OpenMW/apps/openmw/mwmechanics/spellabsorption.cpp

#include "spellabsorption.hpp"

#include <components/misc/rng.hpp>

#include "../mwbase/environment.hpp"
#include "../mwbase/world.hpp"

#include "../mwrender/animation.hpp"

#include "../mwworld/class.hpp"
#include "../mwworld/esmstore.hpp"
#include "../mwworld/inventorystore.hpp"

#include "creaturestats.hpp"
#include "spellutil.hpp"

namespace MWMechanics
{
    float getProbability(const MWMechanics::ActiveSpells& activeSpells)
    {
        float probability = 0.f;
        for(const auto& params : activeSpells)
        {
            for(const auto& effect : params.getEffects())
            {
                if(effect.mEffectId == ESM::MagicEffect::SpellAbsorption)
                {
                    if(probability == 0.f)
                        probability = effect.mMagnitude / 100;
                    else
                    {
                        // If there are different sources of SpellAbsorption effect, multiply failing probability for all effects.
                        // Real absorption probability will be the (1 - total fail chance) in this case.
                        float failProbability = 1.f - probability;
                        failProbability *= 1.f - effect.mMagnitude / 100;
                        probability = 1.f - failProbability;
                    }
                }
            }
        }
        return static_cast<int>(probability * 100);
    }

    bool absorbSpell (const std::string& spellId, const MWWorld::Ptr& caster, const MWWorld::Ptr& target)
    {
        if (spellId.empty() || target.isEmpty() || caster == target || !target.getClass().isActor())
            return false;

        CreatureStats& stats = target.getClass().getCreatureStats(target);
        if (stats.getMagicEffects().get(ESM::MagicEffect::SpellAbsorption).getMagnitude() <= 0.f)
            return false;

        int chance = getProbability(stats.getActiveSpells());
        if (Misc::Rng::roll0to99() >= chance)
            return false;

        const auto& esmStore = MWBase::Environment::get().getWorld()->getStore();
        const ESM::Static* absorbStatic = esmStore.get<ESM::Static>().find("VFX_Absorb");
        MWRender::Animation* animation = MWBase::Environment::get().getWorld()->getAnimation(target);
        if (animation && !absorbStatic->mModel.empty())
            animation->addEffect( "meshes\\" + absorbStatic->mModel, ESM::MagicEffect::SpellAbsorption, false, std::string());
        const ESM::Spell* spell = esmStore.get<ESM::Spell>().search(spellId);
        int spellCost = 0;
        if (spell)
        {
            spellCost = MWMechanics::calcSpellCost(*spell);
        }
        else
        {
            const ESM::Enchantment* enchantment = esmStore.get<ESM::Enchantment>().search(spellId);
            if (enchantment)
                spellCost = getEffectiveEnchantmentCastCost(static_cast<float>(enchantment->mData.mCost), caster);
        }

        // Magicka is increased by the cost of the spell
        DynamicStat<float> magicka = stats.getMagicka();
        magicka.setCurrent(magicka.getCurrent() + spellCost);
        stats.setMagicka(magicka);
        return true;
    }

}