feat(port): Implement GLOBALLY_UNIQUE

data/json/overmap/overmap_special/aircraft_carrier.json

@@ -201,6 +201,6 @@
     "city_distance": [ -1, 1000 ],
     "locations": [ "lake_surface" ],
     "occurrences": [ 75, 100 ],
-    "flags": [ "CLASSIC", "LAKE", "MAN_MADE", "UNIQUE", "MILITARY", "ELECTRIC_GRID" ]
+    "flags": [ "CLASSIC", "LAKE", "MAN_MADE", "UNIQUE", "MILITARY", "ELECTRIC_GRID", "GLOBALLY_UNIQUE" ]
   }
 ]

data/json/overmap/overmap_special/specials.json

@@ -1796,7 +1796,7 @@
     "city_distance": [ 3, -1 ],
     "city_sizes": [ 4, -1 ],
     "occurrences": [ 50, 100 ],
-    "flags": [ "UNIQUE" ]
+    "flags": [ "ELECTRIC_GRID", "UNIQUE", "GLOBALLY_UNIQUE" ]
   },
   {
     "type": "overmap_special",

src/overmap.cpp

@@ -5501,6 +5501,11 @@
         return false;
     }
 
+    if( special.has_flag( "GLOBALLY_UNIQUE" ) &&
+        overmap_buffer.contains_unique_special( special.id ) ) {
+        return false;
+    }
+
     const std::vector<overmap_special_locations> fixed_terrains = special.required_locations();
 
     return std::all_of( fixed_terrains.begin(), fixed_terrains.end(),
@@ -5538,6 +5543,10 @@
         assert( can_place_special( special, p, dir, must_be_unexplored ) );
     }
 
+    if( special.has_flag( "GLOBALLY_UNIQUE" ) ) {
+        overmap_buffer.add_unique_special( special.id );
+    }
+
     const bool grid = special.has_flag( "ELECTRIC_GRID" );
 
     special_placement_result result = special.place( *this, p, dir );
@@ -5941,10 +5950,18 @@
         const float rate = is_true_center && special.has_flag( "ENDGAME" ) ? 1 :
                            zone_ratio[current];
 
+        const bool unique = iter.special_details->has_flag( "UNIQUE" );
+        const bool globally_unique = iter.special_details->has_flag( "GLOBALLY_UNIQUE" );
+
         int amount_to_place;
-        if( special.has_flag( "UNIQUE" ) ) {
+        if( unique || globally_unique ) {
+            const overmap_special_id &id = iter.special_details->id;
+            const overmap_special_placement_constraints &constraints = iter.special_details->get_constraints();
+
             int chance = roll_remainder( min * rate );
-            amount_to_place = x_in_y( chance, max ) ? 1 : 0;
+            //FINGERS CROSSED EMOGI
+            amount_to_place = x_in_y( min, max ) && ( !globally_unique ||
+                              !overmap_buffer.contains_unique_special( id ) ) ? 1 : 0;
         } else {
             // Number of instances normalized to terrain ratio
             float real_max = std::max( static_cast<float>( min ), max * rate );

src/overmapbuffer.cpp

@@ -208,6 +208,7 @@ void overmapbuffer::clear()
 {
     overmaps.clear();
     known_non_existing.clear();
+    placed_unique_specials.clear();
     last_requested_overmap = nullptr;
 }
 
@@ -947,6 +948,19 @@ bool overmapbuffer::check_overmap_special_type( const overmap_special_id &id,
     return om_loc.om->check_overmap_special_type( id, om_loc.local );
 }
 
+void overmapbuffer::add_unique_special( const overmap_special_id &id )
+{
+    if( contains_unique_special( id ) ) {
+        debugmsg( "Unique overmap special placed more than once: %s", id.str() );
+    }
+    placed_unique_specials.emplace( id );
+}
+
+bool overmapbuffer::contains_unique_special( const overmap_special_id &id ) const
+{
+    return placed_unique_specials.find( id ) != placed_unique_specials.end();
+}
+
 static omt_find_params assign_params(
     const std::string &type, int const radius, bool must_be_seen,
     ot_match_type match_type, bool existing_overmaps_only,

src/overmapbuffer.h

@@ -9,11 +9,13 @@
 #include <set>
 #include <string>
 #include <unordered_map>
+#include <unordered_set>
 #include <utility>
 #include <vector>
 
 #include "coordinates.h"
 #include "enums.h"
+#include "json.h"
 #include "memory_fast.h"
 #include "overmap_types.h"
 #include "point.h"
@@ -518,6 +520,9 @@ class overmapbuffer
         // Cached result of previous call to overmapbuffer::get_existing
         overmap mutable *last_requested_overmap;
 
+        // Set of globally unique overmap specials that have already been placed
+        std::unordered_set<overmap_special_id> placed_unique_specials;
+
         /**
          * Get a list of notes in the (loaded) overmaps.
          * @param z only this specific z-level is search for notes.
@@ -551,6 +556,24 @@ class overmapbuffer
                                 const tripoint_abs_omt &loc );
         bool check_overmap_special_type_existing( const overmap_special_id &id,
                 const tripoint_abs_omt &loc );
+
+        /**
+         * Adds the given globally unique overmap special to the list of placed specials.
+         */
+        void add_unique_special( const overmap_special_id &id );
+        /**
+         * Returns true if the given globally unique overmap special has already been placed.
+         */
+        bool contains_unique_special( const overmap_special_id &id ) const;
+        /**
+         * Writes the placed unique specials as a JSON value.
+         */
+        void serialize_placed_unique_specials( JsonOut &json ) const;
+        /**
+         * Reads placed unique specials from JSON and overwrites the global value.
+         */
+        void deserialize_placed_unique_specials( JsonIn &jsin );
+
     private:
         /**
          * Go thorough the monster groups of the overmap and move out-of-bounds

src/savegame.cpp

@@ -34,6 +34,7 @@
 #include "output.h"
 #include "overmap.h"
 #include "overmap_types.h"
+#include "overmapbuffer.h"
 #include "popup.h"
 #include "regional_settings.h"
 #include "scent_map.h"
@@ -1167,6 +1168,8 @@ void game::unserialize_master( std::istream &fin )
                 jsin.read( *faction_manager_ptr );
             } else if( name == "seed" ) {
                 jsin.read( seed );
+            } else if( name == "placed_unique_specials" ) {
+                overmap_buffer.deserialize_placed_unique_specials( jsin );
             } else if( name == "weather" ) {
                 JsonObject w = jsin.get_object();
                 w.read( "lightning", get_weather().lightning_active );
@@ -1202,6 +1205,9 @@ void game::serialize_master( std::ostream &fout )
         json.member( "active_missions" );
         mission::serialize_all( json );
 
+        json.member( "placed_unique_specials" );
+        overmap_buffer.serialize_placed_unique_specials( json );
+
         json.member( "factions", *faction_manager_ptr );
         json.member( "seed", seed );
 
@@ -1283,3 +1289,17 @@ void Creature_tracker::serialize( JsonOut &jsout ) const
     }
     jsout.end_array();
 }
+
+void overmapbuffer::serialize_placed_unique_specials( JsonOut &json ) const
+{
+    json.write_as_array( placed_unique_specials );
+}
+
+void overmapbuffer::deserialize_placed_unique_specials( JsonIn &jsin )
+{
+    placed_unique_specials.clear();
+    jsin.start_array();
+    while( !jsin.end_array() ) {
+        placed_unique_specials.emplace( jsin.get_string() );
+    }
+}