Had to refactor the GameDB to use a list of levels instead of a vector of levels. If you get a _reference_ to an element of a vector, and then resize the vector, you'll get a crash if the realoc moves the data buffer. Using a list is actually what we want.

boss/fight.cpp

@@ -9,9 +9,11 @@ namespace boss {
     $boss_id(boss_id),
     $battle(System::create_battle($world, $boss_id)),
     $ui(world, boss_id, player_id),
-    $host(player_id),
-    $host_combat($world->get<components::Combat>(player_id))
+    $host(player_id)
   {
+    $host_combat = $world->get_if<components::Combat>(player_id);
+    dbc::check($host_combat,
+        fmt::format("No combat for host with player_id={}", player_id));
     $ui.init();
   }
 
@@ -66,7 +68,7 @@ namespace boss {
       case ATTACK:
         if($battle.player_request("kill_enemy")) {
           fmt::println("player requests kill_enemy {} vs. {}",
-              $host_combat.ap, $battle.player_pending_ap());
+              $host_combat->ap, $battle.player_pending_ap());
         } else {
           fmt::println("NO MORE ACTION!");
         }
@@ -138,7 +140,7 @@ namespace boss {
     $ui.update_stats();
     $battle.set($host, "tough_personality", false);
     $battle.set($host, "have_healing", false);
-    $battle.set($host, "health_good", $host_combat.hp > 100);
+    $battle.set($host, "health_good", $host_combat->hp > 100);
   }
 
   void Fight::render(sf::RenderWindow& window) {
@@ -175,7 +177,7 @@ namespace boss {
   }
 
   bool Fight::player_dead() {
-    return $host_combat.hp <= 0;
+    return $host_combat->hp <= 0;
   }
 
   void Fight::init_fight() {

boss/fight.hpp

@@ -28,7 +28,7 @@ namespace boss {
     boss::UI $ui;
     sf::Vector2f mouse_pos{0,0};
     Entity $host = NONE;
-    components::Combat& $host_combat;
+    components::Combat* $host_combat = nullptr;
 
     Fight(shared_ptr<World> world, Entity boss_id, Entity player_id);
 

boss/system.cpp

@@ -29,26 +29,31 @@ namespace boss {
   }
 
   shared_ptr<boss::Fight> System::create_bossfight() {
-    auto& level = GameDB::current_level();
-    auto prev_world = GameDB::current_world();
-    dbc::check(prev_world != nullptr, "Starter world for boss fights can't be null.");
-    auto world = GameDB::clone_load_world(prev_world);
-    auto& config = prev_world->get_the<GameConfig>();
+    // need to copy so we can clone it and keep things working, even
+    // if we don't use things like map and lighting
+    auto level = GameDB::current_level();
+    dbc::check(level.world != nullptr, "Starter world for boss fights can't be null.");
+
+    level.world = GameDB::clone_load_world(level.world);
+
+    auto& config = level.world->get_the<GameConfig>();
 
     auto boss_names = config.bosses.keys();
     auto& level_name = boss_names[level.index % boss_names.size()];
     auto& boss_data = config.bosses[level_name];
 
-    auto boss_id = world->entity();
-    components::configure_entity(*world, boss_id, boss_data["components"]);
+    auto boss_id = level.world->entity();
+    components::configure_entity(*level.world, boss_id, boss_data["components"]);
 
-    initialize_actor_ai(*world, boss_id);
-    dbc::check(world->has<ai::EntityAI>(boss_id), "boss doesn't have an AI");
+    initialize_actor_ai(*level.world, boss_id);
+    dbc::check(level.world->has<ai::EntityAI>(boss_id), "boss doesn't have an AI");
 
-    initialize_actor_ai(*world, level.player);
-    dbc::check(world->has<ai::EntityAI>(level.player), "player/host doesn't have an AI");
+    initialize_actor_ai(*level.world, level.player);
+    dbc::check(level.world->has<ai::EntityAI>(level.player), "player/host doesn't have an AI");
 
-    return make_shared<boss::Fight>(world, boss_id, level.player);
+    GameDB::register_level(level);
+
+    return make_shared<boss::Fight>(level.world, boss_id, level.player);
   }
 
