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https://github.com/vcmi/vcmi.git
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420 lines
14 KiB
C++
420 lines
14 KiB
C++
/*
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* AttackPossibility.cpp, part of VCMI engine
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*
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* Authors: listed in file AUTHORS in main folder
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*
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* License: GNU General Public License v2.0 or later
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* Full text of license available in license.txt file, in main folder
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*
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*/
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#include "StdInc.h"
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#include "AttackPossibility.h"
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#include "../../lib/CStack.h" // TODO: remove
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// Eventually only IBattleInfoCallback and battle::Unit should be used,
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// CUnitState should be private and CStack should be removed completely
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uint64_t averageDmg(const DamageRange & range)
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{
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return (range.min + range.max) / 2;
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}
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void DamageCache::cacheDamage(const battle::Unit * attacker, const battle::Unit * defender, std::shared_ptr<CBattleInfoCallback> hb)
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{
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auto damage = averageDmg(hb->battleEstimateDamage(attacker, defender, 0).damage);
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damageCache[attacker->unitId()][defender->unitId()] = static_cast<float>(damage) / attacker->getCount();
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}
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void DamageCache::buildDamageCache(std::shared_ptr<HypotheticBattle> hb, BattleSide side)
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{
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auto stacks = hb->battleGetUnitsIf([=](const battle::Unit * u) -> bool
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{
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return u->isValidTarget();
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});
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std::vector<const battle::Unit *> ourUnits;
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std::vector<const battle::Unit *> enemyUnits;
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for(auto stack : stacks)
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{
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if(stack->unitSide() == side)
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ourUnits.push_back(stack);
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else
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enemyUnits.push_back(stack);
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}
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for(auto ourUnit : ourUnits)
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{
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if(!ourUnit->alive())
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continue;
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for(auto enemyUnit : enemyUnits)
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{
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if(enemyUnit->alive())
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{
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cacheDamage(ourUnit, enemyUnit, hb);
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cacheDamage(enemyUnit, ourUnit, hb);
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}
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}
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}
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}
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int64_t DamageCache::getDamage(const battle::Unit * attacker, const battle::Unit * defender, std::shared_ptr<CBattleInfoCallback> hb)
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{
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bool wasComputedBefore = damageCache[attacker->unitId()].count(defender->unitId());
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if (!wasComputedBefore)
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cacheDamage(attacker, defender, hb);
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return damageCache[attacker->unitId()][defender->unitId()] * attacker->getCount();
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}
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int64_t DamageCache::getOriginalDamage(const battle::Unit * attacker, const battle::Unit * defender, std::shared_ptr<CBattleInfoCallback> hb)
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{
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if(parent)
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{
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auto attackerDamageMap = parent->damageCache.find(attacker->unitId());
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if(attackerDamageMap != parent->damageCache.end())
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{
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auto targetDamage = attackerDamageMap->second.find(defender->unitId());
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if(targetDamage != attackerDamageMap->second.end())
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{
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return static_cast<int64_t>(targetDamage->second * attacker->getCount());
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}
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}
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}
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return getDamage(attacker, defender, hb);
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}
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AttackPossibility::AttackPossibility(BattleHex from, BattleHex dest, const BattleAttackInfo & attack)
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: from(from), dest(dest), attack(attack)
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{
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this->attack.attackerPos = from;
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this->attack.defenderPos = dest;
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}
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float AttackPossibility::damageDiff() const
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{
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return defenderDamageReduce - attackerDamageReduce - collateralDamageReduce + shootersBlockedDmg;
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}
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float AttackPossibility::damageDiff(float positiveEffectMultiplier, float negativeEffectMultiplier) const
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{
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return positiveEffectMultiplier * (defenderDamageReduce + shootersBlockedDmg)
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- negativeEffectMultiplier * (attackerDamageReduce + collateralDamageReduce);
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}
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float AttackPossibility::attackValue() const
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{
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return damageDiff();
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}
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float hpFunction(uint64_t unitHealthStart, uint64_t unitHealthEnd, uint64_t maxHealth)
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{
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float ratioStart = static_cast<float>(unitHealthStart) / maxHealth;
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float ratioEnd = static_cast<float>(unitHealthEnd) / maxHealth;
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float base = 0.666666f;
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// reduce from max to 0 must be 1.
