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gzdoom/src/p_maputl.cpp

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// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// This source is available for distribution and/or modification
// only under the terms of the DOOM Source Code License as
// published by id Software. All rights reserved.
//
// The source is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
// for more details.
//
// $Log:$
//
// DESCRIPTION:
// Movement/collision utility functions,
// as used by function in p_map.c.
// BLOCKMAP Iterator functions,
// and some PIT_* functions to use for iteration.
//
//-----------------------------------------------------------------------------
#include <stdlib.h>
#include "m_bbox.h"
#include "doomdef.h"
#include "doomstat.h"
#include "p_local.h"
#include "p_3dmidtex.h"
// State.
#include "r_state.h"
#include "templates.h"
#include "po_man.h"
static AActor *RoughBlockCheck (AActor *mo, int index, void *);
//==========================================================================
//
// 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);
return (dx < dy) ? dx+dy-(dx>>1) : dx+dy-(dy>>1);
}
//==========================================================================
//
// P_InterceptVector
//
// Returns the fractional intercept point along the first divline.
//
//==========================================================================
fixed_t P_InterceptVector (const divline_t *v2, const divline_t *v1)
{
#if 0 // [RH] Use 64 bit ints, so long divlines don't overflow
SQWORD den = ( ((SQWORD)v1->dy*v2->dx - (SQWORD)v1->dx*v2->dy) >> FRACBITS );
if (den == 0)
return 0; // parallel
SQWORD num = ((SQWORD)(v1->x - v2->x)*v1->dy + (SQWORD)(v2->y - v1->y)*v1->dx);
return (fixed_t)(num / den);
#elif 0 // This is the original Doom version
fixed_t frac;
fixed_t num;
fixed_t 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 // optimized version of the float debug version. A lot faster on modern systens.
double frac;
double num;
double den;
// There's no need to divide by FRACUNIT here.
// At the end both num and den will contain a factor
// 1/(FRACUNIT*FRACUNIT) so they'll cancel each other out.
double v1x = (double)v1->x;
double v1y = (double)v1->y;
double v1dx = (double)v1->dx;
double v1dy = (double)v1->dy;
double v2x = (double)v2->x;
double v2y = (double)v2->y;
double v2dx = (double)v2->dx;
double v2dy = (double)v2->dy;
den = v1dy*v2dx - v1dx*v2dy;
if (den == 0)
return 0; // parallel
num = (v1x - v2x)*v1dy + (v2y - v1y)*v1dx;
frac = num / den;
return FLOAT2FIXED(frac);
#endif
}
//==========================================================================
//
// P_LineOpening
//
// Sets opentop and openbottom to the window
// through a two sided line.
//
//==========================================================================
void P_LineOpening (FLineOpening &open, AActor *actor, const line_t *linedef,
fixed_t x, fixed_t y, fixed_t refx, fixed_t refy, int flags)
{
if (!(flags & FFCF_ONLY3DFLOORS))
{
sector_t *front, *back;
fixed_t fc, ff, bc, bf;
if (linedef->sidedef[1] == NULL)
{
// single sided line
open.range = 0;
return;
}
front = linedef->frontsector;
back = linedef->backsector;
fc = front->ceilingplane.ZatPoint (x, y);
ff = front->floorplane.ZatPoint (x, y);
bc = back->ceilingplane.ZatPoint (x, y);
bf = back->floorplane.ZatPoint (x, y);
/*Printf ("]]]]]] %d %d\n", ff, bf);*/
open.topsec = fc < bc? front : back;
open.ceilingpic = open.topsec->GetTexture(sector_t::ceiling);
open.top = fc < bc ? fc : bc;
bool usefront;
// [RH] fudge a bit for actors that are moving across lines
// bordering a slope/non-slope that meet on the floor. Note
// that imprecisions in the plane equation mean there is a
// good chance that even if a slope and non-slope look like
// they line up, they won't be perfectly aligned.
