mirror of
https://github.com/juce-framework/JUCE.git
synced 2026-01-09 23:34:20 +00:00
323 lines
12 KiB
C++
323 lines
12 KiB
C++
/*
|
|
==============================================================================
|
|
|
|
This file is part of the JUCE framework.
|
|
Copyright (c) Raw Material Software Limited
|
|
|
|
JUCE is an open source framework subject to commercial or open source
|
|
licensing.
|
|
|
|
By downloading, installing, or using the JUCE framework, or combining the
|
|
JUCE framework with any other source code, object code, content or any other
|
|
copyrightable work, you agree to the terms of the JUCE End User Licence
|
|
Agreement, and all incorporated terms including the JUCE Privacy Policy and
|
|
the JUCE Website Terms of Service, as applicable, which will bind you. If you
|
|
do not agree to the terms of these agreements, we will not license the JUCE
|
|
framework to you, and you must discontinue the installation or download
|
|
process and cease use of the JUCE framework.
|
|
|
|
JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
|
|
JUCE Privacy Policy: https://juce.com/juce-privacy-policy
|
|
JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/
|
|
|
|
Or:
|
|
|
|
You may also use this code under the terms of the AGPLv3:
|
|
https://www.gnu.org/licenses/agpl-3.0.en.html
|
|
|
|
THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
|
|
WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
|
|
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.
|
|
|
|
==============================================================================
|
|
*/
|
|
|
|
namespace juce::dsp
|
|
{
|
|
|
|
//==============================================================================
|
|
/**
|
|
A collection of structs to pass as the template argument when setting the
|
|
interpolation type for the DelayLine class.
|
|
*/
|
|
namespace DelayLineInterpolationTypes
|
|
{
|
|
/**
|
|
No interpolation between successive samples in the delay line will be
|
|
performed. This is useful when the delay is a constant integer or to
|
|
create lo-fi audio effects.
|
|
|
|
@tags{DSP}
|
|
*/
|
|
struct None {};
|
|
|
|
/**
|
|
Successive samples in the delay line will be linearly interpolated. This
|
|
type of interpolation has a low computational cost where the delay can be
|
|
modulated in real time, but it also introduces a low-pass filtering effect
|
|
into your audio signal.
|
|
|
|
@tags{DSP}
|
|
*/
|
|
struct Linear {};
|
|
|
|
/**
|
|
Successive samples in the delay line will be interpolated using a 3rd order
|
|
Lagrange interpolator. This method incurs more computational overhead than
|
|
linear interpolation but reduces the low-pass filtering effect whilst
|
|
remaining amenable to real time delay modulation.
|
|
|
|
@tags{DSP}
|
|
*/
|
|
struct Lagrange3rd {};
|
|
|
|
/**
|
|
Successive samples in the delay line will be interpolated using 1st order
|
|
Thiran interpolation. This method is very efficient, and features a flat
|
|
amplitude frequency response in exchange for less accuracy in the phase
|
|
response. This interpolation method is stateful so is unsuitable for
|
|
applications requiring fast delay modulation.
|
|
|
|
@tags{DSP}
|
|
*/
|
|
struct Thiran {};
|
|
}
|
|
|
|
//==============================================================================
|
|
/**
|
|
A delay line processor featuring several algorithms for the fractional delay
|
|
calculation, block processing, and sample-by-sample processing useful when
|
|
modulating the delay in real time or creating a standard delay effect with
|
|
feedback.
|
|
|
|
Note: If you intend to change the delay in real time, you may want to smooth
|
|
changes to the delay systematically using either a ramp or a low-pass filter.
|
|
|
|
@see SmoothedValue, FirstOrderTPTFilter
|
|
|
|
@tags{DSP}
|
|
*/
|
|
template <typename SampleType, typename InterpolationType = DelayLineInterpolationTypes::Linear>
|
|
class DelayLine
|
|
{
|
|
public:
|
|
//==============================================================================
|
|
/** Default constructor. */
|
|
DelayLine();
|
|
|
|
/** Constructor. */
|
|
explicit DelayLine (int maximumDelayInSamples);
|
|
|
|
//==============================================================================
|
|
/** Sets the delay in samples. */
|
|
void setDelay (SampleType newDelayInSamples);
|
|
|
|
/** Returns the current delay in samples. */
|
|
SampleType getDelay() const;
|
|
|
|
//==============================================================================
|
|
/** Initialises the processor. */
|
|
void prepare (const ProcessSpec& spec);
|
|
|
|
/** Sets a new maximum delay in samples.
