15 tiles sfml

#include <SFML/Graphics.hpp>
#include <vector>
#include <cstdlib>
#include <ctime>

int WinMain()
{
    std::srand(std::time(nullptr));
    sf::RenderWindow gameWindow;
    sf::RenderWindow picWindow;
    gameWindow.create(sf::VideoMode(600, 600), "");
    picWindow.create(sf::VideoMode(600, 600), "");
    gameWindow.setFramerateLimit(60);
    sf::Event event;

    sf::Image img;
    img.loadFromFile("test.jpg");
    sf::Texture fullimgtext;
    fullimgtext.loadFromImage(img);
    sf::Sprite fullsprite;
    fullsprite.setTexture(fullimgtext);
    int factor = img.getSize().x / 4;
    fullsprite.setScale((600.f / 4) / factor, (600.f / 4) / factor);

    std::vector <sf::Sprite> sprite_tiles(16);
    std::vector <sf::Texture> text_tiles(16);

    sf::Image small_img;

    small_img.create(factor, factor, sf::Color::Green);

    for (int m = 0; m < 4; m++) {
        for (int n = 0; n < 4; n++) {
            for (int i = 0; i < factor; ++i) {
                for (int j = 0; j < factor; ++j) {
                    small_img.setPixel(i, j, img.getPixel(i + n * factor, j + m * factor));
                }
            }
            text_tiles[n*4+m].loadFromImage(small_img);
            sprite_tiles[n * 4 + m].setTexture(text_tiles[n * 4 + m]);
            sprite_tiles[n * 4 + m].setScale((600.f / 4) / factor, (600.f / 4) / factor);
            sf::Vector2f pos;
            pos.x = n*150.f;
            pos.y = m*150.f;
            sprite_tiles[n * 4 + m].setPosition(pos);
            sprite_tiles.push_back(sprite_tiles[n * 4 + m]);
        }
    }

    sf::Image img_void;
    img_void.create(600, 600, sf::Color::Green);
    sf::Texture tex_void;
    tex_void.loadFromImage(img_void);
    int void_index = 15;
    text_tiles[15].swap(tex_void);

    sf::Vector2i winpos;
    winpos.x = 355.f;
    winpos.y = 240.f;
    gameWindow.setPosition(winpos);
    winpos.x = 955.f;
    picWindow.setPosition(winpos);

    sf::Text text;
    sf::Font font;
    font.loadFromFile("calibri.ttf");
    text.setFont(font);
    text.setString("press f2 to mix tiles");

    while (gameWindow.isOpen() || picWindow.isOpen()) {
        while (gameWindow.pollEvent(event) || picWindow.pollEvent(event)) {
            if (event.type == sf::Event::Closed) {
                gameWindow.close();
                picWindow.close();
            }
            if (event.key.code == sf::Keyboard::F2) {
                for (int i = 0; i < 50; ++i) {
                    int a = std::rand() % 15;
                    int b = std::rand() % 15;
                    text_tiles[a].swap(text_tiles[b]);
                }
            }
            if (event.type == sf::Event::KeyReleased)
            {


                if (event.key.code == sf::Keyboard::Left && void_index / 4 != 3) {
                    if (void_index < 16)
                    {
                        text_tiles[void_index + 4].swap(text_tiles[void_index]);
                        void_index = void_index + 4;
                    }
                }
                if (event.key.code == sf::Keyboard::Right && void_index / 4 != 0) {
                    if (void_index >= 0)
                    {
                        text_tiles[void_index - 4].swap(text_tiles[void_index]);
                        void_index = void_index - 4;
                    }
                }
                if (event.key.code == sf::Keyboard::Up && void_index % 4 != 3) {
                    if (void_index < 16)
                    {
                        text_tiles[void_index + 1].swap(text_tiles[void_index]);
                        void_index = void_index + 1;
                    }
                }
                if (event.key.code == sf::Keyboard::Down && void_index % 4 != 0) {
                    if (void_index >= 0)
                    {
                        text_tiles[void_index -1].swap(text_tiles[void_index]);
                        void_index = void_index - 1;
                    }
                }

            }

        }

        gameWindow.clear();
        picWindow.clear();

        for (int i = 0; i < 16; ++i)
            gameWindow.draw(sprite_tiles[i]);
        picWindow.draw(fullsprite);
        picWindow.draw(text);

        gameWindow.display();
        picWindow.display();
    }

    return 0;
}