The IDirectSound3DListener::SetRolloffFactor method sets the rolloff factor.
HRESULT SetRolloffFactor(
D3DVALUE flRolloffFactor,
DWORD dwApply
);
If the method succeeds, the return value is DS_OK.
If the method fails, the return value may be DSERR_INVALIDPARAM.
The rolloff factor has a range of DS3D_MINROLLOFFFACTOR (no rolloff) to DS3D_MAXROLLOFFFACTOR (as currently defined, 10 times the rolloff found in the real world). The default value is DS3D_DEFAULTROLLOFFFACTOR (1.0). For additional information, see Rolloff Factor.
Windows NT/2000: Requires Windows 2000.
Windows 95/98: Requires Windows 95 or later. Available as a redistributable for Windows 95.
Header: Declared in dsound.h.
Import Library: Use dsound.lib.