Merge branch 'astoecke-fix-6354-sfx-distance-attenuation' into 'master'

Fade sounds when performing distance-based culling (Fixes #6354)

Closes #6354

See merge request OpenMW/openmw!1341

CHANGELOG.md

@@ -68,6 +68,7 @@
     Bug #6323: Wyrmhaven: Alboin doesn't follower the player character out of his house
     Bug #6326: Detect Enchantment/Key should detect items in unresolved containers
     Bug #6347: PlaceItem/PlaceItemCell/PlaceAt should work with levelled creatures
+    Bug #6354: SFX abruptly cut off after crossing max distance; implement soft fading of sound effects
     Bug #6363: Some scripts in Morrowland fail to work
     Bug #6376: Creatures should be able to use torches
     Feature #890: OpenMW-CS: Column filtering

apps/openmw/mwsound/openal_output.cpp

@@ -1109,13 +1109,8 @@ void OpenAL_Output::initCommon3D(ALuint source, const osg::Vec3f &pos, ALfloat m
     alSource3f(source, AL_VELOCITY, 0.0f, 0.0f, 0.0f);
 }
 
-void OpenAL_Output::updateCommon(ALuint source, const osg::Vec3f& pos, ALfloat maxdist, ALfloat gain, ALfloat pitch, bool useenv, bool is3d)
+void OpenAL_Output::updateCommon(ALuint source, const osg::Vec3f& pos, ALfloat maxdist, ALfloat gain, ALfloat pitch, bool useenv)
 {
-    if(is3d)
-    {
-        if((pos - mListenerPos).length2() > maxdist*maxdist)
-            gain = 0.0f;
-    }
     if(useenv && mListenerEnv == Env_Underwater && !mWaterFilter)
     {
         gain *= 0.9f;
@@ -1243,7 +1238,7 @@ void OpenAL_Output::updateSound(Sound *sound)
     ALuint source = GET_PTRID(sound->mHandle);
 
     updateCommon(source, sound->getPosition(), sound->getMaxDistance(), sound->getRealVolume(),
-                 sound->getPitch(), sound->getUseEnv(), sound->getIs3D());
+                 sound->getPitch(), sound->getUseEnv());
     getALError();
 }
 
@@ -1369,7 +1364,7 @@ void OpenAL_Output::updateStream(Stream *sound)
     ALuint source = stream->mSource;
 
     updateCommon(source, sound->getPosition(), sound->getMaxDistance(), sound->getRealVolume(),
-                 sound->getPitch(), sound->getUseEnv(), sound->getIs3D());
+                 sound->getPitch(), sound->getUseEnv());
     getALError();
 }
 

apps/openmw/mwsound/openal_output.hpp

@@ -53,7 +53,7 @@ namespace MWSound
         void initCommon2D(ALuint source, const osg::Vec3f &pos, ALfloat gain, ALfloat pitch, bool loop, bool useenv);
         void initCommon3D(ALuint source, const osg::Vec3f &pos, ALfloat mindist, ALfloat maxdist, ALfloat gain, ALfloat pitch, bool loop, bool useenv);
 
-        void updateCommon(ALuint source, const osg::Vec3f &pos, ALfloat maxdist, ALfloat gain, ALfloat pitch, bool useenv, bool is3d);
+        void updateCommon(ALuint source, const osg::Vec3f &pos, ALfloat maxdist, ALfloat gain, ALfloat pitch, bool useenv);
 
         OpenAL_Output& operator=(const OpenAL_Output &rhs);
         OpenAL_Output(const OpenAL_Output &rhs);

apps/openmw/mwsound/sound.hpp

@@ -11,7 +11,11 @@ namespace MWSound
     enum PlayModeEx
     {
         Play_2D = 0,
+        Play_StopAtFadeEnd = 1 << 28,
+        Play_FadeExponential = 1 << 29,
+        Play_InFade = 1 << 30,
         Play_3D = 1 << 31,
+        Play_FadeFlagsMask = (Play_StopAtFadeEnd | Play_FadeExponential),
     };
 
