Example of playing sounds with a specific note (e.g. C5# or F4b)

Examples
1

In the following sample you can select a note, octave and accidental via buttons and play the sound. There is a function inside which calculates the half steps from the note given as string, e.g. “C5#”:

calcHalfStepsFromNote(note)

The result is used in a magic formula to calculate the frequency and then the Codea Frequency used in the sound command. I have used the formula from the ABCplayer, thanks to @Fred for pointing me to it.

Screenshot: https://dl.dropbox.com/u/80475380/CodeaForumPictures/sound_notes.png

2

Main tab part 1/1:

--
-- Sample how to play a note by name
-- =================================
--
-- The central formula can calculate the StartFrequency
-- (between 0.0 and 1.0) for
-- the sound function from a half-tone stepping. Calculation
-- used from ABCplayer. Thanks @Fred and the others who found
-- that formula :-)
--
-- The magic calculation formula:
--        f = 440*2^((halfSteps-69)/12)
--        startFrequency = math.sqrt(f/44100*100/8-0.001)
--
-- halfSteps is the number of half steps which our note has
-- from the base. If it is 0, then it plays C0.
--
-- Now in the calcHalfStepsFromNote you can pass a string that
-- contains a note (CDEFGAH), an octave (0 to 8) and
-- an accidental (# or b) which changes the note by a halfstep
-- up or down. The function then uses a lookup table to
-- find the number of half steps for the note, multiplies the
-- octave by 12 and then sums all up. The result is
-- used as halfSteps input in the above formula.
--
-- Have fun,
-- Kilam Malik.

curNote = "C"
curOctave = "3"
curAccidental = ""

baseNr = -1
octaveNr = -1
accidentalNr = -1
frequency = -1
codeaFrequency = -1

buttonsNotes = {}
buttonsOctaves = {}
buttonsAccidentals = {}
buttonPlay = nil

-- cdefgah but sorted by alphabet for quick calc a-cdefgh:
baseNoteLookup = { 9, -1, 0, 2, 4, 5, 7, 11 }

displayMode(FULLSCREEN)
supportedOrientations(LANDSCAPE_ANY)

function calcHalfStepsFromNote(note)
    local base
    local octave
    local accidental

    if string.len(note) == 2 then
        base = string.lower(string.sub(note, 1, 1))
        octave = string.sub(note, 2, 2)
        accidental = ""
    elseif string.len(note) == 3 then
        base = string.lower(string.sub(note, 1, 1))
        octave = string.sub(note, 2, 2)
        accidental = string.lower(string.sub(note, 3, 3))
    else
        return 0
    end

    charNr = string.byte(base) - string.byte("a")
    baseNr = baseNoteLookup[charNr + 1]

    octaveNr = tonumber(octave) + 1

    if accidental== "#" then
        accidentalNr = 1
    elseif accidental == "b" then
        accidentalNr = -1
    else
        accidentalNr = 0
    end

    local halfTones = octaveNr * 12 + baseNr + accidentalNr
    return halfTones
end

function buttonNoteClicked(note)
    curNote = note

    -- Deselect all other buttons in group... have to make a
    -- button group class in the future to do this handling:
    for i = 0, table.maxn(buttonsNotes) do
        if buttonsNotes[i] == nil then
        else
            buttonsNotes[i].selected = false
        end
    end
end

function buttonOctaveClicked(octave)
    curOctave = octave

    -- Deselect all other buttons in group... have to make a
    -- button group class in the future to do this handling:
    for i = 0, table.maxn(buttonsOctaves) do
        if buttonsOctaves[i] == nil then
        else
            buttonsOctaves[i].selected = false
        end
    end
end

function buttonAccidentalClicked(accidental)
    curAccidental = accidental

    -- Deselect all other buttons in group... have to make a
    -- button group class in the future to do this handling:
    for i = 0, table.maxn(buttonsAccidentals) do
        if buttonsAccidentals[i] == nil then
        else
            buttonsAccidentals[i].selected = false
        end
    end
end

function buttonPlayClicked(id)
    local halfSteps = calcHalfStepsFromNote(curNote .. curOctave .. curAccidental)

    frequency = 440*2^((halfSteps-69)/12)
    codeaFrequency = math.sqrt(frequency/44100*100/8-0.001)
    instrument = {Waveform = Waveform, StartFrequency = codeaFrequency, AttackTime = AttackTime, SustainPunch = SustainPunch, DecayTime = DecayTime}
    sound(instrument)

