diff options
Diffstat (limited to 'pathfind.c')
-rw-r--r-- | pathfind.c | 404 |
1 files changed, 229 insertions, 175 deletions
diff --git a/pathfind.c b/pathfind.c index d2d1fd250..5290b86f1 100644 --- a/pathfind.c +++ b/pathfind.c @@ -45,7 +45,6 @@ static bool TPFSetTileBit(TrackPathFinder *tpf, TileIndex tile, int dir) /* allocate a link. if out of links, handle this by returning * that a tile was already visisted. */ if (tpf->num_links_left == 0) { - DEBUG(misc, 4) ("[NTP] no links left\n"); return false; } tpf->num_links_left--; @@ -84,7 +83,6 @@ static bool TPFSetTileBit(TrackPathFinder *tpf, TileIndex tile, int dir) /* get here if we need to add a new link to link, * first, allocate a new link, in the same way as before */ if (tpf->num_links_left == 0) { - DEBUG(misc, 4)("[NTP] no links left\n"); return false; } tpf->num_links_left--; @@ -125,11 +123,6 @@ static const byte _otherdir_mask[4] = { 0x2A, }; -#ifdef DEBUG_TILE_PUSH -extern void dbg_push_tile(TileIndex tile, int track); -extern void dbg_pop_tile(); -#endif - static void TPFMode2(TrackPathFinder *tpf, TileIndex tile, int direction) { uint bits; @@ -198,15 +191,9 @@ static void TPFMode2(TrackPathFinder *tpf, TileIndex tile, int direction) continue_here:; tpf->the_dir = HASBIT(_otherdir_mask[direction],i) ? (i+8) : i; -#ifdef DEBUG_TILE_PUSH - dbg_push_tile(tile, tpf->the_dir); -#endif if (!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, NULL)) { TPFMode2(tpf, tile, _tpf_new_direction[tpf->the_dir]); } -#ifdef DEBUG_TILE_PUSH - dbg_pop_tile(); -#endif tpf->rd = rd; } while (++i, bits>>=1); @@ -327,16 +314,10 @@ static void TPFMode1(TrackPathFinder *tpf, TileIndex tile, int direction) tpf->the_dir = (_otherdir_mask[direction] & (byte)(1 << i)) ? (i+8) : i; rd = tpf->rd; -#ifdef DEBUG_TILE_PUSH - dbg_push_tile(tile, tpf->the_dir); -#endif if (TPFSetTileBit(tpf, tile, tpf->the_dir) && !tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, &tpf->rd.pft_var6) ) { TPFMode1(tpf, tile, _tpf_new_direction[tpf->the_dir]); } -#ifdef DEBUG_TILE_PUSH - dbg_pop_tile(); -#endif tpf->rd = rd; } while (bits != 0); } @@ -422,7 +403,8 @@ void FollowTrack(TileIndex tile, uint16 flags, byte direction, TPFEnumProc *enum typedef struct { TileIndex tile; - uint16 cur_length; + uint16 cur_length; // This is the current length to this tile. + uint16 priority; // This is the current length + estimated length to the goal. byte track; byte depth; byte state; @@ -445,8 +427,9 @@ typedef struct HashLink { } HashLink; typedef struct { - TPFEnumProc *enum_proc; + NTPEnumProc *enum_proc; void *userdata; + TileIndex dest; byte tracktype; uint maxlength; @@ -457,7 +440,7 @@ typedef struct { uint nstack; StackedItem stack[256]; // priority queue of stacked items - uint16 hash_head[0x400]; // hash heads. 0 means unused. 0xFFC0 = length, 0x3F = type + uint16 hash_head[0x400]; // hash heads. 0 means unused. 0xFFFC = length, 0x3 = dir TileIndex hash_tile[0x400]; // tiles. or links. HashLink links[0x400]; // hash links @@ -475,7 +458,7 @@ static inline void HeapifyUp(NewTrackPathFinder *tpf) StackedItem si; int i = ++tpf->nstack; - while (i != 1 && ARR(i).cur_length < ARR(i>>1).cur_length) { + while (i != 1 && ARR(i).priority < ARR(i>>1).priority) { // the child element is larger than the parent item. // swap the child item and the parent item. si = ARR(i); ARR(i) = ARR(i>>1); ARR(i>>1) = si; @@ -500,11 +483,11 @@ static inline void HeapifyDown(NewTrackPathFinder *tpf) while ((j=i*2) <= n) { // figure out which is smaller of the children. - if (j != n && ARR(j).cur_length > ARR(j+1).cur_length) + if (j != n && ARR(j).priority > ARR(j+1).priority) j++; // right item is smaller assert(i <= n && j <= n); - if (ARR(i).cur_length <= ARR(j).cur_length) + if (ARR(i).priority <= ARR(j).priority) break; // base elem smaller