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authortruelight <truelight@openttd.org>2005-09-02 19:10:45 +0000
committertruelight <truelight@openttd.org>2005-09-02 19:10:45 +0000
commitd05f504c01fb88eb8b88d28b5fd5da664e31cd95 (patch)
treed01e499f40fb0d5d315c7530b74c76569fae0840 /ai/trolly/pathfinder.c
parenta181446829c3de933ccccffcc652c0c7b19f9968 (diff)
downloadopenttd-d05f504c01fb88eb8b88d28b5fd5da664e31cd95.tar.xz
(svn r2907) -Codechange: splitted the AIs to their own directory. AINew becomes 'trolly', AIOld becomes 'default', both in their own dir in the 'ai' dir. More AIs to come.
Diffstat (limited to 'ai/trolly/pathfinder.c')
-rw-r--r--ai/trolly/pathfinder.c514
1 files changed, 514 insertions, 0 deletions
diff --git a/ai/trolly/pathfinder.c b/ai/trolly/pathfinder.c
new file mode 100644
index 000000000..aa44014f9
--- /dev/null
+++ b/ai/trolly/pathfinder.c
@@ -0,0 +1,514 @@
+/* $Id$ */
+
+#include "../../stdafx.h"
+#include "../../openttd.h"
+#include "../../debug.h"
+#include "../../functions.h"
+#include "../../map.h"
+#include "../../tile.h"
+#include "../../command.h"
+#include "trolly.h"
+#include "../../depot.h"
+#include "../../variables.h"
+
+#define TEST_STATION_NO_DIR 0xFF
+
+// Tests if a station can be build on the given spot
+// TODO: make it train compatible
+static bool TestCanBuildStationHere(TileIndex tile, byte dir)
+{
+ Player *p = GetPlayer(_current_player);
+
+ if (dir == TEST_STATION_NO_DIR) {
+ int32 ret;
+ // TODO: currently we only allow spots that can be access from al 4 directions...
+ // should be fixed!!!
+ for (dir = 0; dir < 4; dir++) {
+ ret = AiNew_Build_Station(p, p->ainew.tbt, tile, 1, 1, dir, DC_QUERY_COST);
+ if (!CmdFailed(ret)) return true;
+ }
+ return false;
+ }
+
+ // return true if command succeeded, so the inverse of CmdFailed()
+ return !CmdFailed(AiNew_Build_Station(p, p->ainew.tbt, tile, 1, 1, dir, DC_QUERY_COST));
+}
+
+
+static bool IsRoad(TileIndex tile)
+{
+ return
+ // MP_STREET, but not a road depot?
+ (IsTileType(tile, MP_STREET) && !IsTileDepotType(tile, TRANSPORT_ROAD)) ||
+ (IsTileType(tile, MP_TUNNELBRIDGE) && (
+ // road tunnel?
+ ((_m[tile].m5 & 0x80) == 0 && (_m[tile].m5 & 0x4) == 0x4) ||
+ // road bridge?
