Merge pull request #181 from vcmi/feature/drawbridgeMechanics

Feature/drawbridge mechanics

AI/StupidAI/StupidAI.cpp

@@ -108,7 +108,7 @@ BattleAction CStupidAI::activeStack( const CStack * stack )
 	if(stack->type->idNumber == CreatureID::CATAPULT)
 	{
 		BattleAction attack;
-		static const std::vector<int> wallHexes = {50, 183, 182, 130, 62, 29, 12, 95};
+		static const std::vector<int> wallHexes = {50, 183, 182, 130, 78, 29, 12, 95};
 
 		attack.destinationTile = *RandomGeneratorUtil::nextItem(wallHexes, CRandomGenerator::getDefault());
 		attack.actionType = Battle::CATAPULT;

ChangeLog

@@ -11,6 +11,9 @@ GENERAL:
 * New cheat code:
 - vcmiglaurung - gives 5000 crystal dragons into each slot
 
+BATTLES:
+* Drawbridge mechanics implemented (animation still missing)
+
 ADVETURE AI:
 * Fixed AI trying to go through underground rock
 * Fixed several cases causing AI wandering aimlessly

client/CPlayerInterface.cpp

@@ -1012,6 +1012,14 @@ void CPlayerInterface::battleObstaclePlaced(const CObstacleInstance &obstacle)
 	battleInt->obstaclePlaced(obstacle);
 }
 
+void CPlayerInterface::battleGateStateChanged(const EGateState state)
+{
+	EVENT_HANDLER_CALLED_BY_CLIENT;
+	BATTLE_EVENT_POSSIBLE_RETURN;
+
+	battleInt->gateStateChanged(state);
+}
+
 void CPlayerInterface::yourTacticPhase(int distance)
 {
 	THREAD_CREATED_BY_CLIENT;

client/CPlayerInterface.h

@@ -220,6 +220,7 @@ public:
 	void battleCatapultAttacked(const CatapultAttack & ca) override; //called when catapult makes an attack
 	void battleStacksRemoved(const BattleStacksRemoved & bsr) override; //called when certain stack is completely removed from battlefield
 	void battleObstaclePlaced(const CObstacleInstance &obstacle) override;
+	void battleGateStateChanged(const EGateState state) override;
 	void yourTacticPhase(int distance) override;
 
 	//-------------//

client/NetPacksClient.cpp

@@ -658,6 +658,11 @@ void BattleObstaclePlaced::applyCl(CClient * cl)
 	BATTLE_INTERFACE_CALL_IF_PRESENT_FOR_BOTH_SIDES(battleObstaclePlaced, *obstacle);
 }
 
+void BattleUpdateGateState::applyFirstCl(CClient * cl)
+{
+	BATTLE_INTERFACE_CALL_IF_PRESENT_FOR_BOTH_SIDES(battleGateStateChanged, state);
+}
+
 void BattleResult::applyFirstCl( CClient *cl )
 {
 	BATTLE_INTERFACE_CALL_IF_PRESENT_FOR_BOTH_SIDES(battleEnd,this);

client/battle/CBattleInterface.cpp

@@ -1218,9 +1218,14 @@ void CBattleInterface::stackIsCatapulting(const CatapultAttack & ca)
 
 	for(auto attackInfo : ca.attackedParts)
 	{
-		SDL_FreeSurface(siegeH->walls[attackInfo.attackedPart + 2]);
+		int wallId = attackInfo.attackedPart + 2;
-		siegeH->walls[attackInfo.attackedPart + 2] = BitmapHandler::loadBitmap(
+		//gate state changing handled separately
-			siegeH->getSiegeName(attackInfo.attackedPart + 2, curInt->cb->battleGetWallState(attackInfo.attackedPart)));
+		if(wallId == SiegeHelper::GATE)
+			continue;
+
+		SDL_FreeSurface(siegeH->walls[wallId]);
+		siegeH->walls[wallId] = BitmapHandler::loadBitmap(
+			siegeH->getSiegeName(wallId, curInt->cb->battleGetWallState(attackInfo.attackedPart)));
 	}
 }
 
@@ -2735,6 +2740,37 @@ void CBattleInterface::obstaclePlaced(const CObstacleInstance & oi)
 	//CCS->soundh->playSound(sound);
 }
 
+void CBattleInterface::gateStateChanged(const EGateState state)
+{
+	auto oldState = curInt->cb->battleGetGateState();
+	bool playSound = false;
+	int stateId = EWallState::NONE;
+	switch(state)
+	{
+	case EGateState::CLOSED:
+		if(oldState != EGateState::BLOCKED)
+			playSound = true;
+		break;
+	case EGateState::BLOCKED:
+		if(oldState != EGateState::CLOSED)
+			playSound = true;
+		break;
+	case EGateState::OPENED:
+		playSound = true;
+		stateId = EWallState::DAMAGED;
+		break;
+	case EGateState::DESTROYED:
+		stateId = EWallState::DESTROYED;
+		break;
+	}
+
+	SDL_FreeSurface(siegeH->walls[SiegeHelper::GATE]);
+	if(stateId != EWallState::NONE)
+		siegeH->walls[SiegeHelper::GATE] = BitmapHandler::loadBitmap(siegeH->getSiegeName(SiegeHelper::GATE, stateId));
+	if(playSound)
+		CCS->soundh->playSound(soundBase::DRAWBRG);
+}
+
 const CGHeroInstance * CBattleInterface::currentHero() const
 {
 	if(attackingHeroInstance->tempOwner == curInt->playerID)
@@ -2791,11 +2827,11 @@ void CBattleInterface::requestAutofightingAIToTakeAction()
 }
 
