Merge branch 'refactor/prng-2' into 'master'

Save random state and refactor usage of generators

See merge request OpenMW/openmw!1715

apps/openmw/mwbase/world.hpp

@@ -9,6 +9,7 @@
 #include <deque>
 
 #include <components/esm3/cellid.hpp>
+#include <components/misc/rng.hpp>
 
 #include <osg/Timer>
 
@@ -111,6 +112,9 @@ namespace MWBase
 
             virtual ~World() {}
 
+            virtual void setRandomSeed(uint32_t seed) = 0;
+            ///< \param seed The seed used when starting a new game.
+
             virtual void startNewGame (bool bypass) = 0;
             ///< \param bypass Bypass regular game start.
 
@@ -658,6 +662,8 @@ namespace MWBase
             virtual void reportStats(unsigned int frameNumber, osg::Stats& stats) const = 0;
 
             virtual std::vector<MWWorld::Ptr> getAll(const std::string& id) = 0;
+
+            virtual Misc::Rng::Generator& getPrng() = 0;
     };
 }
 

apps/openmw/mwclass/activator.cpp

@@ -120,7 +120,8 @@ namespace MWClass
         if(actor.getClass().isNpc() && actor.getClass().getNpcStats(actor).isWerewolf())
         {
             const MWWorld::ESMStore &store = MWBase::Environment::get().getWorld()->getStore();
-            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfActivator");
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfActivator", prng);
 
             std::shared_ptr<MWWorld::Action> action(new MWWorld::FailedAction("#{sWerewolfRefusal}"));
             if(sound) action->setSound(sound->mId);
@@ -156,6 +157,7 @@ namespace MWClass
         int type = getSndGenTypeFromName(name);
 
         std::vector<const ESM::SoundGenerator*> fallbacksounds;
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
         if (!creatureId.empty())
         {
             std::vector<const ESM::SoundGenerator*> sounds;
@@ -168,9 +170,9 @@ namespace MWClass
             }
 
             if (!sounds.empty())
-                return sounds[Misc::Rng::rollDice(sounds.size())]->mSound;
+                return sounds[Misc::Rng::rollDice(sounds.size(), prng)]->mSound;
             if (!fallbacksounds.empty())
-                return fallbacksounds[Misc::Rng::rollDice(fallbacksounds.size())]->mSound;
+                return fallbacksounds[Misc::Rng::rollDice(fallbacksounds.size(), prng)]->mSound;
         }
         else
         {
@@ -180,7 +182,7 @@ namespace MWClass
                     fallbacksounds.push_back(&*sound);
 
             if (!fallbacksounds.empty())
-                return fallbacksounds[Misc::Rng::rollDice(fallbacksounds.size())]->mSound;
+                return fallbacksounds[Misc::Rng::rollDice(fallbacksounds.size(), prng)]->mSound;
         }
 
         return std::string();

apps/openmw/mwclass/book.cpp

@@ -56,7 +56,8 @@ namespace MWClass
         if(actor.getClass().isNpc() && actor.getClass().getNpcStats(actor).isWerewolf())
         {
             const MWWorld::ESMStore &store = MWBase::Environment::get().getWorld()->getStore();
-            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfItem");
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfItem", prng);
 
             std::shared_ptr<MWWorld::Action> action(new MWWorld::FailedAction("#{sWerewolfRefusal}"));
             if(sound) action->setSound(sound->mId);

apps/openmw/mwclass/container.cpp

@@ -32,7 +32,8 @@ namespace MWClass
 {
     ContainerCustomData::ContainerCustomData(const ESM::Container& container, MWWorld::CellStore* cell)
     {
-        unsigned int seed = Misc::Rng::rollDice(std::numeric_limits<int>::max());
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+        unsigned int seed = Misc::Rng::rollDice(std::numeric_limits<int>::max(), prng);
         // setting ownership not needed, since taking items from a container inherits the
         // container's owner automatically
         mStore.fillNonRandom(container.mInventory, "", seed);
@@ -139,7 +140,8 @@ namespace MWClass
         if(actor.getClass().isNpc() && actor.getClass().getNpcStats(actor).isWerewolf())
         {
             const MWWorld::ESMStore &store = MWBase::Environment::get().getWorld()->getStore();
-            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfContainer");
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfContainer", prng);
 
             std::shared_ptr<MWWorld::Action> action(new MWWorld::FailedAction("#{sWerewolfRefusal}"));
             if(sound) action->setSound(sound->mId);

apps/openmw/mwclass/creature.cpp

@@ -159,7 +159,8 @@ namespace MWClass
 
             resetter.mPtr = {};
 
-            getContainerStore(ptr).fill(ref->mBase->mInventory, ptr.getCellRef().getRefId());
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            getContainerStore(ptr).fill(ref->mBase->mInventory, ptr.getCellRef().getRefId(), prng);
 
             if (hasInventory)
                 getInventoryStore(ptr).autoEquip(ptr);
@@ -264,8 +265,8 @@ namespace MWClass
         osg::Vec3f hitPosition (result.second);
 
         float hitchance = MWMechanics::getHitChance(ptr, victim, ref->mBase->mData.mCombat);
-
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
-        if(Misc::Rng::roll0to99() >= hitchance)
+        if(Misc::Rng::roll0to99(prng) >= hitchance)
         {
             victim.getClass().onHit(victim, 0.0f, false, MWWorld::Ptr(), ptr, osg::Vec3f(), false);
             MWMechanics::reduceWeaponCondition(0.f, false, weapon, ptr);
@@ -392,7 +393,8 @@ namespace MWClass
                 float agilityTerm = stats.getAttribute(ESM::Attribute::Agility).getModified() * getGmst().fKnockDownMult->mValue.getFloat();
                 float knockdownTerm = stats.getAttribute(ESM::Attribute::Agility).getModified()
                         * getGmst().iKnockDownOddsMult->mValue.getInteger() * 0.01f + getGmst().iKnockDownOddsBase->mValue.getInteger();
-                if (ishealth && agilityTerm <= damage && knockdownTerm <= Misc::Rng::roll0to99())
+                auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+                if (ishealth && agilityTerm <= damage && knockdownTerm <= Misc::Rng::roll0to99(prng))
                     stats.setKnockedDown(true);
                 else
                     stats.setHitRecovery(true); // Is this supposed to always occur?
@@ -429,7 +431,8 @@ namespace MWClass
         if(actor.getClass().isNpc() && actor.getClass().getNpcStats(actor).isWerewolf())
         {
             const MWWorld::ESMStore &store = MWBase::Environment::get().getWorld()->getStore();
-            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfCreature");
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfCreature", prng);
 
             std::shared_ptr<MWWorld::Action> action(new MWWorld::FailedAction("#{sWerewolfRefusal}"));
             if(sound) action->setSound(sound->mId);
@@ -642,10 +645,11 @@ namespace MWClass
             }
         }
 
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
         if (!sounds.empty())
-            return sounds[Misc::Rng::rollDice(sounds.size())]->mSound;
+            return sounds[Misc::Rng::rollDice(sounds.size(), prng)]->mSound;
         if (!fallbacksounds.empty())
-            return fallbacksounds[Misc::Rng::rollDice(fallbacksounds.size())]->mSound;
+            return fallbacksounds[Misc::Rng::rollDice(fallbacksounds.size(), prng)]->mSound;
 
         return std::string();
     }

apps/openmw/mwclass/creaturelevlist.cpp

@@ -127,7 +127,8 @@ namespace MWClass
         MWWorld::LiveCellRef<ESM::CreatureLevList> *ref =
             ptr.get<ESM::CreatureLevList>();
 
-        std::string id = MWMechanics::getLevelledItem(ref->mBase, true);
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+        std::string id = MWMechanics::getLevelledItem(ref->mBase, true, prng);
 
         if (!id.empty())
         {

apps/openmw/mwclass/npc.cpp

@@ -394,7 +394,8 @@ namespace MWClass
 
             // inventory
             // setting ownership is used to make the NPC auto-equip his initial equipment only, and not bartered items
-            getInventoryStore(ptr).fill(ref->mBase->mInventory, ptr.getCellRef().getRefId());
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            getInventoryStore(ptr).fill(ref->mBase->mInventory, ptr.getCellRef().getRefId(), prng);
 
             getInventoryStore(ptr).autoEquip(ptr);
         }
@@ -584,7 +585,7 @@ namespace MWClass
 
         float hitchance = MWMechanics::getHitChance(ptr, victim, getSkill(ptr, weapskill));
 
