[C++ SFML 3.0] Punkty na obwodzie kształtu składającego się z kwadratów

std::vector < sf::IntRect > rects;
std::vector < bool > filled;

int side = 16;
int countX = 16;
int countY = 16;

for( int y = 0; y < countY; y += 1 ) {
    for( int x = 0; y < countX; x += 1 ) {
        rects.push_back( sf::IntRect( sf::Vector2i( countX * side, countY * side ), sf::Vector2i( side, side ) ) );
        filled.emplace_back( rand() % 2 == 0 );
    }
}

std::vector < sf::Vector2i > points = getPoints( rects, filled );

for( int i = 0; i < rects.size(); i += 1 ) {
    sf::RectangleShape rectShape( sf::Vector2f( rects[ i ].size ) );
    rectShape.setFillColor(( filled[ i ] ) ? sf::Color::Green
        : sf::Color::Black );
    rectShape.setPosition( sf::Vector2f( rects[ i ].position ) );
    Main::render_window->draw( rectShape );
}