feat: weighted random spawns (#1848)

Rework of #1802 to fix issues with boss spawns and adding a "weight" to
enable users to balance things.

Credits to @Schiffers for the original PR and idea.

config.lua.dist

@@ -207,6 +207,7 @@ onlyPremiumAccount = false
 -- NOTE: buyBlessCommandFee will add fee when player buy bless by command (!bless), active changing value between 1 and 100 (fee percent. ex: 3 = 3%, 30 = 30%)
 -- NOTE: teleportPlayerToVocationRoom will enable oressa to teleport player to his/her room vocation
 -- NOTE: toggleReceiveReward = true, will enable players to choose one of reward exercise weapon by command !reward
+-- NOTE: randomMonsterSpawn = true, will enable monsters from the same spawn to be randomized between them, thus making a variable hunt
 weatherRain = false
 thunderEffect = false
 allConsoleLog = false
@@ -222,6 +223,7 @@ buyAolCommandFee = 0
 buyBlessCommandFee = 0
 teleportPlayerToVocationRoom = true
 toggleReceiveReward = false
+randomMonsterSpawn = false
 
 -- Teleport summon
 -- Set to true will never remove the summon

src/config/config_definitions.hpp

@@ -173,6 +173,7 @@ enum ConfigKey_t : uint16_t {
 	PVP_RATE_DAMAGE_REDUCTION_PER_LEVEL,
 	PVP_RATE_DAMAGE_TAKEN_PER_LEVEL,
 	PZ_LOCKED,
+	RANDOM_MONSTER_SPAWN,
 	RATE_ATTACK_SPEED,
 	RATE_BOSS_ATTACK,
 	RATE_BOSS_DEFENSE,

src/config/configmanager.cpp

@@ -44,6 +44,7 @@ bool ConfigManager::load() {
 		loadBoolConfig(L, OPTIMIZE_DATABASE, "startupDatabaseOptimization", true);
 		loadBoolConfig(L, TOGGLE_MAP_CUSTOM, "toggleMapCustom", true);
 		loadBoolConfig(L, TOGGLE_MAINTAIN_MODE, "toggleMaintainMode", false);
+		loadBoolConfig(L, RANDOM_MONSTER_SPAWN, "randomMonsterSpawn", false);
 		loadStringConfig(L, MAINTAIN_MODE_MESSAGE, "maintainModeMessage", "");
 
 		loadStringConfig(L, IP, "ip", "127.0.0.1");

src/creatures/monsters/spawns/spawn_monster.cpp

@@ -95,17 +95,13 @@ bool SpawnsMonster::loadFromXML(const std::string &filemonstername) {
 					boostedrate = 2;
 				}
 
-				uint32_t interval = pugi::cast<uint32_t>(childMonsterNode.attribute("spawntime").value()) * 1000 * 100 / std::max((uint32_t)1, (g_configManager().getNumber(RATE_SPAWN, __FUNCTION__) * boostedrate * eventschedule));
-				if (interval >= MONSTER_MINSPAWN_INTERVAL && interval <= MONSTER_MAXSPAWN_INTERVAL) {
-					spawnMonster.addMonster(nameAttribute.as_string(), pos, dir, static_cast<uint32_t>(interval));
-				} else {
-					if (interval <= MONSTER_MINSPAWN_INTERVAL) {
-						g_logger().warn("[SpawnsMonster::loadFromXml] - {} {} spawntime cannot be less than {} seconds, set to {} by default.", nameAttribute.as_string(), pos.toString(), MONSTER_MINSPAWN_INTERVAL / 1000, MONSTER_MINSPAWN_INTERVAL / 1000);
-						spawnMonster.addMonster(nameAttribute.as_string(), pos, dir, MONSTER_MINSPAWN_INTERVAL);
-					} else {
-						g_logger().warn("[SpawnsMonster::loadFromXml] - {} {} spawntime can not be more than {} seconds", nameAttribute.as_string(), pos.toString(), MONSTER_MAXSPAWN_INTERVAL / 1000);
-					}
+				pugi::xml_attribute weightAttribute = childMonsterNode.attribute("weight");
+				uint32_t weight = 1;
+				if (weightAttribute) {
+					weight = pugi::cast<uint32_t>(weightAttribute.value());
 				}
+
+				spawnMonster.addMonster(nameAttribute.as_string(), pos, dir, pugi::cast<uint32_t>(childMonsterNode.attribute("spawntime").value()) * 1000, weight);
 			}
 		}
 	}
@@ -150,8 +146,7 @@ void SpawnMonster::startSpawnMonsterCheck() {
 }
 