if (refx == FIXED_MIN ||
abs (ff-bf) > 256)
{
usefront = (ff > bf);
}
else
{
if ((front->floorplane.a | front->floorplane.b) == 0)
usefront = true;
else if ((back->floorplane.a | front->floorplane.b) == 0)
usefront = false;
else
usefront = !P_PointOnLineSide (refx, refy, linedef);
}
if (usefront)
{
open.bottom = ff;
open.bottomsec = front;
open.floorpic = front->GetTexture(sector_t::floor);
open.lowfloor = bf;
}
else
{
open.bottom = bf;
open.bottomsec = back;
open.floorpic = back->GetTexture(sector_t::floor);
open.lowfloor = ff;
}
}
else
{ // Dummy stuff to have some sort of opening for the 3D checks to modify
open.topsec = NULL;
open.ceilingpic.SetInvalid();
open.top = FIXED_MAX;
open.bottomsec = NULL;
open.floorpic.SetInvalid();
open.bottom = FIXED_MIN;
open.lowfloor = FIXED_MAX;
}
// Check 3D floors
if (actor != NULL)
{
P_LineOpening_XFloors(open, actor, linedef, x, y, refx, refy, !!(flags & FFCF_3DRESTRICT));
}
if (actor != NULL && linedef->frontsector != NULL && linedef->backsector != NULL &&
linedef->flags & ML_3DMIDTEX)
{
open.touchmidtex = P_LineOpening_3dMidtex(actor, linedef, open, !!(flags & FFCF_3DRESTRICT));
}
else
{
open.abovemidtex = open.touchmidtex = false;
}
open.range = open.top - open.bottom;
}
//
// THING POSITION SETTING
//
//==========================================================================
//
// P_UnsetThingPosition
// Unlinks a thing from block map and sectors.
// On each position change, BLOCKMAP and other
// lookups maintaining lists of things inside
// these structures need to be updated.
//
//==========================================================================
void AActor::UnlinkFromWorld ()
{
sector_list = NULL;
if (!(flags & MF_NOSECTOR))
{
// invisible things don't need to be in sector list
// unlink from subsector
// killough 8/11/98: simpler scheme using pointers-to-pointers for prev
// pointers, allows head node pointers to be treated like everything else
AActor **prev = sprev;
AActor *next = snext;
if (prev != NULL) // prev will be NULL if this actor gets deleted due to cleaning up from a broken savegame
{
if ((*prev = next)) // unlink from sector list
next->sprev = prev;
snext = NULL;
sprev = (AActor **)(size_t)0xBeefCafe; // Woo! Bug-catching value!
// phares 3/14/98
//
// Save the sector list pointed to by touching_sectorlist.
// In P_SetThingPosition, we'll keep any nodes that represent
// sectors the Thing still touches. We'll add new ones then, and
// delete any nodes for sectors the Thing has vacated. Then we'll
// put it back into touching_sectorlist. It's done this way to
// avoid a lot of deleting/creating for nodes, when most of the
// time you just get back what you deleted anyway.
//
// If this Thing is being removed entirely, then the calling
// routine will clear out the nodes in sector_list.
sector_list = touching_sectorlist;
touching_sectorlist = NULL; //to be restored by P_SetThingPosition
}
}
if (!(flags & MF_NOBLOCKMAP))
{
// [RH] Unlink from all blocks this actor uses
FBlockNode *block = this->BlockNode;
while (block != NULL)
{
if (block->NextActor != NULL)
{
block->NextActor->PrevActor = block->PrevActor;
}
*(block->PrevActor) = block->NextActor;
FBlockNode *next = block->NextBlock;
block->Release ();
block = next;
}
BlockNode = NULL;
}
}
//==========================================================================
//
// P_SetThingPosition
// Links a thing into both a block and a subsector based on it's x y.
// Sets thing->sector properly
//
//==========================================================================
void AActor::LinkToWorld (bool buggy)
{
// link into subsector
sector_t *sec;
if (!buggy || numgamenodes == 0)
{
sec = P_PointInSector (x, y);
}
else
{
sec = LinkToWorldForMapThing ();
}
LinkToWorld (sec);
}
void AActor::LinkToWorld (sector_t *sec)
{
if (sec == NULL)
{
LinkToWorld ();
return;
}
Sector = sec;
subsector = R_PointInSubsector(x, y); // this is from the rendering nodes, not the gameplay nodes!
if ( !(flags & MF_NOSECTOR) )
{
// invisible things don't go into the sector links
// killough 8/11/98: simpler scheme using pointer-to-pointer prev
// pointers, allows head nodes to be treated like everything else
AActor **link = &sec->thinglist;
AActor *next = *link;
if ((snext = next))
next->sprev = &snext;
sprev = link;
*link = this;
// phares 3/16/98
//
// If sector_list isn't NULL, it has a collection of sector
// nodes that were just removed from this Thing.
// Collect the sectors the object will live in by looking at
// the existing sector_list and adding new nodes and deleting
// obsolete ones.
// When a node is deleted, its sector links (the links starting
// at sector_t->touching_thinglist) are broken. When a node is
// added, new sector links are created.
