After creating a viewport, you can call the IDirect3DDevice3::AddViewport method to add it to the device's viewport list. The following example shows what this call might look like:
HRESULT hr;
// lpD3DDevice3 is a valid pointer to a Direct3D
// device object.
hr = lpD3DDevice3->AddViewport(lpD3DViewport3);
if(FAILED(hr))
return hr;
else
{
// Set the viewport properties.
}
Once you've added the viewport to the device, you can set the viewport clipping volume. For more information, see Setting the Viewport Clipping Volume.