     // For testing individual PlayMode flags
@@ -21,13 +25,15 @@ namespace MWSound
     struct SoundParams
     {
         osg::Vec3f mPos;
-        float mVolume = 1;
-        float mBaseVolume = 1;
-        float mPitch = 1;
-        float mMinDistance = 1;
-        float mMaxDistance = 1000;
+        float mVolume = 1.0f;
+        float mBaseVolume = 1.0f;
+        float mPitch = 1.0f;
+        float mMinDistance = 1.0f;
+        float mMaxDistance = 1000.0f;
         int mFlags = 0;
-        float mFadeOutTime = 0;
+        float mFadeVolume = 1.0f;
+        float mFadeTarget = 0.0f;
+        float mFadeStep = 0.0f;
     };
 
     class SoundBase {
@@ -46,19 +52,97 @@ namespace MWSound
         void setPosition(const osg::Vec3f &pos) { mParams.mPos = pos; }
         void setVolume(float volume) { mParams.mVolume = volume; }
         void setBaseVolume(float volume) { mParams.mBaseVolume = volume; }
-        void setFadeout(float duration) { mParams.mFadeOutTime = duration; }
-        void updateFade(float duration)
+        void setFadeout(float duration) { setFade(duration, 0.0, Play_StopAtFadeEnd); }
+
+        /// Fade to the given linear gain within the specified amount of time.
+        /// Note that the fade gain is independent of the sound volume.
+        ///
+        /// \param duration specifies the duration of the fade. For *linear*
+        /// fades (default) this will be exactly the time at which the desired
+        /// volume is reached. Let v0 be the initial volume, v1 be the target
+        /// volume, and t0 be the initial time. Then the volume over time is
+        /// given as
+        ///
+        ///   v(t) =  v0 + (v1 - v0) * (t - t0) / duration  if t <= t0 + duration
+        ///   v(t) =  v1                                    if t >  t0 + duration
+        ///
+        /// For *exponential* fades this determines the time-constant of the
+        /// exponential process describing the fade. In particular, we guarantee
+        /// that we reach v0 + 0.99 * (v1 - v0) within the given duration.
+        ///
+        ///   v(t) = v1 + (v0 - v1) * exp(-4.6 * (t0 - t) / duration)
+        ///
+        /// where -4.6 is approximately log(1%) (i.e., -40 dB).
+        ///
+        /// This interpolation mode is meant for environmental sound effects to
+        /// achieve less jarring transitions.
+        ///
+        /// \param targetVolume is the linear gain that should be reached at
+        /// the end of the fade.
+        ///
+        /// \param flags may be a combination of Play_FadeExponential and
+        /// Play_StopAtFadeEnd. If Play_StopAtFadeEnd is set, stops the sound
+        /// once the fade duration has passed or the target volume has been
+        /// reached. If Play_FadeExponential is set, enables the exponential
+        /// fade mode (see above).
+        void setFade(float duration, float targetVolume, int flags = 0) {
+            // Approximation of log(1%) (i.e., -40 dB).
+            constexpr float minus40Decibel = -4.6f;
+
+            // Do nothing if already at the target, unless we need to trigger a stop event
+            if ((mParams.mFadeVolume == targetVolume) && !(flags & Play_StopAtFadeEnd))
+                return;
+
+            mParams.mFadeTarget = targetVolume;
+            mParams.mFlags = (mParams.mFlags & ~Play_FadeFlagsMask) | (flags & Play_FadeFlagsMask) | Play_InFade;
+            if (duration > 0.0f)
+            {
+                if (mParams.mFlags & Play_FadeExponential)
+                    mParams.mFadeStep = -minus40Decibel / duration;
+                else
+                    mParams.mFadeStep = (mParams.mFadeTarget - mParams.mFadeVolume) / duration;
+            }
+            else
+            {
+                mParams.mFadeVolume = mParams.mFadeTarget;
+                mParams.mFadeStep = 0.0f;
+            }
+        }
+
+        /// Updates the internal fading logic.
+        ///
+        /// \param dt is the time in seconds since the last call to update.
+        ///
+        /// \return true if the sound is still active, false if the sound has
+        /// reached a fading destination that was marked with Play_StopAtFadeEnd.
+        bool updateFade(float dt)
         {
-            if (mParams.mFadeOutTime > 0.0f)
+            // Mark fade as done at this volume difference (-80dB when fading to zero)
+            constexpr float minVolumeDifference = 1e-4f;
+
+            if (!getInFade())
+                return true;
+
+            // Perform the actual fade operation
+            const float deltaBefore = mParams.mFadeTarget - mParams.mFadeVolume;
+            if (mParams.mFlags & Play_FadeExponential)
+                mParams.mFadeVolume += mParams.mFadeStep * deltaBefore * dt;
+            else
+                mParams.mFadeVolume += mParams.mFadeStep * dt;
+            const float deltaAfter = mParams.mFadeTarget - mParams.mFadeVolume;
+
+            // Abort fade if we overshot or reached the minimum difference
+            if ((std::signbit(deltaBefore) != std::signbit(deltaAfter)) || (std::abs(deltaAfter) < minVolumeDifference))
             {
-                float soundDuration = std::min(duration, mParams.mFadeOutTime);
-                mParams.mVolume *= (mParams.mFadeOutTime - soundDuration) / mParams.mFadeOutTime;
-                mParams.mFadeOutTime -= soundDuration;
+                mParams.mFadeVolume = mParams.mFadeTarget;
+                mParams.mFlags &= ~Play_InFade;
             }
+
+            return getInFade() || !(mParams.mFlags & Play_StopAtFadeEnd);
         }
 
