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#include <precomp.hpp>
#include <opencv2/objdetect/objdetect.hpp>
#include <opencv2/core/core.hpp>

cv::SCascade::Channels::Channels(int shr) : shrinkage(shr) {}

void cv::SCascade::Channels::appendHogBins(const cv::Mat gray, std::vector<cv::Mat>& integrals, int bins) const
{
    CV_Assert(gray.type() == CV_8UC1);
    int h = gray.rows;
    int w = gray.cols;
    CV_Assert(!(w % shrinkage) && !(h % shrinkage));

    cv::Mat df_dx, df_dy, mag, angle;
    cv::Sobel(gray, df_dx, CV_32F, 1, 0);
    cv::Sobel(gray, df_dy, CV_32F, 0, 1);

    cv::cartToPolar(df_dx, df_dy, mag, angle, true);
    mag *= (1.f / (8 * sqrt(2)));

    cv::Mat nmag;
    mag.convertTo(nmag, CV_8UC1);

    angle *=  bins/360.f;

    std::vector<cv::Mat> hist;
    for (int bin = 0; bin < bins; ++bin)
        hist.push_back(cv::Mat::zeros(h, w, CV_8UC1));

    for (int y = 0; y < h; ++y)
    {
        uchar* magnitude = nmag.ptr<uchar>(y);
        float* ang = angle.ptr<float>(y);

        for (int x = 0; x < w; ++x)
        {
            hist[ (int)ang[x] ].ptr<uchar>(y)[x] = magnitude[x];
        }
    }

    for(int i = 0; i < bins; ++i)
    {
        cv::Mat shrunk, sum;
        cv::resize(hist[i], shrunk, cv::Size(), 1.0 / shrinkage, 1.0 / shrinkage, CV_INTER_AREA);
        cv::integral(shrunk, sum, cv::noArray(), CV_32S);
        integrals.push_back(sum);
    }

    cv::Mat shrMag;
    cv::resize(nmag, shrMag, cv::Size(), 1.0 / shrinkage, 1.0 / shrinkage, CV_INTER_AREA);
    cv::integral(shrMag, mag, cv::noArray(), CV_32S);
    integrals.push_back(mag);
}

void cv::SCascade::Channels::appendLuvBins(const cv::Mat frame, std::vector<cv::Mat>& integrals) const
{
    CV_Assert(frame.type() == CV_8UC3);
    CV_Assert(!(frame.cols % shrinkage) && !(frame.rows % shrinkage));

    cv::Mat luv, shrunk;
    cv::cvtColor(frame, luv, CV_BGR2Luv);
    cv::resize(luv, shrunk, cv::Size(), 1.0 / shrinkage, 1.0 / shrinkage, CV_INTER_AREA);

    std::vector<cv::Mat> splited;
    split(shrunk, splited);

    for (size_t i = 0; i < splited.size(); ++i)
    {
        cv::Mat sum;
        cv::integral(splited[i], sum, cv::noArray(), CV_32S);
        integrals.push_back(sum);
    }
}