Learning LX: Modulators

Overview

One layer above the Parameter is LXModulator. A modulator is a specialized type of parameter with a value that automatically changes over time. Modulators are runnable components, which means that their operation can be started and stopped. A modulator may also have registered parameters that control its own operation.

Types of Modulators

LFOs

The most basic types of modulators are the LFO family. LFO denotes Low Frequency Oscillation, a common concept in audio synthesis which is also extremely useful in animation.

// A sinusoidal wave that oscillates from 0 to 1 every 2500 milliseconds
SinLFO lfo = new SinLFO("Sin Wave", 0, 1, 2500);

// A triangular wave oscillating from 2 to 5 every 5000 milliseconds
TriangleLFO lfo = new TriangleLFO("Tri Wave", 2, 5, 5000);

// A square wave that switches between -4 and 4 every 1000 milliseconds
SquareLFO lfo = new TriangleLFO("Square Wave", -4, 4, 1000);

// A sawtooth wave that ramps from 5 to 15 every 3000 milliseconds
SawLFO lfo = new SawLFO("Saw Wave", 5, 15, 3000);

Envelopes

Using Modulators

Registration

Modulators must belong to an LXModulationComponent. They should be registered in the component's constructor.

public class MyPattern extends LXPattern {

  public final SinLFO lfo = new SinLFO("Oscillation", 0, 1, 2500);
  
  public MyPattern(LX lx) {
    super(lx);
    // Register the modulator
    addModulator(lfo);
    // Start the modulator running
    lfo.start();
  }
  ...
}

Starting and Stopping

Modulators have a set of methods that control their operation.

// Starts the modulator
modulator.start();

// Stops the modulator
modulator.stop();

// Stops the modulator and resets to initial condition
modulator.reset();

// Re-starts the modulator from initial condition
modulator.trigger();