Stage 3 — First Window

What it is. The stage where 0xide stops being an empty colored rectangle and starts hosting real applications: xdg-shell, the protocol real apps (terminals, browsers) use to become an app window (“toplevel”) rather than a bare surface.

Why it matters. Nothing downstream — tiling, focus, keybindings — means anything without a real window to apply it to.

Deliverable (from KICKOFF.md): map a real client surface. A terminal (foot) appears in 0xide.

How it went

wlr_xdg_shell_create advertises the xdg_wm_base global apps bind to; its new_toplevel signal is hooked (via the shim, since it’s a wl_signal/wl_listener) to handle_new_toplevel, which puts the new window’s surface into the scene graph built in Stage 2.

Two gotchas surfaced here, both now folded into the working notes:

• wlroots’ xdg-shell header itself needs a generated file. It #includes xdg-shell-protocol.h, which isn’t a system header — build.rs generates it with wayland-scanner into OUT_DIR as part of the FFI pipeline from Stage 0.
• A real client refuses to start without a seat. foot failed with “no seats available” until a minimal wl_seat (oxide_seat_create) existed — input handling proper doesn’t land until Stage 4, but the global has to exist earlier than that for any real app to even try connecting.

Verified with: cargo nested -- foot — a terminal appears in the nested window.

Status: done.