 SpawnMonster::~SpawnMonster() {
-	for (const auto &it : spawnedMonsterMap) {
-		std::shared_ptr<Monster> monster = it.second;
+	for (const auto &[_, monster] : spawnedMonsterMap) {
 		monster->setSpawnMonster(nullptr);
 	}
 }
@@ -170,72 +165,100 @@ bool SpawnMonster::isInSpawnMonsterZone(const Position &pos) {
 	return SpawnsMonster::isInZone(centerPos, radius, pos);
 }
 
-bool SpawnMonster::spawnMonster(uint32_t spawnMonsterId, const std::shared_ptr<MonsterType> monsterType, const Position &pos, Direction dir, bool startup /*= false*/) {
+bool SpawnMonster::spawnMonster(uint32_t spawnMonsterId, spawnBlock_t &sb, const std::shared_ptr<MonsterType> monsterType, bool startup /*= false*/) {
+	if (spawnedMonsterMap.contains(spawnMonsterId)) {
+		return false;
+	}
 	auto monster = std::make_shared<Monster>(monsterType);
 	if (startup) {
 		// No need to send out events to the surrounding since there is no one out there to listen!
-		if (!g_game().internalPlaceCreature(monster, pos, true)) {
+		if (!g_game().internalPlaceCreature(monster, sb.pos, true)) {
 			return false;
 		}
 	} else {
-		if (!g_game().placeCreature(monster, pos, false, true)) {
+		if (!g_game().placeCreature(monster, sb.pos, false, true)) {
 			return false;
 		}
 	}
 
-	monster->setDirection(dir);
+	monster->setDirection(sb.direction);
 	monster->setSpawnMonster(this);
-	monster->setMasterPos(pos);
+	monster->setMasterPos(sb.pos);
 
-	spawnedMonsterMap.insert(spawned_pair(spawnMonsterId, monster));
-	spawnMonsterMap[spawnMonsterId].lastSpawn = OTSYS_TIME();
-	g_events().eventMonsterOnSpawn(monster, pos);
-	g_callbacks().executeCallback(EventCallback_t::monsterOnSpawn, &EventCallback::monsterOnSpawn, monster, pos);
+	spawnedMonsterMap[spawnMonsterId] = monster;
+	sb.lastSpawn = OTSYS_TIME();
+	g_events().eventMonsterOnSpawn(monster, sb.pos);
+	g_callbacks().executeCallback(EventCallback_t::monsterOnSpawn, &EventCallback::monsterOnSpawn, monster, sb.pos);
 	return true;
 }
 
-void SpawnMonster::startup() {
-	for (const auto &it : spawnMonsterMap) {
-		uint32_t spawnMonsterId = it.first;
-		const spawnBlock_t &sb = it.second;
-		spawnMonster(spawnMonsterId, sb.monsterType, sb.pos, sb.direction, true);
+void SpawnMonster::startup(bool delayed) {
+	if (g_configManager().getBoolean(RANDOM_MONSTER_SPAWN, __FUNCTION__)) {
+		for (auto it = spawnMonsterMap.begin(); it != spawnMonsterMap.end(); ++it) {
+			auto &[spawnMonsterId, sb] = *it;
+			for (auto &[monsterType, weight] : sb.monsterTypes) {
+				if (monsterType->isBoss()) {
+					continue;
+				}
+				for (auto otherIt = std::next(it); otherIt != spawnMonsterMap.end(); ++otherIt) {
+					auto &[id, otherSb] = *otherIt;
+					if (id == spawnMonsterId) {
+						continue;
+					}
+					if (otherSb.hasBoss()) {
+						continue;
+					}
+					if (otherSb.monsterTypes.contains(monsterType)) {
+						weight += otherSb.monsterTypes[monsterType];
+					}
+					otherSb.monsterTypes.emplace(monsterType, weight);
+					sb.monsterTypes.emplace(monsterType, weight);
+				}
+			}
+		}
+	}
+	for (auto &[spawnMonsterId, sb] : spawnMonsterMap) {
+		const auto &mType = sb.getMonsterType();
+		if (!mType) {
+			continue;
+		}
+		if (delayed) {
+			g_dispatcher().addEvent(std::bind(&SpawnMonster::scheduleSpawn, this, spawnMonsterId, sb, mType, 0, true), "SpawnMonster::startup");
+		} else {
+			scheduleSpawn(spawnMonsterId, sb, mType, 0, true);
+		}
 	}
 }
 
