Gaze: leave SteamVR's gaze action alone during VR games

From curiousjtuber's PR #13: with the gaze service running, SteamVR
restarted its eye tracker every 10 to 13 s of Beat Saber, as if the
headset came off, and each restart took input focus from the game.
The PR stopped every read in a game. Only the action path reaches
SteamVR (UpdateActionState on the gaze set at overlay-global priority,
then GetEyeTrackingDataRelativeToNow); the mmap and our tracker are
read-only files. So only the action is skipped while a scene app runs,
and gaze keeps moving the pointer over the dashboard in a game. The
action source is only used with --source action.

Co-Authored-By: CuriousJ <curious.j.tuber@gmail.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/controller-click-stability.md

@@ -0,0 +1,34 @@
+# Controller desktop click stability
+
+Trigger presses reach KDE immediately, but controller motion within 8 logical
+pixels of the press stays at that position until release. Releasing without a motion outside this
+zone delivers the click at the original position, even if the hand moved during
+release. Moving outside the zone begins a normal drag immediately; returning to
+the zone does not turn it back into a click. There is no hold-duration timer.
+
+This filters overlay pointer content events on desktop monitors only, and only
+presses from hand controllers start it. The 3D mouse (whose laser comes from the
+`ft_pointer` virtual controller), SteamVR UI, separate screen grab bars and
+floating-app title-bar carrying are unaffected. Multi-button gestures keep their
+existing behavior. A motion onto another desktop monitor starts a drag;
+cross-monitor motion is not stabilized.
+
+CLI (runtime preferences, reset to 8 on desktop restart):
+
+```sh
+input/ft-clickctl status
+input/ft-clickctl threshold 8
+input/ft-clickctl threshold 0  # disable without a restart
+```
+
+Thresholds are 0–64 logical pixels, normalized to each panel's KDE scale.
+Status reports held state, suppressed motions, stabilized clicks and drags.
+Changing the threshold while a controller button is held is refused.
+
+This is a separate contribution from desktop mouse/controller ownership. Its
+hardware validation must check small controls, intentional text selection,
+long presses, cross-monitor dragging and simultaneous mouse use. The existing
+renderer laser remains tracked; this change stabilizes desktop input rather
+than smoothing the visual laser. Default threshold is a starting point to test.
+
+Run `scripts/test-controller-click.sh` for the isolated gesture-state tests.

gaze/ft-gaze.cpp

@@ -479,9 +479,24 @@ int main(int argc, char **argv) {
     double lastEmit = 0;
     int actionErrors = 0;
     vr::EVRInputError lastActionError = vr::VRInputError_None;
+    // During a VR game, SteamVR's gaze action is left alone. With ft-gaze reading the eyes, SteamVR
+    // restarted its eye tracker every 10 s or so in a game, as if the headset came off, and each
+    // restart took input focus from the game: Beat Saber paused (PR #13). Of what ft-gaze reads,
+    // only the action reaches SteamVR (the mmap and our tracker are files), so gaze still works
+    // over the dashboard. Games are told apart the way ft-screens does it, by the scene app.
+    bool inGame = false;
+    double nextGameCheck = 0;
 
