# llimphi-video-plane

A spike for "attach video in llimphi": video as a real `wl_subsurface` over
winit's `wl_surface`, so mirada composites it (Phase 1) and eventually scans it
out on an overlay plane, **without going through vello's intermediate texture**.

The wall it validates (Phase 0, already OK): winit does not expose subsurfaces, so
a **second** `wayland-client` connection is mounted over the SAME foreign
`wl_display` (`Backend::from_foreign_display`), winit's `wl_surface` is wrapped
through `ObjectId::from_ptr`, and a child `wl_subsurface` is created on it.
`set_desync` → the child commits on its own; position and ordering are latched on
the parent's commit (which winit does on present; the subsurface tracks the
parent when moved).

Two modes:

- **no arguments** → a solid colour quad (validates the subsurface).
- **`subsurface-spike <file>`** → real frames from that video (Phase 1a), decoded
  by `foreign-av`, uploaded to the subsurface through shm (3 round-robin buffers,
  RGBA→ARGB8888). The winit UI only clears the background.

Keys: `B` = subsurface below/above the parent · `T` = UI background
transparent/opaque (the "hole" the plane peeks through) · `ESC` = quit.

## Use

```sh
cargo run --release -p llimphi-video-plane --bin subsurface-spike
```

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Part of **llimphi** — see [llimphi](../README.md).