 CBattleInterface::SiegeHelper::SiegeHelper(const CGTownInstance *siegeTown, const CBattleInterface * _owner)
-  : owner(_owner), town(siegeTown)
+	: owner(_owner), town(siegeTown)
 {
 	for(int g = 0; g < ARRAY_COUNT(walls); ++g)
 	{
-		walls[g] = BitmapHandler::loadBitmap( getSiegeName(g) );
+		walls[g] = BitmapHandler::loadBitmap(getSiegeName(g));
 	}
 }
 
@@ -2834,75 +2870,83 @@ std::string CBattleInterface::SiegeHelper::getSiegeName(ui16 what, int state) co
 
 	switch(what)
 	{
-	case 0: //background
+	case SiegeHelper::BACKGROUND:
 		return prefix + "BACK.BMP";
-	case 1: //background wall
+	case SiegeHelper::BACKGROUND_WALL:
 		{
 			switch(town->town->faction->index)
 			{
-			case 5: case 4: case 1: case 6:
+			case ETownType::RAMPART:
+			case ETownType::NECROPOLIS:
+			case ETownType::DUNGEON:
+			case ETownType::STRONGHOLD:
 				return prefix + "TPW1.BMP";
 			default:
 				return prefix + "TPWL.BMP";
 			}
 		}
-	case 2: //keep
+	case SiegeHelper::KEEP:
 		return prefix + "MAN" + addit + ".BMP";
-	case 3: //bottom tower
+	case SiegeHelper::BOTTOM_TOWER:
 		return prefix + "TW1" + addit + ".BMP";
-	case 4: //bottom wall
+	case SiegeHelper::BOTTOM_WALL:
 		return prefix + "WA1" + addit + ".BMP";
-	case 5: //below gate
+	case SiegeHelper::WALL_BELLOW_GATE:
 		return prefix + "WA3" + addit + ".BMP";
-	case 6: //over gate
+	case SiegeHelper::WALL_OVER_GATE:
 		return prefix + "WA4" + addit + ".BMP";
-	case 7: //upper wall
+	case SiegeHelper::UPPER_WALL:
 		return prefix + "WA6" + addit + ".BMP";
-	case 8: //upper tower
+	case SiegeHelper::UPPER_TOWER:
 		return prefix + "TW2" + addit + ".BMP";
-	case 9: //gate
+	case SiegeHelper::GATE:
 		return prefix + "DRW" + addit + ".BMP";
-	case 10: //gate arch
+	case SiegeHelper::GATE_ARCH:
 		return prefix + "ARCH.BMP";
-	case 11: //bottom static wall
+	case SiegeHelper::BOTTOM_STATIC_WALL:
 		return prefix + "WA2.BMP";
-	case 12: //upper static wall
+	case SiegeHelper::UPPER_STATIC_WALL:
 		return prefix + "WA5.BMP";
-	case 13: //moat
+	case SiegeHelper::MOAT:
 		return prefix + "MOAT.BMP";
-	case 14: //mlip
+	case SiegeHelper::BACKGROUND_MOAT:
 		return prefix + "MLIP.BMP";
-	case 15: //keep creature cover
+	case SiegeHelper::KEEP_BATTLEMENT:
 		return prefix + "MANC.BMP";
-	case 16: //bottom turret creature cover
+	case SiegeHelper::BOTTOM_BATTLEMENT:
 		return prefix + "TW1C.BMP";
-	case 17: //upper turret creature cover
+	case SiegeHelper::UPPER_BATTLEMENT:
 		return prefix + "TW2C.BMP";
 	default:
 		return "";
 	}
 }
 
-/// What: 1. background wall, 2. keep, 3. bottom tower, 4. bottom wall, 5. wall below gate,
-/// 6. wall over gate, 7. upper wall, 8. upper tower, 9. gate, 10. gate arch, 11. bottom static wall, 12. upper static wall, 13. moat, 14. mlip,
-/// 15. keep turret cover, 16. lower turret cover, 17. upper turret cover
 void CBattleInterface::SiegeHelper::printPartOfWall(SDL_Surface * to, int what)
 {
 	Point pos = Point(-1, -1);
-	auto & ci = owner->siegeH->town->town->clientInfo;
+	auto & ci = town->town->clientInfo;
 
-	if (what >= 1 && what <= 17)
+	if (vstd::iswithin(what, 1, 17))
 	{
 		pos.x = ci.siegePositions[what].x + owner->pos.x;
 		pos.y = ci.siegePositions[what].y + owner->pos.y;
 	}
 
 	if (town->town->faction->index == ETownType::TOWER
-	    && (what == 13 || what == 14))
+		&& (what == SiegeHelper::MOAT || what == SiegeHelper::BACKGROUND_MOAT))
 		return; // no moat in Tower. TODO: remove hardcode somehow?
 
