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Diffstat (limited to 'src/heretic/p_sight.c')
| -rw-r--r-- | src/heretic/p_sight.c | 363 |
1 files changed, 363 insertions, 0 deletions
diff --git a/src/heretic/p_sight.c b/src/heretic/p_sight.c new file mode 100644 index 00000000..002b32a9 --- /dev/null +++ b/src/heretic/p_sight.c @@ -0,0 +1,363 @@ +// 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_sight.c + +#include <stdlib.h> + +#include "doomdef.h" +#include "p_local.h" + +/* +============================================================================== + + P_CheckSight + +This uses specialized forms of the maputils routines for optimized performance + +============================================================================== +*/ + +fixed_t sightzstart; // eye z of looker +fixed_t topslope, bottomslope; // slopes to top and bottom of target + +int sightcounts[3]; + +/* +============== += += PTR_SightTraverse += +============== +*/ + +boolean PTR_SightTraverse(intercept_t * in) +{ + line_t *li; + fixed_t slope; + + li = in->d.line; + +// +// crosses a two sided line +// + P_LineOpening(li); + + if (openbottom >= opentop) // quick test for totally closed doors + return false; // stop + + if (li->frontsector->floorheight != li->backsector->floorheight) + { + slope = FixedDiv(openbottom - sightzstart, in->frac); + if (slope > bottomslope) + bottomslope = slope; + } + + if (li->frontsector->ceilingheight != li->backsector->ceilingheight) + { + slope = FixedDiv(opentop - sightzstart, in->frac); + if (slope < topslope) + topslope = slope; + } + + if (topslope <= bottomslope) + return false; // stop + + return true; // keep going +} + + + +/* +================== += += P_SightBlockLinesIterator += +=================== +*/ + +boolean P_SightBlockLinesIterator(int x, int y) +{ + int offset; + short *list; + line_t *ld; + int s1, s2; + divline_t dl; + + 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; + + s1 = P_PointOnDivlineSide(ld->v1->x, ld->v1->y, &trace); + s2 = P_PointOnDivlineSide(ld->v2->x, ld->v2->y, &trace); + if (s1 == s2) + continue; // line isn't crossed + P_MakeDivline(ld, &dl); + s1 = P_PointOnDivlineSide(trace.x, trace.y, &dl); + s2 = P_PointOnDivlineSide(trace.x + trace.dx, trace.y + trace.dy, + &dl); + if (s1 == s2) + continue; // line isn't crossed + + // try to early out the check + if (!ld->backsector) + return false; // stop checking + + // store the line for later intersection testing + intercept_p->d.line = ld; + intercept_p++; + + } + + return true; // everything was checked +} + +/* +==================== += += P_SightTraverseIntercepts += += Returns true if the traverser function returns true for all lines +==================== +*/ + +boolean P_SightTraverseIntercepts(void) +{ + int count; + fixed_t dist; + intercept_t *scan, *in; + divline_t dl; + + count = intercept_p - intercepts; +// +// calculate intercept distance +// + for (scan = intercepts; scan < intercept_p; scan++) + { + P_MakeDivline(scan->d.line, &dl); + scan->frac = P_InterceptVector(&trace, &dl); + } + +// +// go through in order +// + 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 (!PTR_SightTraverse(in)) + return false; // don't bother going farther + in->frac = INT_MAX; + } + + return true; // everything was traversed +} + + + +/* +================== += += P_SightPathTraverse += += 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_SightPathTraverse(fixed_t x1, fixed_t y1, fixed_t x2, fixed_t y2) +{ + fixed_t xt1, yt1, xt2, yt2; + fixed_t xstep, ystep; + fixed_t partial; + fixed_t xintercept, yintercept; + int mapx, mapy, mapxstep, mapystep; + int count; + + 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; + +// points should never be out of bounds, but check once instead of +// each block + if (xt1 < 0 || yt1 < 0 || xt1 >= bmapwidth || yt1 >= bmapheight + || xt2 < 0 || yt2 < 0 || xt2 >= bmapwidth || yt2 >= bmapheight) + return false; + + 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 (!P_SightBlockLinesIterator(mapx, mapy)) + { + sightcounts[1]++; + 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; + } + + } + + +// +// couldn't early out, so go through the sorted list +// + sightcounts[2]++; + + return P_SightTraverseIntercepts(); +} + + + +/* +===================== += += P_CheckSight += += Returns true if a straight line between t1 and t2 is unobstructed += look from eyes of t1 to any part of t2 += +===================== +*/ + +boolean P_CheckSight(mobj_t * t1, mobj_t * t2) +{ + int s1, s2; + int pnum, bytenum, bitnum; + +// +// check for trivial rejection +// + s1 = (t1->subsector->sector - sectors); + s2 = (t2->subsector->sector - sectors); + pnum = s1 * numsectors + s2; + bytenum = pnum >> 3; + bitnum = 1 << (pnum & 7); + + if (rejectmatrix[bytenum] & bitnum) + { + sightcounts[0]++; + return false; // can't possibly be connected + } + +// +// check precisely +// + sightzstart = t1->z + t1->height - (t1->height >> 2); + topslope = (t2->z + t2->height) - sightzstart; + bottomslope = (t2->z) - sightzstart; + + return P_SightPathTraverse(t1->x, t1->y, t2->x, t2->y); +} |