Web.Audio

wahsp (Web Audio HaSkell Protocol) is a binding for Haskell to the Web Audio API ala blank-canvas. Audio sources, effects, etc. can be combined, manipulated, and otherwise controlled using haskell and are then rendered in the the browser (see the above link for browser compatibility).

Set-Up

webAudio :: WAOptions -> (Document -> IO ()) -> IO ()

webAudio is the starting point for connecting and interacting with the API. A simple example of how to use this is:

 module Main where
 import Web.Audio
 
 main :: IO ()
 main = do
   webAudio 3000 $ \doc -> do
     send doc $ do
       osc1  <- createOscillator 200 0 Sine -- create an OscillatorNode
       gain1 <- createGain 0.5              -- create a GainNode
 
       connect $ osc1 .|. gain1 .||. eCtx   -- connect these nodes together, and then connect them to the audio context
 
       start osc1 -- make sounds!

When running, go to http://localhost:3000/ in a browser to hear a 200Hz sine wave!

More examples can be found here.

data WAOptions

Various options when sending info to the browser

Constructors

WAOptions

Fields

• port :: Int

  which port to send to

• events :: [Int]

  not implemented yet

• debug :: Bool

  turns on debugging, defaults to False

• root :: String

  location of static files

• weak :: Bool

  not implemented yet

Instances

Num WAOptions

Methods

(+) :: WAOptions -> WAOptions -> WAOptions

(-) :: WAOptions -> WAOptions -> WAOptions

(*) :: WAOptions -> WAOptions -> WAOptions

negate :: WAOptions -> WAOptions

abs :: WAOptions -> WAOptions

signum :: WAOptions -> WAOptions

fromInteger :: Integer -> WAOptions

send :: Document -> WebAudio a -> IO a

Connecting nodes, params, and the audio context

The Web Audio API is comprised of nodes (AudioNodes, AudioParams, and the AudioContext) that are connected, input to output, to form a chain comprised of sources, effects, and a destination.

This chain is typically organized as a source -> effects -> destination, where destination is either the AudioContext (if you actually want to produce sound in this chain), some AudioParam (if you want to control a param with an audio signal, e.g. a low-frequency oscillator (lfo)), or some AudioNode.

To chain together AudioNodes and AudioParams, use .|. and end the chain with .||. For example:

osc1  <- createOscillator 200 0 Sine
gain1 <- createGain 0.5

connect $ osc1 .|. gain1 .||. eCtx
start osc1

See the official docs for a more detailed overview.

connect :: AudioGraph AudNode b -> WebAudio ()

Connects the AudioGraph chain (made by connecting AudioNodes, AudioParams, and AudioContexts with .|. and .||.)

(.|.) :: forall b a. AudioNode a => a -> AudioGraph AudNode b -> AudioGraph AudNode b infix 7

Connect the front of the chain of nodes together, end the chain with .||.

(.||.) :: forall b a. AudioNode a => a -> AudioGraph AudNode b -> AudioGraph AudNode b infix 8

End the chain of AudioNodes.

To end the chain at the audio context:

connect $ osc1 .|. gain1 .||. eCtx

To end with an AudioParam (that is located in the AudioNode gain1):

connect $ osc1 .|. gain1 .||. eParam (gain gain1)

To end with the AudioNode gain1:

connect $ osc1 .|. gain1 .||. eNode gain1

connector :: forall b a. AudioNode a => a -> AudioGraph AudNode b -> AudioGraph AudNode b

function implementation of .|.

connectorLast :: forall b a. AudioNode a => a -> AudioGraph AudNode b -> AudioGraph AudNode b

function implementation of .||.

eNode :: AudioNode a => a -> AudioGraph AudNode AudNode

Set the ending node to an AudioNode

eParam :: AudioParam -> AudioGraph AudNode AudioParam

Set the ending node to an AudioParam

eCtx :: AudioGraph AudNode AudioContext

Set the ending node to the AudioContext

Data Types

newtype WebAudio a

Contains the commands and procedures to be sent to the web browser

Constructors

WebAudio (RemoteMonad Command Procedure a)

