The Comment Update

every .js file is now commented with a short description

src/spessasynth_lib/midi_handler/midi_handler.js

@@ -1,6 +1,11 @@
 import { Synthetizer } from '../synthetizer/synthetizer.js'
 import { consoleColors } from '../utils/other.js';
 
+/**
+ * midi_handler.js
+ * purpose: handles the connection between MIDI devices and synthesizer/sequencer via Web MIDI API
+ */
+
 const NO_INPUT = null;
 
 export class MIDIDeviceHandler

src/spessasynth_lib/midi_handler/web_midi_link.js

@@ -1,5 +1,12 @@
 import { Synthetizer } from '../synthetizer/synthetizer.js'
 import { consoleColors } from '../utils/other.js'
+
+/**
+ * web_midi_link.js
+ * purpose: handles the web midi link connection to the synthesizer
+ * https://www.g200kg.com/en/docs/webmidilink/
+ */
+
 export class WebMidiLinkHandler
 {
     /**

src/spessasynth_lib/midi_parser/midi_loader.js

@@ -7,6 +7,11 @@ import {
     readVariableLengthQuantity
 } from "../utils/byte_functions.js";
 import { arrayToHexString, consoleColors, formatTitle } from '../utils/other.js'
+
+/**
+ * midi_loader.js
+ * purpose: parses a midi file for the seqyencer, including things like marker or CC 2/4 loop detection, copyright detection etc.
+ */
 export class MIDI{
     /**
      * Parses a given midi file

src/spessasynth_lib/midi_parser/midi_message.js

@@ -1,5 +1,9 @@
 import {ShiftableByteArray} from "../utils/shiftable_array.js";
 
+/**
+ * midi_message.js
+ * purpose: contains enums for midi events and controllers and functions to parse them
+ */
 
 export class MidiMessage
 {

src/spessasynth_lib/sequencer/sequencer.js

@@ -4,6 +4,11 @@ import { getEvent, messageTypes, midiControllers, MidiMessage } from '../midi_pa
 import { consoleColors, formatTime } from '../utils/other.js'
 import {readBytesAsUintBigEndian} from "../utils/byte_functions.js";
 
+/**
+ * sequencer.js
+ * purpose: plays back the midi file decoded by midi_loader.js, including support for multi-channel midis (adding channels when more than 1 midi port is detected)
+ */
+
 const MIN_NOTE_TIME = 0.02;
 const MAX_NOTEONS_PER_S = 200;
 

src/spessasynth_lib/soundfont/chunk/generators.js

@@ -2,6 +2,11 @@ import { ShiftableByteArray } from '../../utils/shiftable_array.js'
 import { RiffChunk } from './riff_chunk.js'
 import { readByte, signedInt16 } from '../../utils/byte_functions.js'
 
+/**
+ * generators.js
+ * purpose: contains enums for generators and their limis parses reads soundfont generators, sums them and applies limits
+ */
+
 export const generatorTypes = {
     startAddrsOffset: 0,                // sample control - moves sample start point
     endAddrOffset: 1,                   // sample control - moves sample end point

src/spessasynth_lib/soundfont/chunk/instruments.js

@@ -2,6 +2,11 @@ import {RiffChunk} from "./riff_chunk.js";
 import {InstrumentZone} from "./zones.js";
 import {readBytesAsString, readBytesAsUintLittleEndian} from "../../utils/byte_functions.js";
 
+/**
+ * instrument.js
+ * purpose: parses soundfont instrument and stores them as a class
+ */
+
 export class Instrument{
     /**
      * Creates an instrument

src/spessasynth_lib/soundfont/chunk/modulators.js

@@ -4,6 +4,10 @@ import { generatorTypes } from './generators.js'
 import { consoleColors } from '../../utils/other.js'
 import { midiControllers } from '../../midi_parser/midi_message.js'
 
+/**
+ * modulators.js
+ * purpose: parses soundfont modulators and the source enums, also includes the default modulators list
+ **/
 export const modulatorSources = {
     noController: 0,
     noteOnVelocity: 2,

src/spessasynth_lib/soundfont/chunk/presets.js

@@ -5,6 +5,10 @@ import {Sample} from "./samples.js";
 import { Generator, generatorTypes } from './generators.js'
 import { defaultModulators } from './modulators.js'
 
