IDirectSound3DListener8::SetRolloffFactor Method

[アーティクル]
09/10/2011

[The feature associated with this page, DirectSound, is a legacy feature. It has been superseded by WASAPI and Audio Graphs. Media Casting have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use Media Casting instead of DirectSound, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

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

Syntax

HRESULT SetRolloffFactor(
         D3DVALUE flRolloffFactor,
         DWORD dwApply
)

Parameters

flRolloffFactor
Rolloff factor. D3DVALUE is defined as float.

dwApply
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 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.

Return Value

If the method succeeds, the return value is DS_OK. If the method fails, the return value may be DSERR_INVALIDPARAM.

Remarks

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.

Requirements

Header: Declared in DSound.h.

Library: Use Dsound3d.dll.

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