The AudioGraph keeps track of all active audio nodes and their connections.

The primary method of creating a new AudioGraph. It is empty except for the default destination node stored under "__destination" NodeID. This typically represents the speaker output of your device.

See createAudioDestinationNote for more information.

Inserts a new AudioNode into the graph with the supplied id string. If a node already exists at the supplied id, the current node is replaced with the new one.

Queries the graph for the AudioNode at the supplied id string. Can return Just AudioNode or Nothing if no node exists at that id.

Removes the AudioNode at the supplied id string from the graph. This is a no-op if no node exists at that id.

Adds a new connection for the graph to track. There is a guard to prevent duplicate connections being added.

Removes the supplied connection from the graph. If the connection doesn't exist this is a no-op.

AudioNodes are the central focus of an AudioGraph. They represent any arbitrary audio processing node in a graph and can have any number of inputs, outputs, parameters, and properties.

• NodeType specifies the type of AudioNode. Each type is a 1:1 name mapping of its Web Audio counterpart, so you can always refer to the Web Audio documentation for more details.
• Params is a list of audio-rate parameters that the AudioNode exposes. These can be modulated by other AudioNodes. See AudioParam for more information.
• Properties lists an non-audio-rate properties of the AudioNode. These include properties like oscillator waveform type or filter type. Typically these are set once when the node is created. Other AudioNodes cannot connect to a NodeProperty.
• Inputs is a list of all the points another AudioNode can connect to this node. These can either be InputChannels that are numbered from 0, or InputParams that expose the node's params for connection. See NodeInput for more details.
• NumOutputs is an integer stating the number of audio outputs the node has. Note: the Web Audio API treats input/output count and channel count seperately. A node may only have one output but may still be stereo.

A simple type alias for more expressive type annotations. NodeIDs are used as keys in the AudioGraph nodes dictionary.

Describes what type of node an AudioNode represents. These are 1:1 mappings of the audio nodes detailed in the Web Audio API so refer here for more information on each node.

The AudioParam type represents a Web Audio audio param. The follow description is abridged from the Web Audio API docs:

The Web Audio API's AudioParam interface represents an audio-related parameter, usually a parameter of an AudioNode (such as GainNode.gain)

There are two kinds of AudioParam, a-rate and k-rate parameters:

• An a-rate AudioParam takes the current audio parameter value for each sample frame of the audio signal.
• A k-rate AudioParam uses the same initial audio parameter value for the whole block processed, that is 128 sample frames.

The distinction between a-rate and k-rate is useful to know when processing audio, but does not impact how params are used. All AudioParams can be modulated by AudioNodes.

A NodeProperty is used in much the same way as an AudioParam. The key distinction is that NodeProperties cannot be modulated by other AudioNodes.

While their values can be updated programmatically, they cannot be continuously modulated by an audio signal.

Every AudioNode can have some number of inputs, and these inputs can correspond to a direct audio input channel on the node, or an AudioParam.

• InputChannel represents the channel number of an audio input for the node. These are zero-indexed.
• InputParam represents the label of the parameter to connect to.

Creates an AnalyserNode.

AudioNode
    { nodeType = AnalyserNode
    , params = []
    , properties =
        [ NodeProperty { label = "fftSize", value = FFT_Size 2048 }
        , NodeProperty { label = "minDecibels", value = Decibels -100 }
        , NodeProperty { label = "maxDecibels", value = Decibels -30 }
        , NodeProperty { label = "smoothingTimeConstant", value = Number 0.8 }
        ]
    , inputs =
        [ InputChannel 0
        ]
    , numOutputs = 1
    }

Creates an AudioBufferSourceNode.

AudioNode
    { nodeType = AudioBufferSourceNode
    , params =
        [ AudioParam { label = "detune", value = Cents 0 }
        , AudioParam { label = "playbackRate", value = Number 1.0 }
        ]
    , properties =
        [ NodeProperty { label = "buffer", value = Buffer [] }
        , NodeProperty { label = "loop", value = Attribute False }
        , NodeProperty { label = "loopStart", value = Number 0 }
        , NodeProperty { label = "loopEnd", value = Number 0 }
        ]
    , inputs =
        [ InputParam "detune"
        , InputParam "playerbackRate"
        ]
    , numOutputs = 1
    }

Creates an AudioDestinationNode.

AudioNode
    { nodeType = AudioDestinationNode
    , params = []
    , properties = []
    , inputs =
        [ InputChannel 0
        ]
    , numOutputs = 0
    }

Creates a BiquadFilterNode.

AudioNode
    { nodeType = BiquadFilterNode
    , params =
        [ AudioParam { label = "frequency", value = Hertz 350 }
        , AudioParam { label = "detune", value = Cents 0 }
        , AudioParam { label = "Q", value = Number 1.0 }
        ]
    , properties =
        [ NodeProperty { label = "type", value = FilterType Lowpass }
        ]
    , inputs =
        [ InputParam "frequency"
        , InputParam "detune"
        , InputParam "Q"
        ]
    , numOutputs = 1
    }

Creates a ChannelMergerNode.

AudioNode
    { nodeType = ChannelMergerNode
    , params = []
    , properties = []
    , inputs =
        [ InputChannel 0
        , InputChannel 1
        , InputChannel 2
        , InputChannel 3
        , InputChannel 4
        , InputChannel 5
        ]
    , numOutputs = 1
    }

Creates a ChannelSplitterNode.

AudioNode
    { nodeType = ChannelSplitterNode
    , params = []
    , properties = []
    , inputs =
        [ InputChannel 0
        ]
    , numOutputs = 6
    }

Creates a ConstantSourceNode.

