Hi.
(Keeping in mind the idea of reaching as much gamers audience as possible.)
JMonkey runs smoothly on ultra low end dual core laptops if I optimize 3D models, textures and world and use level of detail, billboards and skybox correctly? Or Jmonkey is focused to be mid to high like unity and unreal?
Can I use with libgdx together to use some 2D features? Libgdx got some uber-jars, can I use with this as a addon?
It’s possible to encrypt or at least protect 3d models or png files from the public? Jar files still can be easily decompiled, right?
jMonkey will work on anything from ultra-low-end to ultra-high-end. It all depends on how well your code works and how complex your models are. You can make a game run on Android and an Atom single-core processor with as little as 128Mb RAM if your game can work with those constraints. It almost entirely depends on your ability to develop code that can work with those limitations. Bad code will take longer than well designed and optimized code. Always. So to this extent it relies entirely on you, the developer. A simple scene with a few boxes will whizz away on a raspberry Pi. Anything after that is all on you as the developer, and any slow-down will be as a result of your ability.
You can use Box2D for physics. It’s been done many many times already. You can almost certainly find working code already. LibGDX is not one-to-one compatible, though. It is extremely unlikely that you will be able to use libraries developed for LibGDX with JME “out-of-the-box”. You will most likely have to convert the areas that you need to JME.
This is a minefield of a question. Jmonkey uses .j3o format, so in that respect it will only work for jMonkey. Other than that, it doesn’t matter what lengths you go to to protect your files. If I want them, make no mistake I will get them. Licenses, however, restrict the user from being able to use them commercially, so whomever does extract your models/textures can only really use them personally or face prosecution. This should really be the last thing on your mind.
Now talking about Java, not JMonkey, Java handles good with multiple pngs to animation for games? I’m not planning to use Spine or Spriter/Spriter2 but to use another software that makes the same effect and export in multiples pngs or ogv (doesn’t matter size picture) and it can create sometimes 100+ pngs to just one animation, and not just one, some 2 or more at same time/scene. Is it too much resources to load and make it slow, right?
100 PNGs for a single animation is extremely inefficient on any platform. As for how java handles resources, it will do as good (if not better) than just about any other platform from a language standpoint.
If you do it then you’ll want to put them into one spritesheet and then reference the cells in your shader. I think some folks have posted some libraries that already do animation with sheets like this maybe.