-        if (Misc::Rng::roll0to99() >= hitchance)
+        if (Misc::Rng::roll0to99(world->getPrng()) >= hitchance)
         {
             othercls.onHit(victim, 0.0f, false, weapon, ptr, osg::Vec3f(), false);
             MWMechanics::reduceWeaponCondition(0.f, false, weapon, ptr);
@@ -726,15 +727,16 @@ namespace MWClass
             const MWWorld::ESMStore &store = MWBase::Environment::get().getWorld()->getStore();
             const GMST& gmst = getGmst();
 
-            int chance = store.get<ESM::GameSetting>().find("iVoiceHitOdds")->mValue.getInteger();
+            int chance = store.get<ESM::GameSetting>().find("iVoiceHitOdds")->mValue.getInteger(); 
-            if (Misc::Rng::roll0to99() < chance)
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            if (Misc::Rng::roll0to99(prng) < chance)
                 MWBase::Environment::get().getDialogueManager()->say(ptr, "hit");
 
             // Check for knockdown
             float agilityTerm = stats.getAttribute(ESM::Attribute::Agility).getModified() * gmst.fKnockDownMult->mValue.getFloat();
             float knockdownTerm = stats.getAttribute(ESM::Attribute::Agility).getModified()
                     * gmst.iKnockDownOddsMult->mValue.getInteger() * 0.01f + gmst.iKnockDownOddsBase->mValue.getInteger();
-            if (ishealth && agilityTerm <= damage && knockdownTerm <= Misc::Rng::roll0to99())
+            if (ishealth && agilityTerm <= damage && knockdownTerm <= Misc::Rng::roll0to99(prng))
                 stats.setKnockedDown(true);
             else
                 stats.setHitRecovery(true); // Is this supposed to always occur?
@@ -757,7 +759,7 @@ namespace MWClass
                     MWWorld::InventoryStore::Slot_RightPauldron, MWWorld::InventoryStore::Slot_RightPauldron,
                     MWWorld::InventoryStore::Slot_LeftGauntlet, MWWorld::InventoryStore::Slot_RightGauntlet
                 };
-                int hitslot = hitslots[Misc::Rng::rollDice(20)];
+                int hitslot = hitslots[Misc::Rng::rollDice(20, prng)];
 
                 float unmitigatedDamage = damage;
                 float x = damage / (damage + getArmorRating(ptr));
@@ -773,7 +775,7 @@ namespace MWClass
                 // If there's no item in the carried left slot or if it is not a shield redistribute the hit.
                 if (!hasArmor && hitslot == MWWorld::InventoryStore::Slot_CarriedLeft)
                 {
-                    if (Misc::Rng::rollDice(2) == 0)
+                    if (Misc::Rng::rollDice(2, prng) == 0)
                         hitslot = MWWorld::InventoryStore::Slot_Cuirass;
                     else
                         hitslot = MWWorld::InventoryStore::Slot_LeftPauldron;
@@ -865,7 +867,8 @@ namespace MWClass
         if(actor.getClass().isNpc() && actor.getClass().getNpcStats(actor).isWerewolf())
         {
             const MWWorld::ESMStore &store = MWBase::Environment::get().getWorld()->getStore();
-            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfNPC");
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfNPC", prng);
 
             std::shared_ptr<MWWorld::Action> action(new MWWorld::FailedAction("#{sWerewolfRefusal}"));
             if(sound) action->setSound(sound->mId);

apps/openmw/mwgui/jailscreen.cpp

@@ -87,7 +87,8 @@ namespace MWGui
         std::set<int> skills;
         for (int day=0; day<mDays; ++day)
         {
-            int skill = Misc::Rng::rollDice(ESM::Skill::Length);
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            int skill = Misc::Rng::rollDice(ESM::Skill::Length, prng);
             skills.insert(skill);
 
             MWMechanics::SkillValue& value = player.getClass().getNpcStats(player).getSkill(skill);

apps/openmw/mwgui/pickpocketitemmodel.cpp

@@ -24,13 +24,13 @@ namespace MWGui
         float chance = player.getClass().getSkill(player, ESM::Skill::Sneak);
 
         mSourceModel->update();
-
         // build list of items that player is unable to find when attempts to pickpocket.
         if (hideItems)
         {
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
             for (size_t i = 0; i<mSourceModel->getItemCount(); ++i)
             {
-                if (Misc::Rng::roll0to99() > chance)
+                if (Misc::Rng::roll0to99(prng) > chance)
                     mHiddenItems.push_back(mSourceModel->getItem(i));
             }
         }

apps/openmw/mwgui/waitdialog.cpp

@@ -191,7 +191,7 @@ namespace MWGui
                 if (!region->mSleepList.empty())
                 {
                     // figure out if player will be woken while sleeping
-                    int x = Misc::Rng::rollDice(hoursToWait);
+                    int x = Misc::Rng::rollDice(hoursToWait, world->getPrng());
                     float fSleepRandMod = world->getStore().get<ESM::GameSetting>().find("fSleepRandMod")->mValue.getFloat();
                     if (x < fSleepRandMod * hoursToWait)
                     {

apps/openmw/mwmechanics/actor.cpp

@@ -60,6 +60,11 @@ namespace MWMechanics
         mIsTurningToPlayer = turning;
     }
 
+    Misc::TimerStatus Actor::updateEngageCombatTimer(float duration)
+    {
+        return mEngageCombat.update(duration, MWBase::Environment::get().getWorld()->getPrng());
+    }
+
     void Actor::setPositionAdjusted(bool adjusted)
     {
         mPositionAdjusted = adjusted;

apps/openmw/mwmechanics/actor.hpp

@@ -43,10 +43,7 @@ namespace MWMechanics
         bool isTurningToPlayer() const;
         void setTurningToPlayer(bool turning);
 
-        Misc::TimerStatus updateEngageCombatTimer(float duration)
+        Misc::TimerStatus updateEngageCombatTimer(float duration);
-        {
-            return mEngageCombat.update(duration);
-        }
 
         void setPositionAdjusted(bool adjusted);
         bool getPositionAdjusted() const;
@@ -57,7 +54,7 @@ namespace MWMechanics
         float mTargetAngleRadians{0.f};
         GreetingState mGreetingState{Greet_None};
         bool mIsTurningToPlayer{false};
-        Misc::DeviatingPeriodicTimer mEngageCombat{1.0f, 0.25f, Misc::Rng::deviate(0, 0.25f)};
+        Misc::DeviatingPeriodicTimer mEngageCombat{1.0f, 0.25f, Misc::Rng::deviate(0, 0.25f, MWBase::Environment::get().getWorld()->getPrng())};
         bool mPositionAdjusted;
     };
 

apps/openmw/mwmechanics/actors.cpp

@@ -305,7 +305,7 @@ namespace MWMechanics
         // We chose to use the chance MW would have when run at 60 FPS with the default value of the GMST.
         const float delta = MWBase::Environment::get().getFrameDuration() * 6.f;
         static const float fVoiceIdleOdds = world->getStore().get<ESM::GameSetting>().find("fVoiceIdleOdds")->mValue.getFloat();
-        if (Misc::Rng::rollProbability() * 10000.f < fVoiceIdleOdds * delta && world->getLOS(getPlayer(), actor))
+        if (Misc::Rng::rollProbability(world->getPrng()) * 10000.f < fVoiceIdleOdds * delta && world->getLOS(getPlayer(), actor))
             MWBase::Environment::get().getDialogueManager()->say(actor, "idle");
     }
 

apps/openmw/mwmechanics/aiavoiddoor.cpp

@@ -80,7 +80,8 @@ bool MWMechanics::AiAvoidDoor::isStuck(const osg::Vec3f& actorPos) const
 
 void MWMechanics::AiAvoidDoor::adjustDirection()
 {
-    mDirection = Misc::Rng::rollDice(MAX_DIRECTIONS);
+    auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+    mDirection = Misc::Rng::rollDice(MAX_DIRECTIONS, prng);
 }
 
 float MWMechanics::AiAvoidDoor::getAdjustedAngle() const

apps/openmw/mwmechanics/aicombat.cpp

@@ -370,7 +370,8 @@ namespace MWMechanics
 
                             if (!points.empty())
                             {
-                                ESM::Pathgrid::Point dest = points[Misc::Rng::rollDice(points.size())];
+                                auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+                                ESM::Pathgrid::Point dest = points[Misc::Rng::rollDice(points.size(), prng)];
                                 coords.toWorld(dest);
 
