a587a43ff9
Dual-stage compressor (optical + VCA) with output transformer saturation. - Port-Hamiltonian T4B opto-cell model with implicit trapezoidal integration - Feed-forward VCA with 7 ratios, 6 attack/release presets, Dual release mode - 3 transformer types (Nickel/Iron/Steel) with 4x oversampled waveshaping - Analog-style needle VU meters, horizontal GR meters - Sidechain HPF, stereo link, independent section bypass - Full state save/restore, CI/CD for Windows/macOS/Linux
72 sor
2.3 KiB
C++
72 sor
2.3 KiB
C++
#pragma once
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#include <cmath>
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#include <algorithm>
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// ============================================================
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// Port-Hamiltonian T4B Electro-Optical Compressor Model
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//
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// Models the EL panel (capacitive energy store) coupled to a
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// CdS photoresistor (nonlinear dissipation) using implicit
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// trapezoidal integration with Newton-Raphson iteration.
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//
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// All parameters are normalized for audio-level (0..1) operation.
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// ============================================================
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class OpticalCell
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{
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public:
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OpticalCell();
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void prepare (double sampleRate);
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void reset();
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// Process one sample: sidechain input (linear), returns gain (0..1)
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float processSample (float sidechainLevel, float thresholdLinear);
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// Current GR in dB (for metering, always <= 0)
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float getGainReductionDb() const;
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private:
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double sr = 44100.0;
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double dt = 1.0 / 88200.0; // 2x oversampled time step
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// ---- Port-Hamiltonian State (normalized units) ----
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// EL panel: capacitive energy store
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double q_el = 0.0; // charge state
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double C_el = 0.01; // capacitance (~10ms attack with R_el=1)
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double R_el = 1.0; // series resistance (normalized)
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double eta_el = 50.0; // electro-optical efficiency (scaled for audio levels)
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// CdS photoresistor: nonlinear dissipation
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double R_cds = 100.0; // current resistance (normalized)
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double R_cds_dark = 100.0; // dark resistance (no light → no compression)
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double R_cds_min = 0.01; // minimum resistance (max compression)
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double k_cds = 1.0; // CdS scaling factor
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double gamma = 0.7; // CdS nonlinearity exponent
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// Memory effect (CdS illumination history)
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double lightHistory = 0.0;
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double memoryTau = 2.0; // memory time constant (seconds)
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double memoryAlpha = 0.3; // history influence factor
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// Light state
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double lightOutput = 0.0;
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// Signal path impedance for gain (normalized)
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double R_fixed = 1.0;
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// Current gain (linear)
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double currentGain = 1.0;
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// Implicit solver
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static constexpr int maxNewtonIter = 5;
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static constexpr double newtonTol = 1.0e-8;
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// 2x oversampling
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float prevInput = 0.0f;
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// Core methods
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void solveImplicitStep (double inputLevel);
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void updateGain();
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};
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