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What We're Making The Interface
The Design Recording After clicking on the Record button, when the user presses a key, our program will respond by doing two things. First it will create a new line of text in the EditField for that note, and second it will play the note. To stop recording, the user will again click on the Record button which is labeled "Stop". Playing Properties
Playing a Song dim note as Dictionary dim line, count as integer dim noteLine as String dim currentNote as Integer dim startTime as Double // Clear Old Song Redim Song(-1) // Create Notes count = CountFields(EFNotes.Text, EndOfLine) for line = 1 to count First we declare our variables (duh), then we clear out the old song be redimming the array. Next we're going to loop through every line of text in the field.
// Get Line Data
noteLine = NthField(EFNotes.Text, EndOfLine, line)
// If It's Creating a Note, then Do So
if Left(noteLine, 7) = "NewNote" then
noteLine = Mid(noteLine, 9)
noteLine = Left(noteLine, Len(noteLine) - 1)
Here we're just making sure that the line isn't empty and contains a semblance of a valid NewNote() line. We then strip the line down to its parameters for easy reading. (ie "Pitch=60,Time=0,Velocity=80") Below, we then parse the parameters and create a new note dictionary. Remember that the Velocity parameter is optional which is why we first check to see if it contains a Velocity parameter. Also, notice that the order of the parameters can't be changed since this code is dependent on the order. After we parse it, we append the note to the Song array.
// Create Note
note = New Dictionary
note.Value("Pitch") = Val(NthField(NthField(noteLine, ",", 1), "=", 2))
note.Value("Time") = Val(NthField(NthField(noteLine, ",", 2), "=", 2))
if InStr(noteLine, "Velocity") > 0 then
note.Value("Velocity") = Val(NthField(NthField(noteLine, ",", 3), "=", 2))
end if
// Add Note To Song
Song.Append note
end if
next
The way our recording system works, is that it records the length of time that passes from the beginning of the song until the note is supposed to play. So when playing back a song, we need to know when the song starts, which is what the startTime variable is for. And since each note of the song needs to be played and is only played once, our outer for loop can simply loop through each index of the array. // Start the Clock startTime = Microseconds // Play Each Note of the Song for currentNote = 0 to UBound(Song) This small loop simply churns until it is time for the next note to play. While this tutorial could have been written to read directly from the field rather using a dictionary to store note information, the extra overhead of parsing the text between playing notes might cause the song to drag, causing notes to be played at inconsistent times. This will really only happen if the notes are close together, but hey, it can happen (wink).
// Wait until it's time to play the note
do
loop until Song(currentNote).Value("Time").DoubleValue <= Microseconds - startTime
Below is where we hand off the note to the PlayNote method which actually plays the note. The reason we have a test for whether currentNote is greater than 0, is because if it is, we want to pass the previous note (Song(currentNote - 1)) to the PlayNote method as the second optional parameter, so that it knows which note to stop playing. (Remember that our application will automatically stop the previous note before the "current" one begins to play.) If there was no previous note, then it simply doesn't pass a second parameter at all.