    --encStr = sound( ENCODE, instrument )
    --print(encStr)
    --sound(DATA, encStr)
end

function createButton(name, x, y, w, h, btype, callback)
    local btnImgPressed = image(70, 70)
    setContext(btnImgPressed)
        fill(200, 200, 200, 255)
        rect(0,0,w,h)
        fill(121, 225, 162, 255)
        rect(5,5,w-10,h-10)
        fill(0, 0, 0, 255)
        textMode(CENTER)
        text(name, w/2, h/2)
        fill(255, 255, 255, 255)
        text(name, w/2-1, h/2+1)
    setContext()

    local btnImgNormal = image(w, h)
    setContext(btnImgNormal)
        tint(255, 255, 255, 127)
        sprite(btnImgPressed, w/2, h/2, w, h)
        noTint()
    setContext()

    if btype == 0 then
        b = Button(name, x, y, w, h, btnImgPressed, btnImgPressed, btype, callback)
    else
        b = Button(name, x, y, w, h, btnImgNormal, btnImgPressed, btype, callback)
    end
    return b
end

function setup()
    local b
    -- Create note buttons:
    b = createButton("C", 50, HEIGHT-50, 70, 70, 1, buttonNoteClicked)
    b.selected = true
    table.insert(buttonsNotes, b)
    b = createButton("D", 150, HEIGHT-50, 70, 70, 1, buttonNoteClicked)
    table.insert(buttonsNotes, b)
    b = createButton("E", 250, HEIGHT-50, 70, 70, 1, buttonNoteClicked)
    table.insert(buttonsNotes, b)
    b = createButton("F", 350, HEIGHT-50, 70, 70, 1, buttonNoteClicked)
    table.insert(buttonsNotes, b)
    b = createButton("G", 450, HEIGHT-50, 70, 70, 1, buttonNoteClicked)
    table.insert(buttonsNotes, b)
    b = createButton("A", 550, HEIGHT-50, 70, 70, 1, buttonNoteClicked)
    table.insert(buttonsNotes, b)
    b = createButton("H", 650, HEIGHT-50, 70, 70, 1, buttonNoteClicked)
    table.insert(buttonsNotes, b)

    -- Create octave buttons:
    b = createButton("0", 50, HEIGHT-150, 70, 70, 1, buttonOctaveClicked)
    table.insert(buttonsOctaves, b)
    b = createButton("1", 150, HEIGHT-150, 70, 70, 1, buttonOctaveClicked)
    table.insert(buttonsOctaves, b)
    b = createButton("2", 250, HEIGHT-150, 70, 70, 1, buttonOctaveClicked)
    table.insert(buttonsOctaves, b)
    b = createButton("3", 350, HEIGHT-150, 70, 70, 1, buttonOctaveClicked)
    b.selected = true
    table.insert(buttonsOctaves, b)
    b = createButton("4", 450, HEIGHT-150, 70, 70, 1, buttonOctaveClicked)
    table.insert(buttonsOctaves, b)
    b = createButton("5", 550, HEIGHT-150, 70, 70, 1, buttonOctaveClicked)
    table.insert(buttonsOctaves, b)
    b = createButton("6", 650, HEIGHT-150, 70, 70, 1, buttonOctaveClicked)
    table.insert(buttonsOctaves, b)
    b = createButton("7", 750, HEIGHT-150, 70, 70, 1, buttonOctaveClicked)
    table.insert(buttonsOctaves, b)

    -- Create accitental buttons:
    b = createButton("", 50, HEIGHT-250, 70, 70, 1, buttonAccidentalClicked)
    b.selected = true
    table.insert(buttonsAccidentals, b)
    b = createButton("#", 150, HEIGHT-250, 70, 70, 1, buttonAccidentalClicked)
    table.insert(buttonsAccidentals, b)
    b = createButton("b", 250, HEIGHT-250, 70, 70, 1, buttonAccidentalClicked)
    table.insert(buttonsAccidentals, b)