     while (true) {
         const double now = NowRaw();
+        if (now >= nextGameCheck) {
+            nextGameCheck = now + 0.5;
+            const bool game = vr::VRApplications()->GetCurrentSceneProcessId() != 0;
+            if (game != inGame)
+                std::fprintf(stderr, "ft-gaze: %s\n",
+                             game ? "a VR game is running: SteamVR's gaze action left alone" : "the VR game ended");
+            inGame = game;
+        }
         vr::TrackedDevicePose_t hp;
         sys->GetDeviceToAbsoluteTrackingPose(vr::TrackingUniverseStanding, 0, &hp, 1);
         if (hp.bPoseIsValid) history.Add(now, hp.mDeviceToAbsoluteTracking);
@@ -502,24 +517,26 @@ int main(int argc, char **argv) {
             // SteamVR's action: a room-space origin and fixation point, turned into the head
             // frame so every source reports the same kind of angles.
             std::string action = "{\"ok\":0}";
-            vr::VRActiveActionSet_t active{};
-            active.ulActionSet = set;
-            active.nPriority = vr::k_nActionSetOverlayGlobalPriorityMin;
-            input->UpdateActionState(&active, sizeof active, 1);
-            vr::VREyeTrackingData_t e{};
-            const vr::EVRInputError ae =
-                input->GetEyeTrackingDataRelativeToNow(gaze, vr::TrackingUniverseStanding, 0, &e, sizeof e);
-            if (ae == vr::VRInputError_None && e.bActive && e.bValid) {
-                const Vec3 o{e.vGazeOrigin.v[0], e.vGazeOrigin.v[1], e.vGazeOrigin.v[2]};
-                const Vec3 t{e.vGazeTarget.v[0], e.vGazeTarget.v[1], e.vGazeTarget.v[2]};
-                const Vec3 dHead = RotateInverse(headNow, Normalize(t - o));
-                char extra[96];
-                std::snprintf(extra, sizeof extra, "\"tracked\":%d,\"dist\":%.3f,", int(e.bTracked), Length(t - o));
-                action = SrcJson(list, headNow, dHead, extra);
-            } else if (ae != lastActionError || (verbose && ++actionErrors % 90 == 1)) {
-                std::fprintf(stderr, "ft-gaze: action: error %d active %d valid %d\n", int(ae), int(e.bActive),
-                             int(e.bValid));
-                lastActionError = ae;
+            if (!inGame) {
+                vr::VRActiveActionSet_t active{};
+                active.ulActionSet = set;
+                active.nPriority = vr::k_nActionSetOverlayGlobalPriorityMin;
+                input->UpdateActionState(&active, sizeof active, 1);
+                vr::VREyeTrackingData_t e{};
+                const vr::EVRInputError ae =
+                    input->GetEyeTrackingDataRelativeToNow(gaze, vr::TrackingUniverseStanding, 0, &e, sizeof e);
+                if (ae == vr::VRInputError_None && e.bActive && e.bValid) {
+                    const Vec3 o{e.vGazeOrigin.v[0], e.vGazeOrigin.v[1], e.vGazeOrigin.v[2]};
+                    const Vec3 t{e.vGazeTarget.v[0], e.vGazeTarget.v[1], e.vGazeTarget.v[2]};
+                    const Vec3 dHead = RotateInverse(headNow, Normalize(t - o));
+                    char extra[96];
+                    std::snprintf(extra, sizeof extra, "\"tracked\":%d,\"dist\":%.3f,", int(e.bTracked), Length(t - o));
+                    action = SrcJson(list, headNow, dHead, extra);
+                } else if (ae != lastActionError || (verbose && ++actionErrors % 90 == 1)) {
+                    std::fprintf(stderr, "ft-gaze: action: error %d active %d valid %d\n", int(ae), int(e.bActive),
+                                 int(e.bValid));
+                    lastActionError = ae;
+                }
             }
 
             std::string m1 = "{\"ok\":0}", m2 = m1, left = m1, right = m1, eye = "null";

input/ft-clickctl

@@ -0,0 +1,29 @@
+#!/usr/bin/env python3
+"""Controller desktop click stability over local IPC; no SteamVR client."""
+import argparse
+import json
+import math
+import socket
+
+def request(command):
+    with socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM) as client:
+        client.bind(''); client.settimeout(2)
+        client.sendto(command.encode(), '\0ft_screens')
+        response=client.recv(8192).decode()
+    if response.startswith('error'): raise RuntimeError(response)
+    return response
+
+def main():
+    parser=argparse.ArgumentParser(description=__doc__)
+    sub=parser.add_subparsers(dest='command', required=True)
+    sub.add_parser('status')
+    sub.add_parser('threshold').add_argument('pixels', type=float)
+    args=parser.parse_args()
+    try:
+        if args.command == 'threshold':
+            if not math.isfinite(args.pixels) or not 0 <= args.pixels <= 64:
+                raise ValueError('Threshold must be 0–64 logical pixels; 0 disables stabilization')
+            if request(f'controller-click {args.pixels:g}') != 'ok': raise RuntimeError('Threshold rejected')
+        print(json.dumps(json.loads(request('controller-click?')), indent=2))
+    except (OSError, ValueError, RuntimeError) as error: parser.exit(1, str(error)+'\n')
+if __name__ == '__main__': main()