 	if(pos.x != -1)
 	{
+		//gate have no displayed bitmap when drawbridge is raised
+		if(what == SiegeHelper::GATE)
+		{
+			auto gateState = owner->curInt->cb->battleGetGateState();
+			if(gateState != EGateState::OPENED && gateState != EGateState::DESTROYED)
+				return;
+		}
+
 		blitAt(walls[what], pos.x, pos.y, to);
 	}
 }
@@ -3004,7 +3048,7 @@ void CBattleInterface::showAbsoluteObstacles(SDL_Surface * to)
 			blitAt(getObstacleImage(*oi), pos.x + oi->getInfo().width, pos.y + oi->getInfo().height, to);
 
 	if (siegeH && siegeH->town->hasBuilt(BuildingID::CITADEL))
-		siegeH->printPartOfWall(to, 14); // show moat background
+		siegeH->printPartOfWall(to, SiegeHelper::BACKGROUND_MOAT);
 }
 
 void CBattleInterface::showHighlightedHexes(SDL_Surface * to)
@@ -3415,29 +3459,29 @@ BattleObjectsByHex CBattleInterface::sortObjectsByHex()
 	// Sort wall parts
 	if (siegeH)
 	{
-		sorted.beforeAll.walls.push_back(1);  // 1. background wall
+		sorted.beforeAll.walls.push_back(SiegeHelper::BACKGROUND_WALL);
-		sorted.hex[135].walls.push_back(2);   // 2. keep
+		sorted.hex[135].walls.push_back(SiegeHelper::KEEP);
-		sorted.afterAll.walls.push_back(3);   // 3. bottom tower
+		sorted.afterAll.walls.push_back(SiegeHelper::BOTTOM_TOWER);
-		sorted.hex[182].walls.push_back(4);   // 4. bottom wall
+		sorted.hex[182].walls.push_back(SiegeHelper::BOTTOM_WALL);
-		sorted.hex[130].walls.push_back(5);   // 5. wall below gate,
+		sorted.hex[130].walls.push_back(SiegeHelper::WALL_BELLOW_GATE);
-		sorted.hex[62].walls.push_back(6);    // 6. wall over gate
+		sorted.hex[78].walls.push_back(SiegeHelper::WALL_OVER_GATE);
-		sorted.hex[12].walls.push_back(7);    // 7. upper wall
+		sorted.hex[12].walls.push_back(SiegeHelper::UPPER_WALL);
-		sorted.beforeAll.walls.push_back(8);  // 8. upper tower
+		sorted.beforeAll.walls.push_back(SiegeHelper::UPPER_TOWER);
-		//sorted.hex[94].walls.push_back(9);  // 9. gate // Not implemented it seems
+		sorted.hex[94].walls.push_back(SiegeHelper::GATE);
-		sorted.hex[112].walls.push_back(10);  // 10. gate arch
+		sorted.hex[112].walls.push_back(SiegeHelper::GATE_ARCH);
-		sorted.hex[165].walls.push_back(11);  // 11. bottom static wall
+		sorted.hex[165].walls.push_back(SiegeHelper::BOTTOM_STATIC_WALL);
-		sorted.hex[45].walls.push_back(12);   // 12. upper static wall
+		sorted.hex[45].walls.push_back(SiegeHelper::UPPER_STATIC_WALL);
 
 		if (siegeH && siegeH->town->hasBuilt(BuildingID::CITADEL))
 		{
-			sorted.beforeAll.walls.push_back(13); // 13. moat
+			sorted.beforeAll.walls.push_back(SiegeHelper::MOAT);
-			//sorted.beforeAll.walls.push_back(14); // 14. mlip (moat background terrain), blit as absolute obstacle
+			//sorted.beforeAll.walls.push_back(SiegeHelper::BACKGROUND_MOAT); // blit as absolute obstacle
-			sorted.hex[135].walls.push_back(15);  // 15. keep turret cover
+			sorted.hex[135].walls.push_back(SiegeHelper::KEEP_BATTLEMENT);
 		}
 		if (siegeH && siegeH->town->hasBuilt(BuildingID::CASTLE))
 		{
-			sorted.afterAll.walls.push_back(16);  // 16. lower turret cover
+			sorted.afterAll.walls.push_back(SiegeHelper::BOTTOM_BATTLEMENT);
-			sorted.beforeAll.walls.push_back(17); // 17. upper turret cover
+			sorted.beforeAll.walls.push_back(SiegeHelper::UPPER_BATTLEMENT);
 		}
 	}
 	return sorted;

client/battle/CBattleInterface.h

@@ -148,7 +148,7 @@ private:
 	void activateStack(); //sets activeStack to stackToActivate etc. //FIXME: No, it's not clear at all
 	std::vector<BattleHex> occupyableHexes, //hexes available for active stack
 		attackableHexes; //hexes attackable by active stack
-    bool stackCountOutsideHexes[GameConstants::BFIELD_SIZE]; // hexes that when in front of a unit cause it's amount box to move back
+	bool stackCountOutsideHexes[GameConstants::BFIELD_SIZE]; // hexes that when in front of a unit cause it's amount box to move back
 	BattleHex previouslyHoveredHex; //number of hex that was hovered by the cursor a while ago
 	BattleHex currentlyHoveredHex; //number of hex that is supposed to be hovered (for a while it may be inappropriately set, but will be renewed soon)
 	int attackingHex; //hex from which the stack would perform attack with current cursor
@@ -198,16 +198,32 @@ private:
 		SiegeHelper(const CGTownInstance * siegeTown, const CBattleInterface * _owner); //c-tor
 		~SiegeHelper(); //d-tor
 