|
|
|
|
Also clears the delay line.
|
|
|
|
This may allocate internally, so you should never call it from the audio thread.
|
|
*/
|
|
void setMaximumDelayInSamples (int maxDelayInSamples);
|
|
|
|
/** Gets the maximum possible delay in samples.
|
|
|
|
For very short delay times, the result of getMaximumDelayInSamples() may
|
|
differ from the last value passed to setMaximumDelayInSamples().
|
|
*/
|
|
int getMaximumDelayInSamples() const noexcept { return totalSize - 2; }
|
|
|
|
/** Resets the internal state variables of the processor. */
|
|
void reset();
|
|
|
|
//==============================================================================
|
|
/** Pushes a single sample into one channel of the delay line.
|
|
|
|
Use this function and popSample instead of process if you need to modulate
|
|
the delay in real time instead of using a fixed delay value, or if you want
|
|
to code a delay effect with a feedback loop.
|
|
|
|
@see setDelay, popSample, process
|
|
*/
|
|
void pushSample (int channel, SampleType sample);
|
|
|
|
/** Pops a single sample from one channel of the delay line.
|
|
|
|
Use this function to modulate the delay in real time or implement standard
|
|
delay effects with feedback.
|
|
|
|
@param channel the target channel for the delay line.
|
|
|
|
@param delayInSamples sets the wanted fractional delay in samples, or -1
|
|
to use the value being used before or set with
|
|
setDelay function.
|
|
|
|
@param updateReadPointer should be set to true if you use the function
|
|
once for each sample, or false if you need
|
|
multi-tap delay capabilities.
|
|
|
|
@see setDelay, pushSample, process
|
|
*/
|
|
SampleType popSample (int channel, SampleType delayInSamples = -1, bool updateReadPointer = true);
|
|
|
|
//==============================================================================
|
|
/** Processes the input and output samples supplied in the processing context.
|
|
|
|
Can be used for block processing when the delay is not going to change
|
|
during processing. The delay must first be set by calling setDelay.
|
|
|
|
@see setDelay
|
|
*/
|
|
template <typename ProcessContext>
|
|
void process (const ProcessContext& context) noexcept
|
|
{
|
|
const auto& inputBlock = context.getInputBlock();
|
|
auto& outputBlock = context.getOutputBlock();
|
|
const auto numChannels = outputBlock.getNumChannels();
|
|
const auto numSamples = outputBlock.getNumSamples();
|
|
|
|
jassert (inputBlock.getNumChannels() == numChannels);
|
|
jassert (inputBlock.getNumChannels() == writePos.size());
|
|
jassert (inputBlock.getNumSamples() == numSamples);
|
|
|
|
if (context.isBypassed)
|
|
{
|
|
outputBlock.copyFrom (inputBlock);
|
|
return;
|
|
}
|
|
|
|
for (size_t channel = 0; channel < numChannels; ++channel)
|
|
{
|
|
auto* inputSamples = inputBlock.getChannelPointer (channel);
|
|
auto* outputSamples = outputBlock.getChannelPointer (channel);
|
|
|
|
for (size_t i = 0; i < numSamples; ++i)
|
|
{
|
|
pushSample ((int) channel, inputSamples[i]);
|
|
outputSamples[i] = popSample ((int) channel);
|
|
}
|
|
}
|
|
}
|
|
|
|
private:
|
|
//==============================================================================
|
|
SampleType interpolateSample (int channel)
|
|
{
|
|