input/input-relay.py

@@ -1139,6 +1139,11 @@ def main():
                 # New here: a new device, or one that came back in the same place.
                 for old in [n for n in nodes.values() if n.path == path]:
                     drop(old, "replaced by a new device node")
+                # A new node is root's alone until udev gives it to the input group, a moment
+                # after it appears. Opened in that gap, it would fail and never be tried
+                # again: leave it for the next scan instead.
+                if not os.access(path, os.R_OK):
+                    continue
                 seen[path] = ino
                 node = probe(path)
                 if node and node.volume_keys and not take_volume(node):

screens/compositor.c

@@ -58,6 +58,7 @@
 #include <wlr/util/log.h>
 
 #include "vr.h"
+#include "controller-click.h"
 
 #define MAX_SCREENS 24  // screens and spare outputs
 
@@ -104,6 +105,7 @@ struct server {
     struct wl_list buffers;  // tracked_buffer
     struct wl_event_source *tick;
     struct screen *pointer_focus;
+    struct ft_controller_click controller_click;
     pid_t child;
     // Where typing goes: the screens after a click on one, Steam after a click on another
     // panel. The input relay grabs the keyboards while it's the screens (see keys_update).
@@ -292,6 +294,11 @@ static void handle_vr_event(const struct ft_event *e, void *data) {
         return;
     }
     if (e->screen < 0 || e->screen >= MAX_SCREENS || !s->screens[e->screen]) return;
+    struct ft_event filtered = *e;
+    if (e->screen < s->n_config &&
+        !ft_controller_click_filter(&s->controller_click, &filtered, s->scale[e->screen])) return;
+    e = &filtered;
+    if (e->screen < 0 || e->screen >= MAX_SCREENS || !s->screens[e->screen]) return;
     struct screen *sc = s->screens[e->screen];
     struct wlr_surface *surface = sc->toplevel->base->surface;
     const uint32_t t = now_ms();
@@ -514,7 +521,18 @@ static int control_readable(int fd, uint32_t mask, void *data) {
         unsigned code;
         int value, index, w, h;
         double scale;
-        if (sscanf(buf, "size %d %d %d", &index, &w, &h) == 3) {
+        char tail;
+        if (strcmp(buf, "controller-click?") == 0) {
+            snprintf(reply, sizeof reply,
+                "{\"supported\":true,\"threshold\":%.3f,\"held\":%s,\"dragging\":%s,\"suppressedMotions\":%lu,\"clicks\":%lu,\"drags\":%lu}",
+                s->controller_click.threshold, s->controller_click.held ? "true" : "false",
+                s->controller_click.dragging ? "true" : "false", s->controller_click.suppressed,
+                s->controller_click.clicks, s->controller_click.drags);
+        } else if (sscanf(buf, "controller-click %lf %c", &scale, &tail) == 1) {
+            if (!isfinite(scale) || scale < 0 || scale > 64 || s->controller_click.buttons)
+                snprintf(reply, sizeof reply, "error threshold or held controller button");
+            else { s->controller_click.threshold = scale; snprintf(reply, sizeof reply, "ok"); }
+        } else if (sscanf(buf, "size %d %d %d", &index, &w, &h) == 3) {
             // A new resolution for a screen, live: KWin resizes the screen to match. (KWin makes
             // it this size times its scale; ft-floatd sends spares' sizes divided by theirs.)
             const int min_w = index - 1 < s->n_config ? 320 : 64, min_h = index - 1 < s->n_config ? 200 : 64;
@@ -641,6 +659,7 @@ static bool setup_dmabuf(struct server *s) {
 
