Differenze tra le versioni di "Eseguire un file audio mediante le funzioni di Alure"

Da Gambas-it.org - Wikipedia.
(Creata pagina con ''''ALURE''' è una libreria di utilità per aiutare a gestire le operazioni più comuni con applicazioni ''OpenAL''. Questo include l'enumerazione e l'inizializzazione del dis...')
 
Riga 1: Riga 1:
−
'''ALURE''' è una libreria di utilità per aiutare a gestire le operazioni più comuni con applicazioni ''OpenAL''. Questo include l'enumerazione e l'inizializzazione del dispositivo, il caricamento del file, e l'esecuzione. Lo scopo di questa API è quello di fornire funzionalità pre-organizzate per facilitare e velocizzare la programmazione dello sviluppatore.
+
'''ALURE''' è una libreria di utilità per aiutare a gestire le operazioni più comuni con applicazioni ''OpenAL''. Questo include l'enumerazione e l'inizializzazione del dispositivo, il caricamento del file, e l'esecuzione. Lo scopo di questa [http://it.wikipedia.org/wiki/Application_programming_interface API] è quello di fornire funzionalità pre-organizzate per facilitare e velocizzare la programmazione dello sviluppatore.
  
  
 +
La libreria condivisa contenente le funzioni esterne dell'API di OpenAlure, e che dovrà essere richiamata in Gambas, è attualmente la seguente:
 +
libalure.so.1.2.0
  
