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F10 — Pointer: relative motion, lock & confine ​

The mouselook problem: games and 3D tools need raw deltas with the cursor pinned, and editors need confine-to-region. Each platform splits "hide cursor", "stop cursor", and "raw motion" differently.

Requirements ​

  1. A "mouselook" mode toggled by click/keypress: while active, the cursor is locked (hidden and pinned) and the demo logs raw deltas (pointer rel dx=… dy=…) driving a visible crosshair/angle readout; toggling off restores the cursor exactly where it was locked (or documents that the platform restores it elsewhere).
    • Wayland: zwp_pointer_constraints_v1.lock_pointer + zwp_relative_pointer_v1 for deltas (note wl_pointer.motion stops/continues?).
    • X11: XIGrabDevice + XInput2 raw motion events (XI_RawMotion), or warp-to-center fallback — implement XI2, document the fallback frameworks still use.
    • Win32: RegisterRawInputDevices (WM_INPUT) for deltas + ClipCursor to a 1×1 rect + ShowCursor(FALSE).
    • macOS: CGAssociateMouseAndMouseCursorPosition(false) + NSEvent.deltaX/Y + hide via NSCursor.hide/CGDisplayHideCursor.
  2. A confine-to-region variant (center half of the window): Wayland confine_pointer; X11 pointer barriers (XFixes) or grab-with-confine-to; Win32 ClipCursor(rect); macOS — no public confine API: demonstrate the absence and the event-warp workaround, recording its visible artifacts.
  3. Log accel state: are deltas accelerated or raw per platform/mechanism?

Instrumentation ​

pointer rel dx=… dy=… raw=0|1, lock state=on|off, confine rect=…, plus regular pointer abs x=… y=… while unlocked.

Findings to record ​

  • The lock/confine/raw capability matrix and which combinations are atomic vs assembled.
  • Whether lock can be denied (Wayland: compositor may refuse; log the locked/unlocked events) — a framework API must be async-failable because of this.
  • Cursor-position restoration semantics on unlock.
  • macOS's missing confine and the workaround cost.

Verification ​

Tier C interactive at heart, but: Wayland under headless weston can verify the protocol handshake (constraint granted/denied) — Tier A for that slice; X11 XI2 raw events can be exercised with xdotool under Xvfb (synthetic deltas; mark them). Win32/macOS: A[wine]/A[ssh] for API plumbing, manual queue for feel and edge cases (multi-monitor edges, focus loss while locked).