Exergaming app with skeleton tracking

I want to develop an exergaming app, for a project regarding social impact, that uses motion tracking to promote physical activity. The objective is to match the exercise of a person with the exercise she was supposed to do in the game. A few years ago i developed a little working prototype using this software: https://www.linkedin.com/company/extreme-reality-xtr3d-/about/

This made possible to use a simple smartphone camera without any additional hardware (cameras or sensors).

The company went bankrupt in the meantime and I am searching for similar technologies that allow me to develop my game without additional hardware.

Or in case it doesn’t exist nothing like this what would be the best technology with associated hardware to use.