As seen in the Windows SDK help :
The first step in reading a wave file is to call the WaveOpenFile function. This gets a handle to the file, verifies that it is in RIFF format, and gets information about the wave format. The parameters are the filename and the addresses of three of the variables you have declared:
if (WaveOpenFile(lpzFileName, &hmmio, &pwfx, &mmckinfoParent) != 0)
{
// Failure
}
Note that the wrapper functions all return zero if successful.
The next step is to call the WaveStartDataRead function, causing the file pointer to descend to the data chunk. This function also fills in the MMCKINFO structure for the data chunk, so that you know how much data is available:
if (WaveStartDataRead(&hmmio, &mmckinfoData, &mmckinfoParent) != 0)
{
// Failure
}
The application can now begin copying data from the file to a secondary sound buffer. Normally you don't create the sound buffer until you have obtained the size of the data chunk and the format of the wave. The following code creates a static buffer just large enough to hold all the data in the file.
/* It is assumed that lpds in a valid pointer
to the DirectSound object. */
LPDIRECTSOUNDBUFFER lpdsbStatic;
DSBUFFERDESC dsbdesc;
memset(&dsbdesc, 0, sizeof(DSBUFFERDESC));
dsbdesc.dwSize = sizeof(DSBUFFERDESC);
dsbdesc.dwFlags = DSBCAPS_STATIC;
dsbdesc.dwBufferBytes = mmckinfoData.cksize;
dsbdesc.lpwfxFormat = pwfx;
if FAILED(lpds->CreateSoundBuffer(&dsbdesc, &lpdsbStatic, NULL))
{
WaveCloseReadFile(&hmmio, &pwfx);
return FALSE;
}
Because in this case the application is not streaming the data but simply filling a static buffer, the entire buffer is locked from the beginning. There is no wrap around, so only a single pointer and byte count are required.
LPVOID lpvAudio1;
DWORD dwBytes1;
if FAILED(lpdsbStatic->Lock(
0, // Offset of lock start
0, // Size of lock; ignored in this case
&lpvAudio1, // Address of lock start
&dwBytes1, // Number of bytes locked
NULL, // Wrap around start; not used
NULL, // Wrap around size; not used
DSBLOCK_ENTIREBUFFER)) // Flag
{
// Error handling
Close();
.
.
.
}
The WaveReadFile function copies the data from the file to the buffer pointer and returns zero if successful.
UINT cbBytesRead;
if (WaveReadFile(
hmmio, // file handle
dwBytes1, // no. of bytes to read
(BYTE *) lpvAudio1, // destination
&mmckinfoData, // file chunk info
&cbBytesRead)) // actual no. of bytes read
{
// Handle failure on non-zero return
WaveCloseReadFile(&hmmio, &pwfx);
.
.
.
}
Finally, the application unlocks the buffer and closes the wave file:
lpdsbStatic->Unlock(lpvAudio1, dwBytes1, NULL, 0);
Close();
For a streaming buffer, you would typically call WaveReadFile at regular intervals determined by the current play position. If the locked portion of the buffer wrapped around, of course, you would call WaveReadFile once for each segment of the lock.
Kind regards,
Message Edité par Maxime MULLER le
11-08-2007 10:26 AMMessage Edité par Maxime MULLER le
11-08-2007 10:28 AM
