broken-neees/apu/APU.js

A really broken NEEES emulator that introduces glitches and random bugs on purpose!

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = void 0;
var _AudioRegisters = _interopRequireDefault(require("./AudioRegisters"));
var _FrameSequencer = _interopRequireDefault(require("./FrameSequencer"));
var _PulseChannel = _interopRequireDefault(require("./PulseChannel"));
var _TriangleChannel = _interopRequireDefault(require("./TriangleChannel"));
var _NoiseChannel = _interopRequireDefault(require("./NoiseChannel"));
var _DMCChannel = _interopRequireDefault(require("./DMCChannel"));
function _interopRequireDefault(e) { return e && e.__esModule ? e : { default: e }; }
const FREQ_APU_HZ = 894887;
const APU_SAMPLE_RATE = 44100;
const STEPS_PER_SAMPLE = Math.floor(FREQ_APU_HZ / APU_SAMPLE_RATE);
class APU {
  constructor(cpu) {
    this.cpu = cpu;
    this.sampleCounter = 0;
    this.sample = 0;
    this.registers = new _AudioRegisters.default(this);
    this.frameSequencer = new _FrameSequencer.default(this);
    this.channels = {
      pulses: [new _PulseChannel.default(this, 0, "enablePulse1"), new _PulseChannel.default(this, 1, "enablePulse2")],
      triangle: new _TriangleChannel.default(this),
      noise: new _NoiseChannel.default(this),
      dmc: new _DMCChannel.default(this, this.cpu)
    };
  }
  step(onSample) {
    this.channels.pulses[0].step();
    this.channels.pulses[1].step();
    this.channels.noise.step();
    this.channels.dmc.step();
    this.sampleCounter++;
    this.frameSequencer.step();
    if (this.sampleCounter === STEPS_PER_SAMPLE) {
      this.sampleCounter = 0;
      const pulse1 = this.channels.pulses[0].sample();
      const pulse2 = this.channels.pulses[1].sample();
      const triangle = this.channels.triangle.sample();
      const noise = this.channels.noise.sample();
      const dmc = this.channels.dmc.sample();
      const pulseOut = 0.00752 * (pulse1 + pulse2);
      const tndOut = 0.00851 * triangle + 0.00494 * noise + 0.00335 * dmc;
      this.sample = pulseOut + tndOut;
      onSample(this.sample, pulse1, pulse2, triangle, noise, dmc);
    }
  }
  onQuarterFrameClock() {
    this.channels.pulses[0].quarterFrame();
    this.channels.pulses[1].quarterFrame();
    this.channels.triangle.quarterFrame();
    this.channels.noise.quarterFrame();
  }
  onHalfFrameClock() {
    this.channels.pulses[0].halfFrame();
    this.channels.pulses[1].halfFrame();
    this.channels.triangle.halfFrame();
    this.channels.noise.halfFrame();
  }
}
exports.default = APU;