#5031: Fix accessibility logic for wagons

library/modules/Maps.cpp

@@ -63,6 +63,8 @@ distribution.
 #include "df/world_underground_region.h"
 #include "df/z_level_flags.h"
 
+#include <array>
+#include <utility>
 #include <string>
 #include <vector>
 #include <map>
@@ -757,9 +759,45 @@ bool Maps::ReadGeology(vector<vector<int16_t> > *layer_mats, vector<df::coord2d>
     return true;
 }
 
-uint16_t Maps::getWalkableGroup(df::coord pos) {
+uint16_t getNeighborWalkableGroup(df::map_block * block, df::coord pos) {
+    auto neighborGroup = [block, pos](int dx, int dy) {
+        return index_tile(block->walkable, pos + df::coord(dx, dy, 0));
+    };
+
+    constexpr std::array<std::pair<int, int>, 8> directions = {{
+        {-1, -1}, {0, -1}, {1, -1},
+        {-1,  0},           {1,  0},
+        {-1,  1}, {0,  1}, {1,  1}
+    }};
+
+    for (const auto& [dx, dy] : directions) {
+        uint16_t g = neighborGroup(dx, dy);
+        if (g) return g;
+    }
+    return 0;
+}
+
+uint16_t Maps::getWalkableGroup(df::coord pos)
+{
     auto block = getTileBlock(pos);
-    return block ? index_tile(block->walkable, pos) : 0;
+    if (!block) return 0;
+
+    /*
+     * RAMP_TOP tiles do not have a walkability group assigned to them directly.
+     * To determine walkability, we assign the group of an adjacent tile,
+     * with the constraint that the assigned group matches the walkability group
+     * of the same tile one z-level below.
+     */
+    auto tt = getTileType(pos);
+    if (tt && tileShape(*tt) == df::tiletype_shape::RAMP_TOP) {
+        auto below_group = getWalkableGroup(pos + df::coord(0, 0, -1));
+        if (below_group != 0) {
+            auto neigh_group = getNeighborWalkableGroup(block, pos);
+            return below_group == neigh_group ? neigh_group : 0;
+        }
+    }
+
+    return index_tile(block->walkable, pos);
 }
 
 bool Maps::canWalkBetween(df::coord pos1, df::coord pos2)

plugins/pathable.cpp

@@ -3,6 +3,11 @@
 #include "PluginManager.h"
 #include "TileTypes.h"
 
+#include "df/building_type.h"
+#include "df/building_hatchst.h"
+#include "df/building_bars_floorst.h"
+#include "df/building_grate_floorst.h"
+#include "df/tile_building_occ.h"
 #include "modules/Buildings.h"
 #include "modules/Gui.h"
 #include "modules/Maps.h"
@@ -203,24 +208,88 @@ struct FloodCtx {
         : wgroup(wgroup), wagon_path(wagon_path), entry_tiles(entry_tiles) {}
 };
 
-static bool is_wagon_traversible(FloodCtx & ctx, const df::coord & pos, const df::coord & prev_pos) {
-    if (auto bld = Buildings::findAtTile(pos)) {
-        auto btype = bld->getType();
-        if (btype == df::building_type::Trap || btype == df::building_type::Door)
+static bool is_wagon_dynamic_traversible(df::tiletype_shape shape, const df::coord & pos) {
+    auto bld = Buildings::findAtTile(pos);
+    if (!bld) return false;
+
+    auto btype = bld->getType();
+    // open hatch should be inaccessible regardless of the tile it sits on
+    if (btype == df::building_type::Hatch) {
+        if (shape == df::tiletype_shape::RAMP_TOP)
             return false;
+
+        auto& hatch = *static_cast<df::building_hatchst*>(bld);
+        if (hatch.door_flags.bits.closed)
+            return true;
+    // open floor grate/bar should be inaccessible regardless of the tile it sits on
+    } else if (btype == df::building_type::GrateFloor) {
+        auto& b = *static_cast<df::building_grate_floorst*>(bld);
+        if (b.gate_flags.bits.closed)
+            return true;
+    } else if (btype == df::building_type::BarsFloor) {
+        auto& b = *static_cast<df::building_bars_floorst*>(bld);
+        if (b.gate_flags.bits.closed)
+            return true;
     }
+    // Doors, traps..etc
+    return false;
+}
 
+static bool is_wagon_tile_traversible(df::tiletype_shape shape) {
+    // TODO: smoothed boulders are traversible
+    if (shape == df::tiletype_shape::STAIR_UP || shape == df::tiletype_shape::STAIR_DOWN ||
+            shape == df::tiletype_shape::STAIR_UPDOWN || shape == df::tiletype_shape::BOULDER ||
+            shape == df::tiletype_shape::EMPTY || shape == df::tiletype_shape::NONE)
+        return false;
+    return true;
+}
+
+static bool is_wagon_traversible(FloodCtx & ctx, const df::coord & pos, const df::coord & prev_pos) {
     auto tt = Maps::getTileType(pos);
     if (!tt)
         return false;
 
