314 lines
11 KiB
C++
314 lines
11 KiB
C++
/*
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==============================================================================
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This file is part of the JUCE library.
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Copyright (c) 2017 - ROLI Ltd.
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JUCE is an open source library subject to commercial or open-source
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licensing.
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The code included in this file is provided under the terms of the ISC license
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http://www.isc.org/downloads/software-support-policy/isc-license. Permission
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To use, copy, modify, and/or distribute this software for any purpose with or
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without fee is hereby granted provided that the above copyright notice and
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this permission notice appear in all copies.
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JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
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EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
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DISCLAIMED.
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==============================================================================
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*/
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namespace juce
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{
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//==============================================================================
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/**
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Performs a simple reverb effect on a stream of audio data.
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This is a simple stereo reverb, based on the technique and tunings used in FreeVerb.
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Use setSampleRate() to prepare it, and then call processStereo() or processMono() to
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apply the reverb to your audio data.
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@see ReverbAudioSource
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@tags{Audio}
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*/
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class Reverb
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{
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public:
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//==============================================================================
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Reverb()
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{
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setParameters (Parameters());
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setSampleRate (44100.0);
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}
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//==============================================================================
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/** Holds the parameters being used by a Reverb object. */
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struct Parameters
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{
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float roomSize = 0.5f; /**< Room size, 0 to 1.0, where 1.0 is big, 0 is small. */
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float damping = 0.5f; /**< Damping, 0 to 1.0, where 0 is not damped, 1.0 is fully damped. */
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float wetLevel = 0.33f; /**< Wet level, 0 to 1.0 */
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float dryLevel = 0.4f; /**< Dry level, 0 to 1.0 */
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float width = 1.0f; /**< Reverb width, 0 to 1.0, where 1.0 is very wide. */
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float freezeMode = 0.0f; /**< Freeze mode - values < 0.5 are "normal" mode, values > 0.5
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put the reverb into a continuous feedback loop. */
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};
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//==============================================================================
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/** Returns the reverb's current parameters. */
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const Parameters& getParameters() const noexcept { return parameters; }
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/** Applies a new set of parameters to the reverb.
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Note that this doesn't attempt to lock the reverb, so if you call this in parallel with
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the process method, you may get artifacts.
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*/
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void setParameters (const Parameters& newParams)
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{
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const float wetScaleFactor = 3.0f;
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const float dryScaleFactor = 2.0f;
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const float wet = newParams.wetLevel * wetScaleFactor;
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dryGain.setTargetValue (newParams.dryLevel * dryScaleFactor);
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wetGain1.setTargetValue (0.5f * wet * (1.0f + newParams.width));
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wetGain2.setTargetValue (0.5f * wet * (1.0f - newParams.width));
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gain = isFrozen (newParams.freezeMode) ? 0.0f : 0.015f;
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parameters = newParams;
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updateDamping();
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}
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//==============================================================================
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/** Sets the sample rate that will be used for the reverb.
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You must call this before the process methods, in order to tell it the correct sample rate.
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*/
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void setSampleRate (const double sampleRate)
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{
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jassert (sampleRate > 0);
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static const short combTunings[] = { 1116, 1188, 1277, 1356, 1422, 1491, 1557, 1617 }; // (at 44100Hz)
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static const short allPassTunings[] = { 556, 441, 341, 225 };
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const int stereoSpread = 23;
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const int intSampleRate = (int) sampleRate;
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for (int i = 0; i < numCombs; ++i)
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{
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comb[0][i].setSize ((intSampleRate * combTunings[i]) / 44100);
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comb[1][i].setSize ((intSampleRate * (combTunings[i] + stereoSpread)) / 44100);
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}
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for (int i = 0; i < numAllPasses; ++i)
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{
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allPass[0][i].setSize ((intSampleRate * allPassTunings[i]) / 44100);
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allPass[1][i].setSize ((intSampleRate * (allPassTunings[i] + stereoSpread)) / 44100);
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}
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const double smoothTime = 0.01;
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damping .reset (sampleRate, smoothTime);
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feedback.reset (sampleRate, smoothTime);
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dryGain .reset (sampleRate, smoothTime);
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wetGain1.reset (sampleRate, smoothTime);
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wetGain2.reset (sampleRate, smoothTime);
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}
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/** Clears the reverb's buffers. */
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void reset()
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{
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for (int j = 0; j < numChannels; ++j)
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{
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for (int i = 0; i < numCombs; ++i)
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comb[j][i].clear();
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for (int i = 0; i < numAllPasses; ++i)
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allPass[j][i].clear();
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}
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}
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//==============================================================================
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/** Applies the reverb to two stereo channels of audio data. */
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void processStereo (float* const left, float* const right, const int numSamples) noexcept
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{
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jassert (left != nullptr && right != nullptr);
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for (int i = 0; i < numSamples; ++i)
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{
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const float input = (left[i] + right[i]) * gain;
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float outL = 0, outR = 0;
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const float damp = damping.getNextValue();
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const float feedbck = feedback.getNextValue();
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for (int j = 0; j < numCombs; ++j) // accumulate the comb filters in parallel