if constexpr (std::is_same_v<InterpolationType, DelayLineInterpolationTypes::None>)
|
|
{
|
|
auto index = (readPos[(size_t) channel] + delayInt) % totalSize;
|
|
return bufferData.getSample (channel, index);
|
|
}
|
|
else if constexpr (std::is_same_v<InterpolationType, DelayLineInterpolationTypes::Linear>)
|
|
{
|
|
auto index1 = readPos[(size_t) channel] + delayInt;
|
|
auto index2 = index1 + 1;
|
|
|
|
if (index2 >= totalSize)
|
|
{
|
|
index1 %= totalSize;
|
|
index2 %= totalSize;
|
|
}
|
|
|
|
auto value1 = bufferData.getSample (channel, index1);
|
|
auto value2 = bufferData.getSample (channel, index2);
|
|
|
|
return value1 + delayFrac * (value2 - value1);
|
|
}
|
|
else if constexpr (std::is_same_v<InterpolationType, DelayLineInterpolationTypes::Lagrange3rd>)
|
|
{
|
|
auto index1 = readPos[(size_t) channel] + delayInt;
|
|
auto index2 = index1 + 1;
|
|
auto index3 = index2 + 1;
|
|
auto index4 = index3 + 1;
|
|
|
|
if (index4 >= totalSize)
|
|
{
|
|
index1 %= totalSize;
|
|
index2 %= totalSize;
|
|
index3 %= totalSize;
|
|
index4 %= totalSize;
|
|
}
|
|
|
|
auto* samples = bufferData.getReadPointer (channel);
|
|
|
|
auto value1 = samples[index1];
|
|
auto value2 = samples[index2];
|
|
auto value3 = samples[index3];
|
|
auto value4 = samples[index4];
|
|
|
|
auto d1 = delayFrac - 1.f;
|
|
auto d2 = delayFrac - 2.f;
|
|
auto d3 = delayFrac - 3.f;
|
|
|
|
auto c1 = -d1 * d2 * d3 / 6.f;
|
|
auto c2 = d2 * d3 * 0.5f;
|
|
auto c3 = -d1 * d3 * 0.5f;
|
|
auto c4 = d1 * d2 / 6.f;
|
|
|
|
return value1 * c1 + delayFrac * (value2 * c2 + value3 * c3 + value4 * c4);
|
|
}
|
|
else if constexpr (std::is_same_v<InterpolationType, DelayLineInterpolationTypes::Thiran>)
|
|
{
|
|
auto index1 = readPos[(size_t) channel] + delayInt;
|
|
auto index2 = index1 + 1;
|
|
|
|
if (index2 >= totalSize)
|
|
{
|
|
index1 %= totalSize;
|
|
index2 %= totalSize;
|
|
}
|
|
|
|
auto value1 = bufferData.getSample (channel, index1);
|
|
auto value2 = bufferData.getSample (channel, index2);
|
|
|
|
auto output = approximatelyEqual (delayFrac, (SampleType) 0) ? value1 : value2 + alpha * (value1 - v[(size_t) channel]);
|
|
v[(size_t) channel] = output;
|
|
|
|
return output;
|
|
}
|
|
}
|
|
|
|
//==============================================================================
|
|
void updateInternalVariables()
|
|
{
|
|
if constexpr (std::is_same_v<InterpolationType, DelayLineInterpolationTypes::Lagrange3rd>)
|
|
{
|
|
if (delayFrac < (SampleType) 2.0 && delayInt >= 1)
|
|
{
|
|
delayFrac++;
|
|
delayInt--;
|
|
}
|
|
}
|
|
else if constexpr (std::is_same_v<InterpolationType, DelayLineInterpolationTypes::Thiran>)
|
|
{
|
|
if (delayFrac < (SampleType) 0.618 && delayInt >= 1)
|
|
{
|
|
delayFrac++;
|
|
delayInt--;
|
|
}
|
|
|
|
alpha = (1 - delayFrac) / (1 + delayFrac);
|
|
}
|
|
}
|
|
|
|
//==============================================================================
|
|
double sampleRate;
|
|
|
|
//==============================================================================
|
|
AudioBuffer<SampleType> bufferData;
|
|
std::vector<SampleType> v;
|
|
std::vector<int> writePos, readPos;
|
|
SampleType delay = 0.0, delayFrac = 0.0;
|
|
int delayInt = 0, totalSize = 4;
|
|
SampleType alpha = 0.0;
|
|
};
|
|
|
|
} // namespace juce::dsp
|