feat(port): Allow custom surround monster groups in scenarios (#4665)

* Allow custom surround monster groups in scenarios

dda port CleverRaven/Cataclysm-DDA#47990

* style(autofix.ci): automated formatting

* Update mods

* smol idea

* docs time bay-bee

* style(autofix.ci): automated formatting

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Chaosvolt <chaosvolt@users.noreply.github.com>

data/json/monstergroups/misc.json

@@ -5,6 +5,45 @@
     "is_safe": true,
     "default": "mon_null"
   },
+  {
+    "type": "monstergroup",
+    "name": "GROUP_BLACK_ROAD",
+    "default": "mon_zombie",
+    "monsters": [
+      { "monster": "mon_zombie", "freq": 1, "cost_multiplier": 7, "pack_size": [ 5, 20 ] },
+      { "monster": "mon_zombie", "freq": 1, "cost_multiplier": 13, "pack_size": [ 15, 40 ] },
+      { "monster": "mon_zombie", "freq": 1, "cost_multiplier": 20, "pack_size": [ 25, 60 ] },
+      { "monster": "mon_zombie", "freq": 75, "cost_multiplier": 0 },
+      { "monster": "mon_zombie_fat", "freq": 75, "cost_multiplier": 2 },
+      { "monster": "mon_zombie_fat", "freq": 3, "cost_multiplier": 7, "pack_size": [ 3, 5 ] },
+      { "monster": "mon_zombie_tough", "freq": 75, "cost_multiplier": 3 },
+      { "monster": "mon_zombie_child", "freq": 75, "cost_multiplier": 1 },
+      { "monster": "mon_zombie_rot", "freq": 50, "cost_multiplier": 3 },
+      { "monster": "mon_zombie_crawler", "freq": 25, "cost_multiplier": 3 },
+      { "monster": "mon_zombie_dog", "freq": 20, "cost_multiplier": 2 },
+      { "monster": "mon_zombie_dog", "freq": 1, "cost_multiplier": 4, "pack_size": [ 3, 5 ] },
+      { "monster": "mon_zombie_dog", "freq": 1, "cost_multiplier": 16, "pack_size": [ 5, 8 ] },
+      { "monster": "mon_zombie_dog", "freq": 1, "cost_multiplier": 24, "pack_size": [ 8, 12 ] },
+      { "monster": "mon_dog_zombie_cop", "freq": 5, "cost_multiplier": 4 },
+      { "monster": "mon_dog_zombie_rot", "freq": 5, "cost_multiplier": 5 },
+      { "monster": "mon_zombie_soldier", "freq": 10, "cost_multiplier": 2 },
+      { "monster": "mon_zombie_cop", "freq": 20, "cost_multiplier": 3 },
+      { "monster": "mon_zombie_swat", "freq": 10, "cost_multiplier": 3 },
+      { "monster": "mon_zombie_hazmat", "freq": 10, "cost_multiplier": 3 },
+      { "monster": "mon_zombie_fireman", "freq": 10, "cost_multiplier": 2 },
+      { "monster": "mon_zombie_swimmer", "freq": 10, "cost_multiplier": 5 },
+      { "monster": "mon_zombie_static", "freq": 10, "cost_multiplier": 5 },
+      { "monster": "mon_zombie_survivor", "freq": 1, "cost_multiplier": 25 },
+      { "monster": "mon_zombie_survivor_elite", "freq": 1, "cost_multiplier": 25, "starts": 1440 },
+      { "monster": "mon_beekeeper", "freq": 1, "cost_multiplier": 5 },
+      { "monster": "mon_zombie_technician", "freq": 1, "cost_multiplier": 12 },
+      { "monster": "mon_zombie_runner", "freq": 20, "cost_multiplier": 5, "pack_size": [ 1, 4 ] },
+      { "monster": "mon_feral_human_pipe", "freq": 4, "cost_multiplier": 1, "pack_size": [ 2, 3 ] },
+      { "monster": "mon_feral_human_crowbar", "freq": 4, "cost_multiplier": 1, "pack_size": [ 2, 3 ] },
+      { "monster": "mon_feral_human_axe", "freq": 2, "cost_multiplier": 2, "pack_size": [ 1, 2 ] },
+      { "monster": "mon_zombie_brainless", "freq": 65, "cost_multiplier": 1 }
+    ]
+  },
   {
     "type": "monstergroup",
     "name": "GROUP_CHUD",

