121 lines
6.4 KiB
C++
121 lines
6.4 KiB
C++
#pragma once
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//#include <string>
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//#include <array>
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//#include <cstdint>
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//#include <algorithm>
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//#include <vector>
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//#include <functional>
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#include "common/pimoroni_common.hpp"
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namespace pimoroni {
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// The duration a note is played is determined by the amount of attack,
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// decay, and release, combined with the length of the note as defined by
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// the user.
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//
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// - Attack: number of milliseconds it takes for a note to hit full volume
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// - Decay: number of milliseconds it takes for a note to settle to sustain volume
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// - Sustain: percentage of full volume that the note sustains at (duration implied by other factors)
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// - Release: number of milliseconds it takes for a note to reduce to zero volume after it has ended
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//
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// Attack (750ms) - Decay (500ms) -------- Sustain ----- Release (250ms)
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//
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// + + + +
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// | | | |
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// | | | |
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// | | | |
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// v v v v
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// 0ms 1000ms 2000ms 3000ms 4000ms
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//
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// | XXXX | | | |
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// | X X|XX | | |
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// | X | XXX | | |
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// | X | XXXXXXXXXXXXXX|XXXXXXXXXXXXXXXXXXX| |
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// | X | | |X |
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// | X | | |X |
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// | X | | | X |
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// | X | | | X |
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// | X | | | X |
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// | X | | | X |
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// | X | | | X |
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// | X | | | X |
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// | X + + + | + + + | + + + | + + + | +
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// | X | | | | | | | | | | | | | | | | |
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// |X | | | | | | | | | | | | | | | | |
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// +----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+--->
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enum Waveform {
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NOISE = 128,
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SQUARE = 64,
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SAW = 32,
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TRIANGLE = 16,
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SINE = 8,
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WAVE = 1
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};
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enum class ADSRPhase : uint8_t {
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ATTACK,
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DECAY,
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SUSTAIN,
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RELEASE,
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OFF
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};
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const int16_t sine_waveform[256] = {-32768,-32758,-32729,-32679,-32610,-32522,-32413,-32286,-32138,-31972,-31786,-31581,-31357,-31114,-30853,-30572,-30274,-29957,-29622,-29269,-28899,-28511,-28106,-27684,-27246,-26791,-26320,-25833,-25330,-24812,-24279,-23732,-23170,-22595,-22006,-21403,-20788,-20160,-19520,-18868,-18205,-17531,-16846,-16151,-15447,-14733,-14010,-13279,-12540,-11793,-11039,-10279,-9512,-8740,-7962,-7180,-6393,-5602,-4808,-4011,-3212,-2411,-1608,-804,0,804,1608,2411,3212,4011,4808,5602,6393,7180,7962,8740,9512,10279,11039,11793,12540,13279,14010,14733,15447,16151,16846,17531,18205,18868,19520,20160,20788,21403,22006,22595,23170,23732,24279,24812,25330,25833,26320,26791,27246,27684,28106,28511,28899,29269,29622,29957,30274,30572,30853,31114,31357,31581,31786,31972,32138,32286,32413,32522,32610,32679,32729,32758,32767,32758,32729,32679,32610,32522,32413,32286,32138,31972,31786,31581,31357,31114,30853,30572,30274,29957,29622,29269,28899,28511,28106,27684,27246,26791,26320,25833,25330,24812,24279,23732,23170,22595,22006,21403,20788,20160,19520,18868,18205,17531,16846,16151,15447,14733,14010,13279,12540,11793,11039,10279,9512,8740,7962,7180,6393,5602,4808,4011,3212,2411,1608,804,0,-804,-1608,-2411,-3212,-4011,-4808,-5602,-6393,-7180,-7962,-8740,-9512,-10279,-11039,-11793,-12540,-13279,-14010,-14733,-15447,-16151,-16846,-17531,-18205,-18868,-19520,-20160,-20788,-21403,-22006,-22595,-23170,-23732,-24279,-24812,-25330,-25833,-26320,-26791,-27246,-27684,-28106,-28511,-28899,-29269,-29622,-29957,-30274,-30572,-30853,-31114,-31357,-31581,-31786,-31972,-32138,-32286,-32413,-32522,-32610,-32679,-32729,-32758};
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const uint32_t sample_rate = 22050;
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struct AudioChannel {
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uint8_t waveforms = 0; // bitmask for enabled waveforms (see Waveform enum for values)
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uint16_t frequency = 660; // frequency of the voice (Hz)
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uint16_t volume = UINT16_MAX; // channel volume
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uint16_t attack_ms = 2; // attack period (cannot be zero)
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uint16_t decay_ms = 6; // decay period (cannot be zero)
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uint16_t sustain = UINT16_MAX; // sustain volume
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uint16_t release_ms = 1; // release period
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uint16_t pulse_width = 0x7fff; // duty cycle of square wave (default 50%)
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int16_t noise = 0; // current noise value
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uint32_t waveform_offset = 0; // voice offset (Q8)
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int32_t filter_last_sample = 0;
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bool filter_enable = false;
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uint16_t filter_cutoff_frequency = 0;
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uint32_t adsr_frame = 0; // number of frames into the current ADSR phase
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uint32_t adsr_end_frame = 0; // frame target at which the ADSR changes to the next phase
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uint32_t adsr_level = 0; // the output level at the current frame of the ADSR phase
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int32_t adsr_step = 0; // the amount to increment the level with each frame
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ADSRPhase adsr_phase = ADSRPhase::OFF;
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uint8_t wave_buf_pos = 0; //
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int16_t wave_buffer[64]; // buffer for arbitrary waveforms. small as it's filled by user callback
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void *user_data = nullptr;
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void (*wave_buffer_callback)(AudioChannel &channel);
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void trigger_attack();
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void trigger_decay();
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void trigger_sustain();
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void trigger_release();
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void off();
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void restore();
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};
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class PicoSynth {
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public:
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uint16_t volume = 0x2fff;
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static const uint CHANNEL_COUNT = 8;
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AudioChannel channels[CHANNEL_COUNT];
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int16_t get_audio_frame();
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bool is_audio_playing();
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};
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constexpr float pi = 3.14159265358979323846f;
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}
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