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/*
==============================================================================
This file is part of the JUCE library.
Copyright (c) 2017 - ROLI Ltd.
JUCE is an open source library subject to commercial or open-source
licensing.
By using JUCE, you agree to the terms of both the JUCE 5 End-User License
Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
27th April 2017).
End User License Agreement: www.juce.com/juce-5-licence
Privacy Policy: www.juce.com/juce-5-privacy-policy
Or: You may also use this code under the terms of the GPL v3 (see
www.gnu.org/licenses).
JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
DISCLAIMED.
==============================================================================
*/
namespace juce
{
namespace dsp
{
/**
Generates a signal based on a user-supplied function.
@tags{DSP}
*/
template <typename SampleType>
class Oscillator
{
public:
/** The NumericType is the underlying primitive type used by the SampleType (which
could be either a primitive or vector)
*/
using NumericType = typename SampleTypeHelpers::ElementType<SampleType>::Type;
/** Creates an uninitialised oscillator. Call initialise before first use. */
Oscillator() = default;
/** Creates an oscillator with a periodic input function (-pi..pi).
If lookup table is not zero, then the function will be approximated
with a lookup table.
*/
Oscillator (const std::function<NumericType(NumericType)>& function,
size_t lookupTableNumPoints = 0)
{
initialise (function, lookupTableNumPoints);
}
/** Returns true if the Oscillator has been initialised. */
bool isInitialised() const noexcept { return static_cast<bool> (generator); }
/** Initialises the oscillator with a waveform. */
void initialise (const std::function<NumericType(NumericType)>& function,
size_t lookupTableNumPoints = 0)
{
if (lookupTableNumPoints != 0)
{
auto* table = new LookupTableTransform<NumericType> (function,
-MathConstants<NumericType>::pi,
MathConstants<NumericType>::pi,
lookupTableNumPoints);
lookupTable.reset (table);
generator = [table] (NumericType x) { return (*table) (x); };
}
else
{
generator = function;
}
}
//==============================================================================
/** Sets the frequency of the oscillator. */
void setFrequency (NumericType newFrequency, bool force = false) noexcept
{
if (force)
{
frequency.setCurrentAndTargetValue (newFrequency);
return;
}
frequency.setTargetValue (newFrequency);
}
/** Returns the current frequency of the oscillator. */
NumericType getFrequency() const noexcept { return frequency.getTargetValue(); }
//==============================================================================
/** Called before processing starts. */
void prepare (const ProcessSpec& spec) noexcept
{
sampleRate = static_cast<NumericType> (spec.sampleRate);
rampBuffer.resize ((int) spec.maximumBlockSize);
reset();
}
/** Resets the internal state of the oscillator */
void reset() noexcept
{
phase.reset();
if (sampleRate > 0)
frequency.reset (sampleRate, 0.05);
}
//==============================================================================
/** Returns the result of processing a single sample. */
SampleType JUCE_VECTOR_CALLTYPE processSample (SampleType input) noexcept
{
jassert (isInitialised());
auto increment = MathConstants<NumericType>::twoPi * frequency.getNextValue() / sampleRate;
return input + generator (phase.advance (increment) - MathConstants<NumericType>::pi);
}
/** Processes the input and output buffers supplied in the processing context. */
template <typename ProcessContext>
void process (const ProcessContext& context) noexcept
{
jassert (isInitialised());
auto&& outBlock = context.getOutputBlock();
auto&& inBlock = context.getInputBlock();
// this is an output-only processor
jassert (outBlock.getNumSamples() <= static_cast<size_t> (rampBuffer.size()));
auto len = outBlock.getNumSamples();
auto numChannels = outBlock.getNumChannels();
auto inputChannels = inBlock.getNumChannels();
auto baseIncrement = MathConstants<NumericType>::twoPi / sampleRate;
if (context.isBypassed)
context.getOutputBlock().clear();
if (frequency.isSmoothing())
{
auto* buffer = rampBuffer.getRawDataPointer();
for (size_t i = 0; i < len; ++i)
buffer[i] = phase.advance (baseIncrement * frequency.getNextValue())
- MathConstants<NumericType>::pi;
if (! context.isBypassed)
{
size_t ch;
if (context.usesSeparateInputAndOutputBlocks())
{
for (ch = 0; ch < jmin (numChannels, inputChannels); ++ch)
{
auto* dst = outBlock.getChannelPointer (ch);
auto* src = inBlock.getChannelPointer (ch);
for (size_t i = 0; i < len; ++i)
dst[i] = src[i] + generator (buffer[i]);
}
}
else
{
for (ch = 0; ch < jmin (numChannels, inputChannels); ++ch)
{
auto* dst = outBlock.getChannelPointer (ch);
for (size_t i = 0; i < len; ++i)
dst[i] += generator (buffer[i]);
}
}
for (; ch < numChannels; ++ch)
{
auto* dst = outBlock.getChannelPointer (ch);
for (size_t i = 0; i < len; ++i)
dst[i] = generator (buffer[i]);
}
}
}
else
{
auto freq = baseIncrement * frequency.getNextValue();
auto p = phase;
if (context.isBypassed)
{
frequency.skip (static_cast<int> (len));
p.advance (freq * static_cast<NumericType> (len));
}
else
{
size_t ch;
if (context.usesSeparateInputAndOutputBlocks())
{
for (ch = 0; ch < jmin (numChannels, inputChannels); ++ch)
{
p = phase;
auto* dst = outBlock.getChannelPointer (ch);
auto* src = inBlock.getChannelPointer (ch);
for (size_t i = 0; i < len; ++i)
dst[i] = src[i] + generator (p.advance (freq) - MathConstants<NumericType>::pi);
}
}
else
{
for (ch = 0; ch < jmin (numChannels, inputChannels); ++ch)
{
p = phase;
auto* dst = outBlock.getChannelPointer (ch);
for (size_t i = 0; i < len; ++i)
dst[i] += generator (p.advance (freq) - MathConstants<NumericType>::pi);
}
}
for (; ch < numChannels; ++ch)
{
p = phase;
auto* dst = outBlock.getChannelPointer (ch);
for (size_t i = 0; i < len; ++i)
dst[i] = generator (p.advance (freq) - MathConstants<NumericType>::pi);
}
}
phase = p;
}
}
private:
//==============================================================================
std::function<NumericType(NumericType)> generator;
std::unique_ptr<LookupTableTransform<NumericType>> lookupTable;
Array<NumericType> rampBuffer;
SmoothedValue<NumericType> frequency { static_cast<NumericType> (440.0) };
NumericType sampleRate = 48000.0;
Phase<NumericType> phase;
};
} // namespace dsp
} // namespace juce
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