Convert _city_level to Lua.

This commit translates the original C++ _city_level code into Lua. It
opens up the way for nicer Vault layouts, using a series of subvaults.
Hopefully it doesn't break anything too much! Should be reverted if it
does.

2 files changed, 133 insertions, 74 deletions

diff --git a/crawl-ref/source/dat/layout.des b/crawl-ref/source/dat/layout.des
index a620e3bd0c..0d0cee8a28 100644
--- a/crawl-ref/source/dat/layout.des
+++ b/crawl-ref/source/dat/layout.des
@@ -383,3 +383,128 @@ TAGS: layout allow_dup
 }}
 MAP
 ENDMAP
+
+##############################################################
+# layout_city
+#
+# This replaces dungeon.cc:_city_level().
+#
+NAME: layout_city
+ORIENT: encompass
+TAGS: layout allow_dup
+{{
+    function treasure_area (x1, y1, x2, y2)
+        x2 = x2 + 1
+        y2 = y2 + 1
+
+        if x2 <= x2 or y2 <= y2 then
+            return false
+        end
+
+        if (x2 - x1) * (y2 - y1) >= 40 then
+            return false
+        end
+
+        local tl = dgn.point(x1, y1)
+        local br = dgn.point(x2 - 1, y2 - 1)
+
+        for point in iter.rect_iterator(tl, br) do
+            if is_valid_coord {x = point.x, y = point.y } then
+                if is_passable_coord { x=point.x, y=point.y } or crawl.coinflip() then 
+                    mapgrd[point.x][point.y] = "|"
+                end
+            end
+        end
+
+        return true
+    end
+
+    local gxm, gym = dgn.max_bounds()
+
+    extend_map{width = gxm, height = gym, fill = 'x'}
+    fill_area{fill = 'x'}
+
+
+    local temp_rand = crawl.random2(8)
+    local wall_type_room
+    local wall_type
+    local rooms = {}
+
+    local xs = 0
+    local ys = 0
+    local ax1 = 0
+    local bx2 = 0
+    local ay1 = 0
+    local by2 = 0
+    local i, j
+
+    if temp_rand > 4 then
+        wall_type = 'x'
+    elseif temp_rand  > 2 then
+        wall_type = 'c'
+    else
+        wall_type = 'v'
+    end
+
+    if crawl.one_chance_in(100) then
+        wall_type = 'b'
+    end
+
+    fill_area { x1=8, y1=8, x2=gxm-9, y2=gym-9, fill="." }
+
+    for i = 0, 5 do
+        for j = 0, 4 do
+            xs = 8 + (i * 13)
+            ys = 8 + (j * 14)
+            a1 = xs + crawl.random2avg(5, 2);
+            a2 = ys + crawl.random2avg(5, 2);
+            b1 = xs + 11 - crawl.random2avg(5, 2);
+            b2 = ys + 11 - crawl.random2avg(5, 2);
+
+            temp_rand = crawl.random2(280);
+
+            if temp_rand > 39 and is_valid_coord {x=a1, y=a2} and is_valid_coord{x=b1, y=b2} then
+                if temp_rand > 63 then
+                    wall_type_room = wall_type
+                elseif temp_rand > 54 then
+                    wall_type_room = "c"
+                elseif temp_rand > 45 then
+                    wall_type_room = "x"
+                else
+                    wall_type_room = "v"
+                end
+
+                if crawl.one_chance_in(250) then
+                    wall_type_room = "b"
+                end
+
+                table.insert(rooms, {a1, a2, b1, b2})
+                make_box { x1=a1, y1=a2, x2=b1, y2=b2, wall=wall_type_room }
+
+                if b1 - a1 > 5 and b2 - a2 > 5 and crawl.one_chance_in(8) then
+                    table.insert(rooms, {a1+2, a2+2, b1-2, b2-2})
+                    make_box { x1=a1+2, y1=a2+2, x2=b1-2, y2=b2-2, wall=wall_type_room }
+
+                    if crawl.one_chance_in(3) then
+                        treasure_area(a1+3, a2+3, b1-3, b2-3)
+                    end
+                end
+            end
+        end
+    end
+
+    for _, room in ipairs(rooms) do
+        local doors = 1 + crawl.random2(5) - crawl.random2(3)
+        if doors < 1 then
+            doors = 1
+        end
+
+        if doors > 3 and crawl.one_chance_in(3) then
+            doors = 2
+        end
+
+        make_box_doors {x1=room[1], y1=room[2], x2=room[3], y2=room[4], number=doors}
+    end
+}}
+MAP
+ENDMAP
diff --git a/crawl-ref/source/dungeon.cc b/crawl-ref/source/dungeon.cc
index c9a29e76e7..442ff363b1 100644
--- a/crawl-ref/source/dungeon.cc
+++ b/crawl-ref/source/dungeon.cc
@@ -2561,10 +2561,10 @@ static builder_rc_type _builder_normal(int level_number, char level_type,
 