  
 +
Mostriamo di seguito un semplice codice per ottenere l'esecuzione e l'ascolto di file audio:  |[[#Note|1]]|
 +
'''Private''' isdone As Integer
 +
'''Private''' src As Integer
 +
 +
 +
Library "libalure:1.2.0"
 +
 +
 +
<FONT color=gray>' ''ALboolean alureInitDevice(const ALCchar * name, Const ALCint * attribs)''
 +
' ''Opens the named device, creates a context with the given attributes, and sets that context as current.''
 +
' ''The name and attribute list would be the same as what’s passed to alcOpenDevice and alcCreateContext respectively.''
 +
' ''Returns: AL_FALSE On error.''</font>
 +
'''Private''' Extern alureInitDevice(name As String, attribs As String) As Boolean
 +
 +
<FONT color=gray>' ''void alGenSources(Alsizei n, ALuint *sources)''</font>
 +
'''Private''' Extern alGenSources(n As Integer, sources As Pointer) In "libalut:0.1.0"
 +
 +
<FONT color=gray>' ''ALboolean alureStreamSizeIsMicroSec(ALboolean useUS)''
 +
' ''Specifies if the chunk size value given to the alureCreateStream functions is in bytes (default) or microseconds.''
 +
' ''Returns: Previously set value.''</font>
 +
'''Private''' Extern alureStreamSizeIsMicroSec(useUS As Boolean) As Boolean
 +
 +
<FONT color=gray>' ''alureStream* alureCreateStreamFromFile(Const ALchar * fname, ALsizei chunkLength, ALsizei numBufs, ALuint * bufs)''
 +
' ''Opens a file and sets it up for streaming.  The given chunkLength is the number of bytes, or microseconds worth of bytes if alureStreamSizeIsMicroSec was last called with AL_TRUE,''
 +
' ''each buffer will fill with.  ALURE will optionally generate the specified number of buffer objects, fill them with the beginning of the data,''
 +
' ''then place the new IDs into the provided storage, before returning.  Requires an active context.''
 +
' ''Returns: An opaque handle used To control the opened stream, Or Null On error.''</font>
 +
'''Private''' Extern alureCreateStreamFromFile(fname As String, chunkLength As Integer, numBufs As Integer, bufs As Pointer) As Pointer
 +
 +
<FONT color=gray>' ''ALboolean alurePlaySourceStream(ALuint source, alureStream * stream, ALsizei numBufs, ALsizei loopcount, void( * eos_callback)(void * userdata, ALuint source), void * userdata)''
 +
' ''Starts playing a stream, using the specified source ID.  A stream can only be played if it is not already playing.
 +
' ''<SPAN style="text-decoration:underline">You must call alureUpdate at regular intervals to keep the stream playing, or else the stream will underrun</span>
 +
' ''and cause a break in the playback until an update call can restart it.
 +
' ''If an underrun occurs, the source will enter a stopped state until it is automatically restarted.  Instead, set a flag using the callback to indicate the stream being stopped.''
 +
' ''"'''eos_callback'''": This callback will be called when the stream reaches the end, no more loops are pending, and the source reaches a stopped state.''
 +
' ''It will also be called if an error occured and playback terminated.''
 +
' ''Returns: AL_FALSE On error.''</font>
 +
'''Private''' Extern alurePlaySourceStream(source As Integer, strePnt As Pointer, numBufs As Integer, loopcount As Integer, eos_callback As Pointer, userdata As Pointer) As Boolean
 +
 +
<FONT color=gray>' ''void alureUpdate(void)''
 +
' ''Updates the running list of streams, and checks for stopped sources.''
 +
' ''This makes sure that sources played with alurePlaySourceStream are kept fed from their associated stream, and sources played with alurePlaySource are still playing.''
 +
' ''It will call their callbacks as needed.''</font>
 +
'''Private''' Extern alureUpdate()
 +
 +
<FONT color=gray>' ''ALboolean alureStopSource(ALuint source, ALboolean run_callback)''
 +
' ''Stops the specified source ID, and any associated stream.''
 +
' ''Returns: AL_FALSE On error.''</font>
 +
'''Private''' Extern alureStopSource(source As Integer, run_callback As Boolean) As Boolean
 +
 +
<FONT color=gray>' ''void alDeleteSources(ALsizei n, ALuint * sources)''
 +
' ''This function deletes one or more sources.''</font>
 +
'''Private''' Extern alDeleteSources(n As Integer, sources As Pointer) In "libalut:0.1.0"
 +
 +
<FONT color=gray>' ''ALboolean alureDestroyStream(alureStream * stream, ALsizei numBufs, ALuint * bufs)'
 +
' ''Closes an opened stream.''
 +
' ''Returns: AL_FALSE On error.''</font>
 +
'''Private''' Extern alureDestroyStream(strePnt As Pointer, numBufs As Integer, bufs As Pointer) As Boolean
 +
 +
<FONT color=gray>' ''ALboolean alureShutdownDevice(void)''
 +
' ''Destroys the current context and closes its associated device.''
 +
' ''Returns: AL_FALSE On error.''</font>
 +
'''Private'' Extern alureShutdownDevice() As Boolean
 +
 +
<FONT color=gray>' ''ALboolean alurePauseSource(ALuint source)''
 +
' ''Pauses the specified source ID, and any associated stream. Returns AL_FALSE On Error.''</font>
 +
'''Private''' Extern alurePauseSource(source As Integer) As Boolean
 +
 +
<FONT color=gray>' ''ALboolean alureResumeSource(ALuint source)''
 +
' ''Resumes the specified source ID after being paused. Returns AL_FALSE On Error.''</font>
 +
'''Private''' Extern alureResumeSource(source As Integer) As Boolean
 +
 +
 +
'''Public''' Sub Button1_Click()
 +
 +
  Dim streamP As Pointer
 +
  Dim ver As Boolean
 +
  Dim percorsoFile As String = "''percorso_del_file_audio''"
 +
  Dim lungh As Integer
 +
 +
 +
  alureInitDevice(Null, Null)
 +
 +
  alGenSources(1, VarPtr(src))
 +
 
 +
  alureStreamSizeIsMicroSec(False)
 +
 +
  lungh = Stat(percorsoFile).Size
 +
 
 +
<FONT color=gray>' ''Se si preferisce impostare la durata in base alla dimensione del file audio da eseguire,''
 +
' ''è opportuno passare il valore del secondo parametro almeno pari alla dimensione del file:''</font>
 +
  streamP = alureCreateStreamFromFile(percorsoFile, lungh, 0, Null)
 +
 
 +
  If IsNull(streamP) Then Error.Raise("Impossibile caricare il file Audio !")
 +
 +
 