                                 state = AiCombatStorage::FleeState_RunToDestination;
@@ -464,8 +465,38 @@ namespace MWMechanics
         sequence.mPackages.push_back(std::move(package));
     }
 
+
+    AiCombatStorage::AiCombatStorage() :
+        mAttackCooldown(0.0f),
+        mReaction(MWBase::Environment::get().getWorld()->getPrng()),
+        mTimerCombatMove(0.0f),
+        mReadyToAttack(false),
+        mAttack(false),
+        mAttackRange(0.0f),
+        mCombatMove(false),
+        mRotateMove(false),
+        mLastTargetPos(0, 0, 0),
+        mCell(nullptr),
+        mCurrentAction(),
+        mActionCooldown(0.0f),
+        mStrength(),
+        mForceNoShortcut(false),
+        mShortcutFailPos(),
+        mMovement(),
+        mFleeState(FleeState_None),
+        mLOS(false),
+        mUpdateLOSTimer(0.0f),
+        mFleeBlindRunTimer(0.0f),
+        mUseCustomDestination(false),
+        mCustomDestination()
+    {
+
+    }
+
     void AiCombatStorage::startCombatMove(bool isDistantCombat, float distToTarget, float rangeAttack, const MWWorld::Ptr& actor, const MWWorld::Ptr& target)
     {
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+
         // get the range of the target's weapon
         MWWorld::Ptr targetWeapon = MWWorld::Ptr();
         const MWWorld::Class& targetClass = target.getClass();
@@ -483,7 +514,7 @@ namespace MWMechanics
         
         if (mMovement.mPosition[0] || mMovement.mPosition[1])
         {
-            mTimerCombatMove = 0.1f + 0.1f * Misc::Rng::rollClosedProbability();
+            mTimerCombatMove = 0.1f + 0.1f * Misc::Rng::rollClosedProbability(prng);
             mCombatMove = true;
         }
         else if (isDistantCombat)
@@ -537,11 +568,11 @@ namespace MWMechanics
             // if actor is within range of target's weapon.
             if (std::abs(angleToTarget) > osg::PI / 4)
                 moveDuration = 0.2f;
-            else if (distToTarget <= rangeAttackOfTarget && Misc::Rng::rollClosedProbability() < 0.25)
+            else if (distToTarget <= rangeAttackOfTarget && Misc::Rng::rollClosedProbability(prng) < 0.25)
-                moveDuration = 0.1f + 0.1f * Misc::Rng::rollClosedProbability();
+                moveDuration = 0.1f + 0.1f * Misc::Rng::rollClosedProbability(prng);
             if (moveDuration > 0)
             {
-                mMovement.mPosition[0] = Misc::Rng::rollProbability() < 0.5 ? 1.0f : -1.0f; // to the left/right
+                mMovement.mPosition[0] = Misc::Rng::rollProbability(prng) < 0.5 ? 1.0f : -1.0f; // to the left/right
                 mTimerCombatMove = moveDuration;
                 mCombatMove = true;
             }
@@ -580,7 +611,8 @@ namespace MWMechanics
                 if (!distantCombat)
                     characterController.setAIAttackType(chooseBestAttack(weapon));
 
-                mStrength = Misc::Rng::rollClosedProbability();
+                auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+                mStrength = Misc::Rng::rollClosedProbability(prng);
 
                 const MWWorld::ESMStore &store = MWBase::Environment::get().getWorld()->getStore();
 
@@ -592,11 +624,11 @@ namespace MWMechanics
 
                 // Say a provoking combat phrase
                 const int iVoiceAttackOdds = store.get<ESM::GameSetting>().find("iVoiceAttackOdds")->mValue.getInteger();
-                if (Misc::Rng::roll0to99() < iVoiceAttackOdds)
+                if (Misc::Rng::roll0to99(prng) < iVoiceAttackOdds)
                 {
                     MWBase::Environment::get().getDialogueManager()->say(actor, "attack");
                 }
-                mAttackCooldown = std::min(baseDelay + 0.01 * Misc::Rng::roll0to99(), baseDelay + 0.9);
+                mAttackCooldown = std::min(baseDelay + 0.01 * Misc::Rng::roll0to99(prng), baseDelay + 0.9);
             }
             else
                 mAttackCooldown -= AI_REACTION_TIME;
@@ -657,7 +689,8 @@ std::string chooseBestAttack(const ESM::Weapon* weapon)
         int chop = (weapon->mData.mChop[0] + weapon->mData.mChop[1])/2;
         int thrust = (weapon->mData.mThrust[0] + weapon->mData.mThrust[1])/2;
 
-        float roll = Misc::Rng::rollClosedProbability() * (slash + chop + thrust);
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+        float roll = Misc::Rng::rollClosedProbability(prng) * (slash + chop + thrust);
         if(roll <= slash)
             attackType = "slash";
         else if(roll <= (slash + thrust))

apps/openmw/mwmechanics/aicombat.hpp

@@ -59,29 +59,7 @@ namespace MWMechanics
         bool mUseCustomDestination;
         osg::Vec3f mCustomDestination;
 
-        AiCombatStorage():
+        AiCombatStorage();
-        mAttackCooldown(0.0f),
-        mTimerCombatMove(0.0f),
-        mReadyToAttack(false),
-        mAttack(false),
-        mAttackRange(0.0f),
-        mCombatMove(false),
-        mRotateMove(false),
-        mLastTargetPos(0,0,0),
-        mCell(nullptr),
-        mCurrentAction(),
-        mActionCooldown(0.0f),
-        mStrength(),
-        mForceNoShortcut(false),
-        mShortcutFailPos(),
-        mMovement(),
-        mFleeState(FleeState_None),
-        mLOS(false),
-        mUpdateLOSTimer(0.0f),
-        mFleeBlindRunTimer(0.0f),
-        mUseCustomDestination(false),
-        mCustomDestination()
-        {}
 
         void startCombatMove(bool isDistantCombat, float distToTarget, float rangeAttack, const MWWorld::Ptr& actor, const MWWorld::Ptr& target);
         void updateCombatMove(float duration);

apps/openmw/mwmechanics/aipackage.cpp

@@ -44,6 +44,7 @@ namespace
 MWMechanics::AiPackage::AiPackage(AiPackageTypeId typeId, const Options& options) :
     mTypeId(typeId),
     mOptions(options),
+    mReaction(MWBase::Environment::get().getWorld()->getPrng()),
     mTargetActorRefId(""),
     mTargetActorId(-1),
     mRotateOnTheRunChecks(0),

apps/openmw/mwmechanics/aitimer.hpp

@@ -13,13 +13,20 @@ namespace MWMechanics
         public:
             static constexpr float sDeviation = 0.1f;
 
-            Misc::TimerStatus update(float duration) { return mImpl.update(duration); }
+            AiReactionTimer(Misc::Rng::Generator& prng)
+                : mPrng{ prng }
+                , mImpl{ AI_REACTION_TIME, sDeviation, Misc::Rng::deviate(0, sDeviation, prng) }
+            {
+            }
 
-            void reset() { mImpl.reset(Misc::Rng::deviate(0, sDeviation)); }
+            Misc::TimerStatus update(float duration) { return mImpl.update(duration, mPrng); }
+
+            void reset() { mImpl.reset(Misc::Rng::deviate(0, sDeviation, mPrng)); }
 
         private:
-            Misc::DeviatingPeriodicTimer mImpl {AI_REACTION_TIME, sDeviation,
+            Misc::Rng::Generator& mPrng;
-                                                Misc::Rng::deviate(0, sDeviation)};
+            Misc::DeviatingPeriodicTimer mImpl;
+
     };
 }
 

apps/openmw/mwmechanics/aitravel.cpp

@@ -36,11 +36,13 @@ namespace MWMechanics
 {
     AiTravel::AiTravel(float x, float y, float z, bool repeat, AiTravel*)
         : TypedAiPackage<AiTravel>(repeat), mX(x), mY(y), mZ(z), mHidden(false)
+        , mDestinationCheck(MWBase::Environment::get().getWorld()->getPrng())
     {
     }
 