P_CreateSecNodeList (this, x, y);
touching_sectorlist = sector_list; // Attach to thing
sector_list = NULL; // clear for next time
}
// link into blockmap (inert things don't need to be in the blockmap)
if ( !(flags & MF_NOBLOCKMAP) )
{
int x1 = GetSafeBlockX(x - radius - bmaporgx);
int x2 = GetSafeBlockX(x + radius - bmaporgx);
int y1 = GetSafeBlockY(y - radius - bmaporgy);
int y2 = GetSafeBlockY(y + radius - bmaporgy);
if (x1 >= bmapwidth || x2 < 0 || y1 >= bmapheight || y2 < 0)
{ // thing is off the map
BlockNode = NULL;
}
else
{ // [RH] Link into every block this actor touches, not just the center one
FBlockNode **alink = &this->BlockNode;
x1 = MAX (0, x1);
y1 = MAX (0, y1);
x2 = MIN (bmapwidth - 1, x2);
y2 = MIN (bmapheight - 1, y2);
for (int y = y1; y <= y2; ++y)
{
for (int x = x1; x <= x2; ++x)
{
FBlockNode **link = &blocklinks[y*bmapwidth + x];
FBlockNode *node = FBlockNode::Create (this, x, y);
// Link in to block
if ((node->NextActor = *link) != NULL)
{
(*link)->PrevActor = &node->NextActor;
}
node->PrevActor = link;
*link = node;
// Link in to actor
node->PrevBlock = alink;
node->NextBlock = NULL;
(*alink) = node;
alink = &node->NextBlock;
}
}
}
}
}
//==========================================================================
//
// [RH] LinkToWorldForMapThing
//
// Emulate buggy PointOnLineSide and fix actors that lie on
// lines to compensate for some IWAD maps.
//
//==========================================================================
static int R_PointOnSideSlow (fixed_t x, fixed_t y, node_t *node)
{
// [RH] This might have been faster than two multiplies and an
// add on a 386/486, but it certainly isn't on anything newer than that.
fixed_t dx;
fixed_t dy;
fixed_t left;
fixed_t right;
if (!node->dx)
{
if (x <= node->x)
return node->dy > 0;
return node->dy < 0;
}
if (!node->dy)
{
if (y <= node->y)
return node->dx < 0;
return node->dx > 0;
}
dx = (x - node->x);
dy = (y - node->y);
// Try to quickly decide by looking at sign bits.
if ( (node->dy ^ node->dx ^ dx ^ dy)&0x80000000 )
{
if ( (node->dy ^ dx) & 0x80000000 )
{
// (left is negative)
return 1;
}
return 0;
}
left = FixedMul ( node->dy>>FRACBITS , dx );
right = FixedMul ( dy , node->dx>>FRACBITS );
if (right < left)
{
// front side
return 0;
}
// back side
return 1;
}
sector_t *AActor::LinkToWorldForMapThing ()
{
node_t *node = gamenodes + numgamenodes - 1;
do
{
// Use original buggy point-on-side test when spawning
// things at level load so that the map spots in the
// emerald key room of Hexen MAP01 are spawned on the
// window ledge instead of the blocking floor in front
// of it. Why do I consider it buggy? Because a point
// that lies directly on a line should always be
// considered as "in front" of the line. The orientation
// of the line should be irrelevant.
node = (node_t *)node->children[R_PointOnSideSlow (x, y, node)];
}
while (!((size_t)node & 1));
subsector_t *ssec = (subsector_t *)((BYTE *)node - 1);
if (flags4 & MF4_FIXMAPTHINGPOS)
{
// If the thing is exactly on a line, move it into the subsector
// slightly in order to resolve clipping issues in the renderer.
// This check needs to use the blockmap, because an actor on a
// one-sided line might go into a subsector behind the line, so
// the line would not be included as one of its subsector's segs.
