spessasynth_lib
Version:
MIDI and SoundFont2/DLS library with no compromises
82 lines (79 loc) • 2.9 kB
JavaScript
import { writeWord } from "../../../utils/byte_functions/little_endian.js";
import { IndexedByteArray } from "../../../utils/indexed_array.js";
import { RiffChunk, writeRIFFChunk } from "../riff_chunk.js";
import { Generator, generatorTypes } from "../generator.js";
/**
* @this {BasicSoundBank}
* @returns {IndexedByteArray}
*/
export function getPGEN()
{
// almost identical to igen, except the correct instrument instead of sample gen
// goes through all preset zones and writes generators sequentially (add 4 for terminal)
let pgensize = 4;
for (const preset of this.presets)
{
pgensize += preset.presetZones.reduce((size, z) =>
{
// clear instrument and range generators before determining the size
z.generators = z.generators.filter(g =>
g.generatorType !== generatorTypes.instrument &&
g.generatorType !== generatorTypes.keyRange &&
g.generatorType !== generatorTypes.velRange
);
// unshift vel then key and instrument is last
if (z.velRange.max !== 127 || z.velRange.min !== 0)
{
z.generators.unshift(new Generator(
generatorTypes.velRange,
z.velRange.max << 8 | Math.max(z.velRange.min, 0),
false
));
}
if (z.keyRange.max !== 127 || z.keyRange.min !== 0)
{
z.generators.unshift(new Generator(
generatorTypes.keyRange,
z.keyRange.max << 8 | Math.max(z.keyRange.min, 0),
false
));
}
if (!z.isGlobal)
{
// write the instrument
z.generators.push(new Generator(
generatorTypes.instrument,
this.instruments.indexOf(z.instrument),
false
));
}
return z.generators.length * 4 + size;
}, 0);
}
const pgendata = new IndexedByteArray(pgensize);
let pgenIndex = 0;
for (const preset of this.presets)
{
for (const presetZone of preset.presetZones)
{
// set the start index here
presetZone.generatorZoneStartIndex = pgenIndex;
// write generators
for (const gen of presetZone.generators)
{
// name is deceptive, it works on negatives
writeWord(pgendata, gen.generatorType);
writeWord(pgendata, gen.generatorValue);
}
pgenIndex += presetZone.generators.length;
}
}
// terminal generator, is zero
writeWord(pgendata, 0);
writeWord(pgendata, 0);
return writeRIFFChunk(new RiffChunk(
"pgen",
pgendata.length,
pgendata
));
}