+ ((_m[tile].m5 & 0x80) != 0 && (_m[tile].m5 & 0x2) == 0x2)
+ ));
+}
+
+
+// Checks if a tile 'a' is between the tiles 'b' and 'c'
+#define TILES_BETWEEN(a, b, c) (TileX(a) >= TileX(b) && TileX(a) <= TileX(c) && TileY(a) >= TileY(b) && TileY(a) <= TileY(c))
+
+
+// Check if the current tile is in our end-area
+static int32 AyStar_AiPathFinder_EndNodeCheck(AyStar *aystar, OpenListNode *current)
+{
+ Ai_PathFinderInfo *PathFinderInfo = (Ai_PathFinderInfo*)aystar->user_target;
+ // It is not allowed to have a station on the end of a bridge or tunnel ;)
+ if (current->path.node.user_data[0] != 0) return AYSTAR_DONE;
+ if (TILES_BETWEEN(current->path.node.tile, PathFinderInfo->end_tile_tl, PathFinderInfo->end_tile_br))
+ if (IsTileType(current->path.node.tile, MP_CLEAR) || IsTileType(current->path.node.tile, MP_TREES))
+ if (current->path.parent == NULL || TestCanBuildStationHere(current->path.node.tile, AiNew_GetDirection(current->path.parent->node.tile, current->path.node.tile)))
+ return AYSTAR_FOUND_END_NODE;
+
+ return AYSTAR_DONE;
+}
+
+
+// Calculates the hash
+// Currently it is a 10 bit hash, so the hash array has a max depth of 6 bits (so 64)
+static uint AiPathFinder_Hash(uint key1, uint key2)
+{
+ return (TileX(key1) & 0x1F) + ((TileY(key1) & 0x1F) << 5);
+}
+
+
+// Clear the memory of all the things
+static void AyStar_AiPathFinder_Free(AyStar *aystar)
+{
+ AyStarMain_Free(aystar);
+ free(aystar);
+}
+
+
+static int32 AyStar_AiPathFinder_CalculateG(AyStar *aystar, AyStarNode *current, OpenListNode *parent);
+static int32 AyStar_AiPathFinder_CalculateH(AyStar *aystar, AyStarNode *current, OpenListNode *parent);
+static void AyStar_AiPathFinder_FoundEndNode(AyStar *aystar, OpenListNode *current);
+static void AyStar_AiPathFinder_GetNeighbours(AyStar *aystar, OpenListNode *current);
+
+
+// This creates the AiPathFinder
+AyStar *new_AyStar_AiPathFinder(int max_tiles_around, Ai_PathFinderInfo *PathFinderInfo)
+{
+ PathNode start_node;
+ uint x;
+ uint y;
+ // Create AyStar
+ AyStar *result = malloc(sizeof(AyStar));
+ init_AyStar(result, AiPathFinder_Hash, 1 << 10);
+ // Set the function pointers
+ result->CalculateG = AyStar_AiPathFinder_CalculateG;
+ result->CalculateH = AyStar_AiPathFinder_CalculateH;
+ result->EndNodeCheck = AyStar_AiPathFinder_EndNodeCheck;
+ result->FoundEndNode = AyStar_AiPathFinder_FoundEndNode;
+ result->GetNeighbours = AyStar_AiPathFinder_GetNeighbours;
+
+ result->BeforeExit = NULL;
+
+ result->free = AyStar_AiPathFinder_Free;
+
+ // Set some information
+ result->loops_per_tick = AI_PATHFINDER_LOOPS_PER_TICK;
+ result->max_path_cost = 0;
+ result->max_search_nodes = AI_PATHFINDER_MAX_SEARCH_NODES;
+
+ // Set the user_data to the PathFinderInfo
+ result->user_target = PathFinderInfo;
+
+ // Set the start node
+ start_node.parent = NULL;
+ start_node.node.direction = 0;
+ start_node.node.user_data[0] = 0;
+
+ // Now we add all the starting tiles
+ for (x = TileX(PathFinderInfo->start_tile_tl); x <= TileX(PathFinderInfo->start_tile_br); x++) {
+ for (y = TileY(PathFinderInfo->start_tile_tl); y <= TileY(PathFinderInfo->start_tile_br); y++) {
+ start_node.node.tile = TileXY(x, y);
+ result->addstart(result, &start_node.node, 0);
+ }
+ }
+
+ return result;
+}
+
+
+// To reuse AyStar we sometimes have to clean all the memory
+void clean_AyStar_AiPathFinder(AyStar *aystar, Ai_PathFinderInfo *PathFinderInfo)
+{
