This is a C++ reimplementation of OpenAI's gym environment LunarLander (the continuous version). It works but definitely needs more work.
Since it supports model-based approaches such as AlphaZero (which requires the environment to be clonable for the MCTS), it unfortunately requires a box2d fork that supports getting and setting the sleep time of bodies. The fork is linked in this repository.
To use it, copy both lunar_lander.cpp and lunar_lander.hpp to your project and add the box2d fork as a dependency.
An example for cmake can be found here.
After you're done, do cmake and cmake --build ..
The API follows the standard OpenAI gym API (except for reset(), which requires a generator). As for the generator, I'm open for PRs that move it to the constructor.
std::vector<float> reset(std::mt19937 &generator);
std::tuple<std::vector<float>, double, bool> step(std::vector<double> &action);