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// 10 hp from end costs bit more than 10 hp from start because our goal is to kill unit, not just hurt it
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// ********** 2 * base - ratioStart *********
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// * *
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// * height = ratioStart - ratioEnd *
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// * *
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// ******************** 2 * base - ratioEnd ******
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// S = (a + b) * h / 2
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return (base * (4 - ratioStart - ratioEnd)) * (ratioStart - ratioEnd) / 2 ;
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}
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/// <summary>
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/// How enemy damage will be reduced by this attack
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/// Half bounty for kill, half for making damage equal to enemy health
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/// Bounty - the killed creature average damage calculated against attacker
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/// </summary>
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float AttackPossibility::calculateDamageReduce(
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const battle::Unit * attacker,
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const battle::Unit * defender,
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uint64_t damageDealt,
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DamageCache & damageCache,
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std::shared_ptr<CBattleInfoCallback> state)
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{
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const float HEALTH_BOUNTY = 0.5;
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const float KILL_BOUNTY = 0.5;
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// FIXME: provide distance info for Jousting bonus
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auto attackerUnitForMeasurement = attacker;
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if(!attackerUnitForMeasurement || attackerUnitForMeasurement->isTurret())
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{
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auto ourUnits = state->battleGetUnitsIf([&](const battle::Unit * u) -> bool
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{
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return u->unitSide() != defender->unitSide()
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&& !u->isTurret()
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&& u->creatureId() != CreatureID::CATAPULT
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&& u->creatureId() != CreatureID::BALLISTA
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&& u->creatureId() != CreatureID::FIRST_AID_TENT
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&& u->getCount();
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});
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if(ourUnits.empty())
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attackerUnitForMeasurement = defender;
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else
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attackerUnitForMeasurement = ourUnits.front();
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}
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auto maxHealth = defender->getMaxHealth();
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auto availableHealth = defender->getFirstHPleft() + ((defender->getCount() - 1) * maxHealth);
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vstd::amin(damageDealt, availableHealth);
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auto enemyDamageBeforeAttack = damageCache.getOriginalDamage(defender, attackerUnitForMeasurement, state);
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auto enemiesKilled = damageDealt / maxHealth + (damageDealt % maxHealth >= defender->getFirstHPleft() ? 1 : 0);
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auto damagePerEnemy = enemyDamageBeforeAttack / (double)defender->getCount();
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auto exceedingDamage = (damageDealt % maxHealth);
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float hpValue = (damageDealt / maxHealth);
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if(defender->getFirstHPleft() >= exceedingDamage)
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{
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hpValue += hpFunction(defender->getFirstHPleft(), defender->getFirstHPleft() - exceedingDamage, maxHealth);
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}
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else
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{
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hpValue += hpFunction(defender->getFirstHPleft(), 0, maxHealth);
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hpValue += hpFunction(maxHealth, maxHealth + defender->getFirstHPleft() - exceedingDamage, maxHealth);
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}
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return damagePerEnemy * (enemiesKilled * KILL_BOUNTY + hpValue * HEALTH_BOUNTY);
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}
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int64_t AttackPossibility::evaluateBlockedShootersDmg(
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const BattleAttackInfo & attackInfo,
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BattleHex hex,
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DamageCache & damageCache,
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std::shared_ptr<CBattleInfoCallback> state)
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{
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int64_t res = 0;
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if(attackInfo.shooting)
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return 0;
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auto attacker = attackInfo.attacker;
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auto hexes = attacker->getSurroundingHexes(hex);
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for(BattleHex tile : hexes)
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{
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auto st = state->battleGetUnitByPos(tile, true);
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if(!st || !state->battleMatchOwner(st, attacker))
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continue;
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if(!state->battleCanShoot(st))
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continue;
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// FIXME: provide distance info for Jousting bonus
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BattleAttackInfo rangeAttackInfo(st, attacker, 0, true);
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rangeAttackInfo.defenderPos = hex;
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BattleAttackInfo meleeAttackInfo(st, attacker, 0, false);
