OpenGl, SFML and fps problem :D

[Superman]

Ok, I'm using OpenGL and SFML for my 3d Scene (C++). So far I've created a simple scene and am able to walk trough it and so on... I've calculated my fps and I want to display it in my window (for example in down left corner)... I don't know how to do it. I create my RenderWindow and use it to display my OpenGL scene, and when i try to use it to display any text on it with App.Draw(Text), the whole scene is gone, and all I see in my window is text and background. Is there a way to tell sfml that I only want to display text rather than text and black background (that completly covers my scene)?

Tnx for any advice. I'm new to SFML and I'm loving it so far...

[Laurent]

In SFML 1.5, you have to call window.PreserveOpenGLStates(true) once at the beginning of your program.

[Superman]

That is what I'm looking for, tnx... But it splits my fps in half. Is it possible that a little bit of text is so demanding?

One more thing, I'm getting an unhandled exception when using sf::String even though I'm using my font from hard drive...

Tnc for a quick response...

[Laurent]

That is what I'm looking for, tnx... But it splits my fps in half. Is it possible that a little bit of text is so demanding?

This is the simple solution, which saves and restores all OpenGL states every time you call window.Draw(text). So yes it can be slow.
You can do much better, by saving and restoring yourself only the states that you need.

One more thing, I'm getting an unhandled exception when using sf::String even though I'm using my font from hard drive...

There must be a default constructed sf::String somewhere

Note that both of these issues are completely solved in SFML 2.

[Superman]

Tnx again for help... When is SFML 2 going to be published?

[Laurent]

I don't know yet, you can have a look at the task tracker to get an idea of what has to be done before the release.