From f9da2b6b26ad8737f13732002c491694a32927ce Mon Sep 17 00:00:00 2001
From: Evil Eye <malusluminis@hotmail.com>
Date: Sat, 9 Mar 2024 17:14:43 +0100
Subject: [PATCH] Roll for each region sound

---
 CHANGELOG.md                                |  1 +
 apps/openmw/mwsound/regionsoundselector.cpp | 38 +++------------------
 apps/openmw/mwsound/regionsoundselector.hpp |  3 +-
 apps/openmw/mwsound/soundmanagerimp.cpp     |  5 +--
 4 files changed, 10 insertions(+), 37 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 953801b345..64f0f55fb1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -157,6 +157,7 @@
     Bug #7840: First run of the launcher doesn't save viewing distance as the default value
     Bug #7841: Editor: "Dirty" water heights are saved in modified CELLs
     Bug #7859: AutoCalc flag is not used to calculate potion value
+    Bug #7872: Region sounds use wrong odds
     Feature #2566: Handle NAM9 records for manual cell references
     Feature #3537: Shader-based water ripples
     Feature #5173: Support for NiFogProperty
diff --git a/apps/openmw/mwsound/regionsoundselector.cpp b/apps/openmw/mwsound/regionsoundselector.cpp
index 8fda57596a..89b5526d30 100644
--- a/apps/openmw/mwsound/regionsoundselector.cpp
+++ b/apps/openmw/mwsound/regionsoundselector.cpp
@@ -4,29 +4,18 @@
 #include <components/fallback/fallback.hpp>
 #include <components/misc/rng.hpp>
 
-#include <algorithm>
-#include <numeric>
-
 #include "../mwbase/environment.hpp"
 #include "../mwworld/esmstore.hpp"
 
 namespace MWSound
 {
-    namespace
-    {
-        int addChance(int result, const ESM::Region::SoundRef& v)
-        {
-            return result + v.mChance;
-        }
-    }
-
     RegionSoundSelector::RegionSoundSelector()
         : mMinTimeBetweenSounds(Fallback::Map::getFloat("Weather_Minimum_Time_Between_Environmental_Sounds"))
         , mMaxTimeBetweenSounds(Fallback::Map::getFloat("Weather_Maximum_Time_Between_Environmental_Sounds"))
     {
     }
 
-    std::optional<ESM::RefId> RegionSoundSelector::getNextRandom(float duration, const ESM::RefId& regionName)
+    ESM::RefId RegionSoundSelector::getNextRandom(float duration, const ESM::RefId& regionName)
     {
         mTimePassed += duration;
 
@@ -49,28 +38,11 @@ namespace MWSound
         if (region == nullptr)
             return {};
 
-        if (mSumChance == 0)
+        for (const ESM::Region::SoundRef& sound : region->mSoundList)
         {
-            mSumChance = std::accumulate(region->mSoundList.begin(), region->mSoundList.end(), 0, addChance);
-            if (mSumChance == 0)
-                return {};
+            if (Misc::Rng::roll0to99() < sound.mChance)
+                return sound.mSound;
         }
-
-        const int r = Misc::Rng::rollDice(std::max(mSumChance, 100));
-        int pos = 0;
-
-        const auto isSelected = [&](const ESM::Region::SoundRef& sound) {
-            if (r - pos < sound.mChance)
-                return true;
-            pos += sound.mChance;
-            return false;
-        };
-
-        const auto it = std::find_if(region->mSoundList.begin(), region->mSoundList.end(), isSelected);
-
-        if (it == region->mSoundList.end())
-            return {};
-
-        return it->mSound;
+        return {};
     }
 }
diff --git a/apps/openmw/mwsound/regionsoundselector.hpp b/apps/openmw/mwsound/regionsoundselector.hpp
index 1a9e6e450b..7a7659f56d 100644
--- a/apps/openmw/mwsound/regionsoundselector.hpp
+++ b/apps/openmw/mwsound/regionsoundselector.hpp
@@ -2,7 +2,6 @@
 #define GAME_SOUND_REGIONSOUNDSELECTOR_H
 
 #include <components/esm/refid.hpp>
-#include <optional>
 #include <string>
 
 namespace MWBase
@@ -15,7 +14,7 @@ namespace MWSound
     class RegionSoundSelector
     {
     public:
-        std::optional<ESM::RefId> getNextRandom(float duration, const ESM::RefId& regionName);
+        ESM::RefId getNextRandom(float duration, const ESM::RefId& regionName);
 
         RegionSoundSelector();
 
diff --git a/apps/openmw/mwsound/soundmanagerimp.cpp b/apps/openmw/mwsound/soundmanagerimp.cpp
index 3658be4819..56224b4dcb 100644
--- a/apps/openmw/mwsound/soundmanagerimp.cpp
+++ b/apps/openmw/mwsound/soundmanagerimp.cpp
@@ -900,8 +900,9 @@ namespace MWSound
         if (mCurrentRegionSound && mOutput->isSoundPlaying(mCurrentRegionSound))
             return;
 
-        if (const auto next = mRegionSoundSelector.getNextRandom(duration, cell->getRegion()))
-            mCurrentRegionSound = playSound(*next, 1.0f, 1.0f);
+        ESM::RefId next = mRegionSoundSelector.getNextRandom(duration, cell->getRegion());
+        if (!next.empty())
+            mCurrentRegionSound = playSound(next, 1.0f, 1.0f);
     }
 
     void SoundManager::updateWaterSound()