The GeneratedWaveNode will generate audio using a specified wave type and frequency. Since it is a generating node, it will ignore any input connections.
Common Uses
- Creating synthesized sound effects
- Combining white noise with audio filters to generate wind or other sound effects
Using the GeneratedWaveNode
GeneratedWaveNodes create audio using either a sine wave, square wave, saw wave, triangle wave, or white noise. The WaveFrequency property controls the pitch of the audio, and can be smoothly changed over time using the InterpolateWaveFrequency method. Like other objects, its volume can be controlled using either the Volume or the Decibels property, and interpolated with the InterpolateVolume and InterpolateDecibels methods.
The following code block illustrates how to use a GeneratedWaveNode to make a simple alarm-siren noise.
class SimpleSiren : NadaComponent
{
// Make sure this object has a SoundEmitter component
[Dependency] var Emitter : SoundEmitter;
// Store the GeneratedWaveNode so its properties can be edited later
var WaveNode : GeneratedWaveNode = Audio.GeneratedWaveNode();
// Keep track of whether we are interpolating up or down
var GoingUp : Boolean = true;
function Initialize(init : CogInitializer)
{
// Attach the GeneratedWaveNode to the SoundEmitter
this.Emitter.InputNode.AddInputNode(this.WaveNode);
// Set the node's starting properties
this.WaveNode.WaveFrequency = 200.0;
this.WaveNode.WaveType = SynthWaveType.SawWave;
this.WaveNode.Volume = 0.2;
// Start playing the generated wave
this.WaveNode.Play();
// Start interpolating the frequency
this.ChangeFrequency();
}
function ChangeFrequency()
{
// Check if we should interpolate the frequency up or down
if (this.GoingUp == true)
{
// Interpolate the wave's frequency to 700Hz over 1 second
this.WaveNode.InterpolateWaveFrequency(700.0, 1.0);
// Reset the variable to go down next time
this.GoingUp = false;
}
else
{
// Interpolate the wave's frequency to 500Hz over 1 second
this.WaveNode.InterpolateWaveFrequency(500.0, 1.0);
// Reset the variable to go up next time
this.GoingUp = true;
}
// Call this function again in 1.1 seconds
var sequence = Actions.Sequence(this.Owner.Actions);
Actions.Delay(sequence, 1.1);
Actions.Call(sequence, this.ChangeFrequency);
}
}