Ray tracing in general space time. Currently implemented with the Kerr metric.
Get a C/C++ compiler (with OpenACC capability: https://www.openacc.org/tools).
Get SDL2: https://www.libsdl.org/download-2.0.php
Recommendation on Ubuntu:
sudo apt install libsdl2-dev libsdl2-gfx-dev libsdl2-image-dev libsdl2-ttf-dev libsdl2-mixer-dev
Numpad: numbers, +, -
Arrow keys
WASD
Non numpad number keys: 1,2,3
Enter
LShift