From my recent foray into JME..
- Is it still maintained?
Yes, the majority of the original authors have moved on but new maintainers have stepped up.
- Is it already possible to use it with JOGL rather than LWJGL? If yes, is it easily possible to modify the text rendering to use my own bug fixes for JOGL (in TextRenderer.java)?
Yes, in JME 2 there is a JOGL renderer. However, the text rendering in JME doesn't rely on JOGL's text renderer. JME's LWJGL is also more tried and tested than the JOGL one. Not sure how many people have tried to use the JOGL renderer in JME.
- Is it possible to use JME without JOAL (for example, is it possible to use only JavaSound, JOGG and JORBIS for the sound support)?
I believe so, but there's no plugin's for their sound system to use anything other than OpenAL via LWJGL last time I checked.
- Is it possible to use JME on low end machines (for example under OpenGL 1.3 with an ATI Radeon 7500 or a Geforce 1)?
Yes, as you can imagine rendering would be limited but the renderer in JME2 attempts to not use things that arn't supported - for instance, shaders are ignored where shaders arn't supported.
- JME is a scenegraph too, does it use a cells-and-portals algorithm? If not, is it possible to modify it so that it uses an implementation of it?
It doesn't but you could.
- Does JME contain a system of computation of geographic modifications like the engine of Red Faction 2 (you can break almost all walls, etc...)?
- What kind of spatial subdivisions are available with it?
Not quite sure what you're looking for here. The scene is culled using bounding shapes which are hieachial based on the scenegraph. The terrain renderer has some quad tree based stuff in it. I think the approach is general to add the subdivision based on the type of thing being renderer - but you'd need an original author to tell you that for sure.
- Does it work fine under Solaris?
- Does it work fine with the OpenJDK? Kaffe? GNU Classpath?
No idea. LWJGL works under SolarisX86 now I think. The other JDKs as long as they're compatible with core Java they should work right?
- Does JME provide graphical hardware accelerated components? If not, is it possible to use it with FengGUI or Slick?
It has a series of different GUIs implemented for it. I've used FengGUI, BUI, Slick and Thingle on top of JME in different projects, all of which have been fine to work with.
- Does the JME team need a financial help?
They're an open source collective so probably not. Everyone likes to have some cash to spend on things for the project though so I guess they'd like donations.
- The geometry of my FPS is really extremely simple. If I switch to JME, do I have a chance to get a better frame rate if I use it correctly?
Depends how efficient the original implementation was. A highly tuned custom system for a game nearly always out performs a more generic library approach. You sacrifice performance for ease of development. However, if the developers of the library no a bit more about rendering then they might just surprise the author.
- Does JME include anything that helps to write online games? If not, has someone tried to use it with JGN or Project Darkstar?
No, but JGN provides some great integration tools and has been used to write several multiplayer games with JME.
Project Darkstar doesn't provide anything directly related to JME but again has been used to produce several impressive demos with it.
- Does gimbal lock occur with JME?
Don't think so, Quats all the way.
- Is it possible to use only Java for keyboard and mouse handling and not JInput?
Not sure about this, I guess they depend on LWJGL's input routines.
You'd be better to post this at the JME forums though, very active place with lots of users ready to answer.