+ PathNode start_node;
+ uint x;
+ uint y;
+
+ aystar->clear(aystar);
+
+ // Set the user_data to the PathFinderInfo
+ aystar->user_target = PathFinderInfo;
+
+ // Set the start node
+ start_node.parent = NULL;
+ start_node.node.direction = 0;
+ start_node.node.user_data[0] = 0;
+ start_node.node.tile = PathFinderInfo->start_tile_tl;
+
+ // Now we add all the starting tiles
+ for (x = TileX(PathFinderInfo->start_tile_tl); x <= TileX(PathFinderInfo->start_tile_br); x++) {
+ for (y = TileY(PathFinderInfo->start_tile_tl); y <= TileY(PathFinderInfo->start_tile_br); y++) {
+ if (!(IsTileType(TileXY(x, y), MP_CLEAR) || IsTileType(TileXY(x, y), MP_TREES))) continue;
+ if (!TestCanBuildStationHere(TileXY(x, y), TEST_STATION_NO_DIR)) continue;
+ start_node.node.tile = TileXY(x, y);
+ aystar->addstart(aystar, &start_node.node, 0);
+ }
+ }
+}
+
+
+// The h-value, simple calculation
+static int32 AyStar_AiPathFinder_CalculateH(AyStar *aystar, AyStarNode *current, OpenListNode *parent)
+{
+ Ai_PathFinderInfo *PathFinderInfo = (Ai_PathFinderInfo*)aystar->user_target;
+ int r, r2;
+ if (PathFinderInfo->end_direction != AI_PATHFINDER_NO_DIRECTION) {
+ // The station is pointing to a direction, add a tile towards that direction, so the H-value is more accurate
+ r = DistanceManhattan(current->tile, PathFinderInfo->end_tile_tl + TileOffsByDir(PathFinderInfo->end_direction));
+ r2 = DistanceManhattan(current->tile, PathFinderInfo->end_tile_br + TileOffsByDir(PathFinderInfo->end_direction));
+ } else {
+ // No direction, so just get the fastest route to the station
+ r = DistanceManhattan(current->tile, PathFinderInfo->end_tile_tl);
+ r2 = DistanceManhattan(current->tile, PathFinderInfo->end_tile_br);
+ }
+ // See if the bottomright is faster than the topleft..
+ if (r2 < r) r = r2;
+ return r * AI_PATHFINDER_H_MULTIPLER;
+}
+
+
+// We found the end.. let's get the route back and put it in an array
+static void AyStar_AiPathFinder_FoundEndNode(AyStar *aystar, OpenListNode *current)
+{
+ Ai_PathFinderInfo *PathFinderInfo = (Ai_PathFinderInfo*)aystar->user_target;
+ uint i = 0;
+ PathNode *parent = &current->path;
+
+ do {
+ PathFinderInfo->route_extra[i] = parent->node.user_data[0];
+ PathFinderInfo->route[i++] = parent->node.tile;
+ if (i > lengthof(PathFinderInfo->route)) {
+ // We ran out of space for the PathFinder
+ DEBUG(ai, 0)("[AiPathFinder] Ran out of space in the route[] array!!!");
+ PathFinderInfo->route_length = -1; // -1 indicates out of space
+ return;
+ }
+ parent = parent->parent;
+ } while (parent != NULL);
+ PathFinderInfo->route_length = i;
+ DEBUG(ai, 1)("[Ai-PathFinding] Found route of %d nodes long in %d nodes of searching", i, Hash_Size(&aystar->ClosedListHash));
+}
+
+
+// What tiles are around us.
+static void AyStar_AiPathFinder_GetNeighbours(AyStar *aystar, OpenListNode *current)
+{
+ uint i;
+ int ret;
+ int dir;
+
+ Ai_PathFinderInfo *PathFinderInfo = (Ai_PathFinderInfo*)aystar->user_target;
+
+ aystar->num_neighbours = 0;
+
+ // Go through all surrounding tiles and check if they are within the limits
+ for (i = 0; i < 4; i++) {
+ TileIndex ctile = current->path.node.tile; // Current tile
+ TileIndex atile = ctile + TileOffsByDir(i); // Adjacent tile
+
+ if (TileX(atile) > 1 && TileX(atile) < MapMaxX() - 1 &&
+ TileY(atile) > 1 && TileY(atile) < MapMaxY() - 1) {
+ // We also directly test if the current tile can connect to this tile..