+/**
+ * parses soundfont presets, also includes function for getting the generators and samples from midi note and velocity
+ */
+
 export class Preset {
     /**
      * Creates a preset

src/spessasynth_lib/soundfont/chunk/riff_chunk.js

@@ -1,4 +1,11 @@
-import {ShiftableByteArray} from "../../utils/shiftable_array.js";
+import { ShiftableByteArray } from '../../utils/shiftable_array.js'
+import { readBytesAsString, readBytesAsUintLittleEndian } from '../../utils/byte_functions.js'
+
+/**
+ * riff_chunk.js
+ * reads a riff chunk and stores it as a class
+ */
+
 export class RiffChunk
 {
     /**
@@ -14,4 +21,26 @@ export class RiffChunk
         this.chunkData = data;
     }
 
+}
+
+/**
+ * @param dataArray {ShiftableByteArray}
+ * @param readData {boolean}
+ * @returns {RiffChunk}
+ */
+export function readRIFFChunk(dataArray, readData = true) {
+    let header = readBytesAsString(dataArray, 4)
+
+    let size = readBytesAsUintLittleEndian(dataArray, 4)
+    let chunkData = undefined
+    if (readData) {
+        chunkData = new ShiftableByteArray(size)
+        chunkData.set(dataArray.slice(dataArray.currentIndex, dataArray.currentIndex + size))
+        dataArray.currentIndex += size
+        // for (let i = 0; i < size; i++) {
+        //     chunkData[i] = readByte(dataArray);
+        // }
+    }
+
+    return new RiffChunk(header, size, chunkData)
 }

src/spessasynth_lib/soundfont/chunk/samples.js

@@ -2,15 +2,21 @@ import {RiffChunk} from "./riff_chunk.js";
 import {ShiftableByteArray} from "../../utils/shiftable_array.js";
 import {readByte, readBytesAsUintLittleEndian, readBytesAsString, signedInt8} from "../../utils/byte_functions.js";
 import { consoleColors } from '../../utils/other.js';
+
+/**
+ * samples.js
+ * purpose: parses soundfont samples, resamples if needed.
+ * loads sample data, handles async loading of sf3 compressed samples
+ */
+
+const FIX_SAMPLERATE = 44100;
+
 /**
  * Reads the generatorTranslator from the shdr chunk
  * @param sampleHeadersChunk {RiffChunk}
  * @param smplChunkData {ShiftableByteArray}
  * @returns {Sample[]}
  */
-
-const FIX_SAMPLERATE = 44100    ;
-
 export function readSamples(sampleHeadersChunk, smplChunkData)
 {
     /**

src/spessasynth_lib/soundfont/chunk/zones.js

@@ -6,9 +6,14 @@ import {Sample} from "./samples.js";
 import {Instrument} from "./instruments.js";
 import {Modulator} from "./modulators.js";
 
+/**
+ * zones.js
+ * purpose: reads instrumend and preset zones from soundfont and gets their respective samples and generators and modulators
+ */
+
 export class InstrumentZone {
     /**
-     * Creates a zone (presetinstrument)
+     * Creates a zone (instrument)
      * @param dataArray {ShiftableByteArray}
      */
     constructor(dataArray) {

src/spessasynth_lib/soundfont/soundfont_parser.js

@@ -1,14 +1,19 @@
 import {ShiftableByteArray} from "../utils/shiftable_array.js";
 import {readSamples} from "./chunk/samples.js";
-import { readRIFFChunk, readBytesAsString, readBytesAsUintLittleEndian } from '../utils/byte_functions.js'
+import { readBytesAsString, readBytesAsUintLittleEndian } from '../utils/byte_functions.js'
 import {readGenerators, Generator} from "./chunk/generators.js";
 import {readInstrumentZones, InstrumentZone, readPresetZones} from "./chunk/zones.js";
 import {Preset, readPresets} from "./chunk/presets.js";
 import {readInstruments, Instrument} from "./chunk/instruments.js";
 import {readModulators, Modulator} from "./chunk/modulators.js";
-import {RiffChunk} from "./chunk/riff_chunk.js";
+import { readRIFFChunk, RiffChunk } from './chunk/riff_chunk.js'
 import { consoleColors } from '../utils/other.js'
 