     if (player_in_branch( BRANCH_VAULTS ))
     {
-        if (one_chance_in(3))
-            _city_level(level_number);
-        else
-            _plan_main(level_number, 4);
+        //if (one_chance_in(3))
+        _city_level(level_number);
+        //else
+        //    _plan_main(level_number, 4);
         return BUILD_SKIP;
     }
 
@@ -7122,77 +7122,11 @@ static void _city_level(int level_number)
     dgn_Build_Method += make_stringf(" city_level [%d]", level_number);
     dgn_Layout_Type   = "city";
 
-    int temp_rand;          // probability determination {dlb}
-    // Remember, can have many wall types in one level.
-    dungeon_feature_type wall_type;
-    // Simplifies logic of innermost loop. {dlb}
-    dungeon_feature_type wall_type_room;
-
-    int xs = 0, ys = 0;
-    int x1 = 0, x2 = 0;
-    int y1 = 0, y2 = 0;
-    int i,j;
-
-    temp_rand = random2(8);
-
-    wall_type = ((temp_rand > 4) ? DNGN_ROCK_WALL :     // 37.5% {dlb}
-                 (temp_rand > 1) ? DNGN_STONE_WALL      // 37.5% {dlb}
-                                 : DNGN_METAL_WALL);    // 25.0% {dlb}
-
-    if (one_chance_in(100))
-        wall_type = DNGN_GREEN_CRYSTAL_WALL;
-
-    _make_box( 7, 7, GXM-7, GYM-7, DNGN_FLOOR );
-
-    for (i = 0; i < 5; i++)
-        for (j = 0; j < 4; j++)
-        {
-            xs = 8 + (i * 13);
-            ys = 8 + (j * 14);
-            x1 = xs + random2avg(5, 2);
-            y1 = ys + random2avg(5, 2);
-            x2 = xs + 11 - random2avg(5, 2);
-            y2 = ys + 11 - random2avg(5, 2);
-
-            temp_rand = random2(280);
-
-            if (temp_rand > 39) // 85.7% draw room(s) {dlb}
-            {
-                wall_type_room = ((temp_rand > 63) ? wall_type :       // 77.1%
-                                  (temp_rand > 54) ? DNGN_STONE_WALL : //  3.2%
-                                  (temp_rand > 45) ? DNGN_ROCK_WALL    //  3.2%
-                                                   : DNGN_METAL_WALL); //  2.1%
-
-                if (one_chance_in(250))
-                    wall_type_room = DNGN_GREEN_CRYSTAL_WALL;
-
-                _box_room(x1, x2, y1, y2, wall_type_room);
-
-                // Inner room - neat.
-                if (x2 - x1 > 5 && y2 - y1 > 5 && one_chance_in(8))
-                {
-                    _box_room(x1 + 2, x2 - 2, y1 + 2, y2 - 2, wall_type);
-
-                    // Treasure area... neat.
-                    if (one_chance_in(3))
-                    {
-                        _treasure_area(level_number, x1 + 3, x2 - 3,
-                                       y1 + 3, y2 - 3);
-                    }
-                }
-            }
-        }
-
-    int stair_count = coinflip() ? 4 : 3;
-
-    for (j = 0; j < stair_count; j++)
-        for (i = 0; i < 2; i++)
-        {
-            _place_specific_stair( static_cast<dungeon_feature_type>(
-                                    j + ((i == 0) ? DNGN_STONE_STAIRS_DOWN_I
-                                                  : DNGN_STONE_STAIRS_UP_I)) );
-        }
+    const map_def *vault = find_map_by_name("layout_city");
+    ASSERT(vault);
 
+    bool success = _build_vaults(level_number, vault);
+    dgn_ensure_vault_placed(success, false);
 }
 
 static bool _treasure_area(int level_number, unsigned char ta1_x,