60 lines
1.7 KiB
C++
60 lines
1.7 KiB
C++
#include "Flanger.h"
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namespace serum
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{
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void FlangerUnit::prepare (double sampleRate, int)
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{
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sr = sampleRate;
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const int maxDelay = (int) (sr * 0.03); // 30ms
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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 FlangerUnit::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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lfoPhase = 0.0;
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}
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void FlangerUnit::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 rate = 0.05 + p[0] * 2.0;
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const double depth = (0.3 + p[1] * 4.7) * sr / 1000.0; // 0.3..5 ms
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const double base = 1.5 * sr / 1000.0;
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const float feedback = p[2] * 0.9f;
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for (int i = 0; i < numSamples; ++i)
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{
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const float inL = l[i], inR = r[i];
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lfoPhase += 6.28318530717958647692 * rate / sr;
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if (lfoPhase > 6.28318530717958647692) lfoPhase -= 6.28318530717958647692;
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const double mod = std::sin (lfoPhase) * depth;
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double readPos = writePos - (base + mod);
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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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const float outL = delayL[(size_t) i0] * (1.0f - frac) + delayL[(size_t) i1] * frac;
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const float outR = delayR[(size_t) i0] * (1.0f - frac) + delayR[(size_t) i1] * frac;
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delayL[(size_t) writePos] = inL + outL * feedback;
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delayR[(size_t) writePos] = inR + outR * feedback;
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l[i] = outL;
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r[i] = outR;
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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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