   BattleEngine System::create_battle(std::shared_ptr<DinkyECS::World> world, DinkyECS::Entity boss_id) {

game_level.cpp

@@ -6,6 +6,7 @@
 #include "components.hpp"
 #include "rituals.hpp"
 #include "textures.hpp"
+#include <list>
 
 using lighting::LightRender;
 using std::shared_ptr, std::make_shared;
@@ -20,11 +21,11 @@ namespace GameDB {
   using std::shared_ptr, std::string, std::make_shared;
 
   struct LevelDB {
-    std::vector<GameDB::Level> levels;
+    std::list<GameDB::Level> levels;
     size_t current_level = 0;
   };
 
-  shared_ptr<LevelDB> LDB;
+  shared_ptr<LevelDB> LDB = nullptr;
   bool initialized = false;
 
   LevelScaling scale_level() {
@@ -46,8 +47,18 @@ namespace GameDB {
     return world;
   }
 
+  void register_level(Level level) {
+    // size BEFORE push to get the correct index
+    level.index = LDB->levels.size();
 
-  size_t new_level(std::shared_ptr<DinkyECS::World> prev_world) {
+    LDB->levels.push_back(level);
+
+    dbc::check(level.index == LDB->levels.size() - 1, "Level index is not the same as LDB->levels.size() - 1, off by one error");
+
+    LDB->current_level = level.index;
+  }
+
+  void new_level(std::shared_ptr<DinkyECS::World> prev_world) {
     dbc::check(initialized, "Forgot to call GameDB::init()");
     auto world = clone_load_world(prev_world);
 
@@ -59,16 +70,16 @@ namespace GameDB {
     WorldBuilder builder(*map, *collision);
     builder.generate(*world);
 
-    size_t index = LDB->levels.size();
+    auto lights = make_shared<LightRender>(map->tiles());
 
     auto player = world->get_the<Player>();
 
-    LDB->levels.emplace_back(index, player.entity, map, world,
-        make_shared<LightRender>(map->tiles()), collision);
-
-    dbc::check(index == LDB->levels.size() - 1, "Level index is not the same as LDB->levels.size() - 1, off by one error");
-
-    return index;
+    register_level({
+      .player=player.entity,
+      .map=map,
+      .world=world,
+      .lights=lights,
+      .collision=collision});
   }
 
   void init() {
@@ -89,18 +100,15 @@ namespace GameDB {
 
   Level& create_level() {
     dbc::check(initialized, "Forgot to call GameDB::init()");
-    dbc::check(LDB->current_level < LDB->levels.size(), "attempt to get next level when at end");
 
-    size_t level = new_level(current_world());
-    dbc::check(level == LDB->current_level + 1, "new level index is wrong");
+    new_level(current_world());
 
-    LDB->current_level++;
-    return LDB->levels.at(LDB->current_level);
+    return LDB->levels.back();
   }
 
   Level &current_level() {
     dbc::check(initialized, "Forgot to call GameDB::init()");
-    return LDB->levels.at(LDB->current_level);
+    return LDB->levels.back();
   }
 
   components::Position& player_position() {

game_level.hpp

@@ -13,8 +13,8 @@ namespace components {
 
 namespace GameDB {
   struct Level {
-    size_t index;
-    DinkyECS::Entity player;
+    size_t index = 0;
+    DinkyECS::Entity player = DinkyECS::NONE;
     std::shared_ptr<Map> map = nullptr;
     std::shared_ptr<DinkyECS::World> world = nullptr;
     std::shared_ptr<lighting::LightRender> lights = nullptr;
@@ -31,4 +31,5 @@ namespace GameDB {
 
   std::shared_ptr<DinkyECS::World> clone_load_world(std::shared_ptr<DinkyECS::World> prev_world);
   void load_configs(DinkyECS::World &world);
+  void register_level(Level level);
 }

systems.cpp

@@ -257,7 +257,7 @@ void System::combat(int attack_id) {
     battle.plan();
   }
 
-  battle.dump();
+  // battle.dump();
 
   while(auto act = battle.next()) {
     auto [enemy, enemy_action, cost, host_state] = *act;