int blockx = GetSafeBlockX(x - bmaporgx);
int blocky = GetSafeBlockY(y - bmaporgy);
if ((unsigned int)blockx < (unsigned int)bmapwidth &&
(unsigned int)blocky < (unsigned int)bmapheight)
{
int *list;
for (list = blockmaplump + blockmap[blocky*bmapwidth + blockx] + 1; *list != -1; ++list)
{
line_t *ldef = &lines[*list];
if (ldef->frontsector == ldef->backsector)
{ // Skip two-sided lines inside a single sector
continue;
}
if (ldef->backsector != NULL)
{
if (ldef->frontsector->floorplane == ldef->backsector->floorplane &&
ldef->frontsector->ceilingplane == ldef->backsector->ceilingplane)
{ // Skip two-sided lines without any height difference on either side
continue;
}
}
// Not inside the line's bounding box
if (x + radius <= ldef->bbox[BOXLEFT]
|| x - radius >= ldef->bbox[BOXRIGHT]
|| y + radius <= ldef->bbox[BOXBOTTOM]
|| y - radius >= ldef->bbox[BOXTOP] )
continue;
// Get the exact distance to the line
divline_t dll, dlv;
fixed_t linelen = (fixed_t)sqrt((double)ldef->dx*ldef->dx + (double)ldef->dy*ldef->dy);
P_MakeDivline (ldef, &dll);
dlv.x = x;
dlv.y = y;
dlv.dx = FixedDiv(dll.dy, linelen);
dlv.dy = -FixedDiv(dll.dx, linelen);
fixed_t distance = abs(P_InterceptVector(&dlv, &dll));
if (distance < radius)
{
DPrintf ("%s at (%d,%d) lies on %s line %td, distance = %f\n",
this->GetClass()->TypeName.GetChars(), x>>FRACBITS, y>>FRACBITS,
ldef->dx == 0? "vertical" : ldef->dy == 0? "horizontal" : "diagonal",
ldef-lines, FIXED2FLOAT(distance));
angle_t finean = R_PointToAngle2 (0, 0, ldef->dx, ldef->dy);
if (ldef->backsector != NULL && ldef->backsector == ssec->sector)
{
finean += ANGLE_90;
}
else
{
finean -= ANGLE_90;
}
finean >>= ANGLETOFINESHIFT;
// Get the distance we have to move the object away from the wall
distance = radius - distance;
x += FixedMul(distance, finecosine[finean]);
y += FixedMul(distance, finesine[finean]);
return P_PointInSector (x, y);
}
}
}
}
return ssec->sector;
}
void AActor::SetOrigin (fixed_t ix, fixed_t iy, fixed_t iz)
{
UnlinkFromWorld ();
x = ix;
y = iy;
z = iz;
LinkToWorld ();
floorz = Sector->floorplane.ZatPoint (ix, iy);
ceilingz = Sector->ceilingplane.ZatPoint (ix, iy);
P_FindFloorCeiling(this, FFCF_ONLYSPAWNPOS);
}
FBlockNode *FBlockNode::FreeBlocks = NULL;
FBlockNode *FBlockNode::Create (AActor *who, int x, int y)
{
FBlockNode *block;
if (FreeBlocks != NULL)
{
block = FreeBlocks;
FreeBlocks = block->NextBlock;
}
else
{
block = new FBlockNode;
}
block->BlockIndex = x + y*bmapwidth;
block->Me = who;
block->NextActor = NULL;
block->PrevActor = NULL;
block->PrevBlock = NULL;
block->NextBlock = NULL;
return block;
}
void FBlockNode::Release ()
{
NextBlock = FreeBlocks;
FreeBlocks = this;
}
//
// BLOCK MAP ITERATORS
// For each line/thing in the given mapblock,
// call the passed PIT_* function.
// If the function returns false,
// exit with false without checking anything else.
//
//===========================================================================
//
// FBlockLinesIterator
//
//===========================================================================
extern polyblock_t **PolyBlockMap;
FBlockLinesIterator::FBlockLinesIterator(int _minx, int _miny, int _maxx, int _maxy, bool keepvalidcount)
{
if (!keepvalidcount) validcount++;
minx = _minx;
maxx = _maxx;
miny = _miny;
maxy = _maxy;
Reset();
}
FBlockLinesIterator::FBlockLinesIterator(const FBoundingBox &box)
{
validcount++;
maxy = GetSafeBlockY(box.Top() - bmaporgy);
miny = GetSafeBlockY(box.Bottom() - bmaporgy);
maxx = GetSafeBlockX(box.Right() - bmaporgx);
minx = GetSafeBlockX(box.Left() - bmaporgx);
Reset();
}
//===========================================================================
//
// FBlockLinesIterator :: StartBlock
//
//===========================================================================
void FBlockLinesIterator::StartBlock(int x, int y)
{
curx = x;
cury = y;
if (x >= 0 && y >= 0 && x < bmapwidth && y <bmapheight)
{
int offset = y*bmapwidth + x;
polyLink = PolyBlockMap? PolyBlockMap[offset] : NULL;
polyIndex = 0;
// There is an extra entry at the beginning of every block.
