// 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 "doom_config.h" #include "m_bbox.h" #include "doomdef.h" #include "p_local.h" #include "r_state.h" // State. fixed_t opentop; fixed_t openbottom; fixed_t openrange; fixed_t lowfloor; intercept_t intercepts[MAXINTERCEPTS]; intercept_t* intercept_p; divline_t trace; doom_boolean earlyout; int ptflags; // // P_AproxDistance // Gives an estimation of distance (not exact) // fixed_t P_AproxDistance(fixed_t dx, fixed_t dy) { dx = doom_abs(dx); dy = doom_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; fixed_t dy; fixed_t left; fixed_t 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; int p2; 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; fixed_t dy; fixed_t left; fixed_t 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) { 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; } // // P_LineOpening // Sets opentop and openbottom to the window // through a two sided line. // OPTIMIZE: keep this precalculated // void P_LineOpening(line_t* linedef) { sector_t* front; sector_t* 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. // On each position change, BLOCKMAP and other // lookups maintaining lists ot things inside // these structures need to be updated. // void P_UnsetThingPosition(mobj_t* thing) { int blockx; int 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; int 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 = 0; 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 = 0; thing->bnext = *link; if (*link) (*link)->bprev = thing; *link = thing; } else { // thing is off the map thing->bnext = thing->bprev = 0; } } } // // 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. // // // 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. // doom_boolean P_BlockLinesIterator(int x, int y, doom_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 // doom_boolean P_BlockThingsIterator(int x, int y, doom_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 // // // 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. // doom_boolean PIT_AddLineIntercepts(line_t* ld) { 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) 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 // doom_boolean PIT_AddThingIntercepts(mobj_t* thing) { fixed_t x1; fixed_t y1; fixed_t x2; fixed_t y2; int s1; int s2; doom_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. // doom_boolean P_TraverseIntercepts(traverser_t func, fixed_t maxfrac) { int count; fixed_t dist; intercept_t* scan; intercept_t* in; count = (int)(intercept_p - intercepts); in = 0; // shut up compiler warning while (count--) { dist = DOOM_MAXINT; 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 // UNUSED { // don't check these yet, there 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 = DOOM_MAXINT; } 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. // doom_boolean P_PathTraverse(fixed_t x1, fixed_t y1, fixed_t x2, fixed_t y2, int flags, doom_boolean(*trav) (intercept_t*)) { fixed_t xt1; fixed_t yt1; fixed_t xt2; fixed_t yt2; fixed_t xstep; fixed_t ystep; fixed_t partial; fixed_t xintercept; fixed_t yintercept; int mapx; int mapy; int mapxstep; int 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, doom_abs(x2 - x1)); } else if (xt2 < xt1) { mapxstep = -1; partial = (x1 >> MAPBTOFRAC) & (FRACUNIT - 1); ystep = FixedDiv(y2 - y1, doom_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, doom_abs(y2 - y1)); } else if (yt2 < yt1) { mapystep = -1; partial = (y1 >> MAPBTOFRAC) & (FRACUNIT - 1); xstep = FixedDiv(x2 - x1, doom_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); }