Echo.cpp

Go to the documentation of this file.

/**********************************************************************
 
  Audacity: A Digital Audio Editor
 
  Echo.cpp
 
  Dominic Mazzoni
  Vaughan Johnson (dialog)
 
*******************************************************************//****************************************************************//*******************************************************************/
 
 
#include "Echo.h"
#include "LoadEffects.h"
 
#include <wx/intl.h>
 
#include "../ShuttleGui.h"
#include "../widgets/AudacityMessageBox.h"
#include "../widgets/valnum.h"
 
const EffectParameterMethods& EffectEcho::Parameters() const
{
   static CapturedParameters<EffectEcho,
      Delay, Decay
   > parameters;
   return parameters;
}
 
const ComponentInterfaceSymbol EffectEcho::Symbol
{ XO("Echo") };
 
namespace{ BuiltinEffectsModule::Registration< EffectEcho > reg; }
 
 
struct EffectEcho::Instance
   : public PerTrackEffect::Instance
   , public EffectInstanceWithBlockSize
{
   Instance(const PerTrackEffect& effect)
      : PerTrackEffect::Instance{ effect }
   {}
 
   bool ProcessInitialize(EffectSettings& settings, double sampleRate,
      ChannelNames chanMap) override;
 
   size_t ProcessBlock(EffectSettings& settings,
      const float* const* inBlock, float* const* outBlock, size_t blockLen)  override;
 
   bool ProcessFinalize() noexcept override;
 
   unsigned GetAudioOutCount() const override
   {
      return 1;
   }
 
   unsigned GetAudioInCount() const override
   {
      return 1;
   }
 
   Floats history;
   size_t histPos;
   size_t histLen;
};
 
 
 
std::shared_ptr<EffectInstance> EffectEcho::MakeInstance() const
{
   return std::make_shared<Instance>(*this);
}
 
 
 
 
EffectEcho::EffectEcho()
{
   SetLinearEffectFlag(true);
}
 
EffectEcho::~EffectEcho()
{
}
 
// ComponentInterface implementation
 
ComponentInterfaceSymbol EffectEcho::GetSymbol() const
{
   return Symbol;
}
 
TranslatableString EffectEcho::GetDescription() const
{
   return XO("Repeats the selected audio again and again");
}
 
ManualPageID EffectEcho::ManualPage() const
{
   return L"Echo";
}
 
// EffectDefinitionInterface implementation
 
EffectType EffectEcho::GetType() const
{
   return EffectTypeProcess;
}
 
bool EffectEcho::Instance::ProcessInitialize(
   EffectSettings& settings, double sampleRate, ChannelNames)
{
   auto& echoSettings = GetSettings(settings);  
   if (echoSettings.delay == 0.0)
      return false;
 
   histPos = 0;
   auto requestedHistLen = (sampleCount) (sampleRate * echoSettings.delay);
 
   // Guard against extreme delay values input by the user
   try {
      // Guard against huge delay values from the user.
      // Don't violate the assertion in as_size_t
      if (requestedHistLen !=
            (histLen = static_cast<size_t>(requestedHistLen.as_long_long())))
         throw std::bad_alloc{};
      history.reinit(histLen, true);
   }
   catch ( const std::bad_alloc& ) {
      mProcessor.MessageBox( XO("Requested value exceeds memory capacity.") );
      return false;
   }
 
   return history != NULL;
}
 
bool EffectEcho::Instance::ProcessFinalize() noexcept
{
   return true;
}
 
size_t EffectEcho::Instance::ProcessBlock(EffectSettings& settings,
   const float *const *inBlock, float *const *outBlock, size_t blockLen)
{
   auto& echoSettings = GetSettings(settings);
   
   const float *ibuf = inBlock[0];
   float *obuf = outBlock[0];
 
   for (decltype(blockLen) i = 0; i < blockLen; i++, histPos++)
   {
      if (histPos == histLen)
      {
         histPos = 0;
      }
      history[histPos] = obuf[i] = ibuf[i] + history[histPos] * echoSettings.decay;
   }
 
   return blockLen;
}
 
 
 
struct EffectEcho::Validator
   : EffectUIValidator
{
   Validator(EffectUIClientInterface& effect,
      EffectSettingsAccess& access, const EffectEchoSettings& settings)
      : EffectUIValidator{ effect, access }
      , mSettings{ settings }
   {}
   virtual ~Validator() = default;
 
   Effect& GetEffect() const { return static_cast<Effect&>(mEffect); }
 
   bool ValidateUI() override;
   bool UpdateUI() override;
 
   void PopulateOrExchange(ShuttleGui& S);
 
   EffectEchoSettings mSettings;
};
 
 
 
std::unique_ptr<EffectUIValidator> EffectEcho::PopulateOrExchange(
   ShuttleGui & S, EffectInstance &, EffectSettingsAccess &access,
   const EffectOutputs *)
{
   auto& settings = access.Get();
   auto& myEffSettings = GetSettings(settings);
   auto result = std::make_unique<Validator>(*this, access, myEffSettings);
   result->PopulateOrExchange(S);
   return result;
}
 
 
void EffectEcho::Validator::PopulateOrExchange(ShuttleGui & S)
{
   auto& echoSettings = mSettings;
 
   S.AddSpace(0, 5);
 
   S.StartMultiColumn(2, wxALIGN_CENTER);
   {
      S.Validator<FloatingPointValidator<double>>(
            3, &echoSettings.delay, NumValidatorStyle::NO_TRAILING_ZEROES,
            Delay.min, Delay.max )
         .AddTextBox(XXO("&Delay time (seconds):"), L"", 10);
 
      S.Validator<FloatingPointValidator<double>>(
            3, &echoSettings.decay, NumValidatorStyle::NO_TRAILING_ZEROES,
            Decay.min, Decay.max)
         .AddTextBox(XXO("D&ecay factor:"), L"", 10);
   }
   S.EndMultiColumn();   
}
 
 
bool EffectEcho::Validator::ValidateUI()
{
   mAccess.ModifySettings
   (
      [this](EffectSettings& settings)
   {
      // pass back the modified settings to the MessageBuffer
 
      EffectEcho::GetSettings(settings) = mSettings;
      return nullptr;
   }
   );
 
   return true;
}
 
 
bool EffectEcho::Validator::UpdateUI()
{
   // get the settings from the MessageBuffer and write them to our local copy
   const auto& settings = mAccess.Get();
 
   mSettings = GetSettings(settings);
 
   return true;
}