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338 lines
11 KiB
C
338 lines
11 KiB
C
/* Emacs style mode select -*- C++ -*-
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*-----------------------------------------------------------------------------
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*
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*
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* PrBoom: a Doom port merged with LxDoom and LSDLDoom
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* based on BOOM, a modified and improved DOOM engine
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* Copyright (C) 1999 by
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* id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman
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* Copyright (C) 1999-2000 by
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* Jess Haas, Nicolas Kalkhof, Colin Phipps, Florian Schulze
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* Copyright 2005, 2006 by
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* Florian Schulze, Colin Phipps, Neil Stevens, Andrey Budko
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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* 02111-1307, USA.
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*
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* DESCRIPTION:
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* LineOfSight/Visibility checks, uses REJECT Lookup Table.
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*
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*-----------------------------------------------------------------------------*/
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#include "doomstat.h"
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#include "r_main.h"
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#include "p_map.h"
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#include "p_maputl.h"
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#include "p_setup.h"
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#include "m_bbox.h"
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#include "lprintf.h"
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//
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// P_CheckSight
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//
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// killough 4/19/98:
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// Convert LOS info to struct for reentrancy and efficiency of data locality
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typedef struct {
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fixed_t sightzstart, t2x, t2y; // eye z of looker
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divline_t strace; // from t1 to t2
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fixed_t topslope, bottomslope; // slopes to top and bottom of target
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fixed_t bbox[4];
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fixed_t maxz,minz; // cph - z optimisations for 2sided lines
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} los_t;
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static los_t los; // cph - made static
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//
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// P_DivlineSide
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// Returns side 0 (front), 1 (back), or 2 (on).
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//
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// killough 4/19/98: made static, cleaned up
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inline static int P_DivlineSide(fixed_t x, fixed_t y, const divline_t *node)
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{
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fixed_t left, right;
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return
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!node->dx ? x == node->x ? 2 : x <= node->x ? node->dy > 0 : node->dy < 0 :
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!node->dy ? ( compatibility_level < prboom_4_compatibility ? x : y) == node->y ? 2 : y <= node->y ? node->dx < 0 : node->dx > 0 :
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(right = ((y - node->y) >> FRACBITS) * (node->dx >> FRACBITS)) <
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(left = ((x - node->x) >> FRACBITS) * (node->dy >> FRACBITS)) ? 0 :
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right == left ? 2 : 1;
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}
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//
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// P_CrossSubsector
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// Returns true
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// if strace crosses the given subsector successfully.
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//
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// killough 4/19/98: made static and cleaned up
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static boolean P_CrossSubsector(int num)
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{
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seg_t *seg = segs + subsectors[num].firstline;
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int count;
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fixed_t opentop = 0, openbottom = 0;
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const sector_t *front = NULL, *back = NULL;
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#ifdef RANGECHECK
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if (num >= numsubsectors)
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I_Error("P_CrossSubsector: ss %i with numss = %i", num, numsubsectors);
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#endif
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for (count = subsectors[num].numlines; --count >= 0; seg++) { // check lines
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line_t *line = seg->linedef;
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divline_t divl;
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if(!line) // figgi -- skip minisegs
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continue;
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// allready checked other side?
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if (line->validcount == validcount)
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continue;
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line->validcount = validcount;
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/* OPTIMIZE: killough 4/20/98: Added quick bounding-box rejection test
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* cph - this is causing demo desyncs on original Doom demos.
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* Who knows why. Exclude test for those.
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*/
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if (!demo_compatibility)
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if (line->bbox[BOXLEFT ] > los.bbox[BOXRIGHT ] ||
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line->bbox[BOXRIGHT ] < los.bbox[BOXLEFT ] ||
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line->bbox[BOXBOTTOM] > los.bbox[BOXTOP ] ||
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line->bbox[BOXTOP] < los.bbox[BOXBOTTOM])
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continue;
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// cph - do what we can before forced to check intersection
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if (line->flags & ML_TWOSIDED) {
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// no wall to block sight with?
