Use virtual functions for the decoder

alc/alu.cpp

@@ -765,7 +765,7 @@ void CalcPanningAndFilters(Voice *voice, const float xpos, const float ypos, con
 
     voice->mFlags.reset(VoiceHasHrtf).reset(VoiceHasNfc);
     if(auto *decoder{voice->mDecoder.get()})
-        decoder->mWidthControl = minf(props->EnhWidth, 0.7f);
+        decoder->setWidth(minf(props->EnhWidth, 0.7f));
 
     if(IsAmbisonic(voice->mFmtChannels))
     {

core/uhjfilter.cpp

@@ -174,7 +174,7 @@ void UhjDecoder::decode(const al::span<float*> samples, const size_t samplesToDo
  * where j is a +90 degree phase shift. w is a variable control for the
  * resulting stereo width, with the range 0 <= w <= 0.7.
  */
-void UhjDecoder::decodeStereo(const al::span<float*> samples, const size_t samplesToDo,
+void UhjStereoDecoder::decode(const al::span<float*> samples, const size_t samplesToDo,
     const size_t forwardSamples)
 {
     ASSUME(samplesToDo > 0);

core/uhjfilter.h

@@ -9,6 +9,16 @@
 #include "resampler_limits.h"
 
 
+struct DecoderBase {
+    virtual ~DecoderBase() = default;
+
+    virtual void setWidth(float width) noexcept = 0;
+
+    virtual void decode(const al::span<float*> samples, const size_t samplesToDo,
+        const size_t forwardSamples) = 0;
+};
+
+
 struct UhjFilterBase {
     /* The filter delay is half it's effective size, so a delay of 128 has a
      * FIR length of 256.
@@ -38,7 +48,7 @@ struct UhjEncoder : public UhjFilterBase {
 };
 
 
-struct UhjDecoder : public UhjFilterBase {
+struct UhjDecoder : public DecoderBase, public UhjFilterBase {
     alignas(16) std::array<float,BufferLineSize+MaxResamplerEdge+sFilterDelay> mS{};
     alignas(16) std::array<float,BufferLineSize+MaxResamplerEdge+sFilterDelay> mD{};
     alignas(16) std::array<float,BufferLineSize+MaxResamplerEdge+sFilterDelay> mT{};
@@ -48,13 +58,7 @@ struct UhjDecoder : public UhjFilterBase {
 
     alignas(16) std::array<float,BufferLineSize+MaxResamplerEdge + sFilterDelay*2> mTemp{};
 
-    float mCurrentWidth{-1.0f};
-
-    /**
-     * The width factor for Super Stereo processing. Can be changed in between
-     * calls to decodeStereo, with valid values being between 0...0.7.
-     */
-    float mWidthControl{0.593f};
+    void setWidth(float) noexcept override { }
 
     /**
      * Decodes a 3- or 4-channel UHJ signal into a B-Format signal with FuMa
@@ -65,7 +69,22 @@ struct UhjDecoder : public UhjFilterBase {
      * B-Format decoder, as it needs different shelf filters.
      */
     void decode(const al::span<float*> samples, const size_t samplesToDo,
-        const size_t forwardSamples);
+        const size_t forwardSamples) override;
+
+    DEF_NEWDEL(UhjDecoder)
+};
+
+struct UhjStereoDecoder : public UhjDecoder {
+    float mCurrentWidth{-1.0f};
+
+    /**
+     * The width factor for Super Stereo processing. Can be changed in between
+     * calls to decodeStereo, with valid values being between 0...0.7.
+     */
+    float mWidthControl{0.593f};
+
+    void setWidth(float width) noexcept override
+    { mWidthControl = width; }
 
     /**
      * Applies Super Stereo processing on a stereo signal to create a B-Format
@@ -73,13 +92,10 @@ struct UhjDecoder : public UhjFilterBase {
      * should contain 3 channels, the first two being the left and right stereo
      * channels, and the third left empty.
      */
-    void decodeStereo(const al::span<float*> samples, const size_t samplesToDo,
-        const size_t forwardSamples);
+    void decode(const al::span<float*> samples, const size_t samplesToDo,
+        const size_t forwardSamples) override;
 
-    using DecoderFunc = void (UhjDecoder::*)(const al::span<float*> samples,
-        const size_t samplesToDo, const size_t forwardSamples);
-
-    DEF_NEWDEL(UhjDecoder)
+    DEF_NEWDEL(UhjStereoDecoder)
 };
 
 #endif /* CORE_UHJFILTER_H */

core/voice.cpp

@@ -637,8 +637,8 @@ void Voice::mix(const State vstate, ContextBase *Context, const uint SamplesToDo
             if(mDecoder)
             {
                 SrcBufferSize = SrcBufferSize - PostPadding + MaxResamplerEdge;
-                ((*mDecoder).*mDecoderFunc)(MixingSamples, SrcBufferSize,
-                    srcOffset * likely(vstate == Playing));
+                mDecoder->decode(MixingSamples, SrcBufferSize,
+                    likely(vstate == Playing) ? srcOffset : 0.0f);
             }
             /* Store the last source samples used for next time. */
             if(likely(vstate == Playing))
@@ -853,17 +853,12 @@ void Voice::prepare(DeviceBase *device)
     mPrevSamples.reserve(maxu(2, num_channels));
     mPrevSamples.resize(num_channels);
 
-    if(IsUHJ(mFmtChannels))
-    {
+    if(mFmtChannels == FmtSuperStereo)
+        mDecoder = std::make_unique<UhjStereoDecoder>();
+    else if(IsUHJ(mFmtChannels))
         mDecoder = std::make_unique<UhjDecoder>();
-        mDecoderFunc = (mFmtChannels == FmtSuperStereo) ? &UhjDecoder::decodeStereo
-            : &UhjDecoder::decode;
-    }
     else
-    {
         mDecoder = nullptr;
-        mDecoderFunc = nullptr;
-    }
 
     /* Clear the stepping value explicitly so the mixer knows not to mix this
      * until the update gets applied.

core/voice.h

@@ -219,8 +219,7 @@ struct Voice {
     AmbiScaling mAmbiScaling;
     uint mAmbiOrder;
 
-    std::unique_ptr<UhjDecoder> mDecoder;
-    UhjDecoder::DecoderFunc mDecoderFunc{};
+    std::unique_ptr<DecoderBase> mDecoder;
 
     /** Current target parameters used for mixing. */
     uint mStep{0};