Load/convert samples from all channels at once for mixing

This uses a bit more memory (each voice needs to hold buffers for the
deinterleaved samples of each channel, instead of just one buffer for the
current channel being mixed on the device), but it will allow for handling
formats that need or prefer their channels decoded together.

1 files changed, 8 insertions, 7 deletions

diff --git a/al/source.cpp b/al/source.cpp
index 9be79e9a..5b95e9ed 100644
--- a/al/source.cpp
+++ b/al/source.cpp
@@ -458,9 +458,15 @@ void InitVoice(Voice *voice, ALsource *source, ALbufferQueueItem *BufferList, AL
     voice->mStep = 0;
 
     if(voice->mChans.capacity() > 2 && num_channels < voice->mChans.capacity())
-        al::vector<Voice::ChannelData>{}.swap(voice->mChans);
+    {
+        decltype(voice->mChans){}.swap(voice->mChans);
+        decltype(voice->mVoiceSamples){}.swap(voice->mVoiceSamples);
+    }
     voice->mChans.reserve(maxu(2, num_channels));
     voice->mChans.resize(num_channels);
+    voice->mVoiceSamples.reserve(maxu(2, num_channels));
+    voice->mVoiceSamples.resize(num_channels);
+    std::fill_n(voice->mVoiceSamples.begin(), num_channels, Voice::BufferLine{});
 
     /* Don't need to set the VOICE_IS_AMBISONIC flag if the device is not
      * higher order than the voice. No HF scaling is necessary to mix it.
@@ -468,15 +474,12 @@ void InitVoice(Voice *voice, ALsource *source, ALbufferQueueItem *BufferList, AL
     if(voice->mAmbiOrder && device->mAmbiOrder > voice->mAmbiOrder)
     {
         const uint8_t *OrderFromChan{(voice->mFmtChannels == FmtBFormat2D) ?
-            AmbiIndex::OrderFrom2DChannel().data() :
-            AmbiIndex::OrderFromChannel().data()};
+            AmbiIndex::OrderFrom2DChannel().data() : AmbiIndex::OrderFromChannel().data()};
         const auto scales = BFormatDec::GetHFOrderScales(voice->mAmbiOrder, device->mAmbiOrder);
 
         const BandSplitter splitter{device->mXOverFreq / static_cast<float>(device->Frequency)};
-
         for(auto &chandata : voice->mChans)
         {
-            chandata.mPrevSamples.fill(0.0f);
             chandata.mAmbiScale = scales[*(OrderFromChan++)];
             chandata.mAmbiSplitter = splitter;
             chandata.mDryParams = DirectParams{};
@@ -487,10 +490,8 @@ void InitVoice(Voice *voice, ALsource *source, ALbufferQueueItem *BufferList, AL
     }
     else
     {
-        /* Clear previous samples. */
         for(auto &chandata : voice->mChans)
         {
-            chandata.mPrevSamples.fill(0.0f);
             chandata.mDryParams = DirectParams{};
             std::fill_n(chandata.mWetParams.begin(), device->NumAuxSends, SendParams{});
         }