The cutout composite drew each screen's whole client buffer into a side-by-side buffer on
every tick a hand was in front of it, then waited for the GPU with glFinish (1-6 ms, the
likely cause of the VR frame drops on 2026-10-01). Now:
- A drawn buffer gets a fence and is shown from a later tick once the fence has passed, so
ft-screens never waits for the GPU (except for a panel's first buffer after a pause, so a
stale one never shows). The prediction lead goes from 25 to 36 ms for that tick.
- Nothing is drawn when the client frame and the cutouts haven't changed, and SteamVR
isn't handed the same buffer again.
- When only the cutouts moved, a buffer that holds the same client frame is drawn again
only around the old and new cutouts (scissored).
- "cutouts state" reports draws, partial draws, unchanged ticks, busy ticks, waits and CPU
time per second since the last state; ft-handtest prints the same counts.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- The runtime files move to /run/user/UID/frametop-hands/: the desktop
session deletes /run/user/UID/frametop at every start.
- The cutout copy shader runs at highp: mediump (16-bit on Adreno)
stepped 1.7 texels across a 3440-pixel screen.
- One hand no longer pinches both sides after its left/right call flips
mid-pinch, and --pinch-palm-down (0.6) holds back pinches with the palm
facing down (typing on a lap keyboard).
- ft-camd judges a colour frame fresh by its luma rows only, and logs
per-buffer changes at stale colour frames with FT_CAMD_DEBUG=1.
- hands/run.sh caps skips the setcap when ft-camd already has them.
- The replay tool dumps poses (--poses), and its pinch events carry the
hand id.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
ft-screens' hand cutouts read /run/user/UID/frametop/hands through
hands/include/fh_hands.h instead of their own copy of its offsets.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Where frame-hands tracks a hand between an eye and a screen, that eye sees the
room through the screen. handcut.cpp draws the screen's buffer side by side
(one half per eye) with the hands cut out, only while a hand is in front of it.
The cutouts command turns it on or off. ft-handtest tries it on a test panel.
Not yet tested in the headset.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
