I already have reasonable experience with C++ and OpenGL, and I have recently decided to try out mobile game development. After successfully creating a simple OpenGL ES Android app using Java, I researched ways to target both Android and iOS with as little rewriting code as possible. I tried using Visual Studio 2015's proudly-boasted cross-platform app development tools, but found them to be too new and therefore extremely under-documented. I could build the template projects the program gave to me, but I couldn't figure out how, given these templates, I might add assets into the game or handle touch screen input.
I have an unfortunately specific desire, too specific to find with Google. I want to make an OpenGL ES game using C++, with thin platform-specific wrappers for Android and iOS. People have asked similar questions to me (though not exactly the same), and more than one person responding has stated that what I want to do is not only possible, but relatively easy, since I don't have to worry about UI.
I tried this tutorial, but it's almost three years old and therefore probably designed for older technology, and as a result I ran into various unaccounted-for bugs. As of right now, though, that tutorial is the closest thing to what I want that I've found. Everything else is either Android-only, or recommending that I pay hundreds of dollars a year to use the Marmalade SDK. At times I feel like just writing the code twice, once in Java and once in Objective-C, but I am kept motivated by the knowledge that this solution is possible, but for some reason, not covered anywhere in any modern detail.
To summarise, I want to make an OpenGL ES game for iOS and Android, with a single C++ codebase wrapped in small amounts of platform-specific code. However, despite the fact that several people have recommended this approach, no one can tell me how to do it. Can somebody tell me if it's actually possible, and if so, what I can do or where I can go to learn how?