DirectX SDK

DirectSound3DBuffer.SetVelocity

The DirectSound3DBuffer.SetVelocity method sets the sound buffer's current velocity.

object.SetVelocity(x As Single, _
    y As Single, _
    z As Single, _
    applyFlag As CONST_DS3DAPPLYFLAGS)

object

Object expression that resolves to a DirectSound3DBuffer object.

x, y, and z

Values that represent the coordinates of the new velocity vector. Note that DirectSound may adjust these values to prevent floating-point overflow.

applyFlag

Value indicating when the setting should be applied. This value must be one of the following flags of the CONST_DS3DAPPLYFLAGS enumeration:

DS3D_DEFERRED: Settings are not applied until the application calls the DirectSound3DListener.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.

If the method fails, an error is raised and Err.Number may be set to DSERR_INVALIDPARAM.

Velocity is used for Doppler effects only. It does not actually move the buffer.

The default unit of measurement is meters per second, but this can be changed by using the DirectSound3DListener.SetDistanceFactor method.