 void SpawnMonster::checkSpawnMonster() {
-	checkSpawnMonsterEvent = 0;
+	if (checkSpawnMonsterEvent == 0) {
+		return;
+	}
 
+	checkSpawnMonsterEvent = 0;
 	cleanup();
 
-	uint32_t spawnMonsterCount = 0;
-
-	for (auto &it : spawnMonsterMap) {
-		uint32_t spawnMonsterId = it.first;
-		if (spawnedMonsterMap.find(spawnMonsterId) != spawnedMonsterMap.end()) {
+	for (auto &[spawnMonsterId, sb] : spawnMonsterMap) {
+		if (spawnedMonsterMap.contains(spawnMonsterId)) {
 			continue;
 		}
 
-		spawnBlock_t &sb = it.second;
-		if (!sb.monsterType->canSpawn(sb.pos)) {
+		const auto &mType = sb.getMonsterType();
+		if (!mType) {
+			continue;
+		}
+		if (!mType->canSpawn(sb.pos) || (mType->info.isBlockable && findPlayer(sb.pos))) {
 			sb.lastSpawn = OTSYS_TIME();
 			continue;
 		}
+		if (OTSYS_TIME() < sb.lastSpawn + sb.interval) {
+			continue;
+		}
 
-		if (OTSYS_TIME() >= sb.lastSpawn + sb.interval) {
-			if (sb.monsterType->info.isBlockable && findPlayer(sb.pos)) {
-				sb.lastSpawn = OTSYS_TIME();
-				continue;
-			}
-
-			if (sb.monsterType->info.isBlockable) {
-				spawnMonster(spawnMonsterId, sb.monsterType, sb.pos, sb.direction);
-			} else {
-				scheduleSpawn(spawnMonsterId, sb, 3 * NONBLOCKABLE_SPAWN_MONSTER_INTERVAL);
-			}
-
-			if (++spawnMonsterCount >= static_cast<uint32_t>(g_configManager().getNumber(RATE_SPAWN, __FUNCTION__))) {
-				break;
-			}
+		if (mType->info.isBlockable) {
+			spawnMonster(spawnMonsterId, sb, mType, true);
+		} else {
+			scheduleSpawn(spawnMonsterId, sb, mType, 3 * NONBLOCKABLE_SPAWN_MONSTER_INTERVAL);
 		}
 	}
 
@@ -244,30 +267,29 @@ void SpawnMonster::checkSpawnMonster() {
 	}
 }
 
-void SpawnMonster::scheduleSpawn(uint32_t spawnMonsterId, spawnBlock_t &sb, uint16_t interval) {
+void SpawnMonster::scheduleSpawn(uint32_t spawnMonsterId, spawnBlock_t &sb, const std::shared_ptr<MonsterType> mType, uint16_t interval, bool startup /*= false*/) {
 	if (interval <= 0) {
-		spawnMonster(spawnMonsterId, sb.monsterType, sb.pos, sb.direction);
+		spawnMonster(spawnMonsterId, sb, mType, startup);
 	} else {
 		g_game().addMagicEffect(sb.pos, CONST_ME_TELEPORT);
-		g_dispatcher().scheduleEvent(1400, std::bind(&SpawnMonster::scheduleSpawn, this, spawnMonsterId, sb, interval - NONBLOCKABLE_SPAWN_MONSTER_INTERVAL), "SpawnMonster::scheduleSpawn");
+		g_dispatcher().scheduleEvent(NONBLOCKABLE_SPAWN_MONSTER_INTERVAL, std::bind(&SpawnMonster::scheduleSpawn, this, spawnMonsterId, sb, mType, interval - NONBLOCKABLE_SPAWN_MONSTER_INTERVAL, startup), "SpawnMonster::scheduleSpawn");
 	}
 }
 