// Play Note
if currentNote > 0 then
PlayNote Song(currentNote), Song(currentNote-1)
else
PlayNote Song(currentNote)
end if
next
Playing a Note
Sub PlayNote(CurrentNote as Dictionary, PreviousNote as Dictionary = nil)
// Stop the Previous Note
if PreviousNote <> nil then
NotePlayer1.PlayNote PreviousNote.Value("Pitch").IntegerValue, 0
end if
// Play the Current Note
if CurrentNote.HasKey("Velocity") then
NotePlayer1.PlayNote CurrentNote.Value("Pitch").IntegerValue,
CurrentNote.Value("Velocity").IntegerValue
else
NotePlayer1.PlayNote CurrentNote.Value("Pitch").IntegerValue, 80
end if
End Sub
That aside, all that our PlayNote method does, is stop the previous note (by "playing" it again with a Velocity value of 0), and plays the next note. Starting to Record // Set Caption if me.Value then me.Caption = "Stop" else me.Caption = "Record" end if // Record Notes if me.Value then EFNotes.Text = "" RecStartTime = -1 end if It, as you can see, is fairly simple and straight forward. Remember that the Record button is a toggling BevelButton, and to compliment that, we toggle the button's caption between "Record" and "Stop". Other than that, we remove the text from the field (since when the user presses keys, it will be inserted into the field), and set the RecStartTime variable to -1. This Double property of the window keeps track of when the first note of the song being recorded was pressed. This variable is used very much in the same way that the startTime variable is used in the Play button's code. The only difference is that clock doesn't actually start until the first key is pressed, and the -1 value flags that no key has been pressed yet. Recording Notes
Function KeyDown(Key As String) As Boolean
dim Pitch as Integer, Time as Double
// If we're recording, then record
if BtnRecord.Value then
// Get Pitch
Select Case Key
Case "a"
Pitch = 60 // C
Case "w"
Pitch = 61 // D Flat
Case "s"
Pitch = 62 // D
Case "e"
Pitch = 63 // E Flat
Case "d"
Pitch = 64 // E
Case "f"
Pitch = 65 // F
Case "t"
Pitch = 66 // G Flat
Case "g"
Pitch = 67 // G
Case "y"
Pitch = 68 // A Flat
Case "h"
Pitch = 69 // A
Case "u"
Pitch = 70 // B Flat
Case "j"
Pitch = 71 // B
Case "k"
Pitch = 72 // C
Case "o"
Pitch = 73 // D Flat
Case "l"
Pitch = 74 // D
Case " "
Pitch = -1 // Silence
else
Return true // not a key we recognize
end Select
The Select statement above determines which key was pressed and sets the Pitch value accordingly. If the spacebar is pressed Pitch is -1 to signal that instead of playing another note, it should stop the previous one. If a key is pressed that we don't recognize, we simply ignore it.
// Get Time
if RecStartTime = -1 then RecStartTime = Microseconds
Time = Microseconds - RecStartTime
// Add Note
AddNote Pitch, Time
Above we determine the amount of time that has passed since the first valid key was pressed after clicking the Record button, and then we use the AddNote method to actually add the text to the field and play the note.
// Return True to signal we handled the event
return true
end if
End Function
The AddNote method is the last piece of the puzzle. The first if-statement determines whether or not the note being added is a silencer for the previously played note. If it is, then it modifies the Pitch and Velocity variables in the method to match the Pitch of the previous note and have a velocity of 0 to stop the sound. If the note is not a silencer, then it simply remembers the pitch value in the RecLastPitch window property we added earlier.
Sub AddNote(Pitch as Integer, Time as Double, Velocity As Integer = 80)
dim note as Dictionary
// Remember the Note if Not Silence
if Pitch = -1 then
Pitch = RecLastPitch
Velocity = 0
else
RecLastPitch = Pitch
end if
This if-statement is where the text for the note is added to the field.
// Add The Note
if Velocity = 80 then
EFNotes.Text = EFNotes.Text + "NewNote(Pitch=" + Str(Pitch) + ",Time=" + Str(Time)
+ ")" + EndOfLine
else
EFNotes.Text = EFNotes.Text + "NewNote(Pitch=" + Str(Pitch) + ",Time=" + Str(Time)
+ ",Velocity=" + Str(Velocity) + ")" + EndOfLine
end if
Here we create a temporary note Dictionary and use it with the PlayNote method to play the note. Notice we also remember the last note that was played so that we can pass it to the PlayNote method so it will stop the previous note eliminating the continuous sound. If you're not sure why we're auto-stopping the previously played note, when the project is completed, comment out the line that stops the sound and run the project to learn/hear why.
// Play the Note
note = New Dictionary
note.Value("Pitch") = Pitch
note.Value("Velocity") = Velocity
note.Value("Time") = Time
if RecLastNote <> nil then
PlayNote note, RecLastNote
else
PlayNote note
end if
// Remember Note
RecLastNote = note
End Sub
Finished As always, you can download the project for this tutorial. |
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