Obtaining the IDirectSound3DBuffer Interface

To obtain a pointer to an IDirectSound3DBuffer interface, you must first create a secondary 3-D sound buffer. Do this by using the IDirectSound::CreateSoundBuffer method, specifying the DSBCAPS_CTRL3D flag in the dwFlags member of the DSBUFFERDESC structure parameter. Then, use the IDirectSoundBuffer::QueryInterface method on the resulting buffer to obtain a pointer to an IDirectSound3DBuffer interface for that buffer.

The following example calls the QueryInterface method with the C++ syntax:

// LPDIRECTSOUNDBUFFER lpDsbSecondary;

// The buffer has been created with DSBCAPS_CTRL3D.

LPDIRECTSOUND3DBUFFER lpDs3dBuffer;

HRESULT hr = lpDsbSecondary->QueryInterface(IID_IDirectSound3DBuffer,

(LPVOID *)&lpDs3dBuffer);

if SUCCEEDED(hr)

{

// Set 3-D parameters of this sound.

.

.

.

}

Note Pan control conflicts with 3-D processing. If both DSBCAPS_CTRL3D and DSBCAPS_CTRLPAN are specified when the buffer is created, DirectSound returns an error.