AudioNode
    { nodeType = ConstantSourceNode
    , params =
        [ AudioParam { label = "offset", value = Number 1.0 }
        ]
    , properties = []
    , inputs =
        [ InputParam "offset"
        ]
    , numOutputs = 1
    }

Creates a ConvolverNode.

AudioNode
    { nodeType = ConvolverNode
    , params = []
    , properties =
        [ NodeProperty { label = "buffer", value = Buffer [] }
        , NodeProperty { label = "normalize", value = Attribute False }
        ]
    , inputs =
        [ InputChannel 0
        ]
    , numOutputs = 1
    }

Creates a DelayNode.

AudioNode
    { nodeType = DelayNode
    , params =
        [ AudioParam { label = "delayTime", value = Number 0 }
        ]
    , properties =
        [ NodeProperty { label = "maxDelayTime", value = Number 1.0 }
        ]
    , inputs =
        [ InputChannel 0
        , InputParam "delayTime"
        ]
    , numOutputs = 1
    }

Creates a DynamicsCompressorNode.

AudioNode
    { nodeType = DynamicsCompressorNode
    , params =
        [ AudioParam { label = "threshold", value = Decibels -24 }
        , AudioParam { label = "knee", value = Decibels 30 }
        , AudioParam { label = "ratio", value = Number 12 }
        , AudioParam { label = "attack", value = Number 0.003 }
        , AudioParam { label = "release", value = Number 0.25 }
        ]
    , properties = []
    , inputs =
        [ InputChannel 0
        , InputParam "threshold"
        , InputParam "knee"
        , InputParam "ratio"
        , InputParam "attack"
        , InputParam "release"
        ]
    , numOutputs = 1
    }

Creates a GainNode.

AudioNode
    { nodeType = GainNode
    , params =
        [ AudioParam { label = "gain", value = Number 1.0 }
        ]
    , properties = []
    , inputs =
        [ InputChannel 0
        , InputParam "gain"
        ]
    , numOutputs = 1
    }

Creates an IIRFilterNode.

AudioNode
    { nodeType = IIRFilterNode
    , params =
        [ AudioParam { label = "feedforward", value = Coefficients [] }
        , AudioParam { label = "feedbackward", value = Coefficients [] }
        ]
    , properties = []
    , inputs =
        [ InputChannel 0
        , InputParam "feedforward"
        , InputParam "feedbackward"
        ]
    , numOutputs = 1
    }

Creates an OscillatorNode.

AudioNode
    { nodeType = OscillatorNode
    , params =
        [ AudioParam { label = "frequency", value = Hertz 350 }
        , AudioParam { label = "detune", value = Cents 0 }
        ]
    , properties =
        [ NodeProperty { label = "type", value = WaveformType Sine }
        ]
    , inputs =
        [ InputParam "frequency"
        , InputParam "detune"
        ]
    , numOutputs = 1
    }

Creates a PannerNode.

AudioNode
    { nodeType = PannerNode
    , params =
        [ AudioParam { label = "orientationX", value = Number 1 }
        , AudioParam { label = "orientationY", value = Number 0 }
        , AudioParam { label = "orientationZ", value = Number 0 }
        , AudioParam { label = "positionX", value = Number 0 }
        , AudioParam { label = "positionY", value = Number 0 }
        , AudioParam { label = "positionZ", value = Number 0 }
        ]
    , properties =
        [ NodeProperty { label = "coneInnerAngle", value = Number 360 }
        , NodeProperty { label = "coneOuterAngle", value = Number 0 }
        , NodeProperty { label = "coneOuterGain", value = Number 0 }
        , NodeProperty { label = "distanceModel", value = DistanceModelType Inverse }
        , NodeProperty { label = "maxDistance", value = Number 10000 }
        , NodeProperty { label = "panningModel", value = PanningModelType EqualPower }
        , NodeProperty { label = "refDistance", value = Number 1 }
        , NodeProperty { label = "rolloffFactor", value = Number 1 }
        ]
    , inputs =
        [ InputChannel 0
        , InputParam "orientationX"
        , InputParam "orientationY"
        , InputParam "orientationZ"
        , InputParam "positionX"
        , InputParam "positionY"
        , InputParam "positionZ"
        ]
    , numOutputs = 1
    }

Creates a StereoPannerNode.

AudioNode
    { nodeType = StereoPannerNode
    , params =
        [ AudioParam { label = "pan", value = Number 0 }
        ]
    , properties = []
    , inputs =
        [ InputChannel 0
        , InputParam "pan"
        ]
    , numOutputs = 1
    }

Creates a WaveShaperNode.

AudioNode
    { nodeType = WaveShaperNode
    , params = []
    , properties =
        [ NodeProperty { label = "curve", value = WaveshaperCurve [] }
        , NodeProperty { label = "oversample", value = OversampleType None }
        ]
    , inputs =
        [ InputChannel 0
        ]
    , numOutputs = 1
    }

Update the Value stored in an AudioParam.

Note: If an AudioNode is connected to this param, updateParam will have no effect.

Update the Value stored in a NodeProperty.

A Connection describes how one AudioNode connects to another. A connection can exist in two forms: either a node can connect directly to another node's audio input, or a node can connect to another node's params. The type of connection is detailed by the inputDestination field.

See the NodeInput definition for more information.

-- Connect the output of "oscA" to the first input
-- of "gain".
connect "oscA" 0 "gain" (InputChannel 0)


-- Connect the output of "oscB" to the frequency param
-- of "oscA" to perform frequency modulation.
connect "oscB" 0 "oscA" (InputParam "frequency")

A simple helper function to create a Connection. This is the preferred way to construct Connections to avoid breaking API changes if the Conncection type alias changes.