     AiTravel::AiTravel(float x, float y, float z, AiInternalTravel* derived)
         : TypedAiPackage<AiTravel>(derived), mX(x), mY(y), mZ(z), mHidden(true)
+        , mDestinationCheck(MWBase::Environment::get().getWorld()->getPrng())
     {
     }
 
@@ -51,6 +53,7 @@ namespace MWMechanics
 
     AiTravel::AiTravel(const ESM::AiSequence::AiTravel *travel)
         : TypedAiPackage<AiTravel>(travel->mRepeat), mX(travel->mData.mX), mY(travel->mData.mY), mZ(travel->mData.mZ), mHidden(false)
+        , mDestinationCheck(MWBase::Environment::get().getWorld()->getPrng())
     {
         // Hidden ESM::AiSequence::AiTravel package should be converted into MWMechanics::AiInternalTravel type
         assert(!travel->mHidden);

apps/openmw/mwmechanics/aiwander.cpp

@@ -59,7 +59,8 @@ namespace MWMechanics
 
         osg::Vec3f getRandomPointAround(const osg::Vec3f& position, const float distance)
         {
-            const float randomDirection = Misc::Rng::rollClosedProbability() * 2.0f * osg::PI;
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            const float randomDirection = Misc::Rng::rollClosedProbability(prng) * 2.0f * osg::PI;
             osg::Matrixf rotation;
             rotation.makeRotate(randomDirection, osg::Vec3f(0.0, 0.0, 1.0));
             return position + osg::Vec3f(distance, 0.0, 0.0) * rotation;
@@ -102,6 +103,22 @@ namespace MWMechanics
         {
             return std::vector<unsigned char>(std::begin(idle), std::end(idle));
         }
+
+    }
+
+    AiWanderStorage::AiWanderStorage() :
+        mReaction(MWBase::Environment::get().getWorld()->getPrng()),
+        mState(Wander_ChooseAction),
+        mIsWanderingManually(false),
+        mCanWanderAlongPathGrid(true),
+        mIdleAnimation(0),
+        mBadIdles(),
+        mPopulateAvailableNodes(true),
+        mAllowedNodes(),
+        mTrimCurrentNode(false),
+        mCheckIdlePositionTimer(0),
+        mStuckCount(0)
+    {
     }
 
     AiWander::AiWander(int distance, int duration, int timeOfDay, const std::vector<unsigned char>& idle, bool repeat):
@@ -250,9 +267,10 @@ namespace MWMechanics
             getAllowedNodes(actor, actor.getCell()->getCell(), storage);
         }
 
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
         if (canActorMoveByZAxis(actor) && mDistance > 0) {
             // Typically want to idle for a short time before the next wander
-            if (Misc::Rng::rollDice(100) >= 92 && storage.mState != AiWanderStorage::Wander_Walking) {
+            if (Misc::Rng::rollDice(100, prng) >= 92 && storage.mState != AiWanderStorage::Wander_Walking) {
                 wanderNearStart(actor, storage, mDistance);
             }
 
@@ -262,7 +280,7 @@ namespace MWMechanics
         // randomly idle or wander near spawn point
         else if(storage.mAllowedNodes.empty() && mDistance > 0 && !storage.mIsWanderingManually) {
             // Typically want to idle for a short time before the next wander
-            if (Misc::Rng::rollDice(100) >= 96) {
+            if (Misc::Rng::rollDice(100, prng) >= 96) {
                 wanderNearStart(actor, storage, mDistance);
             } else {
                 storage.setState(AiWanderStorage::Wander_IdleNow);
@@ -330,10 +348,12 @@ namespace MWMechanics
         const auto navigator = world->getNavigator();
         const auto navigatorFlags = getNavigatorFlags(actor);
         const auto areaCosts = getAreaCosts(actor);
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
 
         do {
+
             // Determine a random location within radius of original position
-            const float wanderRadius = (0.2f + Misc::Rng::rollClosedProbability() * 0.8f) * wanderDistance;
+            const float wanderRadius = (0.2f + Misc::Rng::rollClosedProbability(prng) * 0.8f) * wanderDistance;
             if (!isWaterCreature && !isFlyingCreature)
             {
                 // findRandomPointAroundCircle uses wanderDistance as limit for random and not as exact distance
@@ -544,7 +564,8 @@ namespace MWMechanics
 
     void AiWander::setPathToAnAllowedNode(const MWWorld::Ptr& actor, AiWanderStorage& storage, const ESM::Position& actorPos)
     {
-        unsigned int randNode = Misc::Rng::rollDice(storage.mAllowedNodes.size());
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+        unsigned int randNode = Misc::Rng::rollDice(storage.mAllowedNodes.size(), prng);
         ESM::Pathgrid::Point dest(storage.mAllowedNodes[randNode]);
 
         ToWorldCoordinates(dest, actor.getCell()->getCell());
@@ -650,11 +671,11 @@ namespace MWMechanics
 
         for(unsigned int counter = 0; counter < mIdle.size(); counter++)
         {
-            static float fIdleChanceMultiplier = MWBase::Environment::get().getWorld()->getStore()
+            MWBase::World* world = MWBase::Environment::get().getWorld();
-                .get<ESM::GameSetting>().find("fIdleChanceMultiplier")->mValue.getFloat();
+            static float fIdleChanceMultiplier = world->getStore().get<ESM::GameSetting>().find("fIdleChanceMultiplier")->mValue.getFloat();
 
             unsigned short idleChance = static_cast<unsigned short>(fIdleChanceMultiplier * mIdle[counter]);
-            unsigned short randSelect = (int)(Misc::Rng::rollProbability() * int(100 / fIdleChanceMultiplier));
+            unsigned short randSelect = (int)(Misc::Rng::rollProbability(world->getPrng()) * int(100 / fIdleChanceMultiplier));
             if(randSelect < idleChance && randSelect > idleRoll)
             {
                 selectedAnimation = counter + GroupIndex_MinIdle;
@@ -678,7 +699,8 @@ namespace MWMechanics
         if (storage.mAllowedNodes.empty())
             return;
 
-        int index = Misc::Rng::rollDice(storage.mAllowedNodes.size());
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+        int index = Misc::Rng::rollDice(storage.mAllowedNodes.size(), prng);
         ESM::Pathgrid::Point dest = storage.mAllowedNodes[index];
         ESM::Pathgrid::Point worldDest = dest;
         ToWorldCoordinates(worldDest, actor.getCell()->getCell());
@@ -700,7 +722,7 @@ namespace MWMechanics
             // AI will try to move the NPC towards every neighboring node until suitable place will be found
             for (int i = 0; i < initialSize; i++)
             {
-                int randomIndex = Misc::Rng::rollDice(points.size());
+                int randomIndex = Misc::Rng::rollDice(points.size(), prng);
                 ESM::Pathgrid::Point connDest = points[randomIndex];
 
                 // add an offset towards random neighboring node

apps/openmw/mwmechanics/aiwander.hpp

@@ -55,18 +55,7 @@ namespace MWMechanics
         float mCheckIdlePositionTimer;
         int mStuckCount;
 
-        AiWanderStorage():
+        AiWanderStorage();
-            mState(Wander_ChooseAction),
-            mIsWanderingManually(false),
-            mCanWanderAlongPathGrid(true),
-            mIdleAnimation(0),
-            mBadIdles(),
-            mPopulateAvailableNodes(true),
-            mAllowedNodes(),
-            mTrimCurrentNode(false),
-            mCheckIdlePositionTimer(0),
-            mStuckCount(0)
-            {};
 
         void setState(const WanderState wanderState, const bool isManualWander = false)
         {

apps/openmw/mwmechanics/alchemy.cpp

@@ -289,7 +289,8 @@ void MWMechanics::Alchemy::addPotion (const std::string& name)
 
     newRecord.mName = name;
 