Instances

Monad WebAudio

Methods

(>>=) :: WebAudio a -> (a -> WebAudio b) -> WebAudio b

(>>) :: WebAudio a -> WebAudio b -> WebAudio b

return :: a -> WebAudio a

fail :: String -> WebAudio a

Functor WebAudio

Methods

fmap :: (a -> b) -> WebAudio a -> WebAudio b

(<$) :: a -> WebAudio b -> WebAudio a

Applicative WebAudio

Methods

pure :: a -> WebAudio a

(<*>) :: WebAudio (a -> b) -> WebAudio a -> WebAudio b

(*>) :: WebAudio a -> WebAudio b -> WebAudio b

(<*) :: WebAudio a -> WebAudio b -> WebAudio a

Semigroup a => Semigroup (WebAudio a)

Methods

(<>) :: WebAudio a -> WebAudio a -> WebAudio a

sconcat :: NonEmpty (WebAudio a) -> WebAudio a

stimes :: Integral b => b -> WebAudio a -> WebAudio a

Monoid a => Monoid (WebAudio a)

Methods

mempty :: WebAudio a

mappend :: WebAudio a -> WebAudio a -> WebAudio a

mconcat :: [WebAudio a] -> WebAudio a

class JSArg a => AudioNode a where

And AudioNode is an interface for any audio processing module in the Web Audio API

Minimal complete definition

numberOfInputs, numberOfOutputs, channelCount, channelCountMode, channelInterpretation

Methods

numberOfInputs :: a -> Int

numberOfOutputs :: a -> Int

channelCount :: a -> Int

channelCountMode :: a -> ChannelCountMode

channelInterpretation :: a -> ChannelInterpretation

Instances

AudioNode OscillatorNode

Instantizes OscillatorNode with the default values

Methods

numberOfInputs :: OscillatorNode -> Int

numberOfOutputs :: OscillatorNode -> Int

channelCount :: OscillatorNode -> Int

channelCountMode :: OscillatorNode -> ChannelCountMode

channelInterpretation :: OscillatorNode -> ChannelInterpretation

AudioNode GainNode

Methods

numberOfInputs :: GainNode -> Int

numberOfOutputs :: GainNode -> Int

channelCount :: GainNode -> Int

channelCountMode :: GainNode -> ChannelCountMode

channelInterpretation :: GainNode -> ChannelInterpretation

data OscillatorNode

OscillatorNode represents a periodic waveform with a frequency (in hertz), detuning (in cents), an OscillatorNodeType (e.g. a sine wave, square wave, etc.), etc.

Constructors

OscillatorNode

Fields

• indexOsc :: !Int

  Index in javascript, for internal use

• frequencyOsc :: !AudioParam

  the frequency of this oscilaltor

• detuneOsc :: !AudioParam

  how many cents the frequencyOsc is detuned by

• typeOsc :: !OscillatorNodeType

  periodic wave type

• numberOfInputsOsc :: !Int

  number of inputs

• numberOfOutputsOsc :: !Int

  number of outputs

• channelCountOsc :: !Int

  number of channels used when up-mixing and down-mixing

• channelCountModeOsc :: !ChannelCountMode

  The ChannelCountMode of this oscillator

• channelInterpretationOsc :: !ChannelInterpretation

  The ChannelInterpretation of this oscilaltor

Instances

Eq OscillatorNode

Methods

(==) :: OscillatorNode -> OscillatorNode -> Bool

(/=) :: OscillatorNode -> OscillatorNode -> Bool

Read OscillatorNode

Methods

readsPrec :: Int -> ReadS OscillatorNode

readList :: ReadS [OscillatorNode]

readPrec :: ReadPrec OscillatorNode

readListPrec :: ReadPrec [OscillatorNode]

