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sound() function

Introduction

The 'Sounds' chapter of Codea's in-app reference documents most of the sound() function. The function takes one or two parameters and, depending on their values, either plays a sound or encodes a table of parameters into a string that is returned by the function.

sound("encode", parameterTable)

If there are two parameters and the first parameter is "encode", the function sound() assumes that the second parameter is a table specifying the parameters to use when generating a sound. It encodes the parameters in the table into a string that can be used with sound("data", parameterString).

The Codea API provides a global variable ENCODE that refers to the string "encode".

For example:

supportedOrientations(LANDSCAPE_ANY)
function setup()
    -- Add parameters. Function 'changed' is called when they are created or if they change
    parameter.integer("waveform",                 0, 3, 0, changed)    
    parameter.number("attackTime",                0, 3, 0.5, changed)
    parameter.number("sustainTime",               0, 3, 1, changed)
    parameter.number("sustainPunch",              0, 3, 0.0, changed)
    parameter.number("decayTime",                 0, 3, 0.4, changed)
    parameter.number("startFrequency",            0, 2, 0.9, changed)
    parameter.number("minFrequency",              0, 1, 0, changed)
    parameter.number("slide",                   0.9, 1, 0.96, changed)
    parameter.number("deltaSlide",                0, 1, 0.6, changed)
    parameter.number("vibratoDepth",              0, 1, 0.5, changed)
    parameter.number("vibratoSpeed",              0, 1, 0.5, changed)
    parameter.number("changeAmount",              0, 1, 0.6, changed)
    parameter.number("changeSpeed",               0, 1, 0.6, changed)
    parameter.number("squareDuty",                0, 1, 0.5, changed)
    parameter.number("dutySweep",                 0, 1, 0.5, changed)
    parameter.number("repeatSpeed",               0, 1, 0.5, changed)
    parameter.number("phaserSweep",               0, 1, 0.5, changed)
    parameter.number("lowpassFilterCutoff",       0, 1, 0.5, changed)
    parameter.number("lowpassFilterCutoffSweep",  0, 1, 0.5, changed)
    parameter.number("lowpassFilterResonance",    0, 1, 0.5, changed)
    parameter.number("highpassFilterCutoff",      0, 1, 0.5, changed)
    parameter.number("highpassFilterCutoffSweep", 0, 1, 0.5, changed)
    parameter.number("volume",                    0, 1, 1.0, changed)
    isSetup = true
    changed() -- Initialise the parameterString
    textWrapWidth(WIDTH * 0.9)
    fontSize(32)
    fill(255)
end

function draw()
    background(0)
    text(parameterString, WIDTH / 2, HEIGHT / 2)
end

function changed()
    if not isSetup then return end -- All variables need to exist
    parameterTable = {
        Waveform                  = waveform, 
        AttackTime                = math.pow(attackTime - 0.5, 3),
        SustainTime               = math.pow(sustainTime - 0.5, 2),
        SustainPunch              = math.pow(sustainPunch, 2),
        DecayTime                 = decayTime - 0.5,
        StartFrequency            = math.pow(startFrequency, 2),
        MinimumFrequency          = minFrequency,
        Slide                     = math.pow(slide, 5) - 0.5,
        DeltaSlide                = deltaSlide - 0.5,
        VibratoDepth              = math.pow(vibratoDepth - 0.5, 3),
        VibratoSpeed              = vibratoSpeed - 0.5,
        ChangeAmount              = changeAmount - 0.5,
        SquareDuty                = squareDuty - 0.5,
        DutySweep                 = dutySweep - 0.5,
        RepeatSpeed               = repeatSpeed - 0.5,
        PhaserSweep               = phaserSweep - 0.5,
        LowPassFilterCutoff       = 1 - math.pow(lowpassFilterCutoff, 3),
        LowPassFilterCutoffSweep  = math.pow(lowpassFilterCutoffSweep - 0.5, 3),
        LowPassFilterResonance    = lowpassFilterResonance - 0.5,
        HighPassFilterCutoff      = math.pow(highpassFilterCutoff, 3),
        HighPassFilterCutoffSweep = math.pow(highpassFilterCutoffSweep - 0.5, 3),
        Volume                    = volume
    }
    parameterString = sound(ENCODE, parameterTable)
end

sound("decode", ...)

As of Codea version 1.5.1, does nothing and returns nil.

The Codea API provides a global variable DECODE that refers to the string "decode".