-    int index = Misc::Rng::rollDice(6);
+    auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+    int index = Misc::Rng::rollDice(6, prng);
     assert (index>=0 && index<6);
 
     static const char *meshes[] = { "standard", "bargain", "cheap", "fresh", "exclusive", "quality" };
@@ -527,8 +528,8 @@ MWMechanics::Alchemy::Result MWMechanics::Alchemy::createSingle ()
         removeIngredients();
         return Result_RandomFailure;
     }
-
+    auto& prng = MWBase::Environment::get().getWorld()->getPrng();
-    if (getAlchemyFactor() < Misc::Rng::roll0to99())
+    if (getAlchemyFactor() < Misc::Rng::roll0to99(prng))
     {
         removeIngredients();
         return Result_RandomFailure;

apps/openmw/mwmechanics/character.cpp

@@ -193,11 +193,13 @@ public:
 
 std::string CharacterController::chooseRandomGroup (const std::string& prefix, int* num) const
 {
+    auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+
     int numAnims=0;
     while (mAnimation->hasAnimation(prefix + std::to_string(numAnims+1)))
         ++numAnims;
 
-    int roll = Misc::Rng::rollDice(numAnims) + 1; // [1, numAnims]
+    int roll = Misc::Rng::rollDice(numAnims, prng) + 1; // [1, numAnims]
     if (num)
         *num = roll;
     return prefix + std::to_string(roll);
@@ -209,12 +211,13 @@ void CharacterController::refreshHitRecoilAnims(CharacterState& idle)
     bool knockdown = mPtr.getClass().getCreatureStats(mPtr).getKnockedDown();
     bool block = mPtr.getClass().getCreatureStats(mPtr).getBlock();
     bool isSwimming = MWBase::Environment::get().getWorld()->isSwimming(mPtr);
+    auto& prng = MWBase::Environment::get().getWorld()->getPrng();
     if(mHitState == CharState_None)
     {
         if ((mPtr.getClass().getCreatureStats(mPtr).getFatigue().getCurrent() < 0
                 || mPtr.getClass().getCreatureStats(mPtr).getFatigue().getBase() == 0))
         {
-            mTimeUntilWake = Misc::Rng::rollClosedProbability() * 2 + 1; // Wake up after 1 to 3 seconds
+            mTimeUntilWake = Misc::Rng::rollClosedProbability(prng) * 2 + 1; // Wake up after 1 to 3 seconds
             if (isSwimming && mAnimation->hasAnimation("swimknockout"))
             {
                 mHitState = CharState_SwimKnockOut;
@@ -678,7 +681,8 @@ void CharacterController::refreshIdleAnims(const std::string& weapShortGroup, Ch
 
                 // play until the Loop Stop key 2 to 5 times, then play until the Stop key
                 // this replicates original engine behavior for the "Idle1h" 1st-person animation
-                numLoops = 1 + Misc::Rng::rollDice(4); 
+                auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+                numLoops = 1 + Misc::Rng::rollDice(4, prng); 
             }
         }
 
@@ -1131,6 +1135,8 @@ bool CharacterController::updateCarriedLeftVisible(const int weaptype) const
 
 bool CharacterController::updateState(CharacterState idle)
 {
+    auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+
     const MWWorld::Class &cls = mPtr.getClass();
     CreatureStats &stats = cls.getCreatureStats(mPtr);
     int weaptype = ESM::Weapon::None;
@@ -1288,7 +1294,7 @@ bool CharacterController::updateState(CharacterState idle)
                 if(isWerewolf)
                 {
                     const MWWorld::ESMStore &store = MWBase::Environment::get().getWorld()->getStore();
-                    const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfEquip");
+                    const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfEquip", prng);
                     if(sound)
                     {
                         MWBase::SoundManager *sndMgr = MWBase::Environment::get().getSoundManager();
@@ -1563,7 +1569,7 @@ bool CharacterController::updateState(CharacterState idle)
                     mUpperBodyState = UpperCharState_StartToMinAttack;
                     if (isRandomAttackAnimation(mCurrentWeapon))
                     {
-                        mAttackStrength = std::min(1.f, 0.1f + Misc::Rng::rollClosedProbability());
+                        mAttackStrength = std::min(1.f, 0.1f + Misc::Rng::rollClosedProbability(prng));
                         playSwishSound(0.0f);
                     }
                 }
@@ -1596,7 +1602,7 @@ bool CharacterController::updateState(CharacterState idle)
                 // most creatures don't actually have an attack wind-up animation, so use a uniform random value
                 // (even some creatures that can use weapons don't have a wind-up animation either, e.g. Rieklings)
                 // Note: vanilla MW uses a random value for *all* non-player actors, but we probably don't need to go that far.
-                attackStrength = std::min(1.f, 0.1f + Misc::Rng::rollClosedProbability());
+                attackStrength = std::min(1.f, 0.1f + Misc::Rng::rollClosedProbability(prng));
             }
 
             if(weapclass != ESM::WeaponType::Ranged && weapclass != ESM::WeaponType::Thrown)
@@ -1606,7 +1612,7 @@ bool CharacterController::updateState(CharacterState idle)
                 if(isWerewolf)
                 {
                     const MWWorld::ESMStore &store = MWBase::Environment::get().getWorld()->getStore();
-                    const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfSwing");
+                    const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfSwing", prng);
                     if(sound)
                         sndMgr->playSound3D(mPtr, sound->mId, 1.0f, 1.0f);
                 }
@@ -2771,7 +2777,8 @@ void CharacterController::setAIAttackType(const std::string& attackType)
 
 void CharacterController::setAttackTypeRandomly(std::string& attackType)
 {
-    float random = Misc::Rng::rollProbability();
+    MWBase::World* world = MWBase::Environment::get().getWorld();
+    float random = Misc::Rng::rollProbability(world->getPrng());
     if (random >= 2/3.f)
         attackType = "thrust";
     else if (random >= 1/3.f)

apps/openmw/mwmechanics/combat.cpp

@@ -117,7 +117,8 @@ namespace MWMechanics
         const int iBlockMinChance = gmst.find("iBlockMinChance")->mValue.getInteger();
         int x = std::clamp<int>(blockerTerm - attackerTerm, iBlockMinChance, iBlockMaxChance);
 
-        if (Misc::Rng::roll0to99() < x)
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+        if (Misc::Rng::roll0to99(prng) < x)
         {
             // Reduce shield durability by incoming damage
             int shieldhealth = shield->getClass().getItemHealth(*shield);
@@ -212,7 +213,7 @@ namespace MWMechanics
 
             int skillValue = attacker.getClass().getSkill(attacker, weaponSkill);
 
-            if (Misc::Rng::roll0to99() >= getHitChance(attacker, victim, skillValue))
+            if (Misc::Rng::roll0to99(world->getPrng()) >= getHitChance(attacker, victim, skillValue))
             {
                 victim.getClass().onHit(victim, damage, false, projectile, attacker, osg::Vec3f(), false);
                 MWMechanics::reduceWeaponCondition(damage, false, weapon, attacker);
@@ -262,7 +263,7 @@ namespace MWMechanics
             if (victim != getPlayer() && !appliedEnchantment)
             {
                 float fProjectileThrownStoreChance = gmst.find("fProjectileThrownStoreChance")->mValue.getFloat();
-                if (Misc::Rng::rollProbability() < fProjectileThrownStoreChance / 100.f)
+                if (Misc::Rng::rollProbability(world->getPrng()) < fProjectileThrownStoreChance / 100.f)
                     victim.getClass().getContainerStore(victim).add(projectile, 1, victim);
             }
 
@@ -315,6 +316,7 @@ namespace MWMechanics
         bool godmode = attacker == getPlayer() && MWBase::Environment::get().getWorld()->getGodModeState();
         if (godmode)
             return;
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
         for (int i=0; i<3; ++i)
         {
             float magnitude = victim.getClass().getCreatureStats(victim).getMagicEffects().get(ESM::MagicEffect::FireShield+i).getMagnitude();
@@ -334,7 +336,7 @@ namespace MWMechanics
 
             saveTerm *= 1.25f * normalisedFatigue;
 
