can I modify SFML?

[Mr_Blame]

HI 

Do i have permission to distribute games with changed SFML source?

[Jesper Juhl]

Is The License not clear?

[Mr_Blame]

Yes, not clear a little bit... Can you explain it more simple. 

[Rosme]

I don't see how we can explain it without saying what is said in the license. You can modify it, but if you do, you must not claim that you wrote the original SFML, you need to say it was modified, and you need to include the original license.

[Mr_Blame]

how must i name the License file? how must i declare that i modified it?

[Mario]

The very, very short version:

Do whatever you want, as long as you don't claim you've written it.

So if you modify SFML and redistribute the binaries only, no obligations on your side.

[Mr_Blame]

thanks for simple and fast replying 

[Nexus]

@Mr_Blame: It makes really no sense rewording the license here, you'll only get inaccurate representations (such as Mario's, which only mentions 1 of 3 points). You get plenty of more verbose information about zlib/libpng on the Internet if you search.

Regarding how to declare modified versions: that only applies when you redistribute the source code. If you have a GitHub repo for example, you can roughly document the changes of your fork (and the detailed modifications can be seen in the commit history).

Regarding how to name the license file: why rename it at all?

[FRex]

how must i name the License file? how must i declare that i modified it?

It varies, like the original zlib library required you to change some defines to signal the changes.
You could name it SFML-LICENSE or ORIGINAL-LICENSE or anything that is sane and conveys the message that your library is based on SFML that was under zlib originally.
But it's always possible to just say what you want to do and ask if it's okay if you really want to since Laurent (or someone else from the team) is usually checking the forums.
When I needed to steal and alter one function for text layout I just asked too: http://en.sfml-dev.org/forums/index.php?topic=14363
Considering SFML is zlib which is very permissive you don't really need to worry as long as you have some common sense and don't intend to actually do something bad like claim authorship.

[paupav]

You are over thinking it. You just have to clearly say that you have forked SFML. If you do something wrong SFML police will warn you before shooting.