Show OscillatorNode

Methods

showsPrec :: Int -> OscillatorNode -> ShowS

show :: OscillatorNode -> String

showList :: [OscillatorNode] -> ShowS

JSArg OscillatorNode

Methods

showtJS :: OscillatorNode -> Text

AudioNode OscillatorNode

Instantizes OscillatorNode with the default values

Methods

numberOfInputs :: OscillatorNode -> Int

numberOfOutputs :: OscillatorNode -> Int

channelCount :: OscillatorNode -> Int

channelCountMode :: OscillatorNode -> ChannelCountMode

channelInterpretation :: OscillatorNode -> ChannelInterpretation

data OscillatorNodeType

Constructors

Sine

Square

Sawtooth

Triangle

Custom

Instances

Eq OscillatorNodeType

Methods

(==) :: OscillatorNodeType -> OscillatorNodeType -> Bool

(/=) :: OscillatorNodeType -> OscillatorNodeType -> Bool

Read OscillatorNodeType

Methods

readsPrec :: Int -> ReadS OscillatorNodeType

readList :: ReadS [OscillatorNodeType]

readPrec :: ReadPrec OscillatorNodeType

readListPrec :: ReadPrec [OscillatorNodeType]

Show OscillatorNodeType

Methods

showsPrec :: Int -> OscillatorNodeType -> ShowS

show :: OscillatorNodeType -> String

showList :: [OscillatorNodeType] -> ShowS

FromJSON OscillatorNodeType

Methods

parseJSON :: Value -> Parser OscillatorNodeType

parseJSONList :: Value -> Parser [OscillatorNodeType]

data GainNode

Constructors

GainNode

Fields

• indexGain :: !Int
• gain :: !AudioParam
• numberOfInputsGain :: !Int
• numberOfOutputsGain :: !Int
• channelCountGain :: !Int
• channelCountModeGain :: !ChannelCountMode
• channelInterpretationGain :: !ChannelInterpretation

Instances

Eq GainNode

Methods

(==) :: GainNode -> GainNode -> Bool

(/=) :: GainNode -> GainNode -> Bool

Read GainNode

Methods

readsPrec :: Int -> ReadS GainNode

readList :: ReadS [GainNode]

readPrec :: ReadPrec GainNode

readListPrec :: ReadPrec [GainNode]

Show GainNode

Methods

showsPrec :: Int -> GainNode -> ShowS

show :: GainNode -> String

showList :: [GainNode] -> ShowS

JSArg GainNode

Methods

showtJS :: GainNode -> Text

AudioNode GainNode

Methods

numberOfInputs :: GainNode -> Int

numberOfOutputs :: GainNode -> Int

channelCount :: GainNode -> Int

channelCountMode :: GainNode -> ChannelCountMode

channelInterpretation :: GainNode -> ChannelInterpretation

data AudioParam

Constructors

AudioParam AudioParamType Int

Instances

Eq AudioParam

Methods

(==) :: AudioParam -> AudioParam -> Bool

(/=) :: AudioParam -> AudioParam -> Bool

Read AudioParam

Methods

readsPrec :: Int -> ReadS AudioParam

readList :: ReadS [AudioParam]

readPrec :: ReadPrec AudioParam

readListPrec :: ReadPrec [AudioParam]

Show AudioParam

Methods

showsPrec :: Int -> AudioParam -> ShowS

show :: AudioParam -> String

showList :: [AudioParam] -> ShowS

FromJSON AudioParam

Methods

parseJSON :: Value -> Parser AudioParam

parseJSONList :: Value -> Parser [AudioParam]

JSArg AudioParam

Methods

showtJS :: AudioParam -> Text

data ChannelCountMode :: * where

How channels will be matched between connected inputs and output. Detailed description.

