Oring is a work title for a from-scratch Wayland application whose purpose has changed over time.
Currently oring-cal, poorly named as it was meant to be something else, is
aiming to become an example of how to write a Wayland application, that:
- Has a proper main event loop using the thread-safe Wayland client API.
- Reacts to wl_seat and wl_output removals.
- Predicts accurately the time when the output frame will be displayed.
- Falls back to guessing if prediction is not available.
- Rendering is event-triggered, not a CPU&GPU hog like with stupid games.
- Supports triggering rendering from frame callback if more rendering time is needed.
- Uses EGL and GL for the rendering.
- Uses big OpenGL (apparently the myth of GL ES only might still live).
- GL rendering happens in a thread outside of the main thread.
- Has a trivial physical model controlling the rendered scene.
- The physical model uses the predicted presentation timestamp for the rendered scene; use a predicted scene state.
- Input affects the physical simulation.
- Handles input based on the timestamps, not by the moment of receive.
- Predicts pointer motion for the predicted presentation time when pointer is controlling the physical model.
- Draws statistics of frame timings.
- The scene is complicated enough that rendering actually takes a bit of time, just for the sake of emulating something more than a glxgears-level of work load.
- Accommodates when rendering rate cannot keep up with the display.
Obviously, there is a long to way to go.