 void SpawnMonster::cleanup() {
-	auto it = spawnedMonsterMap.begin();
-	while (it != spawnedMonsterMap.end()) {
-		uint32_t spawnMonsterId = it->first;
-		std::shared_ptr<Monster> monster = it->second;
-		if (!monster || monster->isRemoved()) {
-			spawnMonsterMap[spawnMonsterId].lastSpawn = OTSYS_TIME();
-			it = spawnedMonsterMap.erase(it);
-		} else {
-			++it;
+	std::vector<uint32_t> removeList;
+	for (const auto &[spawnMonsterId, monster] : spawnedMonsterMap) {
+		if (monster == nullptr || monster->isRemoved()) {
+			removeList.push_back(spawnMonsterId);
 		}
 	}
+	for (const auto &spawnMonsterId : removeList) {
+		spawnMonsterMap[spawnMonsterId].lastSpawn = OTSYS_TIME();
+		spawnedMonsterMap.erase(spawnMonsterId);
+	}
 }
 
-bool SpawnMonster::addMonster(const std::string &name, const Position &pos, Direction dir, uint32_t scheduleInterval) {
+bool SpawnMonster::addMonster(const std::string &name, const Position &pos, Direction dir, uint32_t scheduleInterval, uint32_t weight /*= 1*/) {
 	std::string variant = "";
 	for (const auto &zone : Zone::getZones(pos)) {
 		if (!zone->getMonsterVariant().empty()) {
@@ -281,34 +303,77 @@ bool SpawnMonster::addMonster(const std::string &name, const Position &pos, Dire
 		return false;
 	}
 
-	this->interval = std::min(this->interval, scheduleInterval);
-
-	spawnBlock_t sb;
-	sb.monsterType = monsterType;
-	sb.pos = pos;
-	sb.direction = dir;
-	sb.interval = scheduleInterval;
-	sb.lastSpawn = 0;
+	uint32_t eventschedule = g_eventsScheduler().getSpawnMonsterSchedule();
+	std::string boostedMonster = g_game().getBoostedMonsterName();
+	int32_t boostedrate = 1;
+	if (name == boostedMonster) {
+		boostedrate = 2;
+	}
+	// eventschedule is a whole percentage, so we need to multiply by 100 to match the order of magnitude of the other values
+	scheduleInterval = scheduleInterval * 100 / std::max((uint32_t)1, (g_configManager().getNumber(RATE_SPAWN, __FUNCTION__) * boostedrate * eventschedule));
+	if (scheduleInterval < MONSTER_MINSPAWN_INTERVAL) {
+		g_logger().warn("[SpawnsMonster::addMonster] - {} {} spawntime cannot be less than {} seconds, set to {} by default.", name, pos.toString(), MONSTER_MINSPAWN_INTERVAL / 1000, MONSTER_MINSPAWN_INTERVAL / 1000);
+		scheduleInterval = MONSTER_MINSPAWN_INTERVAL;
+	} else if (scheduleInterval > MONSTER_MAXSPAWN_INTERVAL) {
+		g_logger().warn("[SpawnsMonster::addMonster] - {} {} spawntime can not be more than {} seconds, set to {} by default", name, pos.toString(), MONSTER_MAXSPAWN_INTERVAL / 1000, MONSTER_MAXSPAWN_INTERVAL / 1000);
+		scheduleInterval = MONSTER_MAXSPAWN_INTERVAL;
+	}
+	this->interval = std::gcd(this->interval, scheduleInterval);
 