// Apparently, id had originally intended for it to be used
// to keep track of things, but the final code does not do that.
list = blockmaplump + *(blockmap + offset) + 1;
}
else
{
// invalid block
list = NULL;
polyLink = NULL;
}
}
//===========================================================================
//
// FBlockLinesIterator :: Next
//
//===========================================================================
line_t *FBlockLinesIterator::Next()
{
while (true)
{
while (polyLink != NULL)
{
if (polyLink->polyobj)
{
if (polyIndex == 0)
{
if (polyLink->polyobj->validcount == validcount)
{
polyLink = polyLink->next;
continue;
}
polyLink->polyobj->validcount = validcount;
}
line_t *ld = polyLink->polyobj->Linedefs[polyIndex];
if (++polyIndex >= (int)polyLink->polyobj->Linedefs.Size())
{
polyLink = polyLink->next;
polyIndex = 0;
}
if (ld->validcount == validcount)
{
continue;
}
else
{
ld->validcount = validcount;
return ld;
}
}
else polyLink = polyLink->next;
}
if (list != NULL)
{
while (*list != -1)
{
line_t *ld = &lines[*list];
list++;
if (ld->validcount != validcount)
{
ld->validcount = validcount;
return ld;
}
}
}
if (++curx > maxx)
{
curx = minx;
if (++cury > maxy) return NULL;
}
StartBlock(curx, cury);
}
}
//===========================================================================
//
// FBlockThingsIterator :: FBlockThingsIterator
//
//===========================================================================
FBlockThingsIterator::FBlockThingsIterator()
: DynHash(0)
{
minx = maxx = 0;
miny = maxy = 0;
ClearHash();
block = NULL;
}
FBlockThingsIterator::FBlockThingsIterator(int _minx, int _miny, int _maxx, int _maxy)
: DynHash(0)
{
minx = _minx;
maxx = _maxx;
miny = _miny;
maxy = _maxy;
ClearHash();
Reset();
}
FBlockThingsIterator::FBlockThingsIterator(const FBoundingBox &box)
: DynHash(0)
{
maxy = GetSafeBlockY(box.Top() - bmaporgy);
miny = GetSafeBlockY(box.Bottom() - bmaporgy);
maxx = GetSafeBlockX(box.Right() - bmaporgx);
minx = GetSafeBlockX(box.Left() - bmaporgx);
ClearHash();
Reset();
}
//===========================================================================
//
// FBlockThingsIterator :: ClearHash
//
//===========================================================================
void FBlockThingsIterator::ClearHash()
{
clearbuf(Buckets, countof(Buckets), -1);
NumFixedHash = 0;
DynHash.Clear();
}
//===========================================================================
//
// FBlockThingsIterator :: StartBlock
//
//===========================================================================
void FBlockThingsIterator::StartBlock(int x, int y)
{
curx = x;
cury = y;
if (x >= 0 && y >= 0 && x < bmapwidth && y <bmapheight)
{
block = blocklinks[y*bmapwidth + x];
}
else
{
// invalid block
block = NULL;
}
}
//===========================================================================
//
// FBlockThingsIterator :: SwitchBlock
//
//===========================================================================
void FBlockThingsIterator::SwitchBlock(int x, int y)
{
minx = maxx = x;
miny = maxy = y;
StartBlock(x, y);
}
//===========================================================================
//
// FBlockThingsIterator :: Next
//
//===========================================================================
AActor *FBlockThingsIterator::Next(bool centeronly)
{
for (;;)
{
while (block != NULL)
{
AActor *me = block->Me;
FBlockNode *mynode = block;
HashEntry *entry;
int i;
block = block->NextActor;
// Don't recheck things that were already checked
if (mynode->NextBlock == NULL && mynode->PrevBlock == &me->BlockNode)
{ // This actor doesn't span blocks, so we know it can only ever be checked once.
return me;
}
if (centeronly)
{
// Block boundaries for compatibility mode
fixed_t blockleft = (curx << MAPBLOCKSHIFT) + bmaporgx;
fixed_t blockright = blockleft + MAPBLOCKSIZE;
fixed_t blockbottom = (cury << MAPBLOCKSHIFT) + bmaporgy;
fixed_t blocktop = blockbottom + MAPBLOCKSIZE;
// only return actors with the center in this block
if (me->x >= blockleft && me->x < blockright &&
me->y >= blockbottom && me->y < blocktop)
{
return me;
}
}
else
{
size_t hash = ((size_t)me >> 3) % countof(Buckets);
for (i = Buckets[hash]; i >= 0; )
{
entry = GetHashEntry(i);
if (entry->Actor == me)
{ // I've already been checked. Skip to the next actor.
break;
}
i = entry->Next;
}
if (i < 0)
{ // Add me to the hash table and return me.
if (NumFixedHash < (int)countof(FixedHash))
{
entry = &FixedHash[NumFixedHash];
entry->Next = Buckets[hash];
Buckets[hash] = NumFixedHash++;
}
else
{
if (DynHash.Size() == 0)
{
DynHash.Grow(50);
}
i = DynHash.Reserve(1);
entry = &DynHash[i];
entry->Next = Buckets[hash];
Buckets[hash] = i + countof(FixedHash);
}
entry->Actor = me;
return me;
}
}
}
if (++curx > maxx)
{
curx = minx;
if (++cury > maxy) return NULL;
}
StartBlock(curx, cury);
}
}
//===========================================================================
//
// FPathTraverse :: Intercepts
//
//===========================================================================
TArray<intercept_t> FPathTraverse::intercepts(128);
//===========================================================================
//
// FPathTraverse :: 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.
