task1.cpp

// Sakshi B.
#include "task1.h"
#include "config.h"
#include <iostream>

// ─────────────────────────────────────────────────────────────────────────────

bool detectCorners(const cv::Mat& gray,
                   std::vector<cv::Point2f>& corners)
{
    corners.clear();

    bool found = cv::findChessboardCorners(
        gray, BOARD_SIZE, corners,
        cv::CALIB_CB_ADAPTIVE_THRESH |
        cv::CALIB_CB_NORMALIZE_IMAGE |
        cv::CALIB_CB_FAST_CHECK);

    if (found) {
        // Refine to sub-pixel accuracy
        cv::cornerSubPix(gray, corners,
                         SUBPIX_WIN, SUBPIX_ZERO,
                         SUBPIX_CRITERIA);
    }
    return found;
}

// ─────────────────────────────────────────────────────────────────────────────

void drawCornersOverlay(cv::Mat& frame,
                        const std::vector<cv::Point2f>& corners,
                        bool found)
{
    if (found) {
        cv::drawChessboardCorners(frame, BOARD_SIZE, corners, found);

        // Corner count + first-corner coordinates
        int n = static_cast<int>(corners.size());
        std::string info =
            "Corners: " + std::to_string(n) +
            "  First: (" +
            std::to_string(static_cast<int>(corners[0].x)) + ", " +
            std::to_string(static_cast<int>(corners[0].y)) + ")";

        cv::putText(frame, info,
                    cv::Point(10, 30),
                    cv::FONT_HERSHEY_SIMPLEX, 0.7,
                    cv::Scalar(0, 255, 0), 2);
    } else {
        cv::putText(frame, "Target NOT detected",
                    cv::Point(10, 30),
                    cv::FONT_HERSHEY_SIMPLEX, 0.8,
                    cv::Scalar(0, 0, 255), 2);
    }

    std::string label = "Task 1 | Checkerboard: " +
                        std::string(found ? "DETECTED" : "SEARCHING...");
    drawStatusBar(frame, label, found);
}

// ─────────────────────────────────────────────────────────────────────────────

void runTask1(int argc, char* argv[])
{
    cv::VideoCapture cap = openVideoSource(argc, argv);
    if (!cap.isOpened()) {
        std::cerr << "[Task1][ERROR] Cannot open video source.\n";
        return;
    }

    std::cout << "=== Task 1: Checkerboard Corner Detection ===\n"
              << "Board: " << BOARD_COLS << " x " << BOARD_ROWS
              << " internal corners\n"
              << "Press 's' to save frame | 'q'/ESC to quit\n\n";

    cv::Mat frame, gray;
    int frameCount = 0, savedCount = 0;

    while (true) {
        cap >> frame;
        if (frame.empty()) { std::cout << "[Task1] End of stream.\n"; break; }
        ++frameCount;

        cv::cvtColor(frame, gray, cv::COLOR_BGR2GRAY);

        std::vector<cv::Point2f> corners;
        bool found = detectCorners(gray, corners);

        drawCornersOverlay(frame, corners, found);

        // Terminal diagnostics every 30 frames
        if (found && frameCount % 30 == 0) {
            std::cout << "[Task1][Frame " << frameCount << "] "
                      << corners.size() << " corners | "
                      << "first=(" << corners[0].x
                      << ", "      << corners[0].y << ")\n";
        }

        cv::imshow("Task 1 - Corner Detection", frame);
        int key = cv::waitKey(1) & 0xFF;
        if (key == 'q' || key == 27) break;
        if (key == 's') {
            std::string fn = "task1_frame_" + std::to_string(++savedCount) + ".png";
            cv::imwrite(fn, frame);
            std::cout << "[Task1][SAVED] " << fn << "\n";
        }
    }

    cap.release();
    cv::destroyAllWindows();
}