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.