64 lines
1.9 KiB
C++
64 lines
1.9 KiB
C++
#include "Chorus.h"
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namespace serum
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{
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void ChorusUnit::prepare (double sampleRate, int)
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{
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sr = sampleRate;
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const int maxDelay = (int) (sr * 0.05); // 50ms
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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 ChorusUnit::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 ChorusUnit::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 = 0.1 + p[0] * 4.9; // 0.1..5 Hz
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const double depth = (0.5 + p[1] * 5.5) * sr / 1000.0; // 0.5..6 ms
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const double base = 8.0 * sr / 1000.0; // 8 ms centre
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const float width = p[2];
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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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delayL[(size_t) writePos] = inL;
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delayR[(size_t) writePos] = inR;
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lfoPhase += 6.28318530717958647692 * rate / sr;
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if (lfoPhase > 6.28318530717958647692) lfoPhase -= 6.28318530717958647692;
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float sumL = 0.0f, sumR = 0.0f;
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for (int v = 0; v < 2; ++v)
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{
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const double mod = std::sin (lfoPhase + v * 3.14159265358979323846) * depth;
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const double d = base + mod + (v == 1 ? width * depth * 0.5 : 0.0);
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double readPos = writePos - d;
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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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sumL += delayL[(size_t) i0] * (1.0f - frac) + delayL[(size_t) i1] * frac;
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sumR += delayR[(size_t) i0] * (1.0f - frac) + delayR[(size_t) i1] * frac;
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}
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l[i] = sumL * 0.5f;
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r[i] = sumR * 0.5f;
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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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