SFML animation without keyboard input - c++

Question

I'm working on a project at the moment which is basically a visualisation of Sort algorithms to explain how they work (rather than an overview). I'm new to using the SFML (or even OpenGL) and have limited experience with the library, but what I'm trying to do is move the drawn sprite to different locations to show the sorting. I've looked over tutorials and examples, but they all take in keyboard input to move the sprite - something that isn't used in this project. Does anyone know exactly how to achieve this?
Here's the current code:
DrawCups.h
class DrawCups
{
public:
DrawCups(sf::RenderWindow& window);
~DrawCups();
void loadImage(const char* pathname, sf::Texture& texture, sf::Sprite& sprite);
void drawCup1();
private:
sf::RenderWindow& _window;
};
DrawCups.cpp (selected function)
void DrawCups::drawCup1()
{
// load our image
sf::Texture cup1; // the texture which will contain our pixel data
sf::Sprite cup1Sprite; // the sprite which will actually draw it
loadImage("./images/InsertionSort/red_cup_1.png", cup1, cup1Sprite);
cup1Sprite.setPosition(sf::Vector2f(150, 230));
_window.draw(cup1Sprite);
}
main.cpp
int main()
{
sf::RenderWindow window(sf::VideoMode(1366, 768), "Sorting Algorithm Visualisation: SFML");
window.setFramerateLimit(60);
while (window.isOpen())
{
sf::Event event;
while (window.pollEvent(event))
{
if (event.type == sf::Event::Closed)
window.close();
}
window.clear(sf::Color::White);
DrawCups drawToWindow(window);;
drawToWindow.drawCup1();
window.display();
}
return 0;
}

Answer 1

Create the image before the loop and update it before you draw it.
DrawCups drawToWindow(window); //Constructor creates the sprite
while (window.isOpen())
{
...
drawToWindow.update(); //Update the position
//Redraw
window.clear(sf::Color::White);
drawToWindow.drawCup1();
window.display();
}
I'm not sure what type of movement you want but the update function can be something like this:
void DrawCups::update()
{
sf::Vector2f pos = this->cup1Sprite.getPosition();
pos.x++; //Move 1 pixel to the left
this->cup1Sprite.setPosition(pos);
}
Obviously change the movement to suit your needs. Make smaller/larger updates if it's moving too fast or slow.