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if ((front = seg->frontsector)->floorheight ==
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(back = seg->backsector)->floorheight &&
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front->ceilingheight == back->ceilingheight)
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continue;
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// possible occluder
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// because of ceiling height differences
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opentop = front->ceilingheight < back->ceilingheight ?
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front->ceilingheight : back->ceilingheight ;
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// because of floor height differences
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openbottom = front->floorheight > back->floorheight ?
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front->floorheight : back->floorheight ;
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// cph - reject if does not intrude in the z-space of the possible LOS
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if ((opentop >= los.maxz) && (openbottom <= los.minz))
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continue;
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}
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{ // Forget this line if it doesn't cross the line of sight
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const vertex_t *v1,*v2;
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v1 = line->v1;
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v2 = line->v2;
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if (P_DivlineSide(v1->x, v1->y, &los.strace) ==
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P_DivlineSide(v2->x, v2->y, &los.strace))
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continue;
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divl.dx = v2->x - (divl.x = v1->x);
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divl.dy = v2->y - (divl.y = v1->y);
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// line isn't crossed?
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if (P_DivlineSide(los.strace.x, los.strace.y, &divl) ==
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P_DivlineSide(los.t2x, los.t2y, &divl))
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continue;
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}
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// cph - if bottom >= top or top < minz or bottom > maxz then it must be
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// solid wrt this LOS
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if (!(line->flags & ML_TWOSIDED) || (openbottom >= opentop) ||
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(opentop < los.minz) || (openbottom > los.maxz))
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return false;
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{ // crosses a two sided line
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/* cph 2006/07/15 - oops, we missed this in 2.4.0 & .1;
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* use P_InterceptVector2 for those compat levels only. */
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fixed_t frac = (compatibility_level == prboom_5_compatibility || compatibility_level == prboom_6_compatibility) ?
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P_InterceptVector2(&los.strace, &divl) :
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P_InterceptVector(&los.strace, &divl);
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if (front->floorheight != back->floorheight) {
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fixed_t slope = FixedDiv(openbottom - los.sightzstart , frac);
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if (slope > los.bottomslope)
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los.bottomslope = slope;
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}
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if (front->ceilingheight != back->ceilingheight)
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{
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fixed_t slope = FixedDiv(opentop - los.sightzstart , frac);
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if (slope < los.topslope)
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los.topslope = slope;
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}
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if (los.topslope <= los.bottomslope)
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return false; // stop
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}
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}
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// passed the subsector ok
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return true;
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}
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//
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// P_CrossBSPNode
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// Returns true
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// if strace crosses the given node successfully.
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//
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// killough 4/20/98: rewritten to remove tail recursion, clean up, and optimize
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// cph - Made to use R_PointOnSide instead of P_DivlineSide, since the latter
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// could return 2 which was ambigous, and the former is
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// better optimised; also removes two casts :-)
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static boolean P_CrossBSPNode_LxDoom(int bspnum)
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{
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while (!(bspnum & NF_SUBSECTOR))
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{
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register const node_t *bsp = nodes + bspnum;
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int side,side2;
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side = R_PointOnSide(los.strace.x, los.strace.y, bsp);
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side2 = R_PointOnSide(los.t2x, los.t2y, bsp);
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if (side == side2)
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bspnum = bsp->children[side]; // doesn't touch the other side
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else // the partition plane is crossed here
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if (!P_CrossBSPNode_LxDoom(bsp->children[side]))
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return 0; // cross the starting side
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else
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bspnum = bsp->children[side^1]; // cross the ending side
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}
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return P_CrossSubsector(bspnum == -1 ? 0 : bspnum & ~NF_SUBSECTOR);
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}
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static boolean P_CrossBSPNode_PrBoom(int bspnum)
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{
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while (!(bspnum & NF_SUBSECTOR))
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{
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register const node_t *bsp = nodes + bspnum;
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int side,side2;
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side = P_DivlineSide(los.strace.x,los.strace.y,(const divline_t *)bsp)&1;
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side2= P_DivlineSide(los.t2x, los.t2y, (const divline_t *) bsp);
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if (side == side2)
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bspnum = bsp->children[side]; // doesn't touch the other side
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else // the partition plane is crossed here
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if (!P_CrossBSPNode_PrBoom(bsp->children[side]))
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return 0; // cross the starting side
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else
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bspnum = bsp->children[side^1]; // cross the ending side
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}
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return P_CrossSubsector(bspnum == -1 ? 0 : bspnum & ~NF_SUBSECTOR);
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}
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/* proff - Moved the compatibility check outside the functions
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* this gives a slight speedup
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*/
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static boolean P_CrossBSPNode(int bspnum)
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{
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/* cph - LxDoom used some R_* funcs here */
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if (compatibility_level == lxdoom_1_compatibility)
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return P_CrossBSPNode_LxDoom(bspnum);
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else
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return P_CrossBSPNode_PrBoom(bspnum);
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}
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//
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// P_CheckSight
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// Returns true
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// if a straight line between t1 and t2 is unobstructed.
