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F01 — First pixel & init cost ​

How much machinery sits between "process starts" and "a software-drawn frame is on screen"? This demo formalizes the measurement the scaffolds already make possible: every platform object touched, every round-trip required, and the wall-clock cost of each step. The per-platform counts and event orders are the baseline every other feature demo builds on.

Requirements ​

  1. Present one software-drawn frame (the scaffold gradient is fine) and exit cleanly shortly after presentation is confirmed (auto-exit keeps the demo Tier-A runnable).
  2. Log a timestamped instrumentation event for every initialization step from init_start to first_pixel_presented — connection/registration, window/surface creation, buffer allocation, the first configure/paint request, and the present itself.
  3. "Presented" must mean what the platform can actually confirm: Wayland — the first wl_buffer committed after xdg_surface.configure was acked (plus the first frame callback); X11 — first XPutImage/XShmPutImage after Expose (note: no true present confirmation without the Present extension — record that); Win32 — return of the first BitBlt inside WM_PAINT; macOS — return of the first drawRect: (note what CoreAnimation may still defer).
  4. Count concepts: distinct platform object/handle types touched before first pixel (e.g. wl_display, wl_registry, wl_compositor, wl_surface, xdg_wm_base, …).
  5. Record LOC of the demo (excluding instrument.d and the c.c shim).

Instrumentation ​

The mandatory event set, plus one step name=<api-call> event per initialization API call. This demo defines instrument.d (monotonic microsecond timestamps, the <monotonic_us> <DEMO> <EVENT_KIND> k=v… line format) that all other demos copy.

Findings to record ​

  • The ordered step list with deltas; total init_start → first_pixel_presented time.
  • Concept count and LOC, copied into the matrix header row.
  • Which steps are round-trips (block on the server/compositor) vs purely local.
  • What "first pixel" even means per platform — where confirmation is impossible, say so.

Verification ​

Wayland/X11: Tier A (headless weston / Xvfb). Win32: Tier A on CI, A[wine] locally. macOS: A[ssh] if the Phase 0 probe verified SSH-launched windows, else Tier C.