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#include "precomp.hpp"

using namespace cv;
using namespace cv::cuda;

#if !defined HAVE_CUDA || !defined(HAVE_OPENCV_CUDAARITHM) || defined(CUDA_DISABLER)

void cv::cuda::FastOpticalFlowBM::operator ()(const GpuMat&, const GpuMat&, GpuMat&, GpuMat&, int, int, Stream&) { throw_no_cuda(); }

#else // HAVE_CUDA

namespace optflowbm_fast
{
    void get_buffer_size(int src_cols, int src_rows, int search_window, int block_window, int& buffer_cols, int& buffer_rows);

    template <typename T>
    void calc(PtrStepSzb I0, PtrStepSzb I1, PtrStepSzf velx, PtrStepSzf vely, PtrStepi buffer, int search_window, int block_window, cudaStream_t stream);
}

void cv::cuda::FastOpticalFlowBM::operator ()(const GpuMat& I0, const GpuMat& I1, GpuMat& flowx, GpuMat& flowy, int search_window, int block_window, Stream& stream)
{
    CV_Assert( I0.type() == CV_8UC1 );
    CV_Assert( I1.size() == I0.size() && I1.type() == I0.type() );

    int border_size = search_window / 2 + block_window / 2;
    Size esize = I0.size() + Size(border_size, border_size) * 2;

    ensureSizeIsEnough(esize, I0.type(), extended_I0);
    ensureSizeIsEnough(esize, I0.type(), extended_I1);

    cuda::copyMakeBorder(I0, extended_I0, border_size, border_size, border_size, border_size, cv::BORDER_DEFAULT, Scalar(), stream);
    cuda::copyMakeBorder(I1, extended_I1, border_size, border_size, border_size, border_size, cv::BORDER_DEFAULT, Scalar(), stream);

    GpuMat I0_hdr = extended_I0(Rect(Point2i(border_size, border_size), I0.size()));
    GpuMat I1_hdr = extended_I1(Rect(Point2i(border_size, border_size), I0.size()));

    int bcols, brows;
    optflowbm_fast::get_buffer_size(I0.cols, I0.rows, search_window, block_window, bcols, brows);

    ensureSizeIsEnough(brows, bcols, CV_32SC1, buffer);

    flowx.create(I0.size(), CV_32FC1);
    flowy.create(I0.size(), CV_32FC1);

    optflowbm_fast::calc<uchar>(I0_hdr, I1_hdr, flowx, flowy, buffer, search_window, block_window, StreamAccessor::getStream(stream));
}

#endif // HAVE_CUDA