public override void SetTextureUnitFiltering( int stage, FilterType type, FilterOptions filter )
{
var texType = _texStageDesc[ stage ].texType;
var texFilter = D3DHelper.ConvertEnum( type, filter, _deviceManager.ActiveDevice.D3D9DeviceCaps, texType );
SetSamplerState(GetSamplerId(stage), D3DHelper.ConvertEnum(type), (int)texFilter);
}