    -- Create play button:
    buttonPlay = createButton("Play", 50, HEIGHT-350, 70, 70, 0, buttonPlayClicked)
end

function touched(touch)
    for i = 0, table.maxn(buttonsNotes) do
        if buttonsNotes[i] == nil then
        else
            buttonsNotes[i]:touched(touch)
        end
    end

    for i = 0, table.maxn(buttonsOctaves) do
        if buttonsOctaves[i] == nil then
        else
            buttonsOctaves[i]:touched(touch)
        end
    end

    for i = 0, table.maxn(buttonsAccidentals) do
        if buttonsAccidentals[i] == nil then
        else
            buttonsAccidentals[i]:touched(touch)
        end
    end

    buttonPlay:touched(touch)
end
3

Main tab part 2/2:

function draw()
    background(255, 255, 255)

    for i = 0, table.maxn(buttonsNotes) do
        if buttonsNotes[i] == nil then
        else
            buttonsNotes[i]:draw()
        end
    end

    for i = 0, table.maxn(buttonsOctaves) do
        if buttonsOctaves[i] == nil then
        else
            buttonsOctaves[i]:draw()
        end
    end

    for i = 0, table.maxn(buttonsAccidentals) do
        if buttonsAccidentals[i] == nil then
        else
            buttonsAccidentals[i]:draw()
        end
    end

    buttonPlay:draw()

    textMode(CORNER)
    local s = "Current selection: " .. curNote .. curOctave .. curAccidental
    fill(0, 0, 0, 255)
    text(s, 10, HEIGHT - 500)

    s = string.format("Note: %d, Octave: %d, Accidental: %d", baseNr, octaveNr, accidentalNr)
    fill(0, 0, 0, 255)
    text(s, 10, HEIGHT - 530)

    s = string.format("Frequency: %f", frequency)
    fill(0, 0, 0, 255)
    text(s, 10, HEIGHT - 560)

    s = string.format("Codea Frequency: %f", codeaFrequency)
    fill(0, 0, 0, 255)
    text(s, 10, HEIGHT - 590)
end
4

Button tab:

Button = class()

function Button:init(id, x, y, w, h, img1, img2, btype, callback)
-- id is sent back to the callback function to use one callback for multiple buttons.
-- x, y, w, h is position and size.
-- img is the picture of the button.
-- btype = 0 is a normal button, btype = 1 is a toggle button.

    self.id = id
    self.x = x
    self.y = y
    self.w = w
    self.h = h
    self.imgNormal = img1
    self.imgPressed = img2
    self.btype = btype
    self.callback = callback


    self.inTouch = false
    self.selected = false
end

function Button:draw()
    local w = self.w
    local h = self.h
    if self.selected or self.inTouch then
        w = w * 1.2
        h = h * 1.2
        sprite(self.imgPressed, self.x, self.y, w, h)
    else

        sprite(self.imgNormal, self.x, self.y, w, h)
    end
end

function Button:hit(x, y)
    if math.abs(self.x - x) <= (self.w / 2)
       and math.abs(self.y - y) <= (self.h / 2) then
        return true
    end

    return false
end

function Button:touched(touch)
    if touch.state == BEGAN then    
        if self:hit(touch.x, touch.y) then
            self.inTouch = true
        end
    elseif touch.state == MOVING and self.inTouch then    
        if self:hit(touch.x, touch.y) then
            self.inTouch = false
        end
    elseif touch.state == ENDED then
        if self.inTouch == true then
            self.callback(self.id)

            if self.btype == 1 then
                -- Callback deselects all buttons, so reselect it if toggle:
                self.selected = true
            end
            self.inTouch = false
        end
    end
end
5

@KilamMalik

Nice job. When I want to learn about the sound functions, this is probably the program I’ll use as a reference. I haven’t looked thru the code yet, but I’m sure you cover everything I’ll want to know. The only suggestion I have is that you add “supportedOrientations(LANDSCAPE_ANY)” at the beginning of the code. I normally use the iPad in portrait mode, so when I started your program I was still in portrait mode and the rightmost button was halfway off the screen. Adding the above code forced the display in landscape mode and everything fit OK.

6

Thanks, added it. I always work in landscape and didnt realize it was missing :slight_smile:

7

@KilamMalik, thank you for this example. Music and sound is my current fad and this will most likely be very helpful.

8

Would it somehow be possible to retrieve a pointer to the real data behind the sound? Would be nice to visualize the wave :slight_smile:

9

@KilamMali can I resize the buttons size, not in the code?