The only requirement for configuring the viewport parameters for a rendering device is to set the viewport's clipping volume. To do this, you initialize and set clipping values for the clipping volume and for the render-target surface. Viewports are commonly set up to render to the full area of the render-target surface, but this isn't a requirement.

The following Microsoft® Visual Basic® code creates settings in a D3DVIEWPORT8 type to achieve this.

Dim viewData As D3DVIEWPORT8

With viewData
    .x = 0: .y = 0
    .Width = Width: .Height = Height
    .MinZ = 0#: .MaxZ = 1#
End With

After setting values in the D3DVIEWPORT8 type, apply the viewport parameters to the device by calling its Direct3DDevice8.SetViewport method.

' The d3dDevice variable contains a valid reference to a 
' Direct3DDevice8 object.
Call d3dDevice.SetViewport(viewData) 

After the call, the viewport parameters are set and will take effect the next time a rendering method is called. To make changes to the viewport parameters, just update the values in the D3DVIEWPORT8 type and call SetViewport again.