# Modern Runtime Linux graphical continuation

## Current checkpoint

Slice L0 completed at
`66f114b258c0c37b51a7c0e04ca0d6441f4b1699`.

The same `AcDream.App` now builds and publishes for `linux-x64`; there is no
Linux gameplay or renderer fork.

Canonical seams:

- `AcDream.Runtime.Platform.ApplicationPathSet` owns XDG/Windows config, data,
  cache, plugin, screenshot, and diagnostic paths for graphical and headless
  hosts.
- `AcDream.App.Platform.GraphicalHostPlatformServices` owns one startup OS,
  architecture, RID, native-dependency manifest, path set, and pacing factory.
- `PlatformFramePacingWaiterFactory` selects the existing Windows
  high-resolution waitable timer or Linux
  `LinuxMonotonicFramePacingWaiter`.
- Linux waiting uses absolute `CLOCK_MONOTONIC` +
  `clock_nanosleep(TIMER_ABSTIME)`, retries `EINTR`, does not busy-spin, and
  rejects use after disposal.
- Windows legacy `%LOCALAPPDATA%\acdream\settings.json` and
  `keybinds.json` are copied only when the new roaming destination is absent.
- bundled plugins are read beside the binary; user plugins are read from the
  portable data root. A successful bundled ID wins; a failed load does not
  reserve the ID.

Exact L0 evidence:

- Windows: Runtime 415, Headless 67, UI 543, App 3,736 / 3 skips, complete
  Release 8,799 / 5 skips.
- native Ubuntu/WSL: Runtime 415, Headless 67, UI 543, 14 L0 App tests.
- exact framework-dependent `linux-x64` publish contains executable, managed
  closure, GLFW, OpenAL Soft, cimgui, shaders, and smoke plugin/manifest;
  direct `ldd` has no unresolved dependency.
- closeout:
  `docs/research/2026-07-27-slice-l0-platform-services.md`.

Rollback:

```text
git revert 66f114b258c0c37b51a7c0e04ca0d6441f4b1699
```

## Next work — L1

Do not claim Linux graphical support merely from publish success. L1 must:

1. start the exact package under the available X11 and Wayland sessions;
2. capture OS/display/compositor/GPU/driver/OpenGL vendor, renderer, version,
   mandatory extensions, swap interval, refresh, DPI, and audio backend before
   renderer construction;
3. create the OpenGL 4.3 core context and reject missing bindless texture or
   shader draw parameters with one actionable report;
4. validate GLFW window/input callbacks, relative mouse/focus, framebuffer
   sizing, clipboard, and monitor facts;
5. initialize OpenAL fail-open exactly as current Windows behavior permits;
6. render a packaged smoke scene, capture a screenshot, and close with zero
   GL/OpenAL/window debt.

Historical test-only issue: two installed-DAT App tests still hard-code
`C:\Turbine\Asheron's Call`. They are not production blockers, but clean them
before claiming the complete App test suite on a clean Linux runner.