//
//===========================================================================
void FPathTraverse::AddLineIntercepts(int bx, int by)
{
FBlockLinesIterator it(bx, by, bx, by, true);
line_t *ld;
while ((ld = it.Next()))
{
int s1;
int 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) continue; // line isn't crossed
// hit the line
P_MakeDivline (ld, &dl);
frac = P_InterceptVector (&trace, &dl);
if (frac < 0) continue; // behind source
intercept_t newintercept;
newintercept.frac = frac;
newintercept.isaline = true;
newintercept.done = false;
newintercept.d.line = ld;
intercepts.Push (newintercept);
}
}
//===========================================================================
//
// FPathTraverse :: AddThingIntercepts
//
//===========================================================================
void FPathTraverse::AddThingIntercepts (int bx, int by, FBlockThingsIterator &it, bool compatible)
{
AActor *thing;
it.SwitchBlock(bx, by);
while ((thing = it.Next(compatible)))
{
int numfronts = 0;
divline_t line;
int i;
if (!compatible)
{
// [RH] Don't check a corner to corner crossection for hit.
// Instead, check against the actual bounding box (but not if compatibility optioned.)
// There's probably a smarter way to determine which two sides
// of the thing face the trace than by trying all four sides...
for (i = 0; i < 4; ++i)
{
switch (i)
{
case 0: // Top edge
line.x = thing->x + thing->radius;
line.y = thing->y + thing->radius;
line.dx = -thing->radius * 2;
line.dy = 0;
break;
case 1: // Right edge
line.x = thing->x + thing->radius;
line.y = thing->y - thing->radius;
line.dx = 0;
line.dy = thing->radius * 2;
break;
case 2: // Bottom edge
line.x = thing->x - thing->radius;
line.y = thing->y - thing->radius;
line.dx = thing->radius * 2;
line.dy = 0;
break;
case 3: // Left edge
line.x = thing->x - thing->radius;
line.y = thing->y + thing->radius;
line.dx = 0;
line.dy = thing->radius * -2;
break;
}
// Check if this side is facing the trace origin
if (P_PointOnDivlineSide (trace.x, trace.y, &line) == 0)
{
numfronts++;
// If it is, see if the trace crosses it
if (P_PointOnDivlineSide (line.x, line.y, &trace) !=
P_PointOnDivlineSide (line.x + line.dx, line.y + line.dy, &trace))
{
// It's a hit
fixed_t frac = P_InterceptVector (&trace, &line);
if (frac < 0)
{ // behind source
continue;
}
intercept_t newintercept;
newintercept.frac = frac;
newintercept.isaline = false;
newintercept.done = false;
newintercept.d.thing = thing;
intercepts.Push (newintercept);
continue;
}
}
}
// If none of the sides was facing the trace, then the trace
// must have started inside the box, so add it as an intercept.