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meleeAttackInfo.defenderPos = hex;
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auto rangeDmg = state->battleEstimateDamage(rangeAttackInfo);
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auto meleeDmg = state->battleEstimateDamage(meleeAttackInfo);
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int64_t gain = averageDmg(rangeDmg.damage) - averageDmg(meleeDmg.damage) + 1;
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res += gain;
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}
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return res;
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}
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AttackPossibility AttackPossibility::evaluate(
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const BattleAttackInfo & attackInfo,
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BattleHex hex,
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DamageCache & damageCache,
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std::shared_ptr<CBattleInfoCallback> state)
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{
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auto attacker = attackInfo.attacker;
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auto defender = attackInfo.defender;
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const std::string cachingStringBlocksRetaliation = "type_BLOCKS_RETALIATION";
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static const auto selectorBlocksRetaliation = Selector::type()(BonusType::BLOCKS_RETALIATION);
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const auto attackerSide = state->playerToSide(state->battleGetOwner(attacker));
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const bool counterAttacksBlocked = attacker->hasBonus(selectorBlocksRetaliation, cachingStringBlocksRetaliation);
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AttackPossibility bestAp(hex, BattleHex::INVALID, attackInfo);
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std::vector<BattleHex> defenderHex;
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if(attackInfo.shooting)
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defenderHex.push_back(defender->getPosition());
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else
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defenderHex = CStack::meleeAttackHexes(attacker, defender, hex);
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for(BattleHex defHex : defenderHex)
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{
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if(defHex == hex) // should be impossible but check anyway
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continue;
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AttackPossibility ap(hex, defHex, attackInfo);
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ap.attackerState = attacker->acquireState();
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ap.shootersBlockedDmg = bestAp.shootersBlockedDmg;
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const int totalAttacks = ap.attackerState->getTotalAttacks(attackInfo.shooting);
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if (!attackInfo.shooting)
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ap.attackerState->setPosition(hex);
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std::vector<const battle::Unit *> defenderUnits;
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std::vector<const battle::Unit *> retaliatedUnits = {attacker};
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std::vector<const battle::Unit *> affectedUnits;
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if (attackInfo.shooting)
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defenderUnits = state->getAttackedBattleUnits(attacker, defender, defHex, true, hex, defender->getPosition());
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else
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{
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defenderUnits = state->getAttackedBattleUnits(attacker, defender, defHex, false, hex, defender->getPosition());
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retaliatedUnits = state->getAttackedBattleUnits(defender, attacker, hex, false, defender->getPosition(), hex);
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// attacker can not melle-attack itself but still can hit that place where it was before moving
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vstd::erase_if(defenderUnits, [attacker](const battle::Unit * u) -> bool { return u->unitId() == attacker->unitId(); });
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if(!vstd::contains_if(retaliatedUnits, [attacker](const battle::Unit * u) -> bool { return u->unitId() == attacker->unitId(); }))
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{
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retaliatedUnits.push_back(attacker);
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}
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}
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// ensure the defender is also affected
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if(!vstd::contains_if(defenderUnits, [defender](const battle::Unit * u) -> bool { return u->unitId() == defender->unitId(); }))
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{
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defenderUnits.push_back(defender);
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}
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affectedUnits = defenderUnits;
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vstd::concatenate(affectedUnits, retaliatedUnits);
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logAi->trace("Attacked battle units count %d, %d->%d", affectedUnits.size(), hex.hex, defHex.hex);
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std::map<uint32_t, std::shared_ptr<battle::CUnitState>> defenderStates;
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for(auto u : affectedUnits)
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{
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if(u->unitId() == attacker->unitId())
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continue;
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auto defenderState = u->acquireState();
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ap.affectedUnits.push_back(defenderState);
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defenderStates[u->unitId()] = defenderState;
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}
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for(int i = 0; i < totalAttacks; i++)
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{
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if(!ap.attackerState->alive() || !defenderStates[defender->unitId()]->alive())
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break;
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for(auto u : defenderUnits)
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{
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auto defenderState = defenderStates.at(u->unitId());
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int64_t damageDealt;
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float defenderDamageReduce;
