cudaTextureDesc can not find readMode

[williamlzw]

  void ImageBuffer::set_texture_descriptor()
  {
          cudaTextureDesc texture_descriptor;
      memset(&texture_descriptor, 0, sizeof(texture_descriptor));
      texture_descriptor.addressMode[0] = cudaAddressModeBorder;
      texture_descriptor.addressMode[1] = cudaAddressModeBorder;
      texture_descriptor.filterMode = cudaFilterModeLinear;
      texture_descriptor.readMode = cudaReadModeNormalizedFloat;//????????????
  }

   CudaTextureDescriptor texture_descriptor = new CudaTextureDescriptor();
              texture_descriptor.addressMode[0] = CUAddressMode.Border;
              texture_descriptor.addressMode[1] = CUAddressMode.Border;
              texture_descriptor.filterMode = CUFilterMode.Linear;