if (numfronts == 0)
{
intercept_t newintercept;
newintercept.frac = 0;
newintercept.isaline = false;
newintercept.done = false;
newintercept.d.thing = thing;
intercepts.Push (newintercept);
}
}
else
{
// Old code for compatibility purposes
fixed_t x1, y1, x2, y2;
int s1, s2;
divline_t dl;
fixed_t frac;
bool 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)
{
dl.x = x1;
dl.y = y1;
dl.dx = x2-x1;
dl.dy = y2-y1;
frac = P_InterceptVector (&trace, &dl);
if (frac >= 0)
{
intercept_t newintercept;
newintercept.frac = frac;
newintercept.isaline = false;
newintercept.done = false;
newintercept.d.thing = thing;
intercepts.Push (newintercept);
}
}
}
}
}
//===========================================================================
//
// FPathTraverse :: Next
//
//===========================================================================
intercept_t *FPathTraverse::Next()
{
intercept_t *in = NULL;
fixed_t dist = FIXED_MAX;
for (unsigned scanpos = intercept_index; scanpos < intercepts.Size (); scanpos++)
{
intercept_t *scan = &intercepts[scanpos];
if (scan->frac < dist && !scan->done)
{
dist = scan->frac;
in = scan;
}
}
if (dist > maxfrac || in == NULL) return NULL; // checked everything in range
in->done = true;
return in;
}
//===========================================================================
//
// FPathTraverse
// Traces a line from x1,y1 to x2,y2,
//
//===========================================================================
FPathTraverse::FPathTraverse (fixed_t x1, fixed_t y1, fixed_t x2, fixed_t y2, int flags)
{
fixed_t xt1, xt2;
fixed_t yt1, yt2;
long long _x1, _x2, _y1, _y2;
fixed_t xstep;
fixed_t ystep;
fixed_t partialx, partialy;
fixed_t xintercept;
fixed_t yintercept;
int mapx;
int mapy;
int mapxstep;
int mapystep;
int count;
validcount++;
intercept_index = intercepts.Size();
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;
if (flags & PT_DELTA)
{
trace.dx = x2;
trace.dy = y2;
}
else
{
trace.dx = x2 - x1;
trace.dy = y2 - y1;
}
_x1 = (long long)x1 - bmaporgx;
_y1 = (long long)y1 - bmaporgy;
x1 -= bmaporgx;
y1 -= bmaporgy;
xt1 = int(_x1 >> MAPBLOCKSHIFT);
yt1 = int(_y1 >> MAPBLOCKSHIFT);
if (flags & PT_DELTA)
{
_x2 = _x1 + x2;
_y2 = _y1 + y2;
xt2 = int(_x2 >> MAPBLOCKSHIFT);
yt2 = int(_y2 >> MAPBLOCKSHIFT);
x2 = (int)_x2;
y2 = (int)_y2;
}
else
{
_x2 = (long long)x2 - bmaporgx;
_y2 = (long long)y2 - bmaporgy;
x2 -= bmaporgx;
y2 -= bmaporgy;
xt2 = int(_x2 >> MAPBLOCKSHIFT);
yt2 = int(_y2 >> MAPBLOCKSHIFT);
}
if (xt2 > xt1)
{
mapxstep = 1;
partialx = FRACUNIT - ((x1>>MAPBTOFRAC)&(FRACUNIT-1));
ystep = FixedDiv (y2-y1,abs(x2-x1));
}
else if (xt2 < xt1)
{
mapxstep = -1;
partialx = (x1>>MAPBTOFRAC)&(FRACUNIT-1);
ystep = FixedDiv (y2-y1,abs(x2-x1));
}
else
{
mapxstep = 0;
partialx = FRACUNIT;
ystep = 256*FRACUNIT;
}
yintercept = int(_y1>>MAPBTOFRAC) + FixedMul (partialx, ystep);
if (yt2 > yt1)
{
mapystep = 1;
partialy = FRACUNIT - ((y1>>MAPBTOFRAC)&(FRACUNIT-1));
xstep = FixedDiv (x2-x1,abs(y2-y1));
}
else if (yt2 < yt1)
{
mapystep = -1;
partialy = (y1>>MAPBTOFRAC)&(FRACUNIT-1);
xstep = FixedDiv (x2-x1,abs(y2-y1));
}
else
{
mapystep = 0;
partialy = FRACUNIT;
xstep = 256*FRACUNIT;
}
xintercept = int(_x1>>MAPBTOFRAC) + FixedMul (partialy, xstep);
// [RH] Fix for traces that pass only through blockmap corners. In that case,
// xintercept and yintercept can both be set ahead of mapx and mapy, so the
// for loop would never advance anywhere.
if (abs(xstep) == FRACUNIT && abs(ystep) == FRACUNIT)
{
if (ystep < 0)
{
partialx = FRACUNIT - partialx;
}
if (xstep < 0)
{
partialy = FRACUNIT - partialy;
}
if (partialx == partialy)
{
xintercept = xt1 << FRACBITS;
yintercept = yt1 << FRACBITS;
}
}
// Step through map blocks.