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float attackerDamageReduce;
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DamageEstimation retaliation;
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auto attackDmg = state->battleEstimateDamage(ap.attack, &retaliation);
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damageDealt = averageDmg(attackDmg.damage);
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vstd::amin(damageDealt, defenderState->getAvailableHealth());
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defenderDamageReduce = calculateDamageReduce(attacker, u, damageDealt, damageCache, state);
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ap.attackerState->afterAttack(attackInfo.shooting, false);
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//FIXME: use ranged retaliation
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attackerDamageReduce = 0;
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if (!attackInfo.shooting && u->unitId() == defender->unitId() && defenderState->ableToRetaliate() && !counterAttacksBlocked)
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{
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for(auto retaliated : retaliatedUnits)
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{
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if(retaliated->unitId() == attacker->unitId())
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{
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int64_t damageReceived = averageDmg(retaliation.damage);
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vstd::amin(damageReceived, ap.attackerState->getAvailableHealth());
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attackerDamageReduce = calculateDamageReduce(defender, retaliated, damageReceived, damageCache, state);
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ap.attackerState->damage(damageReceived);
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}
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else
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{
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auto retaliationCollateral = state->battleEstimateDamage(defender, retaliated, 0);
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int64_t damageReceived = averageDmg(retaliationCollateral.damage);
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vstd::amin(damageReceived, retaliated->getAvailableHealth());
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if(defender->unitSide() == retaliated->unitSide())
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defenderDamageReduce += calculateDamageReduce(defender, retaliated, damageReceived, damageCache, state);
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else
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ap.collateralDamageReduce += calculateDamageReduce(defender, retaliated, damageReceived, damageCache, state);
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defenderStates.at(retaliated->unitId())->damage(damageReceived);
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}
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}
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defenderState->afterAttack(attackInfo.shooting, true);
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}
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bool isEnemy = state->battleMatchOwner(attacker, u);
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// this includes enemy units as well as attacker units under enemy's mind control
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if(isEnemy)
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ap.defenderDamageReduce += defenderDamageReduce;
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// damaging attacker's units (even those under enemy's mind control) is considered friendly fire
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if(attackerSide == u->unitSide())
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ap.collateralDamageReduce += defenderDamageReduce;
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if(u->unitId() == defender->unitId()
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|| (!attackInfo.shooting && CStack::isMeleeAttackPossible(u, attacker, hex)))
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{
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//FIXME: handle RANGED_RETALIATION ?
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ap.attackerDamageReduce += attackerDamageReduce;
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}
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defenderState->damage(damageDealt);
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if(u->unitId() == defender->unitId())
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{
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ap.defenderDead = !defenderState->alive();
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}
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}
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}
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#if BATTLE_TRACE_LEVEL>=2
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logAi->trace("BattleAI AP: %s -> %s at %d from %d, affects %d units: d:%lld a:%lld c:%lld s:%lld",
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attackInfo.attacker->unitType()->getJsonKey(),
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attackInfo.defender->unitType()->getJsonKey(),
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(int)ap.dest, (int)ap.from, (int)ap.affectedUnits.size(),
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ap.defenderDamageReduce, ap.attackerDamageReduce, ap.collateralDamageReduce, ap.shootersBlockedDmg);
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#endif
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if(!bestAp.dest.isValid() || ap.attackValue() > bestAp.attackValue())
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bestAp = ap;
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}
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// check how much damage we gain from blocking enemy shooters on this hex
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bestAp.shootersBlockedDmg = evaluateBlockedShootersDmg(attackInfo, hex, damageCache, state);
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#if BATTLE_TRACE_LEVEL>=1
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logAi->trace("BattleAI best AP: %s -> %s at %d from %d, affects %d units: d:%lld a:%lld c:%lld s:%lld",
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attackInfo.attacker->unitType()->getJsonKey(),
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attackInfo.defender->unitType()->getJsonKey(),
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(int)bestAp.dest, (int)bestAp.from, (int)bestAp.affectedUnits.size(),
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bestAp.defenderDamageReduce, bestAp.attackerDamageReduce, bestAp.collateralDamageReduce, bestAp.shootersBlockedDmg);
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#endif
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//TODO other damage related to attack (eg. fire shield and other abilities)
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return bestAp;
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}
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