     auto shape = tileShape(*tt);
-    if (shape == df::tiletype_shape::STAIR_UP || shape == df::tiletype_shape::STAIR_UPDOWN)
-        return false;
+
+    auto& occ = *Maps::getTileOccupancy(pos);
+    switch (occ.bits.building) {
+        case tile_building_occ::Obstacle: // Statue
+            //FALLTHROUGH
+        case tile_building_occ::Well:
+            //FALLTHROUGH
+        case tile_building_occ::Impassable: // Raised bridge
+            return false;
+
+        case tile_building_occ::Dynamic:
+            // doors(block), levers (block), traps (block), hatches (OK, but block on down ramp)
+            // closed floor grates (OK), closed floor bars (OK)
+            if (is_wagon_dynamic_traversible(shape, pos) == false)
+                return false;
+            break;
+
+        case tile_building_occ::None: // Not occupied by a building
+            //FALLTHROUGH
+        case tile_building_occ::Planned:
+            //FALLTHROUGH
+        case tile_building_occ::Passable:
+            // bed, support, rollers, armor/weapon stand, cage (not trap)
+            // open wall grate/vertical bars, retracted bridge, open floodgate
+            if (is_wagon_tile_traversible(shape) == false)
+                return false;
+            break;
+        case tile_building_occ::Floored:
+            // depot, lowered bridge, retracable bridge, forbidden hatch
+            break;
+        default:
+            //NOTREACHED
+            break;
+    }
 
     if (ctx.wgroup == Maps::getWalkableGroup(pos))
         return true;
 
+    // RAMP_TOP is assigned a walkability group if that commit is accepted
+    // so this test, I think, would be useless.
     if (shape == df::tiletype_shape::RAMP_TOP ) {
         df::coord pos_below = pos + df::coord(0, 0, -1);
         if (Maps::getWalkableGroup(pos_below)) {
@@ -241,30 +310,77 @@ static bool is_wagon_traversible(FloodCtx & ctx, const df::coord & pos, const df
     return false;
 }
 
+static bool is_wagon_traversible_by_ramp(FloodCtx & ctx, const df::coord & pos) {
+    if ((is_wagon_traversible(ctx, pos+df::coord(-1, -1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 0, -1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 1, -1, 0), pos)) || // Top
+
+            (is_wagon_traversible(ctx, pos+df::coord(-1,  0, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 0,  0, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 1,  0, 0), pos)) || // Middle
+
+            (is_wagon_traversible(ctx, pos+df::coord(-1,  1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 0,  1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 1,  1, 0), pos)) || // Bottom
+
+            (is_wagon_traversible(ctx, pos+df::coord(-1, -1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord(-1,  0, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord(-1,  1, 0), pos)) || // Left
+
+            (is_wagon_traversible(ctx, pos+df::coord( 1, -1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 1,  0, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 1,  1, 0), pos))) { // Right
+        return true;
+    }
+    return false;
+}
+
 static void check_wagon_tile(FloodCtx & ctx, const df::coord & pos) {
     if (ctx.seen.contains(pos))
         return;
 
     ctx.seen.emplace(pos);
 
     if (ctx.entry_tiles.contains(pos)) {
-        ctx.wagon_path.emplace(pos);
+        ctx.wagon_path.emplace(pos); // Is this needed?
         ctx.search_edge.emplace(pos);
         return;
     }
 
-    if (is_wagon_traversible(ctx, pos+df::coord(-1, -1, 0), pos) &&
-        is_wagon_traversible(ctx, pos+df::coord( 0, -1, 0), pos) &&
-        is_wagon_traversible(ctx, pos+df::coord( 1, -1, 0), pos) &&
-        is_wagon_traversible(ctx, pos+df::coord(-1,  0, 0), pos) &&
-        is_wagon_traversible(ctx, pos+df::coord( 1,  0, 0), pos) &&
-        is_wagon_traversible(ctx, pos+df::coord(-1,  1, 0), pos) &&
-        is_wagon_traversible(ctx, pos+df::coord( 0,  1, 0), pos) &&
-        is_wagon_traversible(ctx, pos+df::coord( 1,  1, 0), pos))
-    {
+    auto tt = Maps::getTileType(pos);
+    if (!tt)
+        return;
+
+    auto shape = tileShape(*tt);
+    if ((shape != df::tiletype_shape::RAMP_TOP &&
+            (is_wagon_traversible(ctx, pos+df::coord(-1, -1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 0, -1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 1, -1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord(-1,  0, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 1,  0, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord(-1,  1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 0,  1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 1,  1, 0), pos))) ||
+            (shape == df::tiletype_shape::RAMP_TOP && is_wagon_traversible_by_ramp(ctx, pos))) {
+        ctx.wagon_path.emplace(pos);
+        ctx.search_edge.emplace(pos);
+    }
+
+#if 0
+    // Use this if we don't mind red Xs on down ramps
+    if ((is_wagon_traversible(ctx, pos+df::coord(-1, -1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 0, -1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 1, -1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord(-1,  0, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 1,  0, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord(-1,  1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 0,  1, 0), pos) &&
+            is_wagon_traversible(ctx, pos+df::coord( 1,  1, 0), pos))) {
         ctx.wagon_path.emplace(pos);
         ctx.search_edge.emplace(pos);
     }
+#endif
+
 }
 
 // returns true if a continuous 3-wide path can be found to an entry tile
@@ -293,7 +409,10 @@ static bool wagon_flood(color_ostream &out, unordered_set<df::coord> * wagon_pat
         TRACE(log,out).print("checking tile: (%d, %d, %d); pathability group: %d\n", pos.x, pos.y, pos.z,
             Maps::getWalkableGroup(pos));
 
-        if (entry_tiles.contains(pos)) {
+        // Ensure our wagon flood end points lands on an edge tile.
+        // When there is no path to the depot entry_tiles will not
+        // contain any edge tiles.
+        if ((pos.x == 0 || pos.y == 0) && entry_tiles.contains(pos)) {
             found = true;
             if (!wagon_path)
                 break;