Enchanting: fix skill-based cast cost bonus being applied twice

apps/openmw/mwgui/enchantingdialog.cpp

@@ -111,7 +111,7 @@ namespace MWGui
         mCharge->setCaption(boost::lexical_cast<std::string>(mEnchanting.getGemCharge()));
 
         std::stringstream castCost;
-        castCost << mEnchanting.getCastCost();
+        castCost << mEnchanting.getEffectiveCastCost();
         mCastCost->setCaption(castCost.str());
 
         mPrice->setCaption(boost::lexical_cast<std::string>(mEnchanting.getEnchantPrice()));

apps/openmw/mwgui/spellmodel.cpp

@@ -103,9 +103,7 @@ namespace MWGui
                         && item.getClass().canBeEquipped(item, mActor).first == 0)
                     continue;
 
-                float enchantCost = enchant->mData.mCost;
-                int eSkill = mActor.getClass().getSkill(mActor, ESM::Skill::Enchant);
-                int castCost = std::max(1.f, enchantCost - (enchantCost / 100) * (eSkill - 10));
+                int castCost = MWMechanics::getEffectiveEnchantmentCastCost(enchant->mData.mCost, mActor);
 
                 std::string cost = boost::lexical_cast<std::string>(castCost);
                 int currentCharge = int(item.getCellRef().getEnchantmentCharge());

apps/openmw/mwmechanics/enchanting.cpp

@@ -6,6 +6,7 @@
 
 #include "creaturestats.hpp"
 #include "npcstats.hpp"
+#include "spellcasting.hpp"
 
 namespace MWMechanics
 {
@@ -55,7 +56,7 @@ namespace MWMechanics
         enchantment.mData.mCharge = getGemCharge();
         enchantment.mData.mAutocalc = 0;
         enchantment.mData.mType = mCastStyle;
-        enchantment.mData.mCost = getCastCost();
+        enchantment.mData.mCost = getBaseCastCost();
 
         store.remove(mSoulGemPtr, 1, player);
 
@@ -199,23 +200,19 @@ namespace MWMechanics
     }
 
 
-    int Enchanting::getCastCost() const
+    int Enchanting::getBaseCastCost() const
     {
         if (mCastStyle == ESM::Enchantment::ConstantEffect)
             return 0;
 
-        const float enchantCost = getEnchantPoints();
-        MWWorld::Ptr player = MWBase::Environment::get().getWorld()->getPlayerPtr();
-        MWMechanics::NpcStats &stats = player.getClass().getNpcStats(player);
-        int eSkill = stats.getSkill(ESM::Skill::Enchant).getModified();
-
-        /*
-         * Each point of enchant skill above/under 10 subtracts/adds
-         * one percent of enchantment cost while minimum is 1.
-         */
-        const float castCost = enchantCost - (enchantCost / 100) * (eSkill - 10);
+        return getEnchantPoints();
+    }
 
-        return static_cast<int>((castCost < 1) ? 1 : castCost);
+    int Enchanting::getEffectiveCastCost() const
+    {
+        int baseCost = getBaseCastCost();
+        MWWorld::Ptr player = MWBase::Environment::get().getWorld()->getPlayerPtr();
+        return getEffectiveEnchantmentCastCost(baseCost, player);
     }
 
 

apps/openmw/mwmechanics/enchanting.hpp

@@ -36,7 +36,8 @@ namespace MWMechanics
             void nextCastStyle(); //Set enchant type to next possible type (for mOldItemPtr object)
             int getCastStyle() const;
             int getEnchantPoints() const;
-            int getCastCost() const;
+            int getBaseCastCost() const; // To be saved in the enchantment's record
+            int getEffectiveCastCost() const; // Effective cost taking player Enchant skill into account, used for preview purposes in the UI
             int getEnchantPrice() const;
             int getMaxEnchantValue() const;
             int getGemCharge() const;

apps/openmw/mwmechanics/spellcasting.cpp

@@ -689,9 +689,7 @@ namespace MWMechanics
         // Check if there's enough charge left
         if (enchantment->mData.mType == ESM::Enchantment::WhenUsed || enchantment->mData.mType == ESM::Enchantment::WhenStrikes)
         {
-            const float enchantCost = enchantment->mData.mCost;
-            int eSkill = mCaster.getClass().getSkill(mCaster, ESM::Skill::Enchant);
-            const int castCost = std::max(1.f, enchantCost - (enchantCost / 100) * (eSkill - 10));
+            const int castCost = getEffectiveEnchantmentCastCost(enchantment->mData.mCost, mCaster);
 
             if (item.getCellRef().getEnchantmentCharge() == -1)
                 item.getCellRef().setEnchantmentCharge(enchantment->mData.mCharge);
@@ -915,4 +913,16 @@ namespace MWMechanics
 
         return true;
     }
+
+    int getEffectiveEnchantmentCastCost(float castCost, const MWWorld::Ptr &actor)
+    {
+        /*
+         * Each point of enchant skill above/under 10 subtracts/adds
+         * one percent of enchantment cost while minimum is 1.
+         */
+        int eSkill = actor.getClass().getSkill(actor, ESM::Skill::Enchant);
+        const float result = castCost - (castCost / 100) * (eSkill - 10);
+
+        return static_cast<int>((result < 1) ? 1 : result);
+    }
 }

apps/openmw/mwmechanics/spellcasting.hpp

@@ -58,6 +58,8 @@ namespace MWMechanics
     float getEffectMultiplier(short effectId, const MWWorld::Ptr& actor, const MWWorld::Ptr& caster,
                               const ESM::Spell* spell = NULL, const MagicEffects* effects = NULL);
 
+    int getEffectiveEnchantmentCastCost (float castCost, const MWWorld::Ptr& actor);
+
     class CastSpell
     {
     private: