My prépa TIPE in 2009 was about surface acoustic wave touchscreens, with two simulators (a CUDA version on the GPU and a C plus SDL plus OpenMP version on the CPU) and a real experimental rig that classified 9 positions out of 9 with a centimetre of precision. In April 2026 I dug through a NAS backup of my old XPS desktop. The CUDA half is gone. The CPU half survived. This post is the post-mortem: what the project was, what was built, what was lost, and what it took to bring the surviving half back to life on SDL 2.
