63 lines
1.9 KiB
C++
63 lines
1.9 KiB
C++
#include "Delay.h"
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namespace serum
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{
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void DelayUnit::prepare (double sampleRate, int)
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{
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sr = sampleRate;
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const int maxDelay = (int) (sr * 2.1); // 2.1 seconds
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delayL.assign ((size_t) maxDelay, 0.0f);
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delayR.assign ((size_t) maxDelay, 0.0f);
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reset();
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}
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void DelayUnit::reset()
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{
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std::fill (delayL.begin(), delayL.end(), 0.0f);
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std::fill (delayR.begin(), delayR.end(), 0.0f);
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writePos = 0;
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dampL = dampR = 0.0f;
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}
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void DelayUnit::process (float* l, float* r, int numSamples, const float p[4])
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{
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const int len = (int) delayL.size();
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if (len < 4)
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return;
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const double delaySamples = juce::jlimit (2.0, (double) len - 2.0, maps::delayToMs (p[0]) / 1000.0 * sr);
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const float feedback = p[1] * 0.92f;
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const float dampCoef = 1.0f - p[2] * 0.95f; // 1 = no damping
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const float pingpong = p[3];
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for (int i = 0; i < numSamples; ++i)
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{
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double readPos = writePos - delaySamples;
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if (readPos < 0.0) readPos += len;
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const int i0 = (int) readPos;
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const int i1 = (i0 + 1) % len;
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const float frac = (float) (readPos - std::floor (readPos));
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float dl = delayL[(size_t) i0] * (1.0f - frac) + delayL[(size_t) i1] * frac;
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float dr = delayR[(size_t) i0] * (1.0f - frac) + delayR[(size_t) i1] * frac;
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// Damping lowpass in the feedback path.
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dampL = dl * (1.0f - dampCoef) + dampL * dampCoef;
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dampR = dr * (1.0f - dampCoef) + dampR * dampCoef;
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// Ping-pong: cross-feed between channels.
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const float feedL = dampR * pingpong + dampL * (1.0f - pingpong);
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const float feedR = dampL * pingpong + dampR * (1.0f - pingpong);
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delayL[(size_t) writePos] = l[i] + feedL * feedback;
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delayR[(size_t) writePos] = r[i] + feedR * feedback;
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l[i] = dl;
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r[i] = dr;
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writePos = (writePos + 1) % len;
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}
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}
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} // namespace serum
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