 int main(int argc, char **argv) {
     struct server s = {0};
+    s.controller_click.threshold = 8;
     for (int i = 0; i < MAX_SCREENS; ++i) s.scale[i] = 1;
     s.kb_screen = -1;
     const char *socket_name = "ft-screens-0", *control_name = "ft_screens";

screens/controller-click.h

@@ -0,0 +1,46 @@
+#ifndef FT_CONTROLLER_CLICK_H
+#define FT_CONTROLLER_CLICK_H
+#include <math.h>
+#include <linux/input-event-codes.h>
+#include "vr.h"
+struct ft_controller_click {
+    bool held, dragging;
+    int screen;
+    uint32_t buttons;
+    double x, y, threshold, radius;
+    unsigned long suppressed, clicks, drags;
+};
+// Hold the desktop position at press time until movement exceeds a logical-pixel
+// radius. No timer or delayed button-down. Only a hand controller's press starts
+// it: the 3D mouse drives a laser too, and its short drags must stay drags.
+static inline bool ft_controller_click_filter(struct ft_controller_click *c,
+                                              struct ft_event *e, double scale) {
+    if (e->type == FT_BUTTON && e->button >= BTN_LEFT && e->button < BTN_LEFT+8) {
+        uint32_t bit = 1u << (e->button-BTN_LEFT);
+        if (e->pressed) c->buttons |= bit; else c->buttons &= ~bit;
+    }
+    if (e->type == FT_BUTTON && e->pressed) {
+        if (e->button == BTN_LEFT && e->controller && !c->held && c->threshold > 0) {
+            c->held = true; c->dragging = false; c->screen = e->screen;
+            c->x = e->x; c->y = e->y; c->radius = c->threshold * scale;
+        } else if (e->button != BTN_LEFT) {
+            c->held = false; // Multi-button gestures retain their usual semantics.
+        }
+    } else if (e->type == FT_MOTION && c->held && !c->dragging) {
+        if (e->screen == c->screen && hypot(e->x-c->x, e->y-c->y) <= c->radius) {
+            ++c->suppressed;
+            return false;
+        }
+        c->dragging = true; ++c->drags;
+    } else if (e->type == FT_BUTTON && e->button == BTN_LEFT && !e->pressed && c->held) {
+        if (!c->dragging) {
+            e->screen = c->screen; e->x = c->x; e->y = c->y;
+            ++c->clicks;
+        }
+        c->held = false; c->dragging = false;
+    } else if (e->type == FT_LEAVE && c->held) {
+        return false; // Preserve the implicit grab through tiny edge excursions.
+    }
+    return true;
+}
+#endif