-		//filename getters
-		//what: 0 - background,  1 - background wall,  2 - keep,          3 - bottom tower,  4 - bottom wall,
-		//      5 - below gate,  6 - over gate,        7 - upper wall,    8 - upper tower,   9 - gate,
-		//      10 - gate arch, 11 - bottom static    12 - upper static, 13 - moat,         14 - moat background,
-		//      15 - keep battlement, 16 - bottom battlement, 17 - upper battlement;
-		//      state uses EWallState enum
 		std::string getSiegeName(ui16 what) const;
-		std::string getSiegeName(ui16 what, int state) const;
+		std::string getSiegeName(ui16 what, int state) const; // state uses EWallState enum
 
-		void printPartOfWall(SDL_Surface * to, int what);//what: 1 - background wall, 2 - keep, 3 - bottom tower, 4 - bottom wall, 5 - below gate, 6 - over gate, 7 - upper wall, 8 - uppert tower, 9 - gate, 10 - gate arch, 11 - bottom static wall, 12 - upper static wall, 15 - keep creature cover, 16 - bottom turret creature cover, 17 - upper turret creature cover
+		void printPartOfWall(SDL_Surface * to, int what);
+
+		enum EWallVisual
+		{
+			BACKGROUND = 0,
+			BACKGROUND_WALL = 1,
+			KEEP,
+			BOTTOM_TOWER,
+			BOTTOM_WALL,
+			WALL_BELLOW_GATE,
+			WALL_OVER_GATE,
+			UPPER_WALL,
+			UPPER_TOWER,
+			GATE,
+			GATE_ARCH,
+			BOTTOM_STATIC_WALL,
+			UPPER_STATIC_WALL,
+			MOAT,
+			BACKGROUND_MOAT,
+			KEEP_BATTLEMENT,
+			BOTTOM_BATTLEMENT,
+			UPPER_BATTLEMENT
+		};
 
 		friend class CBattleInterface;
 	} * siegeH;
@@ -341,6 +357,8 @@ public:
 	BattleHex fromWhichHexAttack(BattleHex myNumber);
 	void obstaclePlaced(const CObstacleInstance & oi);
 
+	void gateStateChanged(const EGateState state);
+
 	const CGHeroInstance * currentHero() const;
 	InfoAboutHero enemyHero() const;
 

lib/BattleState.cpp

@@ -327,6 +327,8 @@ BattleInfo * BattleInfo::setupBattle( int3 tile, ETerrainType terrain, BFieldTyp
 	//setting up siege obstacles
 	if (town && town->hasFort())
 	{
+		curB->si.gateState = EGateState::CLOSED;
+
 		for (int b = 0; b < curB->si.wallState.size(); ++b)
 		{
 			curB->si.wallState[b] = EWallState::INTACT;

lib/BattleState.h

@@ -33,6 +33,7 @@ class CRandomGenerator;
 struct DLL_LINKAGE SiegeInfo
 {
 	std::array<si8, EWallPart::PARTS_COUNT> wallState;
+	EGateState gateState;
 
 	// return EWallState decreased by value of damage points
 	static EWallState::EWallState applyDamage(EWallState::EWallState state, unsigned int value)
@@ -51,7 +52,7 @@ struct DLL_LINKAGE SiegeInfo
 
 	template <typename Handler> void serialize(Handler &h, const int version)
 	{
-		h & wallState;
+		h & wallState & gateState;
 	}
 };
 

lib/CBattleCallback.cpp

@@ -62,13 +62,13 @@ namespace SiegeStuffThatShouldBeMovedToHandlers //  <=== TODO
 		std::make_pair(183, EWallPart::BOTTOM_TOWER),
 		std::make_pair(182, EWallPart::BOTTOM_WALL),
 		std::make_pair(130, EWallPart::BELOW_GATE),
-		std::make_pair(62,  EWallPart::OVER_GATE),
+		std::make_pair(78,  EWallPart::OVER_GATE),
 		std::make_pair(29,  EWallPart::UPPER_WALL),
 		std::make_pair(12,  EWallPart::UPPER_TOWER),
 		std::make_pair(95,  EWallPart::INDESTRUCTIBLE_PART_OF_GATE),
 		std::make_pair(96,  EWallPart::GATE),
 		std::make_pair(45,  EWallPart::INDESTRUCTIBLE_PART),
-		std::make_pair(78,  EWallPart::INDESTRUCTIBLE_PART),
+		std::make_pair(62,  EWallPart::INDESTRUCTIBLE_PART),
 		std::make_pair(112, EWallPart::INDESTRUCTIBLE_PART),
 		std::make_pair(147, EWallPart::INDESTRUCTIBLE_PART)
 	};
@@ -442,6 +442,15 @@ si8 CBattleInfoEssentials::battleGetWallState(int partOfWall) const
 	return getBattle()->si.wallState[partOfWall];
 }
 
