fix(Playback): Fix 3 specific instruments (e.g. honky-tonk) having a wrong soundfont url -> no playback (#82)

closes #82

src/Playback/BasicAudioPlayer.ts

@@ -17,12 +17,20 @@ export class BasicAudioPlayer implements IAudioPlayer<SoundfontPlayer.Player> {
   protected memoryLoadedSoundFonts: Map<MidiInstrument, SoundfontPlayer.Player> = new Map();
   protected channelToSoundFont: Map<number, number> = new Map();
 
-  public SoundfontInstrumentOptions = {}; // e.g. set { from: 'server.com/soundfonts/' } for soundfont fetching url
+  public SoundfontInstrumentOptions = {
+    from: undefined,
+    nameToUrl: undefined // will be overwritten in constructor
+  }; // e.g. set { from: "server.com/soundfonts/" } for soundfont fetching url, and set nameToUrl to undefined.
+
   /** Multiplicator for gain (volume output). 1 represents the maximum volume in OSMD (100%),
    *  but it looks like soundfont-player is louder with volumes > 1.
    *  E.g. set osmd.PlaybackManager.audioPlayer.GainMultiplier to 3 if you think the player is too quiet. */
   public GainMultiplier: number = 1;
 
+  constructor() {
+    this.SoundfontInstrumentOptions.nameToUrl = this.nameToSoundfontUrl;
+  }
+
   public async open(uniqueInstruments: number[], numberOfinstruments: number = 16): Promise<void> {
     if (this.piano === undefined) {
       this.piano = await SoundfontPlayer.instrument(
@@ -83,7 +91,6 @@ export class BasicAudioPlayer implements IAudioPlayer<SoundfontPlayer.Player> {
   }
 
   public async loadSoundFont(soundId: MidiInstrument): Promise<SoundfontPlayer.Player> {
-
     if (this.memoryLoadedSoundFonts.get(soundId) !== undefined) {
       return this.memoryLoadedSoundFonts.get(soundId);
     }
@@ -102,6 +109,25 @@ export class BasicAudioPlayer implements IAudioPlayer<SoundfontPlayer.Player> {
     return player;
   }
 
+  /** Returns the url for the instrument name's soundfont to be loaded. */
+  public nameToSoundfontUrl(name: string, font: string, format: string): string {
+    // nameToUrl function from soundfont-player.js / lib/index.js
+    format = format === "ogg" ? format : "mp3";
+    font = font === "FluidR3_GM" ? font : "MusyngKite";
+    let url: string =  "https://gleitz.github.io/midi-js-soundfonts/" + font + "/" + name + "-" + format + ".js";
+    // end soundfont-player nameToUrl function. The following fixes bad links.
+
+    const urlReplacements: Object = {
+      "honky_tonk_piano-mp3.js": "honkytonk_piano-mp3.js",
+      "synth_voice-mp3.js": "synth_choir-mp3.js",
+      "lead_8_bass_lead-mp3.js": "lead_8_bass__lead-mp3.js",
+    };
+    for (const key of Object.keys(urlReplacements)) {
+      url = url.replace(key, urlReplacements[key]);
+    }
+    return url;
+  }
+
   public setVolume(instrumentChannel: number, volume: number): void {
     this.channelVolumes[instrumentChannel] = volume;
   }