mapgen: allow placing active bomb items for better craters in Dark Sk…

…ies Above (#48137)

* mapgen: allow activated items to be placed on the map

Add the new item flag "ACTIVATE_ON_PLACE".  Items placed during
mapgen with this flag will be activated immediately after they
are placed on the map.

* Dark Skies Above: use active bombs to create large bomb craters

Use the new ACTIVATE_ON_PLACE flag with active bombs with 1 second
count-downs in a new map special that randomly wrecks buildings
across multiple z-levels.  The bombs have max_noise = 0 and explode
silently to preserve the avatar's hearing.

Co-authored-by: actual-nh <74678550+actual-nh@users.noreply.github.com>

data/json/flags.json

@@ -1820,6 +1820,12 @@
     "type": "json_flag",
     "context": [ "AMMO", "CONSUMABLE" ]
   },
+  {
+    "id": "ACTIVATE_ON_PLACE",
+    "type": "json_flag",
+    "context": [  ],
+    "info": "This item will be activated when it is placed in mapgen."
+  },
   {
     "id": "ACT_IN_FIRE",
     "type": "json_flag",

data/mods/Dark-Skies-Above/mapgen/map_extras/bombed_crater.json

@@ -0,0 +1,47 @@
+[
+  {
+    "id": "tool_dsa_alien_bomb_act",
+    "type": "TOOL",
+    "category": "weapons",
+    "name": { "str": "active alien bomb" },
+    "looks_like": "tool_rdx_charge_act",
+    "description": "This is an alien bomb.  It has been activated and will soon explode, delivering its entire destructive power to everything in sight.",
+    "weight": "4400 g",
+    "volume": "10 L",
+    "price": 0,
+    "to_hit": -5,
+    "bashing": 20,
+    "material": [ "steel" ],
+    "symbol": "(",
+    "color": "light_red",
+    "initial_charges": 1,
+    "max_charges": 1,
+    "turns_per_charge": 1,
+    "explode_in_fire": true,
+    "explosion": { "power": 40000, "max_noise": 0 },
+    "use_action": {
+      "type": "explosion",
+      "no_deactivate_msg": "You've already activated the bomb - clear the area immediately!",
+      "explosion": { "power": 40000, "max_noise": 0 }
+    },
+    "flags": [ "BOMB", "TRADER_AVOID" ]
+  },
+  {
+    "type": "mapgen",
+    "method": "json",
+    "update_mapgen_id": "mx_dsa_bombed_crater",
+    "object": {
+      "place_item": [ { "item": "tool_dsa_alien_bomb_act", "x": 12, "y": 12, "amount": 1, "custom-flags": [ "ACTIVATE_ON_PLACE" ] } ]
+    }
+  },
+  {
+    "id": "mx_dsa_bombed_crater",
+    "type": "map_extra",
+    "name": { "str": "Bomb Crater" },
+    "description": "A bomb crater.",
+    "generator": { "generator_method": "update_mapgen", "generator_id": "mx_dsa_bombed_crater" },
+    "sym": ".",
+    "color": "brown",
+    "autonote": true
+  }
+]

data/mods/Dark-Skies-Above/overrides/region_settings.json

@@ -35,6 +35,7 @@
       },
       "road": {
         "extras": {
+          "mx_dsa_bombed_crater": 200,
           "mx_mayhem": 0,
           "mx_portal": 0,
           "mx_portal_in": 0,
@@ -57,6 +58,7 @@
       "build": {
         "chance": 2,
         "extras": {
+          "mx_dsa_bombed_crater": 200,
           "mx_house_spider": 0,
           "mx_house_wasp": 0,
           "mx_military": 1,

doc/MAPGEN.md

@@ -594,7 +594,8 @@ Example:
 | repeat | (optional) Value: `[ n1, n2 ]`. Spawn item randomly between `n1` and `n2` times. Only makes sense if the coordinates are random. Example: `[ 1, 3 ]` - repeat 1-3 times.
 | custom-flags | (optional) Value: `[ "flag1", "flag2" ]`. Spawn item with specific flags.
 
-
+The special custom flag "ACTIVATE_ON_PLACE" causes the item to be activated as it is placed.  This is useful to have noisemakers that are already turned on as the avatar approaches.  It can also be used with explosives with a 1 second countdown to have locations explode as the avatar approaches, creating uniquely ruined terrain.
+
 ## Extra map features with specials
 **optional** Special map features that do more than just placing furniture / terrain.
 
@@ -1072,4 +1073,3 @@ update_mapgen adds new optional keywords to a few mapgen JSON items.
 place_npc, place_monster, and place_computer can take an optional target boolean. If they have `"target": true` and are
 invoked by update_mapgen with a valid mission, then the NPC, monster, or computer will be marked as the target of the
 mission.
-

src/flag.cpp

@@ -9,6 +9,7 @@ const flag_id flag_NULL = flag_id( "null" ); // intentionally invalid flag
 
 const flag_id flag_ACID( "ACID" );
 const flag_id flag_ACID_IMMUNE( "ACID_IMMUNE" );
+const flag_id flag_ACTIVATE_ON_PLACE( "ACTIVATE_ON_PLACE" );
 const flag_id flag_ACTIVE_CLOAKING( "ACTIVE_CLOAKING" );
 const flag_id flag_ACT_IN_FIRE( "ACT_IN_FIRE" );
 const flag_id flag_ACT_ON_RANGED_HIT( "ACT_ON_RANGED_HIT" );

src/flag.h

@@ -16,6 +16,7 @@ template <typename T> class generic_factory;
 extern const flag_id flag_NULL;
 extern const flag_id flag_ACID;
 extern const flag_id flag_ACID_IMMUNE;
+extern const flag_id flag_ACTIVATE_ON_PLACE;
 extern const flag_id flag_ACTIVE_CLOAKING;
 extern const flag_id flag_ACT_IN_FIRE;
 extern const flag_id flag_ACT_ON_RANGED_HIT;

src/map.cpp

@@ -4484,6 +4484,10 @@ item &map::add_item( const tripoint &p, item new_item )
         new_item.set_var( "reveal_map_center_omt", ms_to_omt_copy( getabs( p ) ) );
     }
 
+    if( new_item.has_flag( flag_ACTIVATE_ON_PLACE ) ) {
+        new_item.activate();
+    }
+
     current_submap->is_uniform = false;
     invalidate_max_populated_zlev( p.z );