+EGateState CBattleInfoEssentials::battleGetGateState() const
+{
+	RETURN_IF_NOT_BATTLE(EGateState::NONE);
+	if(getBattle()->town == nullptr || getBattle()->town->fortLevel() == CGTownInstance::NONE)
+		return EGateState::NONE;
+
+	return getBattle()->si.gateState;
+}
+
 si8 CBattleInfoCallback::battleHasWallPenalty( const CStack * stack, BattleHex destHex ) const
 {
 	return battleHasWallPenalty(stack, stack->position, destHex);
@@ -1134,9 +1143,20 @@ AccessibilityInfo CBattleInfoCallback::getAccesibility() const
 	}
 
 	//gate -> should be before stacks
-	if(battleGetSiegeLevel() > 0 && battleGetWallState(EWallPart::GATE) != EWallState::DESTROYED)
+	if(battleGetSiegeLevel() > 0)
 	{
-		ret[95] = ret[96] = EAccessibility::GATE; //block gate's hexes
+		EAccessibility::EAccessibility accessability = EAccessibility::ACCESSIBLE;
+		switch(battleGetGateState())
+		{
+		case EGateState::CLOSED:
+			accessability = EAccessibility::GATE;
+			break;
+
+		case EGateState::BLOCKED:
+			accessability = EAccessibility::UNAVAILABLE;
+			break;
+		}
+		ret[ESiegeHex::GATE_OUTER] = ret[ESiegeHex::GATE_INNER] = accessability;
 	}
 
 	//tiles occupied by standing stacks
@@ -1157,14 +1177,19 @@ AccessibilityInfo CBattleInfoCallback::getAccesibility() const
 	//walls
 	if(battleGetSiegeLevel() > 0)
 	{
-		static const int permanentlyLocked[] = {12, 45, 78, 112, 147, 165};
+		static const int permanentlyLocked[] = {12, 45, 62, 112, 147, 165};
 		for(auto hex : permanentlyLocked)
 			ret[hex] = EAccessibility::UNAVAILABLE;
 
 		//TODO likely duplicated logic
-		static const std::pair<int, BattleHex> lockedIfNotDestroyed[] = //(which part of wall, which hex is blocked if this part of wall is not destroyed
+		static const std::pair<int, BattleHex> lockedIfNotDestroyed[] =
-			{std::make_pair(2, BattleHex(182)), std::make_pair(3, BattleHex(130)),
+		{
-			std::make_pair(4, BattleHex(62)), std::make_pair(5, BattleHex(29))};
+			//which part of wall, which hex is blocked if this part of wall is not destroyed
+			std::make_pair(2, BattleHex(ESiegeHex::DESTRUCTIBLE_WALL_4)),
+			std::make_pair(3, BattleHex(ESiegeHex::DESTRUCTIBLE_WALL_3)),
+			std::make_pair(4, BattleHex(ESiegeHex::DESTRUCTIBLE_WALL_2)),
+			std::make_pair(5, BattleHex(ESiegeHex::DESTRUCTIBLE_WALL_1))
+		};
 
 		for(auto & elem : lockedIfNotDestroyed)
 		{

lib/CBattleCallback.h

@@ -199,6 +199,7 @@ public:
 	// for determining state of a part of the wall; format: parameter [0] - keep, [1] - bottom tower, [2] - bottom wall,
 	// [3] - below gate, [4] - over gate, [5] - upper wall, [6] - uppert tower, [7] - gate; returned value: 1 - intact, 2 - damaged, 3 - destroyed; 0 - no battle
 	si8 battleGetWallState(int partOfWall) const;
+	EGateState battleGetGateState() const;
 
 	//helpers
 	///returns all stacks, alive or dead or undead or mechanical :)

lib/GameConstants.h

@@ -513,6 +513,29 @@ namespace EWallState
 	};
 }
 
+enum class EGateState : ui8
+{
+	NONE,
+	CLOSED,
+	BLOCKED, //dead or alive stack blocking from outside
+	OPENED,
+	DESTROYED
+};
+
+namespace ESiegeHex
+{
+	enum ESiegeHex : si16
+	{
+		DESTRUCTIBLE_WALL_1 = 29,
+		DESTRUCTIBLE_WALL_2 = 78,
+		DESTRUCTIBLE_WALL_3 = 130,
+		DESTRUCTIBLE_WALL_4 = 182,
+		GATE_BRIDGE = 94,
+		GATE_OUTER = 95,
+		GATE_INNER = 96
+	};
+}
+
 namespace ETileType
 {
 	enum ETileType

lib/IGameEventsReceiver.h

@@ -69,6 +69,7 @@ public:
 	virtual void battleCatapultAttacked(const CatapultAttack & ca){}; //called when catapult makes an attack
 	virtual void battleStacksRemoved(const BattleStacksRemoved & bsr){}; //called when certain stack is completely removed from battlefield
 	virtual void battleObstaclePlaced(const CObstacleInstance &obstacle){};
+	virtual void battleGateStateChanged(const EGateState state){};
 };
 
 class DLL_LINKAGE IGameEventsReceiver

lib/NetPacks.h

@@ -1689,6 +1689,21 @@ struct BattleObstaclePlaced : public CPackForClient //3020
 	}
 };
 