+ // We do this simply by just building the tile!
+
+ // If the next step is a bridge, we have to enter it the right way
+ if (!PathFinderInfo->rail_or_road && IsRoad(atile)) {
+ if (IsTileType(atile, MP_TUNNELBRIDGE)) {
+ // An existing bridge... let's test the direction ;)
+ if ((_m[atile].m5 & 1U) != (i & 1)) continue;
+ // This problem only is valid for tunnels:
+ // When the last tile was not yet a tunnel, check if we enter from the right side..
+ if ((_m[atile].m5 & 0x80) == 0) {
+ if (i != (_m[atile].m5 & 3U)) continue;
+ }
+ }
+ }
+ // But also if we are on a bridge, we can only move a certain direction
+ if (!PathFinderInfo->rail_or_road && IsRoad(ctile)) {
+ if (IsTileType(ctile, MP_TUNNELBRIDGE)) {
+ // An existing bridge/tunnel... let's test the direction ;)
+ if ((_m[ctile].m5 & 1U) != (i & 1)) continue;
+ }
+ }
+
+ if ((AI_PATHFINDER_FLAG_BRIDGE & current->path.node.user_data[0]) != 0 ||
+ (AI_PATHFINDER_FLAG_TUNNEL & current->path.node.user_data[0]) != 0) {
+ // We are a bridge/tunnel, how cool!!
+ // This means we can only point forward.. get the direction from the user_data
+ if (i != (current->path.node.user_data[0] >> 8)) continue;
+ }
+ dir = 0;
+
+ // First, check if we have a parent
+ if (current->path.parent == NULL && current->path.node.user_data[0] == 0) {
+ // If not, this means we are at the starting station
+ if (PathFinderInfo->start_direction != AI_PATHFINDER_NO_DIRECTION) {
+ // We do need a direction?
+ if (AiNew_GetDirection(ctile, atile) != PathFinderInfo->start_direction) {
+ // We are not pointing the right way, invalid tile
+ continue;
+ }
+ }
+ } else if (current->path.node.user_data[0] == 0) {
+ if (PathFinderInfo->rail_or_road) {
+ // Rail check
+ dir = AiNew_GetRailDirection(current->path.parent->node.tile, ctile, atile);
+ ret = DoCommandByTile(ctile, 0, dir, DC_AUTO | DC_NO_WATER, CMD_BUILD_SINGLE_RAIL);
+ if (CmdFailed(ret)) continue;
+#ifdef AI_PATHFINDER_NO_90DEGREES_TURN
+ if (current->path.parent->parent != NULL) {
+ // Check if we don't make a 90degree curve
+ int dir1 = AiNew_GetRailDirection(current->path.parent->parent->node.tile, current->path.parent->node.tile, ctile);
+ if (_illegal_curves[dir1] == dir || _illegal_curves[dir] == dir1) {
+ continue;
+ }
+ }
+#endif
+ } else {
+ // Road check
+ dir = AiNew_GetRoadDirection(current->path.parent->node.tile, ctile, atile);
+ if (IsRoad(ctile)) {
+ if (IsTileType(ctile, MP_TUNNELBRIDGE)) {
+ // We have a bridge, how nicely! We should mark it...
+ dir = 0;
+ } else {
+ // It already has road.. check if we miss any bits!
