I don't know lua but in c++ this works
// ----------------------camera zoom
float deltazoom = (window->KeyDown(Key::Up) - window->KeyDown(Key::Down))*Time::GetSpeed()*0.05;
float zoom = camera->GetZoom() + deltazoom;
zoom = Math::Clamp(zoom, 0.2, 10.0);
camera->SetZoom(zoom);
le is compatible with visual studio 2013. To run le with 2015 you need to set 2013 toolset and( I believe) you need to have vs 2013 on your machine.
The cp files are in the source folder.
Did you start with the blank template?
I would like to see this headbobbing, I have a fear that it might become irritating if it is ON all the time, a bit like the hard sound of footsteps when the player walks on grass.Just my opinion, could be wrong.
I learned c from a book by the inventor of c many years ago before the web existed.It was called "The c programming language" by Kerningham and Richie.I wouldn't rule out books completely , they are convenient.
I use c++ for making games in leadwerks .I don't know lua but don't need it. The leadwerks c++ api is easy to use and you have all your code in one place with c++ AND a main loop you can put your gameplay in.
Best thing to do is take a good look around the editor and see for yourself what it can do.
models re made/animated in a 3d app and placed in the models folder, so that when you run the editor they are automaticly converted to l e format and appear in the asset browser.
in c++ you load the sound file then....
source = Source::Create();
source->SetSound(sound);
source->SetLoopMode(true);
source->Play();
not too different in lua I think.