From 123157b216919f58a6d72fd5b0c8366e2e85a486 Mon Sep 17 00:00:00 2001
From: scrawl <scrawl@baseoftrash.de>
Date: Tue, 15 Jul 2014 21:53:11 +0200
Subject: [PATCH] Implement elemental shield damage to attacker (Feature #1121)

---
 apps/openmw/mwclass/creature.cpp   |  2 ++
 apps/openmw/mwclass/npc.cpp        |  2 ++
 apps/openmw/mwmechanics/combat.cpp | 48 ++++++++++++++++++++++++++++++
 apps/openmw/mwmechanics/combat.hpp |  3 ++
 4 files changed, 55 insertions(+)

diff --git a/apps/openmw/mwclass/creature.cpp b/apps/openmw/mwclass/creature.cpp
index feb6a2714..e78134802 100644
--- a/apps/openmw/mwclass/creature.cpp
+++ b/apps/openmw/mwclass/creature.cpp
@@ -330,6 +330,8 @@ namespace MWClass
             }
         }
 
+        MWMechanics::applyElementalShields(ptr, victim);
+
         if (!weapon.isEmpty() && MWMechanics::blockMeleeAttack(ptr, victim, weapon, damage))
             damage = 0;
 
diff --git a/apps/openmw/mwclass/npc.cpp b/apps/openmw/mwclass/npc.cpp
index e2cb8ba7a..a5175c1f6 100644
--- a/apps/openmw/mwclass/npc.cpp
+++ b/apps/openmw/mwclass/npc.cpp
@@ -630,6 +630,8 @@ namespace MWClass
             }
         }
 
+        MWMechanics::applyElementalShields(ptr, victim);
+
         if (!weapon.isEmpty() && MWMechanics::blockMeleeAttack(ptr, victim, weapon, damage))
             damage = 0;
 
diff --git a/apps/openmw/mwmechanics/combat.cpp b/apps/openmw/mwmechanics/combat.cpp
index 6feb5879b..19f00e81b 100644
--- a/apps/openmw/mwmechanics/combat.cpp
+++ b/apps/openmw/mwmechanics/combat.cpp
@@ -256,4 +256,52 @@ namespace MWMechanics
         return hitchance;
     }
 
+    void applyElementalShields(const MWWorld::Ptr &attacker, const MWWorld::Ptr &victim)
+    {
+        for (int i=0; i<3; ++i)
+        {
+            float magnitude = victim.getClass().getCreatureStats(victim).getMagicEffects().get(ESM::MagicEffect::FireShield+i).mMagnitude;
+
+            if (!magnitude)
+                continue;
+
+            CreatureStats& attackerStats = attacker.getClass().getCreatureStats(attacker);
+            float saveTerm = attacker.getClass().getSkill(attacker, ESM::Skill::Destruction)
+                    + 0.2f * attackerStats.getAttribute(ESM::Attribute::Willpower).getModified()
+                    + 0.1f * attackerStats.getAttribute(ESM::Attribute::Luck).getModified();
+
+            int fatigueMax = attackerStats.getFatigue().getModified();
+            int fatigueCurrent = attackerStats.getFatigue().getCurrent();
+
+            float normalisedFatigue = fatigueMax==0 ? 1 : std::max (0.0f, static_cast<float> (fatigueCurrent)/fatigueMax);
+
+            saveTerm *= 1.25f * normalisedFatigue;
+
+            float roll = std::rand()/ (static_cast<double> (RAND_MAX) + 1) * 100; // [0, 99]
+            float x = std::max(0.f, saveTerm - roll);
+
+            int element = ESM::MagicEffect::FireDamage;
+            if (i == 1)
+                element = ESM::MagicEffect::ShockDamage;
+            if (i == 2)
+                element = ESM::MagicEffect::FrostDamage;
+
+            short resistanceEffect = ESM::MagicEffect::getResistanceEffect(element);
+            short weaknessEffect = ESM::MagicEffect::getWeaknessEffect(element);
+            float elementResistance = 0;
+            if (resistanceEffect != -1)
+                elementResistance += attackerStats.getMagicEffects().get(resistanceEffect).mMagnitude;
+            if (weaknessEffect != -1)
+                elementResistance -= attackerStats.getMagicEffects().get(weaknessEffect).mMagnitude;
+
+            x = std::min(100.f, x + elementResistance);
+
+            static const float fElementalShieldMult = MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fElementalShieldMult")->getFloat();
+            x = fElementalShieldMult * magnitude * (1.f - 0.01f * x);
+            MWMechanics::DynamicStat<float> health = attackerStats.getHealth();
+            health.setCurrent(health.getCurrent() - x);
+            attackerStats.setHealth(health);
+        }
+    }
+
 }
diff --git a/apps/openmw/mwmechanics/combat.hpp b/apps/openmw/mwmechanics/combat.hpp
index bc58227bf..eb89cb820 100644
--- a/apps/openmw/mwmechanics/combat.hpp
+++ b/apps/openmw/mwmechanics/combat.hpp
@@ -19,6 +19,9 @@ void projectileHit (const MWWorld::Ptr& attacker, const MWWorld::Ptr& victim, MW
 /// Get the chance (in percent) for \a attacker to successfully hit \a victim with a given weapon skill value
 float getHitChance (const MWWorld::Ptr& attacker, const MWWorld::Ptr& victim, int skillValue);
 
+/// Applies damage to attacker based on the victim's elemental shields.
+void applyElementalShields(const MWWorld::Ptr& attacker, const MWWorld::Ptr& victim);
+
 }
 
 #endif