+ if ((_m[ctile].m5 & dir) != dir) {
+ // We do miss some pieces :(
+ dir &= ~_m[ctile].m5;
+ } else {
+ dir = 0;
+ }
+ }
+ }
+ // Only destruct things if it is MP_CLEAR of MP_TREES
+ if (dir != 0) {
+ ret = DoCommandByTile(ctile, dir, 0, DC_AUTO | DC_NO_WATER, CMD_BUILD_ROAD);
+ if (CmdFailed(ret)) continue;
+ }
+ }
+ }
+
+ // The tile can be connected
+ aystar->neighbours[aystar->num_neighbours].tile = atile;
+ aystar->neighbours[aystar->num_neighbours].user_data[0] = 0;
+ aystar->neighbours[aystar->num_neighbours++].direction = 0;
+ }
+ }
+
+ // Next step, check for bridges and tunnels
+ if (current->path.parent != NULL && current->path.node.user_data[0] == 0) {
+ TileInfo ti;
+ // First we get the dir from this tile and his parent
+ int dir = AiNew_GetDirection(current->path.parent->node.tile, current->path.node.tile);
+ // It means we can only walk with the track, so the bridge has to be in the same direction
+ TileIndex tile = current->path.node.tile;
+ TileIndex new_tile = tile;
+
+ FindLandscapeHeightByTile(&ti, tile);
+
+ // Bridges can only be build on land that is not flat
+ // And if there is a road or rail blocking
+ if (ti.tileh != 0 ||
+ (PathFinderInfo->rail_or_road && IsTileType(tile + TileOffsByDir(dir), MP_STREET)) ||
+ (!PathFinderInfo->rail_or_road && IsTileType(tile + TileOffsByDir(dir), MP_RAILWAY))) {
+ for (;;) {
+ new_tile += TileOffsByDir(dir);
+
+ // Precheck, is the length allowed?
+ if (!CheckBridge_Stuff(0, GetBridgeLength(tile, new_tile))) break;
+
+ // Check if we hit the station-tile.. we don't like that!
+ if (TILES_BETWEEN(new_tile, PathFinderInfo->end_tile_tl, PathFinderInfo->end_tile_br)) break;
+
+ // Try building the bridge..
+ ret = DoCommandByTile(tile, new_tile, (0 << 8) + (MAX_BRIDGES / 2), DC_AUTO, CMD_BUILD_BRIDGE);
+ if (CmdFailed(ret)) continue;
+ // We can build a bridge here.. add him to the neighbours
+ aystar->neighbours[aystar->num_neighbours].tile = new_tile;
+ aystar->neighbours[aystar->num_neighbours].user_data[0] = AI_PATHFINDER_FLAG_BRIDGE + (dir << 8);
+ aystar->neighbours[aystar->num_neighbours++].direction = 0;
+ // We can only have 12 neighbours, and we need 1 left for tunnels
+ if (aystar->num_neighbours == 11) break;
+ }
+ }
+
+ // Next, check for tunnels!
+ // Tunnels can only be build with tileh of 3, 6, 9 or 12, depending on the direction
+ // For now, we check both sides for this tile.. terraforming gives fuzzy result
+ if ((dir == 0 && ti.tileh == 12) ||
+ (dir == 1 && ti.tileh == 6) ||
+ (dir == 2 && ti.tileh == 3) ||
+ (dir == 3 && ti.tileh == 9)) {
+ // Now simply check if a tunnel can be build
+ ret = DoCommandByTile(tile, (PathFinderInfo->rail_or_road?0:0x200), 0, DC_AUTO, CMD_BUILD_TUNNEL);
+ FindLandscapeHeightByTile(&ti, _build_tunnel_endtile);
+ if (!CmdFailed(ret) && (ti.tileh == 3 || ti.tileh == 6 || ti.tileh == 9 || ti.tileh == 12)) {
+ aystar->neighbours[aystar->num_neighbours].tile = _build_tunnel_endtile;
+ aystar->neighbours[aystar->num_neighbours].user_data[0] = AI_PATHFINDER_FLAG_TUNNEL + (dir << 8);
+ aystar->neighbours[aystar->num_neighbours++].direction = 0;
+ }
+ }
+ }
+}
+
+
+extern uint GetRailFoundation(uint tileh, uint bits);
+extern uint GetRoadFoundation(uint tileh, uint bits);
+extern uint GetBridgeFoundation(uint tileh, byte direction);
+enum {
+ BRIDGE_NO_FOUNDATION = 1 << 0 | 1 << 3 | 1 << 6 | 1 << 9 | 1 << 12,
+};
+
+// The most important function: it calculates the g-value
+static int32 AyStar_AiPathFinder_CalculateG(AyStar *aystar, AyStarNode *current, OpenListNode *parent)
+{
+ Ai_PathFinderInfo *PathFinderInfo = (Ai_PathFinderInfo*)aystar->user_target;
+ int r, res = 0;
+ TileInfo ti, parent_ti;
+
+ // Gather some information about the tile..
