Fix SFML example to build with SFML 3.0

[jjuhl]

No real functional changes, just small tweaks to make the SFML example build with SFML 3.0

[fallahn]

Thanks! I've not kept up with SFML for a while... I assume this isn't compatible with 2.x? If so it might be worth making this a separate example as some people are still using the old version.

[jjuhl]

I haven't tested with SFML 2.x since the only system I have access to ATM only has SFML 3.0.

[fallahn]

OK, well I'll hold off on this until I know for sure - I don't want to break anything for existing users! Thanks 😁

[GuidoBisocoli]

Just wanting to suggest that you could make another folder like SFML3Example and upload this. For the people that is migrating, like me, I downloaded tmxLite for migrating my project and did the migration of tmxLite example just to later see this pull request. I should have checked but still, it can help others :D

I haven't tested with SFML 2.x since the only system I have access to ATM only has SFML 3.0.

I can confirm it won't work on SFML 2.x, there is some code that's not compatible with 2.x like Primitives::Triangles for example.

[jjuhl]

I've managed to get a chance to test with SFML 2 myself and no, it doesn't work. But then again, the original code doesn't work with SFML 3 either.
In my opinion you should either add a SFML 3 example that works or just do a new release that drops support for SFML 2 (and fixes the code to work for SFML3). But, your library, your choice :)
You have my contribution, you can do with it whatever you like :)

[fallahn]

Sure, I'll be happy to have two examples included. If you want to rename yours/move it to its own directory I'll merge the PR 👍

[jjuhl]

Ok. I changed it to create a new example in a new directory ("SFML3Example") and it's now up there as commit aa2fd8d

[fallahn]

Fantastic, thank you!

[jjuhl]

Whoops, there are a few places where I screwed up while rebasing and editing my commit, so in (for example) "SFML3Example/SFMLExample/CMakeLists.txt" I forgot to change the "PROJECT_NAME" to "SFML3_example" and there may be other errors I missed. Sorry about that.

[fallahn]

No worries! I can tidy it up when I have a chance, or you can always submit another PR 😁 Thanks again!