-            float x = std::max(0.f, saveTerm - Misc::Rng::roll0to99());
+            float x = std::max(0.f, saveTerm - Misc::Rng::roll0to99(prng));
 
             int element = ESM::MagicEffect::FireDamage;
             if (i == 1)
@@ -444,7 +446,8 @@ namespace MWMechanics
         MWBase::SoundManager *sndMgr = MWBase::Environment::get().getSoundManager();
         if(isWerewolf)
         {
-            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfHit");
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfHit", prng);
             if(sound)
                 sndMgr->playSound3D(victim, sound->mId, 1.0f, 1.0f);
         }

apps/openmw/mwmechanics/disease.hpp

@@ -52,7 +52,8 @@ namespace MWMechanics
                 continue;
 
             int x = static_cast<int>(fDiseaseXferChance * 100 * resist);
-            if (Misc::Rng::rollDice(10000) < x)
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            if (Misc::Rng::rollDice(10000, prng) < x)
             {
                 // Contracted disease!
                 actor.getClass().getCreatureStats(actor).getSpells().add(spell);

apps/openmw/mwmechanics/enchanting.cpp

@@ -76,7 +76,8 @@ namespace MWMechanics
 
         if(mSelfEnchanting)
         {
-            if(getEnchantChance() <= (Misc::Rng::roll0to99()))
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            if(getEnchantChance() <= (Misc::Rng::roll0to99(prng)))
                 return false;
 
             mEnchanter.getClass().skillUsageSucceeded (mEnchanter, ESM::Skill::Enchant, 2);

apps/openmw/mwmechanics/levelledlist.hpp

@@ -19,7 +19,7 @@ namespace MWMechanics
 {
 
     /// @return ID of resulting item, or empty if none
-    inline std::string getLevelledItem (const ESM::LevelledListBase* levItem, bool creature, Misc::Rng::Generator& prng = Misc::Rng::getGenerator())
+    inline std::string getLevelledItem (const ESM::LevelledListBase* levItem, bool creature, Misc::Rng::Generator& prng)
     {
         const std::vector<ESM::LevelledListBase::LevelItem>& items = levItem->mList;
 

apps/openmw/mwmechanics/mechanicsmanagerimp.cpp

@@ -651,7 +651,8 @@ namespace MWMechanics
         float x = 0;
         float y = 0;
 
-        int roll = Misc::Rng::roll0to99();
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+        int roll = Misc::Rng::roll0to99(prng);
 
         if (type == PT_Admire)
         {
@@ -1570,8 +1571,8 @@ namespace MWMechanics
         }
 
         float target = x - y;
-
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
-        return (Misc::Rng::roll0to99() >= target);
+        return (Misc::Rng::roll0to99(prng) >= target);
     }
 
     void MechanicsManager::startCombat(const MWWorld::Ptr &ptr, const MWWorld::Ptr &target)

apps/openmw/mwmechanics/pickpocket.cpp

@@ -41,7 +41,8 @@ namespace MWMechanics
         int iPickMaxChance = MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>()
                 .find("iPickMaxChance")->mValue.getInteger();
 
-        int roll = Misc::Rng::roll0to99();
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+        int roll = Misc::Rng::roll0to99(prng);
         if (t < pcSneak / iPickMinChance)
         {
             return (roll > int(pcSneak / iPickMinChance));

apps/openmw/mwmechanics/recharge.cpp

@@ -49,7 +49,8 @@ bool rechargeItem(const MWWorld::Ptr &item, const MWWorld::Ptr &gem)
         intelligenceTerm = 1;
 
     float x = (player.getClass().getSkill(player, ESM::Skill::Enchant) + intelligenceTerm + luckTerm) * stats.getFatigueTerm();
-    int roll = Misc::Rng::roll0to99();
+    auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+    int roll = Misc::Rng::roll0to99(prng);
     if (roll < x)
     {
         std::string soul = gem.getCellRef().getSoul();

apps/openmw/mwmechanics/repair.cpp

@@ -44,7 +44,8 @@ void Repair::repair(const MWWorld::Ptr &itemToRepair)
 
     float x = (0.1f * pcStrength + 0.1f * pcLuck + armorerSkill) * fatigueTerm;
 
-    int roll = Misc::Rng::roll0to99();
+    auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+    int roll = Misc::Rng::roll0to99(prng);
     if (roll <= x)
     {
         int y = static_cast<int>(fRepairAmountMult * toolQuality * roll);

apps/openmw/mwmechanics/security.cpp

@@ -54,7 +54,8 @@ namespace MWMechanics
             resultMessage = "#{sLockImpossible}";
         else
         {
-            if (Misc::Rng::roll0to99() <= x)
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            if (Misc::Rng::roll0to99(prng) <= x)
             {
                 lock.getCellRef().unlock();
                 resultMessage = "#{sLockSuccess}";
@@ -98,7 +99,8 @@ namespace MWMechanics
             resultMessage = "#{sTrapImpossible}";
         else
         {
-            if (Misc::Rng::roll0to99() <= x)
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            if (Misc::Rng::roll0to99(prng) <= x)
             {
                 trap.getCellRef().setTrap("");
 

apps/openmw/mwmechanics/spellcasting.cpp

@@ -87,7 +87,8 @@ namespace MWMechanics
                 : ESM::MagicEffect::ResistBlightDisease;
             float x = target.getClass().getCreatureStats(target).getMagicEffects().get(requiredResistance).getMagnitude();
 
-            if (Misc::Rng::roll0to99() <= x)
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            if (Misc::Rng::roll0to99(prng) <= x)
             {
                 // Fully resisted, show message
                 if (target == getPlayer())
@@ -339,7 +340,8 @@ namespace MWMechanics
 
                 // Check success
                 float successChance = getSpellSuccessChance(spell, mCaster, nullptr, true, false);
-                if (Misc::Rng::roll0to99() >= successChance)
+                auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+                if (Misc::Rng::roll0to99(prng) >= successChance)
                 {
                     if (mCaster == getPlayer())
                         MWBase::Environment::get().getWindowManager()->messageBox("#{sMagicSkillFail}");
@@ -403,7 +405,8 @@ namespace MWMechanics
                     + 0.1f * creatureStats.getAttribute (ESM::Attribute::Luck).getModified())
                     * creatureStats.getFatigueTerm();
 
-        int roll = Misc::Rng::roll0to99();
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+        int roll = Misc::Rng::roll0to99(prng);
         if (roll > x)
         {
             // "X has no effect on you"

apps/openmw/mwmechanics/spelleffects.cpp

@@ -35,7 +35,8 @@ namespace
     {
         if(effect.mMinMagnitude == effect.mMaxMagnitude)
             return effect.mMinMagnitude;
-        return effect.mMinMagnitude + Misc::Rng::rollDice(effect.mMaxMagnitude - effect.mMinMagnitude + 1);
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+        return effect.mMinMagnitude + Misc::Rng::rollDice(effect.mMaxMagnitude - effect.mMinMagnitude + 1, prng);
     }
 
     void modifyAiSetting(const MWWorld::Ptr& target, const ESM::ActiveEffect& effect, ESM::MagicEffect::Effects creatureEffect, MWMechanics::CreatureStats::AiSetting setting, float magnitude, bool& invalid)
@@ -305,6 +306,7 @@ namespace
             bool canAbsorb = !(effect.mFlags & ESM::ActiveEffect::Flag_Ignore_SpellAbsorption) && magnitudes.get(ESM::MagicEffect::SpellAbsorption).getMagnitude() > 0.f;
             if(canReflect || canAbsorb)
             {
+                auto& prng = MWBase::Environment::get().getWorld()->getPrng();
                 for(const auto& activeParam : stats.getActiveSpells())
                 {
                     for(const auto& activeEffect : activeParam.getEffects())
@@ -313,14 +315,14 @@ namespace
                             continue;
                         if(activeEffect.mEffectId == ESM::MagicEffect::Reflect)
                         {
-                            if(canReflect && Misc::Rng::roll0to99() < activeEffect.mMagnitude)
+                            if(canReflect && Misc::Rng::roll0to99(prng) < activeEffect.mMagnitude)
                             {
                                 return MWMechanics::MagicApplicationResult::REFLECTED;
                             }
                         }
                         else if(activeEffect.mEffectId == ESM::MagicEffect::SpellAbsorption)
                         {
-                            if(canAbsorb && Misc::Rng::roll0to99() < activeEffect.mMagnitude)
+                            if(canAbsorb && Misc::Rng::roll0to99(prng) < activeEffect.mMagnitude)
                             {
                                 absorbSpell(spellParams.getId(), caster, target);
                                 return MWMechanics::MagicApplicationResult::REMOVED;
@@ -405,8 +407,11 @@ void applyMagicEffect(const MWWorld::Ptr& target, const MWWorld::Ptr& caster, co
                 if(params.getType() == ESM::ActiveSpells::Type_Temporary)
                 {
                     const ESM::Spell* spell = MWBase::Environment::get().getWorld()->getStore().get<ESM::Spell>().search(params.getId());
-                    if(spell && spell->mData.mType == ESM::Spell::ST_Spell)
+                    if (spell && spell->mData.mType == ESM::Spell::ST_Spell)
-                        return Misc::Rng::roll0to99() < magnitude;
+                    {
+                        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+                        return Misc::Rng::roll0to99(prng) < magnitude;
+                    }
                 }
                 return false;
             }, target);

apps/openmw/mwmechanics/spellresistance.cpp

@@ -51,7 +51,8 @@ namespace MWMechanics
         if (castChance > 0)
             x *= 50 / castChance;
 
