| Music.PlayFile | Part of Music module |
| Syntax | Music.PlayFile ( fileName : string )
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| Description | The Music.PlayFile procedure is used to play a file of music.
The file must be in one of the acceptable formats and the machine,
must have the appropriate hardware. The fileName parameter must give the format of the file:
Sounds are produced synchronously on a per process basis. This means that when a process executes a Music.Sound, Music.Play or Music.PlayFile command, it stops until the command is finished. However, other processes will continue executing.
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| Details | To play music while performing any other activity, the call to
Music.PlayFile must be executed in its own process.
The process is then called using the fork command. When a
fork command is given, execution starts on the process (like
a procedure call) and continues following the fork
command at the same time.
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| Example | This program plays the music in the file "branden3.wav"
while drawing ovals on the screen.
process DoMusic
loop
Music.PlayFile ("branden3.wav")
end loop
end DoMusic
fork DoMusic
var x, y, clr : int
loop
x := Rand.Int (0, maxx)
y := Rand.Int (0, maxy)
clr := Rand.Int (0, maxcolor)
Draw.FillOval (x, y, 30, 30, clr)
end loop
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| Execute | |||||||||||||
| Details | To play a sound file requires that the computer be equipped
with a sound card and speakers.
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| Details | The Turing 4.1 software can play files in the following audio
formats: WAVE (.wav) files, MIDI files (.midi or .mid), and MP3
files (.mp3). In general, MIDI files are the most efficient and
thus are the preferred form for longer music pieces like background
music. WAVE files can record anything, not just music, so are often
used for sound effects.
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| Details | The Turing 4.1 software can also play music on a compact disk.
To play the complete contents of the compact disk, the filename
is “cd”. To play a single track from a compact disk, the filename
is “cd:[track number]”.
Music.PlayFile ("cd") % Play the entire CD
Music.PlayFile ("cd:3") % Play the third track on the CD
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| Details | On the PC, different formats of music can play simultaneously. This
means that a program might use a MIDI file as a background soundtrack
and then use WAVE files for individual sound effects. The sound
effects would not interfere with the background music. Playing a
second music file with the same format as an already playing piece
immediately halts the first piece and starts the second. This can
be used to stop a single type of music by playing a short silent
piece of music.
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| Example | This program bounces a maple leaf around the screen with background
music and a sound effect when the maple leaf hits an edge. When the
user presses any key, the program immediately exits.
const STAR_SIZE : int := 80
var pic, x, y, dx, dy : int
var finished : boolean := false
% Play sound effect once.
process Boing
Music.PlayFile ("boing.wav")
end Boing
% Loop playing background music until 'finished' is true.
process BackgroundMusic
loop
exit when finished
Music.PlayFile ("background.mid")
end loop
end BackgroundMusic
% Get the original picture
Draw.FillStar (3, 3, STAR_SIZE - 3, STAR_SIZE - 3, brightred)
pic := Pic.New (0, 0, STAR_SIZE, STAR_SIZE)
cls
% Set the initial location and direction of movement
x := Rand.Int (0, maxx - STAR_SIZE)
y := Rand.Int (0, maxy - STAR_SIZE)
dx := 1
dy := 1
fork BackgroundMusic % Start background music playing
loop
if x + dx < 0 or x + dx > maxx - STAR_SIZE then
dx := -dx
fork Boing
end if
if y + dy < 0 or y + dy > maxy - STAR_SIZE then
dy := -dy
fork Boing
end if
x += dx
y += dy
Pic.Draw (pic, x, y, picCopy)
exit when hasch
Time.Delay (5)
end loop
% Stop the background music.
finished := true
Music.PlayFileStop
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| Execute | |||||||||||||
| See also | Music.PlayFileStop to
halt a music file that is current playing,
Music.PlayFileReturn for
a procedure that starts a music file playing and returns immediately
(meaning that you do not need to use process and fork
statements), and Music.PlayFileLoop
that starts a music file playing continuously until it is stopped
without the use of process or fork.
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| Status | Exported qualified. This means that you can only call the function by calling Music.PlayFile, not by calling PlayFile.
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