 +
  alurePlaySourceStream(src, streamP, 512, 0, eos_callback, Null)
 +
 
 +
  While isdone = 0
 +
    Wait 0.01
 +
    alureUpdate()
 +
  Wend
 +
 
 +
 +
  alureStopSource(src, False)
 +
  alDeleteSources(1, VarPtr(src))
 +
  alureDestroyStream(streamP, 0, Null)
 +
  alureShutdownDevice()
 +
 +
  isdone = 0
 +
 +
'''End'''
 +
 +
 +
 +
'''Public''' Function eos_callback(unused As Pointer, unused2 As Integer)
 +
 +
    isdone = 1
 +
 
 +
'''End'''
 +
 +
 +
<FONT color=gray>' ''Mette in pausa l'esecuzione:''</font>
 +
'''Public''' Sub Button2_Click()
 +
 +
  alurePauseSource(src)
 +
 +
'''End'''
 +
 +
<FONT color=gray>' ''Riprende l'esecuzione:''</font>
 +
'''Public''' Sub Button3_Click()
 +
 +
  alureResumeSource(src)
 +
 +
'''End'''
 +
 +
<FONT color=gray>' ''Arresta l'esecuzione:''</font>
 +
'''Public''' Sub Button4_Click()
 +
 +
  alureStopSource(src, False)
 +
 +
'''End'''
  
−
<FONT color=red><B>Pagina in costruzione !</b></font>
 
  
 +
 +
=Note=
 +
[1] Si è constatato che i file audio eseguibili sono quelli di tipo: wav, mp3, ogg.
  
  

Versione delle 12:07, 24 lug 2013

ALURE è una libreria di utilità per aiutare a gestire le operazioni più comuni con applicazioni OpenAL. Questo include l'enumerazione e l'inizializzazione del dispositivo, il caricamento del file, e l'esecuzione. Lo scopo di questa API è quello di fornire funzionalità pre-organizzate per facilitare e velocizzare la programmazione dello sviluppatore.


La libreria condivisa contenente le funzioni esterne dell'API di OpenAlure, e che dovrà essere richiamata in Gambas, è attualmente la seguente: 

libalure.so.1.2.0


Mostriamo di seguito un semplice codice per ottenere l'esecuzione e l'ascolto di file audio: |1| 

Private isdone As Integer
Private src As Integer


Library "libalure:1.2.0"


' ALboolean alureInitDevice(const ALCchar * name, Const ALCint * attribs)
' Opens the named device, creates a context with the given attributes, and sets that context as current.
' The name and attribute list would be the same as what’s passed to alcOpenDevice and alcCreateContext respectively.
' Returns: AL_FALSE On error.
Private Extern alureInitDevice(name As String, attribs As String) As Boolean

' void alGenSources(Alsizei n, ALuint *sources)
Private Extern alGenSources(n As Integer, sources As Pointer) In "libalut:0.1.0"

' ALboolean alureStreamSizeIsMicroSec(ALboolean useUS)
' Specifies if the chunk size value given to the alureCreateStream functions is in bytes (default) or microseconds.
' Returns: Previously set value.
Private Extern alureStreamSizeIsMicroSec(useUS As Boolean) As Boolean

' alureStream* alureCreateStreamFromFile(Const ALchar * fname, ALsizei chunkLength, ALsizei numBufs, ALuint * bufs)
' Opens a file and sets it up for streaming.  The given chunkLength is the number of bytes, or microseconds worth of bytes if alureStreamSizeIsMicroSec was last called with AL_TRUE,
' each buffer will fill with.  ALURE will optionally generate the specified number of buffer objects, fill them with the beginning of the data,
' then place the new IDs into the provided storage, before returning.  Requires an active context.
' Returns: An opaque handle used To control the opened stream, Or Null On error.
Private Extern alureCreateStreamFromFile(fname As String, chunkLength As Integer, numBufs As Integer, bufs As Pointer) As Pointer

