I'm a Microsoft developer mainly, but there are a couple of small-ish projects I'd like to fiddle with which would benefit from being cross platform.

The platforms I want to target are: Windows, Linux, Mac, Android and preferably iPhone, web (running in a browser).

I need 3D (Around the level of support seen in something like Minecraft (I'm not writing Minecraft)), some networking.

I'm pretty certain Java would work on all except iPhone. Looking at the "related questions" above it's offered up QT (no browser or phone afaik) and also HTML/CSS/Javascript (3D? package for desktop?)

The other alternative is to have seperate versions for seperate platforms, developed with some common code where possible. That option isn't something I know anything about.

Does anyone have experience of this sort of conundrum? I figured here was better than SO, because I imagine there are compromises which extend beyond technical choice.

Finally, this is not a commercial operation, so some of the very expensive cross platform tools are out of the question unless they offer some sort of community edition.

Thanks for your time.