+ FindLandscapeHeightByTile(&ti, current->tile);
+ FindLandscapeHeightByTile(&parent_ti, parent->path.node.tile);
+
+ // Check if we hit the end-tile
+ if (TILES_BETWEEN(current->tile, PathFinderInfo->end_tile_tl, PathFinderInfo->end_tile_br)) {
+ // We are at the end-tile, check if we had a direction or something...
+ if (PathFinderInfo->end_direction != AI_PATHFINDER_NO_DIRECTION && AiNew_GetDirection(current->tile, parent->path.node.tile) != PathFinderInfo->end_direction) {
+ // We are not pointing the right way, invalid tile
+ return AYSTAR_INVALID_NODE;
+ }
+ // If it was valid, drop out.. we don't build on the endtile
+ return 0;
+ }
+
+ // Give everything a small penalty
+ res += AI_PATHFINDER_PENALTY;
+
+ if (!PathFinderInfo->rail_or_road) {
+ // Road has the lovely advantage it can use other road... check if
+ // the current tile is road, and if so, give a good bonus
+ if (IsRoad(current->tile)) {
+ res -= AI_PATHFINDER_ROAD_ALREADY_EXISTS_BONUS;
+ }
+ }
+
+ // We should give a penalty when the tile is going up or down.. this is one way to do so!
+ // Too bad we have to count it from the parent.. but that is not so bad.
+ // We also dislike long routes on slopes, since they do not look too realistic
+ // when there is a flat land all around, they are more expensive to build, and
+ // especially they essentially block the ability to connect or cross the road
+ // from one side.
+ if (parent_ti.tileh != 0 && parent->path.parent != NULL) {
+ // Skip if the tile was from a bridge or tunnel
+ if (parent->path.node.user_data[0] == 0 && current->user_data[0] == 0) {
+ if (PathFinderInfo->rail_or_road) {
+ r = GetRailFoundation(parent_ti.tileh, 1 << AiNew_GetRailDirection(parent->path.parent->node.tile, parent->path.node.tile, current->tile));
+ // Maybe is BRIDGE_NO_FOUNDATION a bit strange here, but it contains just the right information..
+ if (r >= 15 || (r == 0 && (BRIDGE_NO_FOUNDATION & (1 << ti.tileh)))) {
+ res += AI_PATHFINDER_TILE_GOES_UP_PENALTY;
+ } else {
+ res += AI_PATHFINDER_FOUNDATION_PENALTY;
+ }
+ } else {
+ if (!(IsRoad(parent->path.node.tile) && IsTileType(parent->path.node.tile, MP_TUNNELBRIDGE))) {
+ r = GetRoadFoundation(parent_ti.tileh, AiNew_GetRoadDirection(parent->path.parent->node.tile, parent->path.node.tile, current->tile));
+ if (r >= 15 || r == 0)
+ res += AI_PATHFINDER_TILE_GOES_UP_PENALTY;
+ else
+ res += AI_PATHFINDER_FOUNDATION_PENALTY;
+ }
+ }
+ }
+ }
+
+ // Are we part of a tunnel?
+ if ((AI_PATHFINDER_FLAG_TUNNEL & current->user_data[0]) != 0) {
+ // Tunnels are very expensive when build on long routes..
+ // Ironicly, we are using BridgeCode here ;)
+ r = AI_PATHFINDER_TUNNEL_PENALTY * GetBridgeLength(current->tile, parent->path.node.tile);
+ res += r + (r >> 8);
+ }
+
+ // Are we part of a bridge?
