@eroscripts/osr-emu/lib/axis.ts

A web-based graphical emulator for open source strokers.

import { constrain, map } from './util.js';

const MIN_SMOOTH_INTERVAL = 3; // Minimum auto-smooth ramp interval for live commands (ms)
const MAX_SMOOTH_INTERVAL = 100; // Maximum auto-smooth ramp interval for live commands (ms)

/**
 * A class that emulates the behavior of an axis as coded on the OSR Firmware (v3.3)
 */
export default class Axis {
  name = '';

  _startTime = 0;
  _startPosition = 5000;
  _targetTime = 0;
  _targetPosition = 5000;
  _minInterval = MAX_SMOOTH_INTERVAL;

  constructor(name: string) {
    this.name = name;
  }

  set(magnitude: number, ext?: 'S' | 'I', extMagnitude: number = 0) {
    const currentTime = performance.now();
    magnitude = constrain(magnitude, 0, 9999);
    extMagnitude = constrain(extMagnitude, 0, 9999999);

    if (!extMagnitude || (ext !== 'S' && ext !== 'I')) {
      // Live command
      // Update auto-smooth regulator
      const lastInterval = currentTime - this._startTime;
      if (lastInterval > this._minInterval && this._minInterval < MAX_SMOOTH_INTERVAL) {
        this._minInterval += 1;
      }
      else if (lastInterval < this._minInterval && this._minInterval > MIN_SMOOTH_INTERVAL) {
        this._minInterval -= 1;
      }

      this._startPosition = this.getPosition();
      this._targetTime = currentTime + this._minInterval;
    }
    else if (ext === 'S') {
      // Speed command
      const speed = extMagnitude / 100; // Interpret extMagntitude as units per 100 ms.
      this._startPosition = this.getPosition();

      const distance = Math.abs(magnitude - this._startPosition);
      const duration = Math.floor(distance / speed);
      this._targetTime = currentTime + duration;
    }
    else if (ext === 'I') {
      // Interval command
      const duration = extMagnitude; // Interpret extMagnitude as the duration of the move in ms.
      this._startPosition = this.getPosition();
      this._targetTime = currentTime + duration;
    }

    this._startTime = currentTime;
    this._targetPosition = magnitude;
  }

  getPosition() {
    let position; // 0 - 9999
    const currentTime = performance.now();

    if (currentTime > this._targetTime) {
      position = this._targetPosition;
    }
    else if (currentTime > this._startTime) {
      position = map(currentTime, this._startTime, this._targetTime, this._startPosition, this._targetPosition);
    }
    else {
      position = this._startPosition;
    }

    return constrain(position, 0, 9999);
  }
}