+/**
+ * soundfont_parser.js
+ * purpose: parses a soundfont2 file
+ */
+
 export class SoundFont2
 {
     /**

src/spessasynth_lib/synthetizer/fancy_chorus.js

@@ -1,3 +1,8 @@
+/**
+ * fancy_chorus.js
+ * purpose: creates a simple chorus effect node
+ */
+
 const DEFAULT_DELAY = 0.02;
 const DELAY_VARIATION = 0.015;
 

src/spessasynth_lib/synthetizer/native_system/generator_translator.js

@@ -1,6 +1,11 @@
 import {Generator, generatorTypes} from "../../soundfont/chunk/generators.js";
 import {Sample} from "../../soundfont/chunk/samples.js";
 
+/**
+ * generator_translator.js
+ * purpose: translates the generators got from the preset to values understandable by voice.js
+ */
+
 const EMU_ATTENUATION_CORRECTION = 0.4;
 const FREQ_MIN = 0;
 const FREQ_MAX = 22050;

src/spessasynth_lib/synthetizer/native_system/midi_channel.js

@@ -3,6 +3,11 @@ import {Preset} from "../../soundfont/chunk/presets.js";
 import { consoleColors } from '../../utils/other.js'
 import { midiControllers } from '../../midi_parser/midi_message.js'
 
+/**
+ * midi_channel.js
+ * purpose: manages a single midi channel for the native system
+ */
+
 const CHANNEL_LOUDNESS = 0.3;
 
 const dataEntryStates = {

src/spessasynth_lib/synthetizer/native_system/voice.js

@@ -1,5 +1,11 @@
 import { GeneratorTranslator } from './generator_translator.js';
 
+/**
+ * voice.js
+ * purpose: manages a single voice (sample) with the whole synthesis model (oscillator, lowpass filter, gain controller etc.)
+ */
+
+
 /**
  * Creates a new instance of a single sample
  * @param sampleAndGenerators {SampleAndGenerators}

src/spessasynth_lib/synthetizer/native_system/voice_group.js

@@ -1,6 +1,11 @@
 import {Preset} from "../../soundfont/chunk/presets.js";
 import { getVoiceAsync, Voice } from './voice.js'
 
+/**
+ * voice_group.js
+ * purpose: manages the group of voices created by a single noteOn message
+ */
+
 export class VoiceGroup
 {
     /**

src/spessasynth_lib/synthetizer/synthetizer.js

@@ -7,6 +7,11 @@ import { WorkletChannel } from './worklet_system/worklet_channel.js'
 import { EventHandler } from '../utils/synth_event_handler.js'
 import { FancyChorus } from './fancy_chorus.js'
 
+/**
+ * synthesizer.js
+ * purpose: responds to midi messages and called functions, managing the channels and passing the messages to them
+ */
+
 const VOICES_CAP = 450;
 
 export const DEFAULT_GAIN = 1;

src/spessasynth_lib/synthetizer/worklet_system/channel_processor.js

@@ -15,6 +15,11 @@ import { applyVolumeEnvelope } from './worklet_utilities/volume_envelope.js'
 import { applyLowpassFilter } from './worklet_utilities/lowpass_filter.js'
 import { getModEnvValue } from './worklet_utilities/modulation_envelope.js'
 
+/**
+ * channel_processor.js
+ * purpose: manages the channel from the AudioWorkletGlobalScope and renders the audio data
+ */
+
 const CHANNEL_CAP = 400;
 const CONTROLLER_TABLE_SIZE = 147;
 const MIN_NOTE_LENGTH = 0.07; // if the note is released faster than that, it forced to last that long

src/spessasynth_lib/synthetizer/worklet_system/worklet_channel.js

@@ -3,6 +3,12 @@ import { consoleColors } from '../../utils/other.js'
 import { modulatorSources } from '../../soundfont/chunk/modulators.js'
 import { midiControllers } from '../../midi_parser/midi_message.js'
 import { clearSamplesList, getWorkletVoices } from './worklet_utilities/worklet_voice.js'
+
+/**
+ * worklet_channel.sj
+ * purpose: manages a single midi channel in the worklet system and communicates with channel_processor.js
+ */
+
 const CHANNEL_GAIN = 0.5;
 
 export const NON_CC_INDEX_OFFSET = 128;

src/spessasynth_lib/synthetizer/worklet_system/worklet_utilities/lfo.js

@@ -1,3 +1,8 @@
+/**
+ * lfo.js
+ * purpose: low frequency triangel oscillator
+ */
+
 /**
  * Calculates a triangular wave value for the given time
  * @param startTime {number} seconds

src/spessasynth_lib/synthetizer/worklet_system/worklet_utilities/lowpass_filter.js