' ALboolean alurePlaySourceStream(ALuint source, alureStream * stream, ALsizei numBufs, ALsizei loopcount, void( * eos_callback)(void * userdata, ALuint source), void * userdata)
' Starts playing a stream, using the specified source ID.  A stream can only be played if it is not already playing.
' You must call alureUpdate at regular intervals to keep the stream playing, or else the stream will underrun
' and cause a break in the playback until an update call can restart it.
' If an underrun occurs, the source will enter a stopped state until it is automatically restarted.  Instead, set a flag using the callback to indicate the stream being stopped.
' "eos_callback": This callback will be called when the stream reaches the end, no more loops are pending, and the source reaches a stopped state.
' It will also be called if an error occured and playback terminated.
' Returns: AL_FALSE On error.
Private Extern alurePlaySourceStream(source As Integer, strePnt As Pointer, numBufs As Integer, loopcount As Integer, eos_callback As Pointer, userdata As Pointer) As Boolean

' void alureUpdate(void)
' Updates the running list of streams, and checks for stopped sources.
' This makes sure that sources played with alurePlaySourceStream are kept fed from their associated stream, and sources played with alurePlaySource are still playing.
' It will call their callbacks as needed.
Private Extern alureUpdate()

' ALboolean alureStopSource(ALuint source, ALboolean run_callback)
' Stops the specified source ID, and any associated stream.
' Returns: AL_FALSE On error.
Private Extern alureStopSource(source As Integer, run_callback As Boolean) As Boolean

' void alDeleteSources(ALsizei n, ALuint * sources)
' This function deletes one or more sources.
Private Extern alDeleteSources(n As Integer, sources As Pointer) In "libalut:0.1.0"

' ALboolean alureDestroyStream(alureStream * stream, ALsizei numBufs, ALuint * bufs)'
' Closes an opened stream.
' Returns: AL_FALSE On error.
Private Extern alureDestroyStream(strePnt As Pointer, numBufs As Integer, bufs As Pointer) As Boolean

' ALboolean alureShutdownDevice(void)
' Destroys the current context and closes its associated device.
' Returns: AL_FALSE On error.
'Private Extern alureShutdownDevice() As Boolean

' ALboolean alurePauseSource(ALuint source)
' Pauses the specified source ID, and any associated stream. Returns AL_FALSE On Error.
Private Extern alurePauseSource(source As Integer) As Boolean

' ALboolean alureResumeSource(ALuint source)
' Resumes the specified source ID after being paused. Returns AL_FALSE On Error.
Private Extern alureResumeSource(source As Integer) As Boolean


Public Sub Button1_Click()

 Dim streamP As Pointer
 Dim ver As Boolean
 Dim percorsoFile As String = "percorso_del_file_audio"
 Dim lungh As Integer


 alureInitDevice(Null, Null)

 alGenSources(1, VarPtr(src))
 
 alureStreamSizeIsMicroSec(False)

 lungh = Stat(percorsoFile).Size
 
' Se si preferisce impostare la durata in base alla dimensione del file audio da eseguire,
' è opportuno passare il valore del secondo parametro almeno pari alla dimensione del file:
 streamP = alureCreateStreamFromFile(percorsoFile, lungh, 0, Null)
 
 If IsNull(streamP) Then Error.Raise("Impossibile caricare il file Audio !")

 
 alurePlaySourceStream(src, streamP, 512, 0, eos_callback, Null)
 
 While isdone = 0
   Wait 0.01
   alureUpdate()
 Wend
 

 alureStopSource(src, False)
 alDeleteSources(1, VarPtr(src))
 alureDestroyStream(streamP, 0, Null)
 alureShutdownDevice()

 isdone = 0

End



Public Function eos_callback(unused As Pointer, unused2 As Integer)

   isdone = 1
 
End


' Mette in pausa l'esecuzione:
Public Sub Button2_Click()

 alurePauseSource(src)

End

' Riprende l'esecuzione:
Public Sub Button3_Click()

 alureResumeSource(src)

End

' Arresta l'esecuzione:
Public Sub Button4_Click()

 alureStopSource(src, False)

End


Note

[1] Si è constatato che i file audio eseguibili sono quelli di tipo: wav, mp3, ogg.


Riferimenti

Estratto da "https://www.gambas-it.org/wiki/index.php?title=Eseguire_un_file_audio_mediante_le_funzioni_di_Alure&oldid=13427"