         const osg::Vec3f &getPosition() const { return mParams.mPos; }
-        float getRealVolume() const { return mParams.mVolume * mParams.mBaseVolume; }
+        float getRealVolume() const { return mParams.mVolume * mParams.mBaseVolume * mParams.mFadeVolume; }
         float getPitch() const { return mParams.mPitch; }
         float getMinDistance() const { return mParams.mMinDistance; }
         float getMaxDistance() const { return mParams.mMaxDistance; }
@@ -69,6 +153,7 @@ namespace MWSound
         bool getIsLooping() const { return mParams.mFlags & MWSound::PlayMode::Loop; }
         bool getDistanceCull() const { return mParams.mFlags & MWSound::PlayMode::RemoveAtDistance; }
         bool getIs3D() const { return mParams.mFlags & Play_3D; }
+        bool getInFade() const { return mParams.mFlags & Play_InFade; }
 
         void init(const SoundParams& params)
         {

apps/openmw/mwsound/soundmanagerimp.cpp

@@ -33,6 +33,8 @@ namespace MWSound
     namespace
     {
         constexpr float sMinUpdateInterval = 1.0f / 30.0f;
+        constexpr float sSfxFadeInDuration = 1.0f;
+        constexpr float sSfxFadeOutDuration = 1.0f;
 
         WaterSoundUpdaterSettings makeWaterSoundUpdaterSettings()
         {
@@ -47,6 +49,24 @@ namespace MWSound
 
             return settings;
         }
+
+        float initialFadeVolume(float squaredDist, Sound_Buffer *sfx, Type type, PlayMode mode)
+        {
+            // If a sound is farther away than its maximum distance, start playing it with a zero fade volume.
+            // It can still become audible once the player moves closer.
+            const float maxDist = sfx->getMaxDist();
+            if (squaredDist > (maxDist * maxDist))
+                return 0.0f;
+
+            // This is a *heuristic* that causes environment sounds to fade in. The idea is the following:
+            // - Only looped sounds playing through the effects channel are environment sounds
+            // - Do not fade in sounds if the player is already so close that the sound plays at maximum volume
+            const float minDist = sfx->getMinDist();
+            if ((squaredDist > (minDist * minDist)) && (type == Type::Sfx) && (mode & PlayMode::Loop))
+                return 0.0f;
+
+            return 1.0;
+        }
     }
 
     // For combining PlayMode and Type flags
@@ -517,7 +537,8 @@ namespace MWSound
             return nullptr;
 
         const osg::Vec3f objpos(ptr.getRefData().getPosition().asVec3());
-        if ((mode & PlayMode::RemoveAtDistance) && (mListenerPos - objpos).length2() > 2000 * 2000)
+        const float squaredDist = (mListenerPos - objpos).length2();
+        if ((mode & PlayMode::RemoveAtDistance) && squaredDist > 2000 * 2000)
             return nullptr;
 
         // Look up the sound in the ESM data
@@ -548,6 +569,7 @@ namespace MWSound
                 params.mPos = objpos;
                 params.mVolume = volume * sfx->getVolume();
                 params.mBaseVolume = volumeFromType(type);
+                params.mFadeVolume = initialFadeVolume(squaredDist, sfx, type, mode);
                 params.mPitch = pitch;
                 params.mMinDistance = sfx->getMinDist();
                 params.mMaxDistance = sfx->getMaxDist();
@@ -576,12 +598,15 @@ namespace MWSound
         Sound_Buffer *sfx = mSoundBuffers.load(Misc::StringUtils::lowerCase(soundId));
         if(!sfx) return nullptr;
 
+        const float squaredDist = (mListenerPos - initialPos).length2();
+
         SoundPtr sound = getSoundRef();
         sound->init([&] {
             SoundParams params;
             params.mPos = initialPos;
             params.mVolume = volume * sfx->getVolume();
             params.mBaseVolume = volumeFromType(type);
+            params.mFadeVolume = initialFadeVolume(squaredDist, sfx, type, mode);
             params.mPitch = pitch;
             params.mMinDistance = sfx->getMinDist();
             params.mMaxDistance = sfx->getMaxDist();
@@ -777,10 +802,10 @@ namespace MWSound
                 break;
             case WaterSoundAction::SetVolume:
                 mNearWaterSound->setVolume(update.mVolume * sfx->getVolume());
+                mNearWaterSound->setFade(sSfxFadeInDuration, 1.0f, Play_FadeExponential);
                 break;
             case WaterSoundAction::FinishSound:
-                mOutput->finishSound(mNearWaterSound);
-                mNearWaterSound = nullptr;
+                mNearWaterSound->setFade(sSfxFadeOutDuration, 0.0f, Play_FadeExponential | Play_StopAtFadeEnd);
                 break;
             case WaterSoundAction::PlaySound:
                 if (mNearWaterSound)
@@ -830,6 +855,28 @@ namespace MWSound
         return {WaterSoundAction::DoNothing, nullptr};
     }
 
