calibration.c

#include <stdio.h>
#include "tobii_research_eyetracker.h"
#include "tobii_research_calibration.h"

#if _WIN32 || _WIN64
#include <windows.h>
static void sleep_ms(int time) {
    Sleep(time);
}
#else
#include <unistd.h>
static void sleep_ms(int time) {
    usleep(time * 1000);
}
#endif

void calibration_example(TobiiResearchEyeTracker* eyetracker) {

    /* Enter calibration mode. */
    TobiiResearchStatus status = tobii_research_screen_based_calibration_enter_calibration_mode(eyetracker);
    char* serial_number;
    tobii_research_get_serial_number(eyetracker, &serial_number);

    printf("Entered calibration mode for eye tracker with serial number %s \n.", serial_number);

    tobii_research_free_string(serial_number);
    /* Define the points on screen we should calibrate at. */
    /* The coordinates are normalized, i.e. (0.0, 0.0) is the upper left corner and (1.0, 1.0) is the lower right corner. */
    {
        #define NUM_OF_POINTS  5U

        TobiiResearchNormalizedPoint2D points_to_calibrate[NUM_OF_POINTS] = \
                {{0.5f, 0.5f}, {0.1f, 0.1f}, {0.1f, 0.9f}, {0.9f, 0.1f}, {0.9f, 0.9f}};
        size_t i = 0;


        for(; i < NUM_OF_POINTS; i++) {
            TobiiResearchNormalizedPoint2D* point = &points_to_calibrate[i];
            printf("Show a point on screen at (%f,%f).\n", point->x, point->y);

            //  Wait a little for user to focus.
            sleep_ms(700);

            printf("Collecting data at (%f,%f).\n", point->x, point->y);
            if (tobii_research_screen_based_calibration_collect_data(eyetracker, point->x, point->y) != TOBII_RESEARCH_STATUS_OK) {
                /* Try again if it didn't go well the first time. */
                /* Not all eye tracker models will fail at this point, but instead fail on ComputeAndApply. */
                tobii_research_screen_based_calibration_collect_data(eyetracker, point->x, point->y);
            }
        }


        printf("Computing and applying calibration.\n");
        TobiiResearchCalibrationResult* calibration_result = NULL;
        status = tobii_research_screen_based_calibration_compute_and_apply(eyetracker, &calibration_result);

        if (status == TOBII_RESEARCH_STATUS_OK && calibration_result->status == TOBII_RESEARCH_CALIBRATION_SUCCESS) {
            printf("Compute and apply returned %i and collected at %zu points.\n", status, calibration_result->calibration_point_count);
        } else {
            printf("Calibration failed!\n");
        }

        /* Free calibration result when done using it */
        tobii_research_free_screen_based_calibration_result(calibration_result);

        /* Analyze the data and maybe remove points that weren't good. */
        TobiiResearchNormalizedPoint2D* recalibrate_point = &points_to_calibrate[1];
        printf("Removing calibration point at (%f,%f).\n", recalibrate_point->x, recalibrate_point->y);
        status = tobii_research_screen_based_calibration_discard_data(eyetracker, recalibrate_point->x, recalibrate_point->y);

        /* Redo collection at the discarded point */
        printf("Show a point on screen at (%f,%f).\n", recalibrate_point->x, recalibrate_point->y);
        tobii_research_screen_based_calibration_collect_data(eyetracker, recalibrate_point->x, recalibrate_point->y);

        /* Compute and apply again. */
        printf("Computing and applying calibration.\n");
        status = tobii_research_screen_based_calibration_compute_and_apply(eyetracker, &calibration_result);

        if (status == TOBII_RESEARCH_STATUS_OK && calibration_result->status == TOBII_RESEARCH_CALIBRATION_SUCCESS) {
            printf("Compute and apply returned %i and collected at %zu points.\n", status, calibration_result->calibration_point_count);
        } else {
            printf("Calibration failed!\n");
        }

        /* Free calibration result when done using it */
        tobii_research_free_screen_based_calibration_result(calibration_result);
        /* See that you're happy with the result. */
    }
    /* The calibration is done. Leave calibration mode. */
    status = tobii_research_screen_based_calibration_leave_calibration_mode(eyetracker);

    printf("Left calibration mode.\n");

}