-        float roll = Misc::Rng::rollClosedProbability() * 100;
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+        float roll = Misc::Rng::rollClosedProbability(prng) * 100;
         if (magicEffect->mData.mFlags & ESM::MagicEffect::NoMagnitude)
             roll -= resistance;
 

apps/openmw/mwmechanics/trading.cpp

@@ -57,7 +57,8 @@ namespace MWMechanics
             + gmst.find("fBargainOfferBase")->mValue.getFloat()
             + int(pcTerm - npcTerm);
 
-        int roll = Misc::Rng::rollDice(100) + 1;
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+        int roll = Misc::Rng::rollDice(100, prng) + 1;
 
         // reject if roll fails
         // (or if player tries to buy things and get money)

apps/openmw/mwscript/containerextensions.cpp

@@ -61,7 +61,8 @@ namespace
             }
             else
             {
-                std::string itemId = MWMechanics::getLevelledItem(itemPtr.get<ESM::ItemLevList>()->mBase, false);
+                auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+                std::string itemId = MWMechanics::getLevelledItem(itemPtr.get<ESM::ItemLevList>()->mBase, false, prng);
                 if (itemId.empty())
                     return;
                 MWWorld::ManualRef manualRef(MWBase::Environment::get().getWorld()->getStore(), itemId, 1);

apps/openmw/mwscript/miscextensions.cpp

@@ -111,7 +111,8 @@ namespace MWScript
                         throw std::runtime_error (
                             "random: argument out of range (Don't be so negative!)");
 
-                    runtime.push (static_cast<Interpreter::Type_Float>(::Misc::Rng::rollDice(limit))); // [o, limit)
+                    auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+                    runtime.push (static_cast<Interpreter::Type_Float>(::Misc::Rng::rollDice(limit, prng))); // [o, limit)
                 }
         };
 

apps/openmw/mwstate/statemanagerimp.cpp

@@ -466,6 +466,7 @@ void MWState::StateManager::loadGame (const Character *character, const std::str
                 case ESM::REC_LEVI:
                 case ESM::REC_CREA:
                 case ESM::REC_CONT:
+                case ESM::REC_RAND:
                     MWBase::Environment::get().getWorld()->readRecord(reader, n.toInt(), contentFileMap);
                     break;
 

apps/openmw/mwworld/class.cpp

@@ -333,7 +333,8 @@ namespace MWWorld
         if(actor.getClass().isNpc() && actor.getClass().getNpcStats(actor).isWerewolf())
         {
             const MWWorld::ESMStore &store = MWBase::Environment::get().getWorld()->getStore();
-            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfItem");
+            auto& prng = MWBase::Environment::get().getWorld()->getPrng();
+            const ESM::Sound *sound = store.get<ESM::Sound>().searchRandom("WolfItem", prng);
 
             std::shared_ptr<MWWorld::Action> action(new MWWorld::FailedAction("#{sWerewolfRefusal}"));
             if(sound) action->setSound(sound->mId);

apps/openmw/mwworld/containerstore.hpp

@@ -221,7 +221,7 @@ namespace MWWorld
             virtual bool stacks (const ConstPtr& ptr1, const ConstPtr& ptr2) const;
             ///< @return true if the two specified objects can stack with each other
 
-            void fill (const ESM::InventoryList& items, const std::string& owner, Misc::Rng::Generator& seed = Misc::Rng::getGenerator());
+            void fill (const ESM::InventoryList& items, const std::string& owner, Misc::Rng::Generator& seed);
             ///< Insert items into *this.
 
             void fillNonRandom (const ESM::InventoryList& items, const std::string& owner, unsigned int seed);

apps/openmw/mwworld/store.cpp

@@ -125,7 +125,7 @@ namespace MWWorld
         return (dit != mDynamic.end());
     }
     template<typename T>
-    const T *Store<T>::searchRandom(const std::string &id) const
+    const T *Store<T>::searchRandom(const std::string &id, Misc::Rng::Generator& prng) const
     {
         std::vector<const T*> results;
         std::copy_if(mShared.begin(), mShared.end(), std::back_inserter(results),
@@ -134,7 +134,7 @@ namespace MWWorld
                     return Misc::StringUtils::ciCompareLen(id, item->mId, id.size()) == 0;
                 });
         if(!results.empty())
-            return results[Misc::Rng::rollDice(results.size())];
+            return results[Misc::Rng::rollDice(results.size(), prng)];
         return nullptr;
     }
     template<typename T>

apps/openmw/mwworld/store.hpp

@@ -10,6 +10,7 @@
 
 #include <components/esm/records.hpp>
 #include <components/misc/stringops.hpp>
+#include <components/misc/rng.hpp>
 
 #include "../mwdialogue/keywordsearch.hpp"
 
@@ -183,7 +184,7 @@ namespace MWWorld
         bool isDynamic(const std::string &id) const;
 
         /** Returns a random record that starts with the named ID, or nullptr if not found. */
-        const T *searchRandom(const std::string &id) const;
+        const T *searchRandom(const std::string &id, Misc::Rng::Generator& prng) const;
 
         // calls `search` and throws an exception if not found
         const T *find(const std::string &id) const;

apps/openmw/mwworld/worldimp.cpp

@@ -283,6 +283,9 @@ namespace MWWorld
 
         MWBase::Environment::get().getWindowManager()->updatePlayer();
         mCurrentDate->setup(mGlobalVariables);
+
+        // Initial seed.
+        mPrng.seed(mRandomSeed);
     }
 
     void World::clear()
@@ -338,6 +341,10 @@ namespace MWWorld
 
     void World::write (ESM::ESMWriter& writer, Loading::Listener& progress) const
     {
+        writer.startRecord(ESM::REC_RAND);
+        writer.writeHNOString("RAND", Misc::Rng::serialize(mPrng));
+        writer.endRecord(ESM::REC_RAND);
+
         // Active cells could have a dirty fog of war, sync it to the CellStore first
         for (CellStore* cellstore : mWorldScene->getActiveCells())
         {
@@ -376,6 +383,12 @@ namespace MWWorld
                 reader.getHNT(mTeleportEnabled, "TELE");
                 reader.getHNT(mLevitationEnabled, "LEVT");
                 return;
+            case ESM::REC_RAND:
+                {
+                    auto data = reader.getHNOString("RAND");
+                    Misc::Rng::deserialize(data, mPrng);
+                }
+                break;
             case ESM::REC_PLAY:
                 mStore.checkPlayer();
                 mPlayer->readRecord(reader, type);
@@ -544,7 +557,12 @@ namespace MWWorld
         mProjectileManager->clear();
     }
 
-    const ESM::Cell *World::getExterior (const std::string& cellName) const
+    void World::setRandomSeed(uint32_t seed)
+    {
+        mRandomSeed = seed;
+    }
+
+    const ESM::Cell* World::getExterior(const std::string& cellName) const
     {
         // first try named cells
         const ESM::Cell *cell = mStore.get<ESM::Cell>().searchExtByName (cellName);
@@ -3709,9 +3727,10 @@ namespace MWWorld
         static int iNumberCreatures = mStore.get<ESM::GameSetting>().find("iNumberCreatures")->mValue.getInteger();
         int numCreatures = 1 + Misc::Rng::rollDice(iNumberCreatures); // [1, iNumberCreatures]
 
+        auto& prng = MWBase::Environment::get().getWorld()->getPrng();
         for (int i=0; i<numCreatures; ++i)
         {
-            std::string selectedCreature = MWMechanics::getLevelledItem(list, true);
+            std::string selectedCreature = MWMechanics::getLevelledItem(list, true, prng);
             if (selectedCreature.empty())
                 continue;
 