than smallest, done! // swap parent with the child @@ -544,8 +527,11 @@ static bool NtpVisit(NewTrackPathFinder *tpf, TileIndex tile, uint dir, uint len // two tiles with the same hash, need to make a link // allocate a link. if out of links, handle this by returning // that a tile was already visisted. - if (tpf->num_links_left == 0) + if (tpf->num_links_left == 0) { + DEBUG(ntp, 1) ("[NTP] no links left"); return false; + } + tpf->num_links_left--; link = tpf->new_link++; @@ -575,8 +561,10 @@ static bool NtpVisit(NewTrackPathFinder *tpf, TileIndex tile, uint dir, uint len /* get here if we need to add a new link to link, * first, allocate a new link, in the same way as before */ - if (tpf->num_links_left == 0) - return false; + if (tpf->num_links_left == 0) { + DEBUG(ntp, 1) ("[NTP] no links left"); + return false; + } tpf->num_links_left--; new_link = tpf->new_link++; @@ -638,155 +626,239 @@ static const uint16 _is_upwards_slope[15] = { }; +#define DIAG_FACTOR 3 +#define STR_FACTOR 2 + + +static uint DistanceMoo(TileIndex t0, TileIndex t1) +{ + const uint dx = abs(TileX(t0) - TileX(t1)); + const uint dy = abs(TileY(t0) - TileY(t1)); + + const uint straightTracks = 2 * min(dx, dy); /* The number of straight (not full length) tracks */ + /* OPTIMISATION: + * Original: diagTracks = max(dx, dy) - min(dx,dy); + * Proof: + * (dx-dy) - straightTracks == (min + max) - straightTracks = min + // max - 2 * min = max - min */ + const uint diagTracks = dx + dy - straightTracks; /* The number of diagonal (full tile length) tracks. */ + + return diagTracks*DIAG_FACTOR + straightTracks*STR_FACTOR; +} + +// These has to be small cause the max length of a track +// is currently limited to 16384 + +static const byte _length_of_track[16] = { + DIAG_FACTOR,DIAG_FACTOR,STR_FACTOR,STR_FACTOR,STR_FACTOR,STR_FACTOR,0,0, + DIAG_FACTOR,DIAG_FACTOR,STR_FACTOR,STR_FACTOR,STR_FACTOR,STR_FACTOR,0,0 +}; + // new more optimized pathfinder for trains... +// Tile is the tile the train is at. +// direction is the tile the train is moving towards. + static void NTPEnum(NewTrackPathFinder *tpf, TileIndex tile, uint direction) { - uint bits, tile_org; - int i; + uint bits, tile_org, track; StackedItem si; FindLengthOfTunnelResult flotr; + int estimation; - si.cur_length = 0; + // Need to have a special case for the start. + // We shouldn't call the callback for the current tile. + si.cur_length = 1; // Need to start at 1 cause 0 is a reserved value. si.depth = 0; si.state = 0; + goto start_at; -restart: - if (IsTileType(tile, MP_TUNNELBRIDGE) && (_m[tile].m5 & 0xF0) == 0) { - /* This is a tunnel tile */ - if ( (uint)(_m[tile].m5 & 3) != (direction ^ 2)) { /* ^ 2 is reversing the direction */ - /* We are not just driving out of the tunnel */ - if ( (uint)(_m[tile].m5 & 3) != direction || ((_m[tile].m5>>1)&6) != tpf->tracktype) - /* We are not driving into the tunnel, or it - * is an invalid tunnel */ - goto stop_search; - flotr = FindLengthOfTunnel(tile, direction); - si.cur_length += flotr.length; - tile = flotr.tile; - } - } + for(;;) { + // Get the next item to search from from the priority queue + do { + if (tpf->nstack == 0) + return; // nothing left? then we're done! + si = tpf->stack[0]; + tile = si.tile; - // remember the start tile so we know if we're in an inf loop. - tile_org = tile; + HeapifyDown(tpf); + // Make sure we havn't already visited this tile. + } while (!NtpCheck(tpf, tile, _tpf_prev_direction[si.track], si.cur_length)); - for(;;) { - int track; + // Add the length of this track. + si.cur_length += _length_of_track[si.track]; - tile += TileOffsByDir(direction); +callback_and_continue: + if (tpf->enum_proc(tile, tpf->userdata, si.first_track, si.cur_length)) + return; - // too long search length? bail out. - if (++si.cur_length >= tpf->maxlength) { - DEBUG(misc,4) ("[NTP] cur_length