Intoduce PASSIVE_CASTING mode for opening battle spells

* now at least one "caster" object is present

lib/GameConstants.h

@@ -414,7 +414,8 @@ namespace ECastingMode
 	{
 		HERO_CASTING, AFTER_ATTACK_CASTING, //also includes cast before attack
 		MAGIC_MIRROR, CREATURE_ACTIVE_CASTING, ENCHANTER_CASTING,
-		SPELL_LIKE_ATTACK	
+		SPELL_LIKE_ATTACK, 
+		PASSIVE_CASTING//f.e. opening battle spells
 	};
 }
 

lib/spells/BattleSpellMechanics.cpp

@@ -27,10 +27,8 @@ void HealingSpellMechanics::applyBattleEffects(const SpellCastEnvironment* env,
 	for(auto & attackedCre : ctx.attackedCres)
 	{
 		StacksHealedOrResurrected::HealInfo hi;
-		hi.stackID = (attackedCre)->ID;
-		int stackHPgained = hpGained;
-		if(ctx.caster != nullptr)
-			stackHPgained = ctx.caster->getSpellBonus(owner, hpGained, attackedCre);
+		hi.stackID = (attackedCre)->ID;		
+		int stackHPgained = ctx.caster->getSpellBonus(owner, hpGained, attackedCre);
 		hi.healedHP = attackedCre->calculateHealedHealthPoints(stackHPgained, resurrect);
 		hi.lowLevelResurrection = (healLevel == EHealLevel::RESURRECT);
 		shr.healedStacks.push_back(hi);

lib/spells/CDefaultSpellMechanics.cpp

@@ -230,15 +230,17 @@ void DefaultSpellMechanics::battleCast(const SpellCastEnvironment * env, BattleS
 	
 	//check it there is opponent hero
 	const ui8 otherSide = 1-parameters.casterSide;
-	const CGHeroInstance * otherHero = parameters.cb->battleGetFightingHero(otherSide);
+	const CGHeroInstance * otherHero = nullptr;
+	if(parameters.cb->battleHasHero(otherSide))
+		otherHero = parameters.cb->battleGetFightingHero(otherSide);
 	int spellCost = 0;
 
 	//calculate spell cost
-	if(parameters.casterHero)
+	if(parameters.mode == ECastingMode::HERO_CASTING)
 	{
 		spellCost = parameters.cb->battleGetSpellCost(owner, parameters.casterHero);
 
-		if(parameters.mode == ECastingMode::HERO_CASTING && nullptr != otherHero) //handle mana channel
+		if(nullptr != otherHero) //handle mana channel
 		{			
 			int manaChannel = 0;
 			for(const CStack * stack : parameters.cb->battleGetAllStacks(true)) //TODO: shouldn't bonus system handle it somehow?
@@ -303,8 +305,16 @@ void DefaultSpellMechanics::battleCast(const SpellCastEnvironment * env, BattleS
 	ctx.effectValue = 0;
 	if(parameters.casterStack)
 		ctx.caster = parameters.casterStack;
+	else if(parameters.casterHero)
+		ctx.caster = parameters.casterHero;
 	else if(parameters.mode == ECastingMode::HERO_CASTING)
 		ctx.caster = parameters.cb->battleGetFightingHero(parameters.casterSide);
+	
+	if(ctx.caster == nullptr)
+	{
+		env->complain("No spell-caster provided.");
+		return;
+	}
 
 	if(parameters.casterStack)
 	{
@@ -325,7 +335,7 @@ void DefaultSpellMechanics::battleCast(const SpellCastEnvironment * env, BattleS
 	env->sendAndApply(&sc);
 
 	//spend mana
-	if(parameters.casterHero)
+	if(parameters.mode == ECastingMode::HERO_CASTING)
 	{
 		SetMana sm;
 		sm.absolute = false;
@@ -527,9 +537,9 @@ void DefaultSpellMechanics::applyBattleEffects(const SpellCastEnvironment * env,
 		{
 			BattleStackAttacked bsa;
 			if(spellDamage != 0)
-				bsa.damageAmount = owner->adjustRawDamage(parameters.casterHero, attackedCre, spellDamage) >> chainLightningModifier;
+				bsa.damageAmount = owner->adjustRawDamage(ctx.caster, attackedCre, spellDamage) >> chainLightningModifier;
 			else
-				bsa.damageAmount = owner->calculateDamage(parameters.casterHero, attackedCre, ctx.effectLevel, ctx.effectPower) >> chainLightningModifier;
+				bsa.damageAmount = owner->calculateDamage(ctx.caster, attackedCre, ctx.effectLevel, ctx.effectPower) >> chainLightningModifier;
 
 			ctx.sc.dmgToDisplay += bsa.damageAmount;
 
@@ -888,7 +898,7 @@ void DefaultSpellMechanics::prepareBattleCast(const BattleSpellCastParameters& p
 	sc.skill = parameters.spellLvl;
 	sc.tile = parameters.destination;
 	sc.dmgToDisplay = 0;
-	sc.castByHero = nullptr != parameters.casterHero;
+	sc.castByHero = parameters.mode == ECastingMode::HERO_CASTING;
 	sc.casterStack = (parameters.casterStack ? parameters.casterStack->ID : -1);
 	sc.manaGained = 0;	
 }

lib/spells/CSpellHandler.cpp

@@ -390,8 +390,7 @@ int CSpell::adjustRawDamage(const ISpellCaster * caster, const CStack * affected
 		}
 	}
 
-	if(nullptr != caster) //todo: make sure that caster always present
-		ret = caster->getSpellBonus(this, ret, affectedCreature);
+	ret = caster->getSpellBonus(this, ret, affectedCreature);
 
 	return ret;
 }

server/CGameHandler.cpp

@@ -5290,8 +5290,8 @@ void CGameHandler::runBattle()
 			parameters.destination = BattleHex::INVALID;
 			parameters.casterSide = i;
 			parameters.casterColor = h->tempOwner;	
-			parameters.casterHero = nullptr;
-			parameters.mode = ECastingMode::HERO_CASTING;
+			parameters.casterHero = h;
+			parameters.mode = ECastingMode::PASSIVE_CASTING;
 			parameters.casterStack = nullptr;	
 			parameters.selectedStack = nullptr;