Constructors

Max :: ChannelCountMode

ClampedMax :: ChannelCountMode

Explicit :: ChannelCountMode

Instances

Eq ChannelCountMode

Methods

(==) :: ChannelCountMode -> ChannelCountMode -> Bool

(/=) :: ChannelCountMode -> ChannelCountMode -> Bool

Read ChannelCountMode

Methods

readsPrec :: Int -> ReadS ChannelCountMode

readList :: ReadS [ChannelCountMode]

readPrec :: ReadPrec ChannelCountMode

readListPrec :: ReadPrec [ChannelCountMode]

Show ChannelCountMode

Methods

showsPrec :: Int -> ChannelCountMode -> ShowS

show :: ChannelCountMode -> String

showList :: [ChannelCountMode] -> ShowS

FromJSON ChannelCountMode

Methods

parseJSON :: Value -> Parser ChannelCountMode

parseJSONList :: Value -> Parser [ChannelCountMode]

data AudioParamType

Which type of AudioParam

Constructors

Gain

Frequency

Detune

Instances

Eq AudioParamType

Methods

(==) :: AudioParamType -> AudioParamType -> Bool

(/=) :: AudioParamType -> AudioParamType -> Bool

Read AudioParamType

Methods

readsPrec :: Int -> ReadS AudioParamType

readList :: ReadS [AudioParamType]

readPrec :: ReadPrec AudioParamType

readListPrec :: ReadPrec [AudioParamType]

Show AudioParamType

Methods

showsPrec :: Int -> AudioParamType -> ShowS

show :: AudioParamType -> String

showList :: [AudioParamType] -> ShowS

Procedures

Instantiation functions

createOscillator

Arguments

:: Double

Frequency (in hertz)

-> Double

Detuning (in cents)

-> OscillatorNodeType

Waveform type

-> WebAudio OscillatorNode

creates an oscillator with a frequency (in hertz), a detuning value (in cents), and an OscillatorNodeType (e.g. a sine wave, square wave, etc.)

createGain :: Double -> WebAudio GainNode

Create a gain node with a gain value, typically between 0.0 and 1.0

Other Procedures

audioContext :: AudioContext

A function that returns an AudioContext

maxValue :: AudioParam -> WebAudio Double

Get the maximum value of an AudioParam

minValue :: AudioParam -> WebAudio Double

Get the minimum value of an AudioParam

value :: AudioParam -> WebAudio Double

Get the current value of an AudioParam

currentTime :: WebAudio Double

Get the current time in the sessions (in seconds). This represents the amount of time that has passed since the session was instantiated

Playback control

OscillatorNode specific playback controls

start :: OscillatorNode -> WebAudio ()

Immediately start playback of an OscillatorNode

startWhen :: OscillatorNode -> Double -> WebAudio ()

Start playing an OscillatorNode at t seconds. If t has already passed, it will immediately stop

stop :: OscillatorNode -> WebAudio ()

Immediately stop playback of an OscillatorNode

stopWhen :: OscillatorNode -> Double -> WebAudio ()

Stop playing an OscillatorNode at t seconds. If t has already passed, it will immediately stop

Disconnecting functions

disconnect :: AudioNode a => a -> WebAudio ()

Disconnect all outgoing connections from AudioNode n

disconnectOutput :: AudioNode a => a -> Int -> WebAudio ()

Disconnect a specific output

disconnectOutputInput :: AudioNode a => a -> a -> Int -> Int -> WebAudio ()

disconnectDestNode :: AudioNode a => a -> a -> WebAudio ()

disconnectDestNodeSpec :: AudioNode a => a -> a -> Int -> WebAudio ()

disconnectDestParam :: AudioNode a => a -> AudioParam -> WebAudio ()

disconnectDestParamSpec :: AudioNode a => a -> AudioParam -> Int -> WebAudio ()

Change AudioParam value

Different functions for altering the values of AudioParams (immediately, ramping, etc.)

setValue :: AudioParam -> Double -> WebAudio ()

setValueAtTime :: AudioParam -> Double -> Double -> WebAudio ()

linearRampToValueAtTime :: AudioParam -> Double -> Double -> WebAudio ()

exponentialRampToValueAtTime :: AudioParam -> Double -> Double -> WebAudio ()

setTargetAtTime :: AudioParam -> Double -> Double -> Double -> WebAudio ()

cancelScheduledValues :: AudioParam -> Double -> WebAudio ()