IDirectSound3DListener::SetVelocity
HRESULT SetVelocity(D3DVALUE x,
D3DVALUE y, D3DVALUE z, DWORD dwApply);
Sets the listener's velocity.
·Returns DS_OK if successful, or DSERR_INVALIDPARAM otherwise.
x, y, and z
Values whose types are D3DVALUE and that represent the coordinates of the listener's new velocity vector.
dwApply
Value indicating when the setting should be applied. This value must be one of the following:
DS3D_DEFERRED Settings are not applied until the application calls the IDirectSound3DListener::CommitDeferredSettings method. This allows the application to change several settings and generate a single recalculation.
DS3D_IMMEDIATE Settings are applied immediately, causing the system to recalculate the 3D coordinates for all 3D sound buffers.
Velocity is used only for Doppler effects. It does not actually move the listener. To change the listener's position, use the IDirectSound3DListener::SetPosition method. The default velocity is (0,0,0).