Where is ptr pointing for a cuda::GpuMat?

[cudawarped]

@Kansai

My question is, in terms of speed (performance) , is there some penalty to use the simpler
dOutput(iRow, iCol) rather than a GpuMat and then ptr and step ??

I doubt it as nvcc will heavily optimize your code and the resulting instructions may even be the same in both cases. If you really want you can check by examining the resulting ptx.

@Kansai

Edit: Turns out I cannot use ptr inside a kernel, and I have to pass data and step directly. Just found out

I am not sure why you can’t use cv::cuda::PtrStepSzf because this is how device data is passed to “most” (at least from my quick search) of the CUDA kernels in OpenCV.