# Modern Runtime Linux graphical continuation

## Current checkpoint

Slice L0 completed at
`66f114b258c0c37b51a7c0e04ca0d6441f4b1699`.
Slice L1's implementation checkpoint landed at
`11501d52cad942850d88f83490710faf1d5cdf28`.

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
```

## L1 implementation checkpoint

Canonical seams:

- `ACDREAM_DISPLAY_PROTOCOL=auto|x11|wayland` selects one immutable backend
  before `Window.Create`.
- `GraphicalWindowBackendSelection` configures Silk's exact GLFW backend and
  makes the packaged GLFW 3.4 native library win over older system installs.
- `GraphicalCapabilityRecord` captures platform, RID, display protocol, GL
  identity/extensions/limits, framebuffer, input/window, audio, and terminal
  ownership into one atomic report.
- `GraphicalGlFunctionProbe` actively validates bindless texture,
  draw-parameters plus MDI, SSBO, timer query, sRGB/depth/stencil FBO, and
  persistent coherent buffer behavior before renderer construction.
- Unsupported contexts exit with code 4 and a precise report. No legacy
  renderer or fabricated fallback is introduced.
- Studio screenshot shutdown is deferred until the completed render frame;
  accepted and rejected startup paths both report zero terminal ownership.

Evidence:

- native Windows 11 + AMD Radeon RX 9070 XT: every active GL probe passes,
  OpenAL submits playback and disposes, the packaged smoke frame is intact,
  and terminal ownership is zero;
- WSLg X11 and Wayland: packaged GLFW 3.4 and protocol selection are correct,
  but llvmpipe lacks mandatory `GL_ARB_bindless_texture`;
- WSLg with `GALLIUM_DRIVER=d3d12` reaches the AMD GPU and OpenGL 4.6, but
  still lacks mandatory `GL_ARB_bindless_texture`; this is a WSLg/Mesa
  capability limit, not an acdream package-resolution defect;
- App tests pass 3,763 / 3 skips; the complete Release suite passes
  8,826 / 5 skips;
- checkpoint:
  `docs/research/2026-07-27-slice-l1-graphical-capability-checkpoint.md`.

Rollback:

```text
git revert 11501d52cad942850d88f83490710faf1d5cdf28
```

## Deferred continuation

Do not claim native Linux graphical support from WSLg. Run the exact
`linux-x64` package on a physical Linux AMD RadeonSI or supported NVIDIA
driver under the available X11/Wayland sessions. It must pass the same
capability report, packaged smoke frame, input/window/audio checks, and
zero-debt shutdown. The user deferred this physical-driver gate and Slices
L2–L6 on 2026-07-27. L2 has not started; resume at the physical L1 gate.