return false;
}
}
return true;
}
bool FTraceInfo::CheckSectorPlane (const sector_t *sector, bool checkFloor)
{
secplane_t plane;
if (checkFloor)
{
plane = sector->floorplane;
}
else
{
plane = sector->ceilingplane;
}
fixed_t den = TMulScale16 (plane.a, Vx, plane.b, Vy, plane.c, Vz);
if (den != 0)
{
fixed_t num = TMulScale16 (plane.a, StartX,
plane.b, StartY,
plane.c, StartZ) + plane.d;
fixed_t hitdist = FixedDiv (-num, den);
if (hitdist > EnterDist && hitdist < MaxDist)
{
Results->X = StartX + FixedMul (Vx, hitdist);
Results->Y = StartY + FixedMul (Vy, hitdist);
Results->Z = StartZ + FixedMul (Vz, hitdist);
Results->Distance = hitdist;
Results->Fraction = FixedDiv (hitdist, MaxDist);
return true;
}
}
return false;
}
static bool EditTraceResult (DWORD flags, FTraceResults &res)
{
if (flags & TRACE_NoSky)
{ // Throw away sky hits
if (res.HitType == TRACE_HitFloor || res.HitType == TRACE_HitCeiling)
{
if (res.HitTexture == skyflatnum)
{
res.HitType = TRACE_HitNone;
return false;
}
}
else if (res.HitType == TRACE_HitWall)
{
if (res.Tier == TIER_Upper &&
res.Line->frontsector->GetTexture(sector_t::ceiling) == skyflatnum &&
res.Line->backsector->GetTexture(sector_t::ceiling) == skyflatnum)
{
res.HitType = TRACE_HitNone;
return false;
}
}
}
return true;
}
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