@@ -3999,4 +4018,10 @@ namespace MWWorld
     {
         return mCells.getAll(id);
     }
+
+    Misc::Rng::Generator& World::getPrng()
+    {
+        return mPrng;
+    }
+
 }

apps/openmw/mwworld/worldimp.hpp

@@ -4,6 +4,7 @@
 #include <osg/ref_ptr>
 
 #include <components/settings/settings.hpp>
+#include <components/misc/rng.hpp>
 
 #include "../mwbase/world.hpp"
 
@@ -84,7 +85,7 @@ namespace MWWorld
             GroundcoverStore mGroundcoverStore;
             LocalScripts mLocalScripts;
             MWWorld::Globals mGlobalVariables;
-
+            Misc::Rng::Generator mPrng;
             Cells mCells;
 
             std::string mCurrentWorldSpace;
@@ -129,6 +130,8 @@ namespace MWWorld
             std::map<MWWorld::Ptr, MWWorld::DoorState> mDoorStates;
             ///< only holds doors that are currently moving. 1 = opening, 2 = closing
 
+            uint32_t mRandomSeed{};
+
             // not implemented
             World (const World&);
             World& operator= (const World&);
@@ -193,6 +196,8 @@ namespace MWWorld
 
             virtual ~World();
 
+            void setRandomSeed(uint32_t seed) override;
+
             void startNewGame (bool bypass) override;
             ///< \param bypass Bypass regular game start.
 
@@ -736,6 +741,8 @@ namespace MWWorld
             void reportStats(unsigned int frameNumber, osg::Stats& stats) const override;
 
             std::vector<MWWorld::Ptr> getAll(const std::string& id) override;
+
+            Misc::Rng::Generator& getPrng() override;
     };
 }
 

apps/openmw_test_suite/detournavigator/navigator.cpp

@@ -820,12 +820,12 @@ namespace
 
         const auto result = findRandomPointAroundCircle(*mNavigator, mAgentHalfExtents, mStart, 100.0, Flag_walk);
 
-        ASSERT_THAT(result, Optional(Vec3fEq(69.6253509521484375, 531.29852294921875, -2.6667339801788330078125)))
+        ASSERT_THAT(result, Optional(Vec3fEq(70.35845947265625, 335.592041015625, -2.6667339801788330078125)))
             << (result ? *result : osg::Vec3f());
 
         const auto distance = (*result - mStart).length();
 
-        EXPECT_FLOAT_EQ(distance, 73.536231994628906) << distance;
+        EXPECT_FLOAT_EQ(distance, 125.80865478515625) << distance;
     }
 
     TEST_F(DetourNavigatorNavigatorTest, multiple_threads_should_lock_tiles)

components/esm/defs.hpp

@@ -178,6 +178,9 @@ enum RecNameInts : unsigned int
 
     // format 16 - Lua scripts in saved games
     REC_LUAM = fourCC("LUAM"),  // LuaManager data
+
+    // format 21 - Random state in saved games.
+    REC_RAND = fourCC("RAND"),  // Random state.
 };
 
 /// Common subrecords

components/esm3/savedgame.cpp

@@ -4,7 +4,7 @@
 #include "esmwriter.hpp"
 
 unsigned int ESM::SavedGame::sRecordId = ESM::REC_SAVE;
-int ESM::SavedGame::sCurrentFormat = 20;
+int ESM::SavedGame::sCurrentFormat = 21;
 
 void ESM::SavedGame::load (ESMReader &esm)
 {

components/misc/rng.cpp

@@ -2,6 +2,9 @@
 
 #include <chrono>
 #include <random>
+#include <sstream>
+
+#include <components/debug/debuglog.hpp>
 
 namespace Misc::Rng
 {
@@ -12,33 +15,72 @@ namespace Misc::Rng
         return sGenerator;
     }
 
+    std::string serialize(const Generator& prng)
+    {
+        std::stringstream ss;
+        ss << prng;
+
+        return ss.str();
+    }
+
+    void deserialize(std::string_view data, Generator& prng)
+    {
+        std::stringstream ss;
+        ss << data;
+
+        ss.seekg(0);
+        ss >> prng;
+    }
+
+    unsigned int generateDefaultSeed()
+    {
+        auto res = static_cast<unsigned int>(std::chrono::high_resolution_clock::now().time_since_epoch().count());
+        return res;
+    }
+
     void init(unsigned int seed)
     {
         sGenerator.seed(seed);
     }
 
+    float rollProbability()
+    {
+        return std::uniform_real_distribution<float>(0, 1 - std::numeric_limits<float>::epsilon())(getGenerator());
+    }
+
     float rollProbability(Generator& prng)
     {
         return std::uniform_real_distribution<float>(0, 1 - std::numeric_limits<float>::epsilon())(prng);
     }
 
+    float rollClosedProbability()
+    {
+        return std::uniform_real_distribution<float>(0, 1)(getGenerator());
+    }
+
     float rollClosedProbability(Generator& prng)
     {
         return std::uniform_real_distribution<float>(0, 1)(prng);
     }
 
+    int rollDice(int max)
+    {
+        return max > 0 ? std::uniform_int_distribution<int>(0, max - 1)(getGenerator()) : 0;
+    }
+
     int rollDice(int max, Generator& prng)
     {
         return max > 0 ? std::uniform_int_distribution<int>(0, max - 1)(prng) : 0;
     }
 
-    unsigned int generateDefaultSeed()
+    float deviate(float mean, float deviation)
     {
-        return static_cast<unsigned int>(std::chrono::high_resolution_clock::now().time_since_epoch().count());
+        return std::uniform_real_distribution<float>(mean - deviation, mean + deviation)(getGenerator());
     }
 
     float deviate(float mean, float deviation, Generator& prng)
     {
         return std::uniform_real_distribution<float>(mean - deviation, mean + deviation)(prng);
     }
+
 }

components/misc/rng.hpp

@@ -3,17 +3,21 @@
 
 #include <cassert>
 #include <random>
+#include <string_view>
 
 /*
   Provides central implementation of the RNG logic
 */
 namespace Misc::Rng
 {
-
+    /// The use of a rather minimalistic prng is preferred to avoid saving a lot of state in the save game.
-    using Generator = std::mt19937;
+    using Generator = std::minstd_rand;
 
     Generator& getGenerator();
 
+    std::string serialize(const Generator& prng);
+    void deserialize(std::string_view data, Generator& prng);
+
     /// returns default seed for RNG
     unsigned int generateDefaultSeed();
 
@@ -21,19 +25,23 @@ namespace Misc::Rng
     void init(unsigned int seed = generateDefaultSeed());
 
     /// return value in range [0.0f, 1.0f)  <- note open upper range.
-    float rollProbability(Generator& prng = getGenerator());
+    float rollProbability();
+    float rollProbability(Generator& prng);
   
     /// return value in range [0.0f, 1.0f]  <- note closed upper range.
-    float rollClosedProbability(Generator& prng = getGenerator());
+    float rollClosedProbability();
+    float rollClosedProbability(Generator& prng);
 
     /// return value in range [0, max)  <- note open upper range.
-    int rollDice(int max, Generator& prng = getGenerator());
+    int rollDice(int max);
+    int rollDice(int max, Generator& prng);
 
     /// return value in range [0, 99]
-    inline int roll0to99(Generator& prng = getGenerator()) { return rollDice(100, prng); }
+    inline int roll0to99(Generator& prng) { return rollDice(100, prng); }
-
+    inline int roll0to99() { return rollDice(100); }
-    float deviate(float mean, float deviation, Generator& prng = getGenerator());
 
+    float deviate(float mean, float deviation);
+    float deviate(float mean, float deviation, Generator& prng);
 }
 
 #endif

components/misc/timer.hpp

@@ -18,7 +18,7 @@ namespace Misc
                 : mPeriod(period), mDeviation(deviation), mTimeLeft(timeLeft)
             {}
 
-            TimerStatus update(float duration)
+            TimerStatus update(float duration, Rng::Generator& prng)
             {
                 if (mTimeLeft > 0)
                 {
@@ -26,7 +26,7 @@ namespace Misc
                     return TimerStatus::Waiting;
                 }
 
-                mTimeLeft = Rng::deviate(mPeriod, mDeviation);
+                mTimeLeft = Rng::deviate(mPeriod, mDeviation, prng);
                 return TimerStatus::Elapsed;
             }