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>
The tracked hands arrive 30-60 ms after the cameras saw them and reach the
displays later still, so holes trailed moving hands. Track each hand's palm
velocity in the room and move its capsules ahead to about when the frame is
on the displays, every tick, so the holes also move smoothly between tracker
updates. Slow hands aren't moved (their velocity is noise). The control
socket gets cutouts predict on|off and cutouts lead <ms>.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A capsule end near the eyes' plane projects far across a screen with a huge
radius, so one bad hand estimate there tore a hole through the screens for a
moment. Clip capsules 12 cm in front of the eye, as the tracker now does too.
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>