+ if ((AI_PATHFINDER_FLAG_BRIDGE & current->user_data[0]) != 0) {
+ // That means for every length a penalty
+ res += AI_PATHFINDER_BRIDGE_PENALTY * GetBridgeLength(current->tile, parent->path.node.tile);
+ // Check if we are going up or down, first for the starting point
+ // In user_data[0] is at the 8th bit the direction
+ if (!(BRIDGE_NO_FOUNDATION & (1 << parent_ti.tileh))) {
+ if (GetBridgeFoundation(parent_ti.tileh, (current->user_data[0] >> 8) & 1) < 15)
+ res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;
+ }
+ // Second for the end point
+ if (!(BRIDGE_NO_FOUNDATION & (1 << ti.tileh))) {
+ if (GetBridgeFoundation(ti.tileh, (current->user_data[0] >> 8) & 1) < 15)
+ res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;
+ }
+ if (parent_ti.tileh == 0) res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;
+ if (ti.tileh == 0) res += AI_PATHFINDER_BRIDGE_GOES_UP_PENALTY;
+ }
+
+ // To prevent the AI from taking the fastest way in tiles, but not the fastest way
+ // in speed, we have to give a good penalty to direction changing
+ // This way, we get almost the fastest way in tiles, and a very good speed on the track
+ if (!PathFinderInfo->rail_or_road) {
+ if (parent->path.parent != NULL &&
+ AiNew_GetDirection(current->tile, parent->path.node.tile) != AiNew_GetDirection(parent->path.node.tile, parent->path.parent->node.tile)) {
+ // When road exists, we don't like turning, but its free, so don't be to piggy about it
+ if (IsRoad(parent->path.node.tile))
+ res += AI_PATHFINDER_DIRECTION_CHANGE_ON_EXISTING_ROAD_PENALTY;
+ else
+ res += AI_PATHFINDER_DIRECTION_CHANGE_PENALTY;
+ }
+ } else {
+ // For rail we have 1 exeption: diagonal rail..
+ // So we fetch 2 raildirection. That of the current one, and of the one before that
+ if (parent->path.parent != NULL && parent->path.parent->parent != NULL) {
+ int dir1 = AiNew_GetRailDirection(parent->path.parent->node.tile, parent->path.node.tile, current->tile);
+ int dir2 = AiNew_GetRailDirection(parent->path.parent->parent->node.tile, parent->path.parent->node.tile, parent->path.node.tile);
+ // First, see if we are on diagonal path, that is better than straight path
+ if (dir1 > 1) { res -= AI_PATHFINDER_DIAGONAL_BONUS; }
+
+ // First see if they are different
+ if (dir1 != dir2) {
+ // dir 2 and 3 are 1 diagonal track, and 4 and 5.
+ if (!(((dir1 == 2 || dir1 == 3) && (dir2 == 2 || dir2 == 3)) || ((dir1 == 4 || dir1 == 5) && (dir2 == 4 || dir2 == 5)))) {
+ // It is not, so we changed of direction
+ res += AI_PATHFINDER_DIRECTION_CHANGE_PENALTY;
+ }
+ if (parent->path.parent->parent->parent != NULL) {
+ int dir3 = AiNew_GetRailDirection(parent->path.parent->parent->parent->node.tile, parent->path.parent->parent->node.tile, parent->path.parent->node.tile);
+ // Check if we changed 3 tiles of direction in 3 tiles.. bad!!!
+ if ((dir1 == 0 || dir1 == 1) && dir2 > 1 && (dir3 == 0 || dir3 == 1)) {
+ res += AI_PATHFINDER_CURVE_PENALTY;
+ }
+ }
+ }
+ }
+ }
+
+ // Res should never be below zero.. if so, make it zero!
+ if (res < 0) { res = 0; }
+
+ // Return our value
+ return res;
+}