From 20a0040bdb88084846c5da633f82635318428cc5 Mon Sep 17 00:00:00 2001
From: scrawl <scrawl@baseoftrash.de>
Date: Tue, 15 Jul 2014 22:06:46 +0200
Subject: [PATCH] Apply elemental shield magnitude to element resistance
 (Closes #1121)

---
 apps/openmw/mwmechanics/combat.cpp       |  8 +-----
 apps/openmw/mwmechanics/spellcasting.cpp | 32 ++++++++++++++++--------
 apps/openmw/mwmechanics/spellcasting.hpp |  5 ++++
 3 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/apps/openmw/mwmechanics/combat.cpp b/apps/openmw/mwmechanics/combat.cpp
index 19f00e81b..5908e79cd 100644
--- a/apps/openmw/mwmechanics/combat.cpp
+++ b/apps/openmw/mwmechanics/combat.cpp
@@ -286,13 +286,7 @@ namespace MWMechanics
             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;
+            float elementResistance = MWMechanics::getEffectResistanceAttribute(element, &attackerStats.getMagicEffects());
 
             x = std::min(100.f, x + elementResistance);
 
diff --git a/apps/openmw/mwmechanics/spellcasting.cpp b/apps/openmw/mwmechanics/spellcasting.cpp
index 1b0c444ab..9253a9453 100644
--- a/apps/openmw/mwmechanics/spellcasting.cpp
+++ b/apps/openmw/mwmechanics/spellcasting.cpp
@@ -148,6 +148,27 @@ namespace MWMechanics
         return school;
     }
 
+    float getEffectResistanceAttribute (short effectId, const MagicEffects* actorEffects)
+    {
+        short resistanceEffect = ESM::MagicEffect::getResistanceEffect(effectId);
+        short weaknessEffect = ESM::MagicEffect::getWeaknessEffect(effectId);
+
+        float resistance = 0;
+        if (resistanceEffect != -1)
+            resistance += actorEffects->get(resistanceEffect).mMagnitude;
+        if (weaknessEffect != -1)
+            resistance -= actorEffects->get(weaknessEffect).mMagnitude;
+
+        if (effectId == ESM::MagicEffect::FireDamage)
+            resistance += actorEffects->get(ESM::MagicEffect::FireShield).mMagnitude;
+        if (effectId == ESM::MagicEffect::ShockDamage)
+            resistance += actorEffects->get(ESM::MagicEffect::LightningShield).mMagnitude;
+        if (effectId == ESM::MagicEffect::FrostDamage)
+            resistance += actorEffects->get(ESM::MagicEffect::FrostShield).mMagnitude;
+
+        return resistance;
+    }
+
     float getEffectResistance (short effectId, const MWWorld::Ptr& actor, const MWWorld::Ptr& caster,
                                const ESM::Spell* spell, const MagicEffects* effects)
     {
@@ -163,16 +184,7 @@ namespace MWMechanics
         float resisted = 0;
         if (magicEffect->mData.mFlags & ESM::MagicEffect::Harmful)
         {
-
-            short resistanceEffect = ESM::MagicEffect::getResistanceEffect(effectId);
-            short weaknessEffect = ESM::MagicEffect::getWeaknessEffect(effectId);
-
-            float resistance = 0;
-            if (resistanceEffect != -1)
-                resistance += magicEffects->get(resistanceEffect).mMagnitude;
-            if (weaknessEffect != -1)
-                resistance -= magicEffects->get(weaknessEffect).mMagnitude;
-
+            float resistance = getEffectResistanceAttribute(effectId, magicEffects);
 
             float willpower = stats.getAttribute(ESM::Attribute::Willpower).getModified();
             float luck = stats.getAttribute(ESM::Attribute::Luck).getModified();
diff --git a/apps/openmw/mwmechanics/spellcasting.hpp b/apps/openmw/mwmechanics/spellcasting.hpp
index b526a4353..2de187ae4 100644
--- a/apps/openmw/mwmechanics/spellcasting.hpp
+++ b/apps/openmw/mwmechanics/spellcasting.hpp
@@ -35,6 +35,11 @@ namespace MWMechanics
     int getSpellSchool(const std::string& spellId, const MWWorld::Ptr& actor);
     int getSpellSchool(const ESM::Spell* spell, const MWWorld::Ptr& actor);
 
+    /// Get the resistance attribute against an effect for a given actor. This will add together
+    /// ResistX and Weakness to X effects relevant against the given effect.
+    float getEffectResistanceAttribute (short effectId, const MagicEffects* actorEffects);
+
+    /// Get the effective resistance against an effect casted by the given actor in the given spell (optional).
     /// @return >=100 for fully resisted. can also return negative value for damage amplification.
     /// @param effects Override the actor's current magicEffects. Useful if there are effects currently
     ///                being applied (but not applied yet) that should also be considered.