More members of Mixer are const

src/AudioIO.cpp

@@ -1953,8 +1953,11 @@ bool AudioIO::AllocateBuffers(
                   1,
                   std::max( mPlaybackSamplesToCopy, mPlaybackQueueMinimum ),
                   false,
-                  mRate, floatSample, false);
-               mPlaybackMixers[i]->ApplyTrackGains(false);
+                  mRate, floatSample,
+                  false, // low quality dithering and resampling
+                  nullptr,
+                  false // don't apply track gains
+               );
             }
          }
 

src/Mix.cpp

@@ -240,9 +240,11 @@ Mixer::Mixer(const WaveTrackConstArray &inputTracks,
              double startTime, double stopTime,
              unsigned numOutChannels, size_t outBufferSize, bool outInterleaved,
              double outRate, sampleFormat outFormat,
-             bool highQuality, MixerSpec *mixerSpec)
+             bool highQuality, MixerSpec *mixerSpec, bool applyTrackGains)
    : mNumInputTracks { inputTracks.size() }
 
+   , mApplyTrackGains{ applyTrackGains }
+
    // This is the number of samples grabbed in one go from a track
    // and placed in a queue, when mixing with resampling.
    // (Should we use WaveTrack::GetBestBlockSize instead?)
@@ -252,6 +254,9 @@ Mixer::Mixer(const WaveTrackConstArray &inputTracks,
    , mNumChannels{ numOutChannels }
    , mGains{ mNumChannels }
 
+   , mFormat{ outFormat }
+   , mRate{ outRate }
+
    , mMayThrow{ mayThrow }
 {
    mHighQuality = highQuality;
@@ -270,10 +275,7 @@ Mixer::Mixer(const WaveTrackConstArray &inputTracks,
    mTime = startTime;
    mBufferSize = outBufferSize;
    mInterleaved = outInterleaved;
-   mRate = outRate;
    mSpeed = 1.0;
-   mFormat = outFormat;
-   mApplyTrackGains = true;
    if( mixerSpec && mixerSpec->GetNumChannels() == mNumChannels &&
          mixerSpec->GetNumTracks() == mNumInputTracks )
       mMixerSpec = mixerSpec;
@@ -351,11 +353,6 @@ void Mixer::MakeResamplers()
       mResample[i] = std::make_unique<Resample>(mHighQuality, mMinFactor[i], mMaxFactor[i]);
 }
 
-void Mixer::ApplyTrackGains(bool apply)
-{
-   mApplyTrackGains = apply;
-}
-
 void Mixer::Clear()
 {
    for (unsigned int c = 0; c < mNumBuffers; c++) {

src/Mix.h

@@ -106,16 +106,11 @@ class AUDACITY_DLL_API Mixer {
          double startTime, double stopTime,
          unsigned numOutChannels, size_t outBufferSize, bool outInterleaved,
          double outRate, sampleFormat outFormat,
-         bool highQuality = true, MixerSpec *mixerSpec = NULL);
+         bool highQuality = true, MixerSpec *mixerSpec = nullptr,
+         bool applytTrackGains = true);
 
    virtual ~ Mixer();
 
-   //
-   // Setup
-   //
-
-   void ApplyTrackGains(bool apply = true); // True by default
-
    //
    // Processing
    //
@@ -165,18 +160,18 @@ class AUDACITY_DLL_API Mixer {
  private:
 
     // Input
-   size_t           mNumInputTracks;
+   const size_t     mNumInputTracks;
    ArrayOf<WaveTrackCache> mInputTrack;
    bool             mbVariableRates;
    const BoundedEnvelope *mEnvelope;
    ArrayOf<sampleCount> mSamplePos;
-   bool             mApplyTrackGains;
+   const bool       mApplyTrackGains;
    Doubles          mEnvValues;
    double           mT0; // Start time
    double           mT1; // Stop time (none if mT0==mT1)
    double           mTime;  // Current time (renamed from mT to mTime for consistency with AudioIO - mT represented warped time there)
    ArrayOf<std::unique_ptr<Resample>> mResample;
-   size_t           mQueueMaxLen;
+   const size_t     mQueueMaxLen;
    FloatBuffers     mSampleQueue;
    ArrayOf<int>     mQueueStart;
    ArrayOf<int>     mQueueLen;
@@ -185,21 +180,21 @@ class AUDACITY_DLL_API Mixer {
 
    // Output
    size_t              mMaxOut;
-   unsigned         mNumChannels;
+   const unsigned   mNumChannels;
    Floats           mGains;
    unsigned         mNumBuffers;
    size_t              mBufferSize;
    size_t              mInterleavedBufferSize;
-   sampleFormat     mFormat;
+   const sampleFormat mFormat;
    bool             mInterleaved;
    ArrayOf<SampleBuffer> mBuffer, mTemp;
    Floats           mFloatBuffer;
-   double           mRate;
+   const double     mRate;
    double           mSpeed;
    bool             mHighQuality;
    std::vector<double> mMinFactor, mMaxFactor;
 
-   bool             mMayThrow;
+   const bool       mMayThrow;
 };
 
 #endif