// Count is present to prevent a round off error
// from skipping the break statement.
mapx = xt1;
mapy = yt1;
bool compatible = (flags & PT_COMPATIBLE) && (i_compatflags & COMPATF_HITSCAN);
// we want to use one list of checked actors for the entire operation
FBlockThingsIterator btit;
for (count = 0 ; count < 100 ; count++)
{
if (flags & PT_ADDLINES)
{
AddLineIntercepts(mapx, mapy);
}
if (flags & PT_ADDTHINGS)
{
AddThingIntercepts(mapx, mapy, btit, compatible);
}
if (mapx == xt2 && mapy == yt2)
{
break;
}
// [RH] Handle corner cases properly instead of pretending they don't exist.
switch ((((yintercept >> FRACBITS) == mapy) << 1) | ((xintercept >> FRACBITS) == mapx))
{
case 0: // neither xintercept nor yintercept match!
count = 100; // Stop traversing, because somebody screwed up.
break;
case 1: // xintercept matches
xintercept += xstep;
mapy += mapystep;
break;
case 2: // yintercept matches
yintercept += ystep;
mapx += mapxstep;
break;
case 3: // xintercept and yintercept both match
// The trace is exiting a block through its corner. Not only does the block
// being entered need to be checked (which will happen when this loop
// continues), but the other two blocks adjacent to the corner also need to
// be checked.
if (!compatible)
{
if (flags & PT_ADDLINES)
{
AddLineIntercepts(mapx + mapxstep, mapy);
AddLineIntercepts(mapx, mapy + mapystep);
}
if (flags & PT_ADDTHINGS)
{
AddThingIntercepts(mapx + mapxstep, mapy, btit, false);
AddThingIntercepts(mapx, mapy + mapystep, btit, false);
}
xintercept += xstep;
yintercept += ystep;
mapx += mapxstep;
mapy += mapystep;
}
else
{
count = 100; // Doom originally did not handle this case so do the same in compatibility mode.
}
break;
}
}
maxfrac = FRACUNIT;
}
FPathTraverse::~FPathTraverse()
{
intercepts.Resize(intercept_index);
}
//===========================================================================
//
// P_RoughMonsterSearch
//
// Searches though the surrounding mapblocks for monsters/players
// distance is in MAPBLOCKUNITS
//===========================================================================
AActor *P_RoughMonsterSearch (AActor *mo, int distance, bool onlyseekable)
{
return P_BlockmapSearch (mo, distance, RoughBlockCheck, (void *)onlyseekable);
}
AActor *P_BlockmapSearch (AActor *mo, int distance, AActor *(*check)(AActor*, int, void *), void *params)
{
int blockX;
int blockY;
int startX, startY;
int blockIndex;
int firstStop;
int secondStop;
int thirdStop;
int finalStop;
int count;
AActor *target;
startX = GetSafeBlockX(mo->x-bmaporgx);
startY = GetSafeBlockY(mo->y-bmaporgy);
validcount++;
if (startX >= 0 && startX < bmapwidth && startY >= 0 && startY < bmapheight)
{
if ( (target = check (mo, startY*bmapwidth+startX, params)) )
{ // found a target right away
return target;
}
}
for (count = 1; count <= distance; count++)
{
blockX = clamp (startX-count, 0, bmapwidth-1);
blockY = clamp (startY-count, 0, bmapheight-1);
blockIndex = blockY*bmapwidth+blockX;
firstStop = startX+count;
if (firstStop < 0)
{
continue;
}
if (firstStop >= bmapwidth)
{
firstStop = bmapwidth-1;
}
secondStop = startY+count;
if (secondStop < 0)
{
continue;
}
if (secondStop >= bmapheight)
{
secondStop = bmapheight-1;
}
thirdStop = secondStop*bmapwidth+blockX;
secondStop = secondStop*bmapwidth+firstStop;
firstStop += blockY*bmapwidth;
finalStop = blockIndex;
// Trace the first block section (along the top)
for (; blockIndex <= firstStop; blockIndex++)
{
if ( (target = check (mo, blockIndex, params)) )
{
return target;
}
}
// Trace the second block section (right edge)
for (blockIndex--; blockIndex <= secondStop; blockIndex += bmapwidth)
{
if ( (target = check (mo, blockIndex, params)) )
{
return target;
}
}
// Trace the third block section (bottom edge)
for (blockIndex -= bmapwidth; blockIndex >= thirdStop; blockIndex--)
{
if ( (target = check (mo, blockIndex, params)) )
{
return target;
}
}
// Trace the final block section (left edge)
for (blockIndex++; blockIndex > finalStop; blockIndex -= bmapwidth)
{
if ( (target = check (mo, blockIndex, params)) )
{
return target;
}
}
}
return NULL;
}
//===========================================================================
//
// RoughBlockCheck
//
//===========================================================================
static AActor *RoughBlockCheck (AActor *mo, int index, void *param)
{
bool onlyseekable = param != NULL;
FBlockNode *link;
for (link = blocklinks[index]; link != NULL; link = link->NextActor)
{
if (link->Me != mo)
{
if (onlyseekable && !mo->CanSeek(link->Me))
{
continue;
}
if (mo->IsOkayToAttack (link->Me))
{
return link->Me;
}
}
}
return NULL;
}
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