sf::RenderWindow window(sf::VideoMode(640, 480));
sf::Texture texture;
texture.create(640, 480);
sf::Sprite sprite(texture);
sf::Uint8* pixelsArray = new sf::Uint8[640 * 480 * 4];
//UPDATING PIXELS ARRAY
pixelsArray [x + y*640 * i] = 0-256;
so on..
//UPDATING WINDOW
texture.update(pixels);
window.draw(sprite);
window.display();