screens/tests/controller-click-test.c

@@ -0,0 +1,42 @@
+#include <assert.h>
+#include "../controller-click.h"
+static struct ft_event event(enum ft_event_type t, bool down, double x, double y) {
+    return (struct ft_event){.type=t,.screen=0,.button=BTN_LEFT,.pressed=down,.controller=true,.x=x,.y=y};
+}
+int main(void) {
+    struct ft_controller_click c={.threshold=8};
+    struct ft_event e=event(FT_BUTTON,true,100,100);
+    assert(ft_controller_click_filter(&c,&e,2));
+    e=event(FT_MOTION,false,112,108);
+    assert(!ft_controller_click_filter(&c,&e,2));
+    assert(c.held && !c.dragging && c.suppressed==1);
+    e=event(FT_BUTTON,false,116,111);
+    assert(ft_controller_click_filter(&c,&e,2));
+    assert(e.x==100 && e.y==100 && c.clicks==1 && !c.held);
+    e=event(FT_BUTTON,true,100,100);ft_controller_click_filter(&c,&e,1);
+    e=event(FT_MOTION,false,109,100);assert(ft_controller_click_filter(&c,&e,1));
+    assert(c.dragging && c.drags==1);
+    e=event(FT_MOTION,false,101,100);assert(ft_controller_click_filter(&c,&e,1));
+    e=event(FT_BUTTON,false,103,100);assert(ft_controller_click_filter(&c,&e,1));
+    assert(e.x==103 && c.clicks==1 && !c.held && !c.dragging);
+    e=event(FT_BUTTON,true,100,100);ft_controller_click_filter(&c,&e,1);
+    e=event(FT_LEAVE,false,0,0);assert(!ft_controller_click_filter(&c,&e,1));
+    e=event(FT_BUTTON,false,800,900);e.screen=1;ft_controller_click_filter(&c,&e,1);
+    assert(e.screen==0 && e.x==100 && c.clicks==2);
+    e=event(FT_BUTTON,true,100,100);ft_controller_click_filter(&c,&e,1);
+    e=event(FT_MOTION,false,101,100);e.screen=1;
+    assert(ft_controller_click_filter(&c,&e,1) && c.dragging);
+    e=event(FT_BUTTON,false,101,100);ft_controller_click_filter(&c,&e,1);
+    c.threshold=0;
+    e=event(FT_BUTTON,true,100,100);ft_controller_click_filter(&c,&e,1);
+    e=event(FT_MOTION,false,101,100);assert(ft_controller_click_filter(&c,&e,1) && !c.held);
+    c.threshold=8;
+    e=event(FT_BUTTON,true,100,100);ft_controller_click_filter(&c,&e,1);
+    e=event(FT_BUTTON,true,100,100);e.button=BTN_RIGHT;ft_controller_click_filter(&c,&e,1);
+    assert(!c.held);
+    // The 3D mouse's laser: a short drag stays a drag, and the release stays where it was.
+    e=event(FT_BUTTON,true,100,100);e.controller=false;assert(ft_controller_click_filter(&c,&e,1) && !c.held);
+    e=event(FT_MOTION,false,104,100);assert(ft_controller_click_filter(&c,&e,1));
+    e=event(FT_BUTTON,false,106,100);e.controller=false;
+    assert(ft_controller_click_filter(&c,&e,1) && e.x==106 && c.clicks==2 && c.suppressed==1);
+}

screens/vr.cpp

@@ -1330,7 +1330,8 @@ void UpdateCatcher() {
     for (int k = 0; k < 3; ++k) params.vSource.v[k] = l.m[k][3], params.vDirection.v[k] = -l.m[k][2];
     for (auto &[i, s] : g_screens) {
         if (!s.visible) continue;
-        std::vector<vr::VROverlayHandle_t> parts(s.All().begin(), s.All().end());
+        const auto all = s.All();  // one copy: two calls give two temporaries, not one range
+        std::vector<vr::VROverlayHandle_t> parts(all.begin(), all.end());
         for (const auto &[k, sub] : s.subs) parts.push_back(sub.overlay);
         for (auto o : parts) {
             vr::VROverlayIntersectionResults_t hit;
@@ -1741,6 +1742,7 @@ void ft_vr_poll(void (*handle)(const struct ft_event *, void *), void *data) {
                     e.type = FT_BUTTON;
                     e.button = LinuxButton(ev.data.mouse.button);
                     e.pressed = ev.eventType == vr::VREvent_MouseButtonDown;
+                    e.controller = IsHandController(ev.trackedDeviceIndex);
                     at();
                     if (!e.pressed && s.titleCarry) e.x = s.carryX, e.y = s.carryY, s.titleCarry = false;
                     if (e.pressed) {

screens/vr.h

@@ -25,6 +25,7 @@ struct ft_event {
     double x, y;      // FT_MOTION: buffer pixels from the top left
     uint32_t button;  // FT_BUTTON: linux BTN_*
     bool pressed;
+    bool controller;  // FT_BUTTON: from a hand controller's laser (not the 3D mouse's)
     double dx, dy;    // FT_SCROLL: notches (positive dy: scroll down)
     uint32_t key;     // FT_KEY: linux KEY_* from our keyboard (pressed: down or up)
 };

scripts/test-controller-click.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+set -euo pipefail
+root=$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)
+"$root/scripts/frame.sh" -C screens 'mkdir -p build; gcc -std=c11 -Wall -Wextra -Werror tests/controller-click-test.c -lm -o build/controller-click-test && build/controller-click-test'