Why does sf::Texture have a m_pixelsFlipped member?

• tl;dr: needed to support SFML's origin being in top-left corner instead of OpenGL's bottom-left corner
• See: https://github.com/SFML/SFML/issues/1733#issuecomment-761708945

Why does sf::Texture have a m_cacheId member?

• m_cacheId is used as a caching optimization strategy in sf::RenderTarget. If the last used texture's cache ID matches the cache ID of the texture currently used to draw, there's no need to rebind it. The reason why a custom cache ID is used instead of the OpenGL-provided texture ID is that the latter might be "recycled" by OpenGL after a texture is destroyed and another one is created, while the former is guaranteed to always be unique.

Why are textures unbound during sf::RenderTarget::clear?

• tl;dr: possible driver bug
• See: https://en.sfml-dev.org/forums/index.php?topic=9350.msg106570#msg106570