+struct BattleUpdateGateState : public CPackForClient//3021
+{
+	BattleUpdateGateState(){type = 3021;};
+
+	void applyFirstCl(CClient *cl);
+
+	DLL_LINKAGE void applyGs(CGameState *gs);
+
+	EGateState state;
+	template <typename Handler> void serialize(Handler &h, const int version)
+	{
+		h & state;
+	}
+};
+
 
 struct ShowInInfobox : public CPackForClient //107
 {

lib/NetPacksLib.cpp

@@ -1225,6 +1225,12 @@ DLL_LINKAGE void BattleObstaclePlaced::applyGs( CGameState *gs )
 	gs->curB->obstacles.push_back(obstacle);
 }
 
+DLL_LINKAGE void BattleUpdateGateState::applyGs(CGameState *gs)
+{
+	if(gs->curB)
+		gs->curB->si.gateState = state;
+}
+
 void BattleResult::applyGs( CGameState *gs )
 {
 	for (CStack *s : gs->curB->stacks)

lib/registerTypes/RegisterTypes.h

@@ -270,6 +270,7 @@ void registerTypesClientPacks2(Serializer &s)
 	s.template registerType<CPackForClient, SetStackEffect>();
 	s.template registerType<CPackForClient, BattleTriggerEffect>();
 	s.template registerType<CPackForClient, BattleObstaclePlaced>();
+	s.template registerType<CPackForClient, BattleUpdateGateState>();
 	s.template registerType<CPackForClient, BattleSetStackProperty>();
 	s.template registerType<CPackForClient, StacksInjured>();
 	s.template registerType<CPackForClient, BattleResultsApplied>();

server/CGameHandler.cpp

@@ -1005,7 +1005,8 @@ int CGameHandler::moveStack(int stack, BattleHex dest)
 		assert(gs->curB->isInTacticRange(dest));
 	}
 
-	if(curStack->position == dest)
+	auto start = curStack->position;
+	if(start == dest)
 		return 0;
 
 	//initing necessary tables
@@ -1032,16 +1033,60 @@ int CGameHandler::moveStack(int stack, BattleHex dest)
 		return 0;
 	}
 
-	std::pair< std::vector<BattleHex>, int > path = gs->curB->getPath(curStack->position, dest, curStack);
+	bool canUseGate = false;
+	auto dbState = gs->curB->si.gateState;
+	if(battleGetSiegeLevel() > 0 && !curStack->attackerOwned &&
+		dbState != EGateState::DESTROYED &&
+		dbState != EGateState::BLOCKED)
+	{
+		canUseGate = true;
+	}
+
+	std::pair< std::vector<BattleHex>, int > path = gs->curB->getPath(start, dest, curStack);
 
 	ret = path.second;
 
 	int creSpeed = gs->curB->tacticDistance ? GameConstants::BFIELD_SIZE : curStack->Speed();
 