+    void SoundManager::cull3DSound(SoundBase *sound)
+    {
+        // Hard-coded distance of 2000.0f is from vanilla Morrowind
+        const float maxDist = sound->getDistanceCull() ? 2000.0f : sound->getMaxDistance();
+        const float squaredMaxDist = maxDist * maxDist;
+
+        const osg::Vec3f pos = sound->getPosition();
+        const float squaredDist = (mListenerPos - pos).length2();
+
+        if (squaredDist > squaredMaxDist)
+        {
+            // If getDistanceCull() is set, delete the sound after it has faded out
+            sound->setFade(sSfxFadeOutDuration, 0.0f, Play_FadeExponential | (sound->getDistanceCull() ? Play_StopAtFadeEnd : 0));
+        }
+        else
+        {
+            // Fade sounds back in once they are in range
+            sound->setFade(sSfxFadeInDuration, 1.0f, Play_FadeExponential);
+        }
+    }
+
+
     void SoundManager::updateSounds(float duration)
     {
         // We update active say sounds map for specific actors here
@@ -884,20 +931,15 @@ namespace MWSound
             {
                 Sound *sound = sndidx->first.get();
 
-                if(!ptr.isEmpty() && sound->getIs3D())
+                if (sound->getIs3D())
                 {
-                    const ESM::Position &pos = ptr.getRefData().getPosition();
-                    const osg::Vec3f objpos(pos.asVec3());
-                    sound->setPosition(objpos);
-
-                    if(sound->getDistanceCull())
-                    {
-                        if((mListenerPos - objpos).length2() > 2000*2000)
-                            mOutput->finishSound(sound);
-                    }
+                    if (!ptr.isEmpty())
+                        sound->setPosition(ptr.getRefData().getPosition().asVec3());
+
+                    cull3DSound(sound);
                 }
 
-                if(!mOutput->isSoundPlaying(sound))
+                if(!sound->updateFade(duration) || !mOutput->isSoundPlaying(sound))
                 {
                     mOutput->finishSound(sound);
                     if (sound == mUnderwaterSound)
@@ -909,8 +951,6 @@ namespace MWSound
                 }
                 else
                 {
-                    sound->updateFade(duration);
-
                     mOutput->updateSound(sound);
                     ++sndidx;
                 }
@@ -926,28 +966,24 @@ namespace MWSound
         {
             MWWorld::ConstPtr ptr = sayiter->first;
             Stream *sound = sayiter->second.get();
-            if(!ptr.isEmpty() && sound->getIs3D())
+            if (sound->getIs3D())
             {
-                MWBase::World *world = MWBase::Environment::get().getWorld();
-                const osg::Vec3f pos = world->getActorHeadTransform(ptr).getTrans();
-                sound->setPosition(pos);
-
-                if(sound->getDistanceCull())
+                if (!ptr.isEmpty())
                 {
-                    if((mListenerPos - pos).length2() > 2000*2000)
-                        mOutput->finishStream(sound);
+                    MWBase::World *world = MWBase::Environment::get().getWorld();
+                    sound->setPosition(world->getActorHeadTransform(ptr).getTrans());
                 }
+
+                cull3DSound(sound);
             }
 
-            if(!mOutput->isStreamPlaying(sound))
+            if(!sound->updateFade(duration) || !mOutput->isStreamPlaying(sound))
             {
                 mOutput->finishStream(sound);
-                mActiveSaySounds.erase(sayiter++);
+                sayiter = mActiveSaySounds.erase(sayiter);
             }
             else
             {
-                sound->updateFade(duration);
-
                 mOutput->updateStream(sound);
                 ++sayiter;
             }

apps/openmw/mwsound/soundmanagerimp.hpp

@@ -34,6 +34,7 @@ namespace MWSound
 {
     class Sound_Output;
     struct Sound_Decoder;
+    class SoundBase;
     class Sound;
     class Stream;
 
@@ -111,6 +112,8 @@ namespace MWSound
         void advanceMusic(const std::string& filename);
         void startRandomTitle();
 
+        void cull3DSound(SoundBase *sound);
+
         void updateSounds(float duration);
         void updateRegionSound(float duration);
         void updateWaterSound();