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// Uses REJECT.
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//
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// killough 4/20/98: cleaned up, made to use new LOS struct
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boolean P_CheckSight(mobj_t *t1, mobj_t *t2)
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{
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const sector_t *s1 = t1->subsector->sector;
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const sector_t *s2 = t2->subsector->sector;
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int pnum = (s1-sectors)*numsectors + (s2-sectors);
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// First check for trivial rejection.
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// Determine subsector entries in REJECT table.
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//
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// Check in REJECT table.
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if (rejectmatrix[pnum>>3] & (1 << (pnum&7))) // can't possibly be connected
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return false;
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// killough 4/19/98: make fake floors and ceilings block monster view
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if ((s1->heightsec != -1 &&
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((t1->z + t1->height <= sectors[s1->heightsec].floorheight &&
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t2->z >= sectors[s1->heightsec].floorheight) ||
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(t1->z >= sectors[s1->heightsec].ceilingheight &&
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t2->z + t1->height <= sectors[s1->heightsec].ceilingheight)))
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||
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(s2->heightsec != -1 &&
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((t2->z + t2->height <= sectors[s2->heightsec].floorheight &&
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t1->z >= sectors[s2->heightsec].floorheight) ||
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(t2->z >= sectors[s2->heightsec].ceilingheight &&
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t1->z + t2->height <= sectors[s2->heightsec].ceilingheight))))
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return false;
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/* killough 11/98: shortcut for melee situations
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* same subsector? obviously visible
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* cph - compatibility optioned for demo sync, cf HR06-UV.LMP */
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if ((t1->subsector == t2->subsector) &&
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(compatibility_level >= mbf_compatibility))
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return true;
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// An unobstructed LOS is possible.
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// Now look from eyes of t1 to any part of t2.
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validcount++;
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los.topslope = (los.bottomslope = t2->z - (los.sightzstart =
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t1->z + t1->height -
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(t1->height>>2))) + t2->height;
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los.strace.dx = (los.t2x = t2->x) - (los.strace.x = t1->x);
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los.strace.dy = (los.t2y = t2->y) - (los.strace.y = t1->y);
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if (t1->x > t2->x)
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los.bbox[BOXRIGHT] = t1->x, los.bbox[BOXLEFT] = t2->x;
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else
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los.bbox[BOXRIGHT] = t2->x, los.bbox[BOXLEFT] = t1->x;
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if (t1->y > t2->y)
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los.bbox[BOXTOP] = t1->y, los.bbox[BOXBOTTOM] = t2->y;
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else
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los.bbox[BOXTOP] = t2->y, los.bbox[BOXBOTTOM] = t1->y;
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/* cph - calculate min and max z of the potential line of sight
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* For old demos, we disable this optimisation by setting them to
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* the extremes */
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switch (compatibility_level) {
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case lxdoom_1_compatibility:
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if (los.sightzstart < t2->z) {
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los.maxz = t2->z + t2->height; los.minz = los.sightzstart;
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} else if (los.sightzstart > t2->z + t2->height) {
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los.maxz = los.sightzstart; los.minz = t2->z;
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} else {
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los.maxz = t2->z + t2->height; los.minz = t2->z;
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}
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break;
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default:
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los.maxz = INT_MAX; los.minz = INT_MIN;
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}
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// the head node is the last node output
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return P_CrossBSPNode(numnodes-1);
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}
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