Click stability: only a hand controller's press starts it

The 3D mouse drives SteamVR's laser through the ft_pointer virtual
controller, so its events reach the screens the same way a controller's
do. The filter held every press, which turned the mouse's short drags
(selecting a character or two, nudging a slider) into clicks. Mark
button events from hand controllers and start the filter only on those.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/controller-click-stability.md

@@ -6,10 +6,12 @@ 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. Native mouse
-input, 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.
+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):
 

screens/controller-click.h

@@ -11,7 +11,8 @@ struct ft_controller_click {
     unsigned long suppressed, clicks, drags;
 };
 // Hold the desktop position at press time until movement exceeds a logical-pixel
-// radius. No timer, delayed button-down, or change to native mouse input.
+// 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) {
@@ -19,7 +20,7 @@ static inline bool ft_controller_click_filter(struct ft_controller_click *c,
         if (e->pressed) c->buttons |= bit; else c->buttons &= ~bit;
     }
     if (e->type == FT_BUTTON && e->pressed) {
-        if (e->button == BTN_LEFT && !c->held && c->threshold > 0) {
+        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) {

screens/tests/controller-click-test.c

@@ -1,7 +1,7 @@
 #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,.x=x,.y=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};
@@ -34,4 +34,9 @@ int main(void) {
     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

@@ -1741,6 +1741,7 @@ 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)
 };