Bug #1055: Check power use and mana before starting cast animation

apps/openmw/mwbase/world.hpp

@@ -414,6 +414,13 @@ namespace MWBase
 
             virtual bool toggleGodMode() = 0;
 
+            /**
+             * @brief startSpellCast attempt to start casting a spell. Might fail immediately if conditions are not met.
+             * @param actor
+             * @return true if the spell can be casted (i.e. the animation should start)
+             */
+            virtual bool startSpellCast (const MWWorld::Ptr& actor) = 0;
+
             virtual void castSpell (const MWWorld::Ptr& actor) = 0;
 
             virtual void launchProjectile (const std::string& id, bool stack, const ESM::EffectList& effects,

apps/openmw/mwmechanics/character.cpp

@@ -505,10 +505,14 @@ bool CharacterController::updateNpcState(bool onground, bool inwater, bool isrun
             mAttackType.clear();
             if(mWeaponType == WeapType_Spell)
             {
+                // Unset casting flag, otherwise pressing the mouse button down would
+                // continue casting every frame if there is no animation
+                mPtr.getClass().getCreatureStats(mPtr).setAttackingOrSpell(false);
+
                 const MWWorld::ESMStore &store = MWBase::Environment::get().getWorld()->getStore();
 
                 const std::string spellid = stats.getSpells().getSelectedSpell();
-                if(!spellid.empty())
+                if(!spellid.empty() && MWBase::Environment::get().getWorld()->startSpellCast(mPtr))
                 {
                     static const std::string schools[] = {
                         "alteration", "conjuration", "destruction", "illusion", "mysticism", "restoration"

apps/openmw/mwmechanics/spellcasting.cpp

@@ -300,9 +300,10 @@ namespace MWMechanics
             if (item.getCellRef().mEnchantmentCharge == -1)
                 item.getCellRef().mEnchantmentCharge = enchantment->mData.mCharge;
 
-            if (mCaster.getRefData().getHandle() == "player" && item.getCellRef().mEnchantmentCharge < castCost)
+            if (item.getCellRef().mEnchantmentCharge < castCost)
             {
                 // TODO: Should there be a sound here?
+                if (mCaster.getRefData().getHandle() == "player")
                     MWBase::Environment::get().getWindowManager()->messageBox("#{sMagicInsufficientCharge}");
                 return false;
             }
@@ -370,33 +371,7 @@ namespace MWMechanics
             fatigue.setCurrent(std::max(0.f, fatigue.getCurrent() - fatigueLoss));
             stats.setFatigue(fatigue);
 
-            // Check mana
             bool fail = false;
-            DynamicStat<float> magicka = stats.getMagicka();
-            if (magicka.getCurrent() < spell->mData.mCost)
-            {
-                MWBase::Environment::get().getWindowManager()->messageBox("#{sMagicInsufficientSP}");
-                fail = true;
-            }
-
-            // Reduce mana
-            if (!fail)
-            {
-                magicka.setCurrent(magicka.getCurrent() - spell->mData.mCost);
-                stats.setMagicka(magicka);
-            }
-
-            // If this is a power, check if it was already used in last 24h
-            if (!fail && spell->mData.mType & ESM::Spell::ST_Power)
-            {
-                if (stats.canUsePower(spell->mId))
-                    stats.usePower(spell->mId);
-                else
-                {
-                    MWBase::Environment::get().getWindowManager()->messageBox("#{sPowerAlreadyUsed}");
-                    fail = true;
-                }
-            }
 
             // Check success
             int successChance = getSpellSuccessChance(spell, mCaster);

apps/openmw/mwworld/worldimp.cpp

@@ -2049,15 +2049,56 @@ namespace MWWorld
         }
     }
 
+    bool World::startSpellCast(const Ptr &actor)
+    {
+        MWMechanics::CreatureStats& stats = actor.getClass().getCreatureStats(actor);
+
+        std::string message;
+        bool fail = false;
+        bool isPlayer = (actor == getPlayer().getPlayer());
+
+        std::string selectedSpell = stats.getSpells().getSelectedSpell();
+
+        if (!selectedSpell.empty())
+        {
+            const ESM::Spell* spell = getStore().get<ESM::Spell>().search(selectedSpell);
+
+            // Check mana
+            MWMechanics::DynamicStat<float> magicka = stats.getMagicka();
+            if (magicka.getCurrent() < spell->mData.mCost)
+            {
+                message = "#{sMagicInsufficientSP}";
+                fail = true;
+            }
+
+            // If this is a power, check if it was already used in the last 24h
+            if (!fail && spell->mData.mType & ESM::Spell::ST_Power)
+            {
+                if (stats.canUsePower(spell->mId))
+                    stats.usePower(spell->mId);
+                else
+                {
+                    message = "#{sPowerAlreadyUsed}";
+                    fail = true;
+                }
+            }
+
+            // Reduce mana
+            magicka.setCurrent(magicka.getCurrent() - spell->mData.mCost);
+            stats.setMagicka(magicka);
+        }
+
+        if (isPlayer && fail)
+            MWBase::Environment::get().getWindowManager()->messageBox(message);
+
+        return !fail;
+    }
+
     void World::castSpell(const Ptr &actor)
     {
         MWMechanics::CreatureStats& stats = actor.getClass().getCreatureStats(actor);
         InventoryStore& inv = actor.getClass().getInventoryStore(actor);
 
-        // Unset casting flag, otherwise pressing the mouse button down would continue casting every frame if using an enchantment
-        // (which casts instantly without an animation)
-        stats.setAttackingOrSpell(false);
-
         MWWorld::Ptr target = getFacedObject();
 
         std::string selectedSpell = stats.getSpells().getSelectedSpell();

apps/openmw/mwworld/worldimp.hpp

@@ -499,6 +499,17 @@ namespace MWWorld
 
             virtual bool toggleGodMode();
 
+            /**
+             * @brief startSpellCast attempt to start casting a spell. Might fail immediately if conditions are not met.
+             * @param actor
+             * @return true if the spell can be casted (i.e. the animation should start)
+             */
+            virtual bool startSpellCast (const MWWorld::Ptr& actor);
+
+            /**
+             * @brief Cast the actual spell, should be called mid-animation
+             * @param actor
+             */
             virtual void castSpell (const MWWorld::Ptr& actor);
 
             virtual void launchProjectile (const std::string& id, bool stack, const ESM::EffectList& effects,