data/json/scenarios.json

@@ -39,7 +39,8 @@
     "description": "Whether due to stubbornness, ignorance, or just plain bad luck, you missed the evacuation, and are stuck in a large building full of the risen dead.",
     "allowed_locs": [ "sloc_mall_loading_area", "sloc_mall_food_court", "sloc_apartments_rooftop", "sloc_hospital", "sloc_bastion_fort" ],
     "start_name": "In Large Building",
-    "flags": [ "SUR_START", "CITY_START", "LONE_START" ]
+    "surround_groups": [ [ "GROUP_BLACK_ROAD", 70.0 ] ],
+    "flags": [ "CITY_START", "LONE_START" ]
   },
   {
     "type": "scenario",
@@ -65,7 +66,8 @@
       "sloc_town_hall"
     ],
     "start_name": "In Town",
-    "flags": [ "SUR_START", "CITY_START", "LONE_START" ]
+    "surround_groups": [ [ "GROUP_BLACK_ROAD", 70.0 ] ],
+    "flags": [ "CITY_START", "LONE_START" ]
   },
   {
     "type": "scenario",
@@ -332,7 +334,8 @@
       "sloc_bastion_fort"
     ],
     "start_name": "Outside Town",
-    "flags": [ "SUR_START", "WIN_START", "LONE_START" ],
+    "surround_groups": [ [ "GROUP_BLACK_ROAD", 70.0 ] ],
+    "flags": [ "WIN_START", "LONE_START" ],
     "add_professions": true,
     "professions": [
       "sheltered_survivor",

data/mods/Magiclysm/scenarios.json

@@ -3,7 +3,8 @@
     "type": "scenario",
     "id": "lost_faith",
     "name": "Lost Faith",
-    "flags": [ "SUR_START", "LONE_START" ],
+    "surround_groups": [ [ "GROUP_CHURCH_ZOMBIE", 70.0 ] ],
+    "flags": [ "LONE_START" ],
     "points": 2,
     "description": "You've been preaching your faith for a long time, but the recent events have begun to make you doubt it.  Wandering in your temple, you just found books that may restore your faith or shatter it completely.",
     "start_name": "Church",

data/mods/more_classes_scenarios/cs_scenarios.json

@@ -20,7 +20,8 @@
       "specops"
     ],
     "start_name": "Fema Camp",
-    "flags": [ "HELI_CRASH", "SUR_START", "FIRE_START", "INFECTED", "CHALLENGE" ]
+    "surround_groups": [ [ "GROUP_BLACK_ROAD", 70.0 ] ],
+    "flags": [ "HELI_CRASH", "FIRE_START", "INFECTED", "CHALLENGE" ]
   },
   {
     "type": "scenario",
@@ -31,7 +32,7 @@
     "allowed_locs": [ "sloc_mansion", "sloc_mansion_entrance" ],
     "professions": [ "maid" ],
     "start_name": "Mansion",
-    "flags": [ "SUR_START" ]
+    "surround_groups": [ [ "GROUP_BLACK_ROAD", 70.0 ] ]
   },
   {
     "type": "scenario",

doc/src/content/docs/en/mod/json/reference/json_flags.md

@@ -1371,7 +1371,6 @@ These branches are also the valid entries for the categories of `dreams` in `dre
 - `LONE_START` If starting NPC spawn option is switched to "Scenario-based", this scenario won't
   spawn a fellow NPC on game start.
 - `SCEN_ONLY` Profession can be chosen only as part of the appropriate scenario.
-- `SUR_START` Surrounded start, zombies outside the starting location.
 
