--- a/pathfind.c Tue Jul 19 07:20:48 2005 +0000
+++ b/pathfind.c Tue Jul 19 11:42:40 2005 +0000
@@ -45,7 +45,6 @@
/* 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 @@
/* 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 @@
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 @@
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 @@
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 @@
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 @@
} HashLink;
typedef struct {
- TPFEnumProc *enum_proc;
+ NTPEnumProc *enum_proc;
void *userdata;
+ TileIndex dest;
byte tracktype;
uint maxlength;
@@ -457,7 +440,7 @@
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 @@
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 @@
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 @@
// 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 @@
/* 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 @@
};
+#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;
-
-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;
- }
- }
-
- // remember the start tile so we know if we're in an inf loop.
- tile_org = tile;
+ goto start_at;
for(;;) {
- int track;
-
- tile += TileOffsByDir(direction);
-
- // too long search length? bail out.
- if (++si.cur_length >= tpf->maxlength) {
- DEBUG(misc,4) ("[NTP] cur_length too big\n");
- goto stop_search;
- }
+ // 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;
- // 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;
- }
+ HeapifyDown(tpf);
+ // Make sure we havn't already visited this tile.
+ } while (!NtpCheck(tpf, tile, _tpf_prev_direction[si.track], si.cur_length));
- // 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.
+ // Add the length of this track.
+ si.cur_length += _length_of_track[si.track];
- // intersection? then we need to branch the search space,
- // can't handle that from here.
- if (KILL_FIRST_BIT(bits) != 0) break;
+callback_and_continue:
+ if (tpf->enum_proc(tile, tpf->userdata, si.first_track, si.cur_length))
+ return;
- track = _new_track[FIND_FIRST_BIT(bits)][direction];
+ direction = _tpf_new_direction[si.track];
- // 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;
+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
+ }
}
- // railway tile with signals..?
- if (HasSignals(tile)) {
- byte m3;
+ // This is a special loop used to go through
+ // a rail net and find the first intersection
+ tile_org = tile;
+ for(;;) {
+ tile += TileOffsByDir(direction);
- 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.
- }
+ // too long search length? bail out.
+ if (si.cur_length >= tpf->maxlength) {
+ DEBUG(ntp,1) ("[NTP] cur_length too big");
+ bits = 0;
+ break;
}
- if (tpf->enum_proc(tile, tpf->userdata, track, si.cur_length, &si.state))
- goto stop_search; // we should stop searching in this direction
+ // 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;
+
+ // Check that the tile contains exactly one track
+ if (bits == 0 || KILL_FIRST_BIT(bits) != 0)
+ break;
+
+ ///////////////////
+ // 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;
+ }
+
+ // 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;
+ }
+
+ track = _new_track[FIND_FIRST_BIT(bits)][direction];
+ si.cur_length += _length_of_track[track];
+
+ // 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;
+ }
+
+ // 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 (tpf->enum_proc(tile, tpf->userdata, si.first_track, si.cur_length))
+ return;
+ }
+
+ // continue with the next track
+ direction = _tpf_new_direction[track];
+ assert(direction != 0xFF);
+
+ // safety check if we're running around chasing our tail... (infinite loop)
+ if (tile == tile_org) {
+ bits = 0;
+ break;
+ }
}
- // continue with the next track
- direction = _tpf_new_direction[track];
- assert(direction != 0xFF);
-
- // check if we're running around chasing our tail... (infinite loop)
- if (tile == tile_org)
- goto stop_search;
- }
-
- // 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.
+ // There are no tracks to choose between.
+ // Stop searching in this direction
+ if (bits == 0)
+ continue;
- // we should continue searching. determine new direction.
- direction = _tpf_new_direction[i];
- goto restart; // use tail recursion optimization.
- }
-
- ////////////////
- // We got multiple tracks to choose between (intersection).
- // Branch the search space into several branches.
- // Push each alternative on the stack.
- ////////////////
+ ////////////////
+ // We got multiple tracks to choose between (intersection).
+ // Branch the search space into several branches.
+ ////////////////
- // 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++;
+ // 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 @@
// 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);