@@ -1,6 +1,12 @@
 import { generatorTypes } from '../../../soundfont/chunk/generators.js'
 import { absCentsToHz, decibelAttenuationToGain } from './unit_converter.js'
 
+/**
+ * lowpass_filter.js
+ * purpose: applies a low pass filter to a voice
+ */
+
+
 /**
  * Applies a low-pass filter to the given buffer
  * @param voice {WorkletVoice} the voice we're working on

src/spessasynth_lib/synthetizer/worklet_system/worklet_utilities/modulation_envelope.js

@@ -3,6 +3,10 @@ import { generatorTypes } from '../../../soundfont/chunk/generators.js'
 import { getModulatorCurveValue } from './modulator_curves.js'
 import { modulatorCurveTypes } from '../../../soundfont/chunk/modulators.js'
 
+/**
+ * modulation_envelope.js
+ * purpose: calculates the modulation envelope for the given voice
+ */
 const PEAK = 1;
 
 // 1000 should be precise enough

src/spessasynth_lib/synthetizer/worklet_system/worklet_utilities/modulator_curves.js

@@ -1,5 +1,9 @@
 import { modulatorCurveTypes } from '../../../soundfont/chunk/modulators.js'
 
+/**
+ * modulator_curves.js
+ * precomputes modulator concave and conves curves and calculates a curve value for a given polarity, direction and type
+ */
 
 // the length of the precomputed curve tables
 export const MOD_PRECOMPUTED_LENGTH = 16384;

src/spessasynth_lib/synthetizer/worklet_system/worklet_utilities/stereo_panner.js

@@ -1,5 +1,10 @@
 import { HALF_PI } from './unit_converter.js'
 
+/**
+ * stereo_panner.js
+ * purpose: pans a given voice out to the stereo output and to the effects' outputs
+ */
+
 /**
  * Pans the voice to the given output buffers
  * @param pan {number} 0-1 , 0.5 is middle

src/spessasynth_lib/synthetizer/worklet_system/worklet_utilities/unit_converter.js

@@ -1,3 +1,8 @@
+/**
+ * unit_converter.js
+ * purpose: converts soundfont units into more useable values with the use of lookup tables to improve performance
+ */
+
 
 // timecent lookup table
 const MIN_TIMECENT = -15000;

src/spessasynth_lib/synthetizer/worklet_system/worklet_utilities/volume_envelope.js

@@ -1,6 +1,11 @@
 import { decibelAttenuationToGain, timecentsToSeconds } from './unit_converter.js'
 import { generatorTypes } from '../../../soundfont/chunk/generators.js'
 
+/**
+ * volume_envelope.js
+ * purpose: applies a volume envelope for a given voice
+ */
+
 const DB_SILENCE = 100;
 const GAIN_SILENCE = 0.005;
 

src/spessasynth_lib/synthetizer/worklet_system/worklet_utilities/wavetable_oscillator.js

@@ -1,3 +1,9 @@
+/**
+ * wavetable_oscillator.js
+ * purpose: plays back raw audio data at an arbitrary playback rate
+ */
+
+
 /**
  * Fills the output buffer with raw sample data
  * @param voice {WorkletVoice} the voice we're working on

src/spessasynth_lib/synthetizer/worklet_system/worklet_utilities/worklet_modulator.js

@@ -2,6 +2,11 @@ import { NON_CC_INDEX_OFFSET } from '../worklet_channel.js'
 import { modulatorSources } from '../../../soundfont/chunk/modulators.js'
 import { getModulatorCurveValue, MOD_PRECOMPUTED_LENGTH } from './modulator_curves.js'
 
+/**
+ * worklet_modulator.js
+ * purpose: precomputes all curve types and computes modulators
+ */
+
 /**
  * Computes a given modulator
  * @param controllerTable {Int16Array} all midi controllers as 14bit values + the non controller indexes, starting at 128