204 lines
6.5 KiB
C++
Executable file
204 lines
6.5 KiB
C++
Executable file
/* Audio Library for Teensy 3.X
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* Copyright (c) 2017, TeensyAudio PSU Team
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*
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* Development of this audio library was sponsored by PJRC.COM, LLC.
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* Please support PJRC's efforts to develop open source
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* software by purchasing Teensy or other PJRC products.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice, development funding notice, and this permission
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* notice shall be included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#pragma once
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#include "Arduino.h"
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#include "AudioStream.h"
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#include <math.h>
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#include <stdint.h>
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#define WAVETABLE_CENTS_SHIFT(C) (pow(2.0, (C)/1200.0))
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#define WAVETABLE_NOTE_TO_FREQUENCY(N) (440.0 * pow(2.0, ((N) - 69) / 12.0))
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#define WAVETABLE_DECIBEL_SHIFT(dB) (pow(10.0, (dB)/20.0))
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class AudioSynthWavetable : public AudioStream
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{
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public:
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struct sample_data {
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// SAMPLE VALUES
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const int16_t* sample;
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const bool LOOP;
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const int INDEX_BITS;
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const float PER_HERTZ_PHASE_INCREMENT;
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const uint32_t MAX_PHASE;
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const uint32_t LOOP_PHASE_END;
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const uint32_t LOOP_PHASE_LENGTH;
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const uint16_t INITIAL_ATTENUATION_SCALAR;
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// VOLUME ENVELOPE VALUES
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const uint32_t DELAY_COUNT;
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const uint32_t ATTACK_COUNT;
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const uint32_t HOLD_COUNT;
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const uint32_t DECAY_COUNT;
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const uint32_t RELEASE_COUNT;
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const int32_t SUSTAIN_MULT;
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// VIRBRATO VALUES
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const uint32_t VIBRATO_DELAY;
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const uint32_t VIBRATO_INCREMENT;
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const float VIBRATO_PITCH_COEFFICIENT_INITIAL;
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const float VIBRATO_PITCH_COEFFICIENT_SECOND;
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// MODULATION VALUES
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const uint32_t MODULATION_DELAY;
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const uint32_t MODULATION_INCREMENT;
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const float MODULATION_PITCH_COEFFICIENT_INITIAL;
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const float MODULATION_PITCH_COEFFICIENT_SECOND;
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const int32_t MODULATION_AMPLITUDE_INITIAL_GAIN;
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const int32_t MODULATION_AMPLITUDE_SECOND_GAIN;
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};
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static const int32_t UNITY_GAIN = INT32_MAX;
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static constexpr float SAMPLES_PER_MSEC = (AUDIO_SAMPLE_RATE_EXACT/1000.0);
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static const int32_t LFO_SMOOTHNESS = 3;
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static constexpr float LFO_PERIOD = (AUDIO_BLOCK_SAMPLES/(1 << (LFO_SMOOTHNESS-1)));
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static const int32_t ENVELOPE_PERIOD = 8;
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struct instrument_data {
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const uint8_t sample_count;
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const uint8_t* sample_note_ranges;
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const sample_data* samples;
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};
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enum { DEFAULT_AMPLITUDE = 90 };
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enum { TRIANGLE_INITIAL_PHASE = -0x40000000 };
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enum envelopeStateEnum { STATE_IDLE, STATE_DELAY, STATE_ATTACK, STATE_HOLD, STATE_DECAY, STATE_SUSTAIN, STATE_RELEASE };
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public:
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/**
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* Class constructor.
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*/
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AudioSynthWavetable(void) : AudioStream(0, NULL) {}
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/**
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* @brief Set the instrument_data struct to be used as the playback instrument.
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*
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* A wavetable uses a set of samples to generate sound.
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* This function is used to set the instrument samples.
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* @param instrument a struct of type instrument_data, commonly prodced from a
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* decoded SoundFont file using the SoundFont Decoder Script which accompanies this library.
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*/
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void setInstrument(const instrument_data& instrument) {
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cli();
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this->instrument = &instrument;
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current_sample = NULL;
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env_state = STATE_IDLE;
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state_change = true;
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sei();
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}
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/**
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* @brief Changes the amplitude to 'v'
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*
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* A value of 0 will set the synth output to minimum amplitude
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* (i.e., no output). A value of 1 will set the output to the
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* maximum amplitude. Amplitude is set linearly with intermediate
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* values.
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* @param v a value between 0.0 and 1.0
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*/
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void amplitude(float v) {
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v = (v < 0.0) ? 0.0 : (v > 1.0) ? 1.0 : v;
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tone_amp = (uint16_t)(UINT16_MAX*v);
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}
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/**
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* @brief Scale midi_amp to a value between 0.0 and 1.0
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* using a logarithmic tranformation.
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*
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* @param midi_amp a value between 0 and 127
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* @return a value between 0.0 to 1.0
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*/
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static float midi_volume_transform(int midi_amp) {
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// scale midi_amp which is 0 t0 127 to be between
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// 0 and 1 using a logarithmic transformation
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return powf(midi_amp / 127.0, 4);
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}
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/**
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* @brief Convert a MIDI note value to
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* its corresponding frequency.
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*
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* @param note a value between 0 and 127
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* @return a frequency
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*/
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static float noteToFreq(int note) {
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float exp = note * (1.0 / 12.0) + 3.0313597;
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return powf(2.0, exp);
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}
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/**
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* @brief Convert a frequency to the corressponding
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* MIDI note value.
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*
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* @param freq the frequency value as a float to convert
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* @return a MIDI note (between 0 - 127)
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*/
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static int freqToNote(float freq) {
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return 12*log2f(freq) - 35.8763164;
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}
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// Defined in AudioSynthWavetable.cpp
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void stop(void);
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// TODO: amplitude should be 0 to 1.0 scale
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void playFrequency(float freq, int amp = DEFAULT_AMPLITUDE);
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void playNote(int note, int amp = DEFAULT_AMPLITUDE);
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bool isPlaying(void) { return env_state != STATE_IDLE; }
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void setFrequency(float freq);
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virtual void update(void);
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envelopeStateEnum getEnvState(void) { return env_state; }
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private:
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void setState(int note, int amp, float freq);
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volatile bool state_change = false;
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volatile const instrument_data* instrument = NULL;
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volatile const sample_data* current_sample = NULL;
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//sample output state
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volatile uint32_t tone_phase = 0;
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volatile uint32_t tone_incr = 0;
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volatile uint16_t tone_amp = 0;
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//volume environment state
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volatile envelopeStateEnum env_state = STATE_IDLE;
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volatile int32_t env_count = 0;
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volatile int32_t env_mult = 0;
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volatile int32_t env_incr = 0;
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//vibrato LFO state
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volatile uint32_t vib_count = 0;
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volatile uint32_t vib_phase = 0;
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volatile int32_t vib_pitch_offset_init = 0;
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volatile int32_t vib_pitch_offset_scnd = 0;
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//modulation LFO state
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volatile uint32_t mod_count = 0;
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volatile uint32_t mod_phase = TRIANGLE_INITIAL_PHASE;
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volatile int32_t mod_pitch_offset_init = 0;
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volatile int32_t mod_pitch_offset_scnd = 0;
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};
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