+	auto isGateDrawbridgeHex = [&](BattleHex hex) -> bool
+	{
+		if(gs->curB->town->subID == ETownType::FORTRESS && hex == ESiegeHex::GATE_BRIDGE)
+			return true;
+		if(hex == ESiegeHex::GATE_OUTER)
+			return true;
+		if(hex == ESiegeHex::GATE_INNER)
+			return true;
+
+		return false;
+	};
+
+	auto occupyGateDrawbridgeHex = [&](BattleHex hex) -> bool
+	{
+		if(isGateDrawbridgeHex(hex))
+			return true;
+
+		if(curStack->doubleWide())
+		{
+			BattleHex otherHex = curStack->occupiedHex(hex);
+			if(otherHex.isValid() && isGateDrawbridgeHex(otherHex))
+				return true;
+		}
+
+		return false;
+	};
+
 	if(curStack->hasBonusOfType(Bonus::FLYING))
 	{
 		if(path.second <= creSpeed && path.first.size() > 0)
 		{
+			if(canUseGate && dbState != EGateState::OPENED &&
+				occupyGateDrawbridgeHex(dest))
+			{
+				BattleUpdateGateState db;
+				db.state = EGateState::OPENED;
+				sendAndApply(&db);
+			}
+
 			//inform clients about move
 			BattleStackMoved sm;
 			sm.stack = curStack->ID;
@@ -1059,6 +1104,72 @@ int CGameHandler::moveStack(int stack, BattleHex dest)
 		std::vector<BattleHex> tiles;
 		const int tilesToMove = std::max((int)(path.first.size() - creSpeed), 0);
 		int v = path.first.size()-1;
+		path.first.push_back(start);
+
+		// check if gate need to be open or closed at some point
+		BattleHex openGateAtHex, gateMayCloseAtHex;
+		if(canUseGate)
+		{
+			for(int i = path.first.size()-1; i >= 0; i--)
+			{
+				auto needOpenGates = [&](BattleHex hex) -> bool
+				{
+					if(gs->curB->town->subID == ETownType::FORTRESS && hex == ESiegeHex::GATE_BRIDGE)
+						return true;
+					if(hex == ESiegeHex::GATE_BRIDGE && i-1 >= 0 && path.first[i-1] == ESiegeHex::GATE_OUTER)
+						return true;
+					else if(hex == ESiegeHex::GATE_OUTER || hex == ESiegeHex::GATE_INNER)
+						return true;
+
+					return false;
+				};
+
+				auto hex = path.first[i];
+				if(!openGateAtHex.isValid() && dbState != EGateState::OPENED)
+				{
+					if(needOpenGates(hex))
+						openGateAtHex = path.first[i+1];
+
+					//TODO we need find batter way to handle double-wide stacks
+					//currently if only second occupied stack part is standing on gate / bridge hex then stack will start to wait for bridge to lower before it's needed. Though this is just a visual bug.
+					if(curStack->doubleWide())
+					{
+						BattleHex otherHex = curStack->occupiedHex(hex);
+						if(otherHex.isValid() && needOpenGates(otherHex))
+							openGateAtHex = path.first[i+2];
+					}
+
+					//gate may be opened and then closed during stack movement, but not other way around
+					if(openGateAtHex.isValid())
+						dbState = EGateState::OPENED;
+				}
+
+				if(!gateMayCloseAtHex.isValid() && dbState != EGateState::CLOSED)
+				{
+					if(hex == ESiegeHex::GATE_INNER && i-1 >= 0 && path.first[i-1] != ESiegeHex::GATE_OUTER)
+					{
+						gateMayCloseAtHex = path.first[i-1];
+					}
+					if(gs->curB->town->subID == ETownType::FORTRESS)
+					{
+						if(hex == ESiegeHex::GATE_BRIDGE && i-1 >= 0 && path.first[i-1] != ESiegeHex::GATE_OUTER)
+						{
+							gateMayCloseAtHex = path.first[i-1];
+						}
+						else if(hex == ESiegeHex::GATE_OUTER && i-1 >= 0 &&
+							path.first[i-1] != ESiegeHex::GATE_INNER &&
+							path.first[i-1] != ESiegeHex::GATE_BRIDGE)
+						{
+							gateMayCloseAtHex = path.first[i-1];
+						}
+					}
+					else if(hex == ESiegeHex::GATE_OUTER && i-1 >= 0 && path.first[i-1] != ESiegeHex::GATE_INNER)
+					{
+						gateMayCloseAtHex = path.first[i-1];
+					}
+				}
+			}
+		}
 
 		bool stackIsMoving = true;
 
@@ -1070,22 +1181,35 @@ int CGameHandler::moveStack(int stack, BattleHex dest)
 				break;
 			}
 
-			for(bool obstacleHit = false; (!obstacleHit) && (v >= tilesToMove); --v)
+			bool gateStateChanging = false;
+			//special handling for opening gate on from starting hex
+			if(openGateAtHex.isValid() && openGateAtHex == start)
+				gateStateChanging = true;
+			else
 			{
-				BattleHex hex = path.first[v];
+				for(bool obstacleHit = false; (!obstacleHit) && (!gateStateChanging) && (v >= tilesToMove); --v)
-				tiles.push_back(hex);
-
-				//if we walked onto something, finalize this portion of stack movement check into obstacle
-				if((obstacle = battleGetObstacleOnPos(hex, false)))
-					obstacleHit = true;
-
-				if(curStack->doubleWide())
 				{
-					BattleHex otherHex = curStack->occupiedHex(hex);
+					BattleHex hex = path.first[v];
+					tiles.push_back(hex);
 
-					//two hex creature hit obstacle by backside
+					if((openGateAtHex.isValid() && openGateAtHex == hex) ||
-					if(otherHex.isValid() && ((obstacle2 = battleGetObstacleOnPos(otherHex, false))))
+						(gateMayCloseAtHex.isValid() && gateMayCloseAtHex == hex))
+					{
+						gateStateChanging = true;
+					}
+
+					//if we walked onto something, finalize this portion of stack movement check into obstacle
+					if((obstacle = battleGetObstacleOnPos(hex, false)))
 						obstacleHit = true;
+
+					if(curStack->doubleWide())
+					{
+						BattleHex otherHex = curStack->occupiedHex(hex);
+
+						//two hex creature hit obstacle by backside
+						if(otherHex.isValid() && ((obstacle2 = battleGetObstacleOnPos(otherHex, false))))
+							obstacleHit = true;
+					}
 				}
 			}
 
