Loading sf::Texture from seperate thread requires glFlush()

[silbinarywolf]

In the latest 2.0 release, this bug is still apparently an issue and I have to use glFlush() at the end of my threads execution.

I only know of the solution thanks to this thread from last month:
http://en.sfml-dev.org/forums/index.php?topic=10344.15

[retep998]

I can confirm that several of my users had the same issue where if I didn't flush after loading a texture from a thread, the textures would often end up corrupt or wouldn't load at all. Granted I was using straight up OpenGL and not SFML's sf::Texture, but the point remains that this is a real issue. Simply adding a glFlush at the end of every texture load is not ideal as that can drastically reduce performance, but having to bother the user with issues such as having to flush isn't ideal either.
For specifics on the hardware/software, Windows with Nvidia or Intel caused the issue, while Windows with AMD or any linux or mac platform I tested did not have the issue. Nvidia had corrupt textures, while Intel simply had blank missing textures.

[LaurentGomila]

Actually, calling glFlush() might be a solution. It would be needed only after loading resources (sf::Font, sf::Texture, sf::Shader), which is usually not done 60 times per second and already expensive anyway.