+	spawnBlock_t* sb = nullptr;
 	uint32_t spawnMonsterId = spawnMonsterMap.size() + 1;
-	spawnMonsterMap[spawnMonsterId] = sb;
+	for (auto &[id, maybeSb] : spawnMonsterMap) {
+		if (maybeSb.pos == pos) {
+			sb = &maybeSb;
+			spawnMonsterId = id;
+			break;
+		}
+	}
+	if (sb) {
+		if (sb->monsterTypes.contains(monsterType)) {
+			g_logger().error("[SpawnMonster] Monster {} already exists in spawn block at {}", name, pos.toString());
+			return false;
+		}
+		if (monsterType->isBoss() && sb->monsterTypes.size() > 0) {
+			g_logger().error("[SpawnMonster] Boss monster {} has been added to spawn block with other monsters. This is not allowed.", name);
+			return false;
+		}
+		if (sb->hasBoss()) {
+			g_logger().error("[SpawnMonster] Monster {} has been added to spawn block with a boss. This is not allowed.", name);
+			return false;
+		}
+	}
+	if (!sb) {
+		sb = &spawnMonsterMap.emplace(spawnMonsterId, spawnBlock_t()).first->second;
+	}
+	sb->monsterTypes.emplace(monsterType, weight);
+	sb->pos = pos;
+	sb->direction = dir;
+	sb->interval = scheduleInterval;
+	sb->lastSpawn = 0;
 	return true;
 }
 
 void SpawnMonster::removeMonster(std::shared_ptr<Monster> monster) {
-	for (auto it = spawnedMonsterMap.begin(), end = spawnedMonsterMap.end(); it != end; ++it) {
-		if (it->second == monster) {
-			spawnedMonsterMap.erase(it);
+	uint32_t spawnMonsterId = 0;
+	for (const auto &[id, m] : spawnedMonsterMap) {
+		if (m == monster) {
+			spawnMonsterId = id;
 			break;
 		}
 	}
+	spawnedMonsterMap.erase(spawnMonsterId);
 }
 
 void SpawnMonster::setMonsterVariant(const std::string &variant) {
 	for (auto &it : spawnMonsterMap) {
-		auto variantName = variant + it.second.monsterType->typeName;
-		auto variantType = g_monsters().getMonsterType(variantName, false);
-		it.second.monsterType = variantType ? variantType : it.second.monsterType;
+		std::unordered_map<std::shared_ptr<MonsterType>, uint32_t> monsterTypes;
+		for (const auto &[monsterType, weight] : it.second.monsterTypes) {
+			auto variantName = variant + monsterType->typeName;
+			auto variantType = g_monsters().getMonsterType(variantName, false);
+			monsterTypes.emplace(variantType, weight);
+		}
+		it.second.monsterTypes = monsterTypes;
 	}
 }
 
@@ -318,3 +383,44 @@ void SpawnMonster::stopEvent() {
 		checkSpawnMonsterEvent = 0;
 	}
 }
+
+std::shared_ptr<MonsterType> spawnBlock_t::getMonsterType() const {
+	if (monsterTypes.empty()) {
+		return nullptr;
+	}
+	uint32_t totalWeight = 0;
+	for (const auto &[mType, weight] : monsterTypes) {
+		if (!mType) {
+			continue;
+		}
+		if (mType->isBoss()) {
+			if (monsterTypes.size() > 1) {
+				g_logger().warn("[SpawnMonster] Boss monster {} has been added to spawn block with other monsters. This is not allowed.", mType->name);
+			}
+			return mType;
+		}
+		totalWeight += weight;
+	}
+	uint32_t randomWeight = uniform_random(0, totalWeight - 1);
+	// order monsters by weight DESC
+	std::vector<std::pair<std::shared_ptr<MonsterType>, uint32_t>> orderedMonsterTypes(monsterTypes.begin(), monsterTypes.end());
+	std::sort(orderedMonsterTypes.begin(), orderedMonsterTypes.end(), [](const auto &a, const auto &b) {
+		return a.second > b.second;
+	});
+	for (const auto &[mType, weight] : orderedMonsterTypes) {
+		if (randomWeight < weight) {
+			return mType;
+		}
+		randomWeight -= weight;
+	}
+	return nullptr;
+}
+
+bool spawnBlock_t::hasBoss() const {
+	for (const auto &[monsterType, weight] : monsterTypes) {
+		if (monsterType->isBoss()) {
+			return true;
+		}
+	}
+	return false;
+}