too big\n"); - goto stop_search; + direction = _tpf_new_direction[si.track]; + +start_at: + // If the tile is the entry tile of a tunnel, and we're not going out of the tunnel, + // need to find the exit of the tunnel. + if (IsTileType(tile, MP_TUNNELBRIDGE)) { + if ((_m[tile].m5 & 0xF0) == 0 && + (uint)(_m[tile].m5 & 3) != (direction ^ 2)) { + /* This is a tunnel tile */ + /* We are not just driving out of the tunnel */ + if ( (uint)(_m[tile].m5 & 3) != direction || ((_m[tile].m5>>1)&6) != tpf->tracktype) + /* We are not driving into the tunnel, or it + * is an invalid tunnel */ + continue; + flotr = FindLengthOfTunnel(tile, direction); + si.cur_length += flotr.length * DIAG_FACTOR; + tile = flotr.tile; + // tile now points to the exit tile of the tunnel + } } - // Not a regular rail tile? - // Then we can't use the code below, but revert to more general code. - if (!IsTileType(tile, MP_RAILWAY) || !IsPlainRailTile(tile)) { - bits = GetTileTrackStatus(tile, TRANSPORT_RAIL) & _tpfmode1_and[direction]; - bits = (bits | (bits >> 8)) & 0x3F; - if (bits == 0) goto stop_search; - break; - } + // This is a special loop used to go through + // a rail net and find the first intersection + tile_org = tile; + for(;;) { + tile += TileOffsByDir(direction); - // regular rail tile, determine the tracks that are actually reachable. - bits = _m[tile].m5 & _bits_mask[direction]; - if (bits == 0) goto stop_search; // no tracks there? stop searching. + // too long search length? bail out. + if (si.cur_length >= tpf->maxlength) { + DEBUG(ntp,1) ("[NTP] cur_length too big"); + bits = 0; + break; + } - // intersection? then we need to branch the search space, - // can't handle that from here. - if (KILL_FIRST_BIT(bits) != 0) break; + // Not a regular rail tile? + // Then we can't use the code below, but revert to more general code. + if (!IsTileType(tile, MP_RAILWAY) || !IsPlainRailTile(tile)) { + // We found a tile which is not a normal railway tile. + // Determine which tracks that exist on this tile. + bits = GetTileTrackStatus(tile, TRANSPORT_RAIL) & _tpfmode1_and[direction]; + bits = (bits | (bits >> 8)) & 0x3F; - track = _new_track[FIND_FIRST_BIT(bits)][direction]; + // Check that the tile contains exactly one track + if (bits == 0 || KILL_FIRST_BIT(bits) != 0) + break; - // Check if this rail is an upwards slope. If it is, then add a penalty. - // Small optimization here.. if (track&7)>1 then it can't be a slope so we avoid calling GetTileSlope - if ((track & 7) <= 1 && (_is_upwards_slope[GetTileSlope(tile, NULL)] & (1 << track)) ) { - // upwards slope. add some penalty. - si.cur_length += 2; - } + /////////////////// + // If we reach here, the tile has exactly one track. + // tile - index to a tile that is not rail tile, but still straight (with optional signals) + // bits - bitmask of which track that exist on the tile (exactly one bit is set) + // direction - which direction are we moving in? + /////////////////// + si.track = _new_track[FIND_FIRST_BIT(bits)][direction]; + si.cur_length += _length_of_track[si.track]; + goto callback_and_continue; + } - // railway tile with signals..? - if (HasSignals(tile)) { - byte m3; - - m3 = _m[tile].m3; - if (!(m3 & SignalAlongTrackdir(track))) { - // if one way signal not pointing towards us, stop going in this direction. - if (m3 & SignalAgainstTrackdir(track)) - goto stop_search; - } else if (_m[tile].m2 & SignalAlongTrackdir(track)) { - // green signal in our direction. either one way or two way. - si.state |= 1; - } else { - // reached a red signal. - if (m3 & SignalAgainstTrackdir(track)) { - // two way red signal. unless we passed another green signal on the way, - // stop going in this direction. - // this is to prevent us from going into a full platform. - if (!