@@ -1121,6 +1245,26 @@ int CGameHandler::moveStack(int stack, BattleHex dest)
 				processObstacle(obstacle);
 				if(curStack->alive())
 					processObstacle(obstacle2);
+
+				if(gateStateChanging)
+				{
+					if(curStack->position == openGateAtHex)
+					{
+						openGateAtHex = BattleHex();
+						//only open gate if stack is still alive
+						if(curStack->alive())
+						{
+							BattleUpdateGateState db;
+							db.state = EGateState::OPENED;
+							sendAndApply(&db);
+						}
+					}
+					else if(curStack->position == gateMayCloseAtHex)
+					{
+						gateMayCloseAtHex = BattleHex();
+						updateGateState();
+					}
+				}
 			}
 			else
 				//movement finished normally: we reached destination
@@ -1731,8 +1875,13 @@ void CGameHandler::setupBattle( int3 tile, const CArmedInstance *armies[2], cons
 	sendAndApply(&bs);
 }
 
-void CGameHandler::checkForBattleEnd()
+void CGameHandler::checkBattleStateChanges()
 {
+	//check if drawbridge state need to be changes
+	if(battleGetSiegeLevel() > 0)
+		updateGateState();
+
+	//check if battle ended
 	if(auto result = battleIsFinished())
 	{
 		setBattleResult(BattleResult::NORMAL, *result);
@@ -3466,6 +3615,39 @@ bool CGameHandler::queryReply(QueryID qid, ui32 answer, PlayerColor player)
 
 static EndAction end_action;
 
+void CGameHandler::updateGateState()
+{
+	BattleUpdateGateState db;
+	db.state = gs->curB->si.gateState;
+	if(gs->curB->si.wallState[EWallPart::GATE] == EWallState::DESTROYED)
+	{
+		db.state = EGateState::DESTROYED;
+	}
+	else if(db.state == EGateState::OPENED)
+	{
+		if(!gs->curB->battleGetStackByPos(BattleHex(ESiegeHex::GATE_OUTER), false) &&
+			!gs->curB->battleGetStackByPos(BattleHex(ESiegeHex::GATE_INNER), false))
+		{
+			if(gs->curB->town->subID == ETownType::FORTRESS)
+			{
+				if(!gs->curB->battleGetStackByPos(BattleHex(ESiegeHex::GATE_BRIDGE), false))
+					db.state = EGateState::CLOSED;
+			}
+			else if(gs->curB->battleGetStackByPos(BattleHex(ESiegeHex::GATE_BRIDGE)))
+				db.state = EGateState::BLOCKED;
+			else
+				db.state = EGateState::CLOSED;
+		}
+	}
+	else if(gs->curB->battleGetStackByPos(BattleHex(ESiegeHex::GATE_BRIDGE), false))
+		db.state = EGateState::BLOCKED;
+	else
+		db.state = EGateState::CLOSED;
+
+	if(db.state != gs->curB->si.gateState)
+		sendAndApply(&db);
+}
+
 bool CGameHandler::makeBattleAction( BattleAction &ba )
 {
 	bool ok = true;
@@ -4218,7 +4400,7 @@ bool CGameHandler::makeCustomAction( BattleAction &ba )
 			{
 				battleMadeAction.setn(true);
 			}
-			checkForBattleEnd();
+			checkBattleStateChanges();
 			if(battleResult.get())
 			{
 				battleMadeAction.setn(true);
@@ -5605,7 +5787,7 @@ void CGameHandler::runBattle()
 					break;
 				}
 				//we're after action, all results applied
-				checkForBattleEnd(); //check if this action ended the battle
+				checkBattleStateChanges(); //check if this action ended the battle
 
 				if(next != nullptr)
 				{
@@ -5657,7 +5839,7 @@ bool CGameHandler::makeAutomaticAction(const CStack *stack, BattleAction &ba)
 	sendAndApply(&bsa);
 
 	bool ret = makeBattleAction(ba);
-	checkForBattleEnd();
+	checkBattleStateChanges();
 	return ret;
 }
 

server/CGameHandler.h

@@ -115,7 +115,7 @@ public:
 	void endBattle(int3 tile, const CGHeroInstance *hero1, const CGHeroInstance *hero2); //ends battle
 	void prepareAttack(BattleAttack &bat, const CStack *att, const CStack *def, int distance, int targetHex); //distance - number of hexes travelled before attacking
 	void applyBattleEffects(BattleAttack &bat, const CStack *att, const CStack *def, int distance, bool secondary); //damage, drain life & fire shield
-	void checkForBattleEnd();
+	void checkBattleStateChanges();
 	void setupBattle(int3 tile, const CArmedInstance *armies[2], const CGHeroInstance *heroes[2], bool creatureBank, const CGTownInstance *town);
 	void setBattleResult(BattleResult::EResult resultType, int victoriusSide);
 	void duelFinished();
@@ -203,6 +203,7 @@ public:
 	PlayerColor getPlayerAt(CConnection *c) const;
 
 	void playerMessage( PlayerColor player, const std::string &message, ObjectInstanceID currObj);
+	void updateGateState();
 	bool makeBattleAction(BattleAction &ba);
 	bool makeAutomaticAction(const CStack *stack, BattleAction &ba); //used when action is taken by stack without volition of player (eg. unguided catapult attack)
 	bool makeCustomAction(BattleAction &ba);