From 14a8ca579b20137e10ced47987a34ed8de9f8da6 Mon Sep 17 00:00:00 2001
From: Chris Robinson <chris.kcat@gmail.com>
Date: Thu, 12 Sep 2024 02:54:58 -0700
Subject: [PATCH] Set AL_METERS_PER_UNIT for the listener's DistanceFactor

---
 src/dsoundoal.cpp     | 11 ++++++++++-
 src/dsoundoal.h       |  1 +
 src/primarybuffer.cpp | 10 +++++++++-
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/dsoundoal.cpp b/src/dsoundoal.cpp
index 4351422..7681b17 100644
--- a/src/dsoundoal.cpp
+++ b/src/dsoundoal.cpp
@@ -187,6 +187,7 @@ ds::expected<std::unique_ptr<SharedDevice>,HRESULT> CreateDeviceShare(const GUID
     };
     const std::array sExtensionList{
         ExtensionEntry{"EAX5.0", EXT_EAX},
+        ExtensionEntry{"ALC_EXT_EFX", EXT_EFX},
         ExtensionEntry{"AL_EXT_FLOAT32", EXT_FLOAT32},
         ExtensionEntry{"AL_EXT_MCFORMATS", EXT_MCFORMATS},
         ExtensionEntry{"AL_EXT_STATIC_BUFFER", EXT_STATIC_BUFFER}
@@ -195,7 +196,15 @@ ds::expected<std::unique_ptr<SharedDevice>,HRESULT> CreateDeviceShare(const GUID
     std::bitset<ExtensionCount> extensions{};
     for(auto &ext : sExtensionList)
     {
-        if(alIsExtensionPresent(ext.name))
+        if(std::string_view{ext.name}.substr(0,3) == "ALC")
+        {
+            if(alcIsExtensionPresent(aldev.get(), ext.name))
+            {
+                extensions.set(ext.flag);
+                TRACE("CreateDeviceShare Found extension %s\n", ext.name);
+            }
+        }
+        else if(alIsExtensionPresent(ext.name))
         {
             extensions.set(ext.flag);
             TRACE("CreateDeviceShare Found extension %s\n", ext.name);
diff --git a/src/dsoundoal.h b/src/dsoundoal.h
index cd700cb..8db03b6 100644
--- a/src/dsoundoal.h
+++ b/src/dsoundoal.h
@@ -25,6 +25,7 @@ struct BufferSubList;
 
 enum Extensions : uint8_t {
     EXT_EAX,
+    EXT_EFX,
     EXT_FLOAT32,
     EXT_MCFORMATS,
     EXT_STATIC_BUFFER,
diff --git a/src/primarybuffer.cpp b/src/primarybuffer.cpp
index 66ff7f2..da309b9 100644
--- a/src/primarybuffer.cpp
+++ b/src/primarybuffer.cpp
@@ -631,7 +631,11 @@ void PrimaryBuffer::setParams(const DS3DLISTENER &params, const std::bitset<Flag
         alListenerfv(AL_ORIENTATION, ori.data());
     }
     if(flags.test(DistanceFactor))
+    {
         alSpeedOfSound(343.3f / params.flDistanceFactor);
+        if(mParent.haveExtension(EXT_EFX))
+            alListenerf(AL_METERS_PER_UNIT, params.flDistanceFactor);
+    }
     if(flags.test(RolloffFactor))
     {
         for(Buffer *buffer : mParent.get3dBuffers())
@@ -862,9 +866,13 @@ HRESULT STDMETHODCALLTYPE PrimaryBuffer::Listener3D::SetDistanceFactor(D3DVALUE
     else
     {
         ALSection alsection{self->mContext};
+        alcSuspendContext(self->mContext);
         self->mImmediate.flDistanceFactor = distanceFactor;
-        alSpeedOfSound(343.3f/distanceFactor);
+        alSpeedOfSound(343.3f / distanceFactor);
+        if(self->mParent.haveExtension(EXT_EFX))
+            alListenerf(AL_METERS_PER_UNIT, distanceFactor);
         alGetError();
+        alcProcessContext(self->mContext);
     }
 
     return S_OK;