(si.state&1)) - goto stop_search; - } - // add some penalty since this path has a red signal on it. - // only add this penalty max 2 times. - if ((si.state & 6) != 4) { - si.cur_length += 10; - si.state += 2; // remember that we added penalty. - } + // Regular rail tile, determine which tracks exist. + bits = _m[tile].m5 & 0x3F; + if (bits == 0) + break; // None at all? + + // Make sure that the tile contains exactly ONE track + if (KILL_FIRST_BIT(bits) != 0) { + // It contained many tracks, + // but first, mask out the tracks that are not reachable + bits &= _bits_mask[direction]; + break; } - if (tpf->enum_proc(tile, tpf->userdata, track, si.cur_length, &si.state)) - goto stop_search; // we should stop searching in this direction - } + track = _new_track[FIND_FIRST_BIT(bits)][direction]; + si.cur_length += _length_of_track[track]; - // continue with the next track - direction = _tpf_new_direction[track]; - assert(direction != 0xFF); + // Check if this rail is an upwards slope. If it is, then add a penalty. + // Small optimization here.. if (track&7)>1 then it can't be a slope so we avoid calling GetTileSlope + if ((track & 7) <= 1 && (_is_upwards_slope[GetTileSlope(tile, NULL)] & (1 << track)) ) { + // upwards slope. add some penalty. + si.cur_length += 4*DIAG_FACTOR; + } - // check if we're running around chasing our tail... (infinite loop) - if (tile == tile_org) - goto stop_search; - } + // railway tile with signals..? + if (HasSignals(tile)) { + byte m3; + + m3 = _m[tile].m3; + if (!(m3 & SignalAlongTrackdir(track))) { + // if one way signal not pointing towards us, stop going in this direction. + if (m3 & SignalAgainstTrackdir(track)) { + bits = 0; + break; + } + } else if (_m[tile].m2 & SignalAlongTrackdir(track)) { + // green signal in our direction. either one way or two way. + si.state |= 3; + } else { + // reached a red signal. + if (m3 & SignalAgainstTrackdir(track)) { + // two way red signal. unless we passed another green signal on the way, + // stop going in this direction. + // this is to prevent us from going into a full platform. + if (!(si.state&1)) { + bits = 0; + break; + } + } + if (!(si.state & 2)) { + // Is this the first signal we see? And it's red... add penalty + si.cur_length += 10*DIAG_FACTOR; + si.state += 2; // remember that we added penalty. + // Because we added a penalty, we can't just continue as usual. + // Need to get out and let A* do it's job with + // possibly finding an even shorter path. + break; + } + } - // if only one possible track to choose from, just continue - if (KILL_FIRST_BIT(bits) == 0) { - i = _new_track[FIND_FIRST_BIT(bits)][direction]; - // call the callback to check if we've reached the destination - if (tpf->enum_proc(tile, tpf->userdata, i, si.cur_length, &si.state)) - goto stop_search; // we should stop searching in this direction. + if (tpf->enum_proc(tile, tpf->userdata, si.first_track, si.cur_length)) + return; + } - // we should continue searching. determine new direction. - direction = _tpf_new_direction[i]; - goto restart; // use tail recursion optimization. - } + // continue with the next track + direction = _tpf_new_direction[track]; + assert(direction != 0xFF); - //////////////// - // We got multiple tracks to choose between (intersection). - // Branch the search space into several branches. - // Push each alternative on the stack. - //////////////// - - // Increase recursion depth counter, and - // Check so the depth is not too big.. to prevent enourmous slowdown. - if (si.depth >= _patches.pf_maxdepth) { - DEBUG(misc, 4) ("[NTP] depth too big\n"); - goto stop_search; - } - si.depth++; + // safety check if we're running around chasing our tail... (infinite loop) + if (tile == tile_org) { + bits = 0; + break; + } + } + + // There are no tracks to choose between. + // Stop searching in this direction + if (bits == 0) + continue; + + //////////////// + // We got multiple tracks to choose between (intersection). + // Branch the search space into several branches. + //////////////// + + // Check if we've already visited this intersection. + // If we've already visited it with a better length, then + // there's no point in visiting it again. + if (!NtpVisit(tpf, tile, direction, si.cur_length)) + continue; - // Check if we've already visited this intersection. - // If we've already visited it with a better length, then - // there's no point in visiting it again. - if (NtpVisit(tpf, tile, direction, si.cur_length)) { // Push all possible alternatives that we can reach from here // onto the priority heap. + // 'bits' contains the tracks that we can choose between. + + // First compute the estimated distance to the target. + // This is used to implement A* + estimation = 0; + if (tpf->dest != 0) + estimation = DistanceMoo(tile, tpf->dest); + + si.depth++; si.tile = tile; do { si.track = _new_track[FIND_FIRST_BIT(bits)][direction]; + si.priority = si.cur_length + estimation; + // out of stack items, bail out? if (tpf->nstack >= lengthof(tpf->stack)) { - DEBUG(misc, 4) ("[NTP] out of stack\n"); + DEBUG(ntp, 1) ("[NTP] out of stack"); break; } + tpf->stack[tpf->nstack] = si; HeapifyUp(tpf); } while ((bits = KILL_FIRST_BIT(bits)) != 0); @@ -795,54 +867,36 @@ restart: // so the code outside knows which path is better. // also randomize the order in which we search through them. if (si.depth == 1) { - uint32 r = Random(); - assert(tpf->nstack == 2 || tpf->nstack == 3); - if (r&1) swap_byte(&tpf->stack[0].track, &tpf->stack[1].track); - if (tpf->nstack != 2) { - byte t = tpf->stack[2].track; - if (r&2) swap_byte(&tpf->stack[0].track, &t); - if (r&4) swap_byte(&tpf->stack[1].track, &t); - tpf->stack[2].first_track = tpf->stack[2].track = t; + assert(tpf->nstack == 1 || tpf->nstack == 2 || tpf->nstack == 3); + if (tpf->nstack != 1) { + uint32 r = Random(); + if (r&1) swap_byte(&tpf->stack[0].track, &tpf->stack[1].track); + if (tpf->nstack != 2) { + byte t = tpf->stack[2].track; + if (r&2) swap_byte(&tpf->stack[0].track, &t); + if (r&4) swap_byte(&tpf->stack[1].track, &t); + tpf->stack[2].first_track = tpf->stack[2].track = t; + } + tpf->stack[0].first_track = tpf->stack[0].track; + tpf->stack[1].first_track = tpf->stack[1].track; } - tpf->stack[0].first_track = tpf->stack[0].track; - tpf->stack[1].first_track = tpf->stack[1].track; } - } - -stop_search: - // Now continue searching from the intersection that has the lowest - // cost. - // Pop the lowest cost item from the priority heap. - do { - if (tpf->nstack == 0) - return; // nothing left? then we're done! - si = tpf->stack[0]; - tile = si.tile; - HeapifyDown(tpf); - - // First check if we've already visited the tile we're just about to continue at. - // If we've already visited it, no point in continuing from there. - // Then call the callback. - } while ( - !NtpCheck(tpf, tile, _tpf_prev_direction[si.track], si.cur_length) || // already have better path to that tile? - tpf->enum_proc(tile, tpf->userdata, si.track, si.cur_length, &si.state) - ); - - direction = _tpf_new_direction[si.track]; - goto restart; + // Continue with the next from the queue... + } } // new pathfinder for trains. better and faster. -void NewTrainPathfind(TileIndex tile, byte direction, TPFEnumProc *enum_proc, void *data, byte *cache) +void NewTrainPathfind(TileIndex tile, TileIndex dest, byte direction, NTPEnumProc *enum_proc, void *data) { NewTrackPathFinder tpf; + tpf.dest = dest; tpf.userdata = data; tpf.enum_proc = enum_proc; tpf.tracktype = 0; - tpf.maxlength = _patches.pf_maxlength; + tpf.maxlength = min(_patches.pf_maxlength * 3, 10000); tpf.nstack = 0; tpf.new_link = tpf.links; tpf.num_links_left = lengthof(tpf.links); |