 #### Season Flags
 

doc/src/content/docs/en/mod/json/reference/scenarios.md

@@ -83,6 +83,20 @@ Example for mods:
 }
 ```
 
+## `surround_groups`
+
+(optional, array with group and density number)
+
+This replaces the `SUR_START` flag for scenarios, specifies groups of monsters which spawn in the
+area surrounding the scenario's staritng location.
+
+```json
+"surround_groups": [ [ "GROUP_BLACK_ROAD", 70.0 ] ],
+```
+
+The string defines the ID of which monstergroup will be spawned in the surrounding area, while the
+number is the density of spawns. 70.0 replicates the value of the original `SUR_START` behavior.
+
 ## `flags`
 
 (optional, array of strings)

doc/src/content/docs/en/mod/json/tutorial/modding.md

@@ -126,7 +126,8 @@ Below you will find the JSON definition for the game's built-in `Large Building`
       "hospital_9"
     ],
     "start_name": "In Large Building",
-    "flags": ["SUR_START", "CITY_START", "LONE_START"]
+    "surround_groups": [["GROUP_BLACK_ROAD", 70.0]],
+    "flags": ["CITY_START", "LONE_START"]
   }
 ]
 ```

src/game.cpp

@@ -645,12 +645,19 @@ bool game::start_game()
     }
     //Load NPCs. Set nearby npcs to active.
     load_npcs();
-    // Spawn the monsters
-    const bool spawn_near =
-        get_option<bool>( "BLACK_ROAD" ) || g->scen->has_flag( "SUR_START" );
-    // Surrounded start ones
+
+    // Spawn the monsters for `Surrounded` starting scenarios
+    std::vector<std::pair<mongroup_id, float>> surround_groups = get_scenario()->surround_groups();
+    const bool surrounded_start_scenario = !surround_groups.empty();
+    const bool surrounded_start_options = get_option<bool>( "BLACK_ROAD" );
+    if( surrounded_start_options && !surrounded_start_scenario ) {
+        surround_groups.emplace_back( mongroup_id( "GROUP_BLACK_ROAD" ), 70.0f );
+    }
+    const bool spawn_near = surrounded_start_options || surrounded_start_scenario;
     if( spawn_near ) {
-        start_loc.surround_with_monsters( omtstart, mongroup_id( "GROUP_ZOMBIE" ), 70 );
+        for( const std::pair<mongroup_id, float> &sg : surround_groups ) {
+            start_loc.surround_with_monsters( omtstart, sg.first, sg.second );
+        }
     }
 
     m.spawn_monsters( !spawn_near ); // Static monsters

src/scenario.cpp

@@ -94,6 +94,10 @@ void scenario::load( const JsonObject &jo, const std::string & )
     if( jo.has_string( "vehicle" ) ) {
         _starting_vehicle = vproto_id( jo.get_string( "vehicle" ) );
     }
+
+    for( JsonArray ja : jo.get_array( "surround_groups" ) ) {
+        _surround_groups.emplace_back( mongroup_id( ja.get_string( 0 ) ), ja.get_float( 1 ) );
+    }
 }
 
 const scenario *scenario::generic()
@@ -462,4 +466,8 @@ const std::vector<mission_type_id> &scenario::missions() const
 {
     return _missions;
 }
+const std::vector<std::pair<mongroup_id, float>> &scenario::surround_groups() const
+{
+    return _surround_groups;
+}
 // vim:ts=4:sw=4:et:tw=0:fdm=marker:

src/scenario.h

@@ -52,6 +52,8 @@ class scenario
         void load( const JsonObject &jo, const std::string &src );
         bool scenario_traits_conflict_with_profession_traits( const profession &p ) const;
 
+        std::vector<std::pair<mongroup_id, float>> _surround_groups;
+
     public:
         //these three aren't meant for external use, but had to be made public regardless
         scenario();
@@ -113,6 +115,7 @@ class scenario
 
         const std::vector<mission_type_id> &missions() const;
 
+        const std::vector<std::pair<mongroup_id, float>> &surround_groups() const;
 };
 
 struct scen_blacklist {