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{
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outL += comb[0][j].process (input, damp, feedbck);
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outR += comb[1][j].process (input, damp, feedbck);
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}
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for (int j = 0; j < numAllPasses; ++j) // run the allpass filters in series
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{
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outL = allPass[0][j].process (outL);
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outR = allPass[1][j].process (outR);
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}
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const float dry = dryGain.getNextValue();
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const float wet1 = wetGain1.getNextValue();
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const float wet2 = wetGain2.getNextValue();
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left[i] = outL * wet1 + outR * wet2 + left[i] * dry;
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right[i] = outR * wet1 + outL * wet2 + right[i] * dry;
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}
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}
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/** Applies the reverb to a single mono channel of audio data. */
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void processMono (float* const samples, const int numSamples) noexcept
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{
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jassert (samples != nullptr);
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for (int i = 0; i < numSamples; ++i)
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{
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const float input = samples[i] * gain;
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float output = 0;
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const float damp = damping.getNextValue();
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const float feedbck = feedback.getNextValue();
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for (int j = 0; j < numCombs; ++j) // accumulate the comb filters in parallel
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output += comb[0][j].process (input, damp, feedbck);
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for (int j = 0; j < numAllPasses; ++j) // run the allpass filters in series
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output = allPass[0][j].process (output);
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const float dry = dryGain.getNextValue();
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const float wet1 = wetGain1.getNextValue();
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samples[i] = output * wet1 + samples[i] * dry;
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}
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}
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private:
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//==============================================================================
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static bool isFrozen (const float freezeMode) noexcept { return freezeMode >= 0.5f; }
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void updateDamping() noexcept
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{
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const float roomScaleFactor = 0.28f;
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const float roomOffset = 0.7f;
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const float dampScaleFactor = 0.4f;
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if (isFrozen (parameters.freezeMode))
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setDamping (0.0f, 1.0f);
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else
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setDamping (parameters.damping * dampScaleFactor,
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parameters.roomSize * roomScaleFactor + roomOffset);
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}
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void setDamping (const float dampingToUse, const float roomSizeToUse) noexcept
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{
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damping.setTargetValue (dampingToUse);
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feedback.setTargetValue (roomSizeToUse);
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}
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//==============================================================================
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class CombFilter
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{
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public:
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CombFilter() noexcept {}
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void setSize (const int size)
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{
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if (size != bufferSize)
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{
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bufferIndex = 0;
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buffer.malloc (size);
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bufferSize = size;
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}
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clear();
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}
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void clear() noexcept
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{
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last = 0;
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buffer.clear ((size_t) bufferSize);
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}
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float process (const float input, const float damp, const float feedbackLevel) noexcept
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{
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const float output = buffer[bufferIndex];
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last = (output * (1.0f - damp)) + (last * damp);
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JUCE_UNDENORMALISE (last);
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float temp = input + (last * feedbackLevel);
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JUCE_UNDENORMALISE (temp);
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buffer[bufferIndex] = temp;
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bufferIndex = (bufferIndex + 1) % bufferSize;
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return output;
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}
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private:
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HeapBlock<float> buffer;
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int bufferSize = 0, bufferIndex = 0;
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float last = 0.0f;
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JUCE_DECLARE_NON_COPYABLE (CombFilter)
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};
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//==============================================================================
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class AllPassFilter
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{
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public:
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AllPassFilter() noexcept {}
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void setSize (const int size)
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{
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if (size != bufferSize)
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{
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bufferIndex = 0;
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buffer.malloc (size);
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bufferSize = size;
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}
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clear();
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}
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void clear() noexcept
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{
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buffer.clear ((size_t) bufferSize);
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}
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float process (const float input) noexcept
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{
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const float bufferedValue = buffer [bufferIndex];
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float temp = input + (bufferedValue * 0.5f);
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JUCE_UNDENORMALISE (temp);
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buffer [bufferIndex] = temp;
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bufferIndex = (bufferIndex + 1) % bufferSize;
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return bufferedValue - input;
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}
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private:
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HeapBlock<float> buffer;
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int bufferSize = 0, bufferIndex = 0;
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JUCE_DECLARE_NON_COPYABLE (AllPassFilter)
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};
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//==============================================================================
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enum { numCombs = 8, numAllPasses = 4, numChannels = 2 };
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Parameters parameters;
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float gain;
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CombFilter comb [numChannels][numCombs];
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AllPassFilter allPass [numChannels][numAllPasses];
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SmoothedValue<float> damping, feedback, dryGain, wetGain1, wetGain2;
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JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Reverb)
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};
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} // namespace juce
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