Microsoft DirectX 9.0


The SetRolloffFactor method sets the rolloff factor, which determines the rate of attenuation over distance.


HRESULT SetRolloffFactor(
  D3DVALUE flRolloffFactor, 
  DWORD dwApply 



Rolloff factor. D3DVALUE is defined as float.


Value that specifies when the setting should be applied. This value must be one of the following:

Value Description
DS3D_DEFERRED Settings are not applied until the application calls the IDirectSound3DListener8::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 3-D coordinates for all 3-D sound buffers.

Return Values

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 (defined as 10 times the rolloff found in the real world). The default value is DS3D_DEFAULTROLLOFFFACTOR (1.0). For more information, see Rolloff Factor.


  Header: Declared in dsound.h.

See Also