AnalogTapeModel

Physical modelling signal processing for analog tape recording
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BypassProcessor.h (2104B)

      1 #ifndef BYPASSPROCESSOR_H_INCLUDED
      2 #define BYPASSPROCESSOR_H_INCLUDED
      3 
      4 #include <JuceHeader.h>
      5 
      6 /** Utility class for *smoothly* bypassing a processor */
      7 class BypassProcessor
      8 {
      9 public:
     10     BypassProcessor() = default;
     11 
     12     static bool toBool (const std::atomic<float>* param)
     13     {
     14         return static_cast<bool> (param->load());
     15     }
     16 
     17     void prepare (int samplesPerBlock, int numChannels, bool onOffParam)
     18     {
     19         prevOnOffParam = onOffParam;
     20         fadeBuffer.setSize (numChannels, samplesPerBlock);
     21         bufferCopied = false;
     22     }
     23 
     24     /**
     25       * Call this at the start of your processBlock().
     26       * If it returns false, you can safely skip all other
     27       * processing.
     28       */
     29     bool processBlockIn (AudioBuffer<float>& block, bool onOffParam)
     30     {
     31         if (! onOffParam && ! prevOnOffParam)
     32             return false; // NOLINT
     33 
     34         if (onOffParam != prevOnOffParam)
     35         {
     36             fadeBuffer.makeCopyOf (block, true);
     37             bufferCopied = true;
     38         }
     39 
     40         return true;
     41     }
     42 
     43     void processBlockOut (AudioBuffer<float>& block, bool onOffParam)
     44     {
     45         if (onOffParam == prevOnOffParam)
     46             return;
     47 
     48         if (! bufferCopied)
     49             return; // parameter was changed in the middle of the buffer, let's wait for the next one!
     50 
     51         const auto numChannels = block.getNumChannels();
     52         const auto numSamples = block.getNumSamples();
     53 
     54         float startGain = ! onOffParam ? 1.0f // fade out
     55                                        : 0.0f; // fade in
     56         float endGain = 1.0f - startGain;
     57 
     58         block.applyGainRamp (0, numSamples, startGain, endGain);
     59         for (int ch = 0; ch < numChannels; ++ch)
     60             block.addFromWithRamp (ch, 0, fadeBuffer.getReadPointer (ch), numSamples, 1.0f - startGain, 1.0f - endGain);
     61 
     62         prevOnOffParam = onOffParam;
     63         bufferCopied = false;
     64     }
     65 
     66 private:
     67     bool prevOnOffParam = false;
     68     bool bufferCopied = false;
     69     AudioBuffer<float> fadeBuffer;
     70 
     71     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (BypassProcessor)
     72 };
     73 
     74 #endif // BYPASSPROCESSOR_H_INCLUDED