tlib/synth/tx_voice.h

#pragma once
#include "../util/audio_math.h"
#include "ivoice.h"
#include "tx_envelope.h"
#include "tx_operator.h"
#include "tx_sineosc.h"

namespace trnr {

class tx_voice : public ivoice {
public:
	tx_voice()
		: algorithm {0}
		, pitch_env_amt {0.f}
		, feedback_amt {0.f}
		, bit_resolution(12.f)
	{
	}

	bool gate = false;
	bool trigger = false;
	int midi_note = 0;
	float velocity = 1.f;
	float additional_pitch_mod = 0.f; // modulates pitch in frequency

	int algorithm;
	float pitch_env_amt;
	float feedback_amt;
	float bit_resolution;
	tx_sineosc feedback_osc;
	tx_envelope pitch_env;
	tx_operator op1;
	tx_operator op2;
	tx_operator op3;

	void note_on(int _note, float _velocity) override
	{
		this->gate = true;
		this->trigger = true;
		midi_note = _note;
		velocity = _velocity;
	}

	void note_off() override { this->gate = false; }

	// modulates the pitch in semitones
	void modulate_pitch(float _pitch) override { this->pitch_mod = _pitch; }

	float process_sample() override
	{
		float pitch_env_signal = pitch_env.process_sample(gate, trigger) * pitch_env_amt;
		float pitched_freq = midi_to_frequency(midi_note + pitch_mod + additional_pitch_mod) + pitch_env_signal;

		float output = 0.f;

		// mix operator signals according to selected algorithm
		switch (algorithm) {
		case 0:
			output = calc_algo1(pitched_freq);
			break;
		case 1:
			output = calc_algo2(pitched_freq);
			break;
		case 2:
			output = calc_algo3(pitched_freq);
			break;
		case 3:
			output = calc_algo4(pitched_freq);
			break;
		default:
			output = calc_algo1(pitched_freq);
			break;
		}

		// reset trigger
		trigger = false;

		return redux(output, bit_resolution);
	}

	bool is_busy() override
	{
		return gate || op1.envelope.is_busy() || op2.envelope.is_busy() || op3.envelope.is_busy();
	}

	void set_samplerate(double samplerate) override
	{
		pitch_env.set_samplerate(samplerate);
		feedback_osc.set_samplerate(samplerate);
		op1.set_samplerate(samplerate);
		op2.set_samplerate(samplerate);
		op3.set_samplerate(samplerate);
	}

	void set_phase_reset(bool phase_reset)
	{
		op1.oscillator.phase_reset = phase_reset;
		op2.oscillator.phase_reset = phase_reset;
		op3.oscillator.phase_reset = phase_reset;
		feedback_osc.phase_reset = phase_reset;
	}

private:
	const float MOD_INDEX_COEFF = 4.f;
	float pitch_mod = 0.f; // modulates pitch in semi-tones

	float calc_algo1(const float frequency)
	{
		float fb_freq = frequency * op3.ratio;
		float fb_mod_index = (feedback_amt * MOD_INDEX_COEFF);
		float fb_signal = feedback_osc.process_sample(trigger, fb_freq) * fb_mod_index;

		float op3_Freq = frequency * op3.ratio;
		float op3_mod_index = (op3.amplitude * MOD_INDEX_COEFF);
		float op3_signal = op3.process_sample(gate, trigger, op3_Freq, velocity, fb_signal) * op3_mod_index;

		float op2_freq = frequency * op2.ratio;
		float op2_mod_index = (op2.amplitude * MOD_INDEX_COEFF);
		float op2_signal = op2.process_sample(gate, trigger, op2_freq, velocity, op3_signal) * op2_mod_index;

		float op1_freq = frequency * op1.ratio;
		return op1.process_sample(gate, trigger, op1_freq, velocity, op2_signal) * op1.amplitude;
	}

	float calc_algo2(const float frequency)
	{
		float fb_freq = frequency * op3.ratio;
		float fb_mod_index = (feedback_amt * MOD_INDEX_COEFF);
		float fb_signal = feedback_osc.process_sample(trigger, fb_freq) * fb_mod_index;

		float op3_freq = frequency * op3.ratio;
		float op3_signal = op3.process_sample(gate, trigger, op3_freq, velocity, fb_signal) * op3.amplitude;

		float op2_freq = frequency * op2.ratio;
		float op2_mod_index = (op2.amplitude * MOD_INDEX_COEFF);
		float op2_signal = op2.process_sample(gate, trigger, op2_freq, velocity) * op2_mod_index;

		float op1_freq = frequency * op1.ratio;
		float op1_signal = op1.process_sample(gate, trigger, op1_freq, velocity, op2_signal) * op1.amplitude;

		return op1_signal + op3_signal;
	}

	float calc_algo3(const float frequency)
	{
		float fb_freq = frequency * op3.ratio;
		float fb_mod_index = (feedback_amt * MOD_INDEX_COEFF);
		float fb_signal = feedback_osc.process_sample(trigger, fb_freq) * fb_mod_index;

		float op3_freq = frequency * op3.ratio;
		float op3_signal = op3.process_sample(gate, trigger, op3_freq, velocity, fb_signal) * op3.amplitude;

		float op2_freq = frequency * op2.ratio;
		float op2_signal = op2.process_sample(gate, trigger, op2_freq, velocity) * op2.amplitude;

		float op1_freq = frequency * op1.ratio;
		float op1_signal = op1.process_sample(gate, trigger, op1_freq, velocity) * op1.amplitude;

		return op1_signal + op2_signal + op3_signal;
	}

	float calc_algo4(const float frequency)
	{
		float fb_freq = frequency * op3.ratio;
		float fb_mod_index = (feedback_amt * MOD_INDEX_COEFF);
		float fb_signal = feedback_osc.process_sample(trigger, fb_freq) * fb_mod_index;

		float op3_freq = frequency * op3.ratio;
		float op3_mod_index = (op3.amplitude * MOD_INDEX_COEFF);
		float op3_signal = op3.process_sample(gate, trigger, op3_freq, velocity, fb_signal) * op3_mod_index;

		float op2_freq = frequency * op2.ratio;
		float op2_mod_index = (op2.amplitude * MOD_INDEX_COEFF);
		float op2_signal = op2.process_sample(gate, trigger, op2_freq, velocity) * op2_mod_index;

		float op1_freq = frequency * op1.ratio;
		return op1.process_sample(gate, trigger, op1_freq, velocity, op2_signal + op3_signal) * op1.amplitude;
	}

	float redux(float& value, float resolution)
	{
		float res = powf(2, resolution);
		value = roundf(value * res) / res;

		return value;
	}
};
} // namespace trnr