Motion capture: camera selection dropdown

Replace camera index spinbox with a combo listing detected cameras by
name. On Linux enumerates /dev/video* and reads device names from sysfs
(fast, no probing). Fallback probes cv2.VideoCapture indices 0-7 on
other platforms. Simulation entry always appended as last option.

Also adds explicit simulation mode (index -1) to tracker.start() and a
rescan button (⟳) in both the main window and the Settings > Plugins
widget.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 36 insertions, 10 deletions

diff --git a/plugins/motion_capture/plugin.py b/plugins/motion_capture/plugin.py
index d4bf497..e5d37c7 100644
--- a/plugins/motion_capture/plugin.py
+++ b/plugins/motion_capture/plugin.py
@@ -22,7 +22,8 @@ from __future__ import annotations
 from typing import Any, Dict, List, Optional
 
 from PyQt6.QtWidgets import (
-    QDoubleSpinBox, QFormLayout, QLabel, QSpinBox, QWidget,
+    QComboBox, QDoubleSpinBox, QFormLayout, QHBoxLayout,
+    QLabel, QPushButton, QWidget,
 )
 
 from plugins.base_plugin import LabPlugin, PluginAction, PluginContext
@@ -90,17 +91,26 @@ class MotionCapturePlugin(LabPlugin):
         ]
 
     def get_settings_widget(self) -> Optional[QWidget]:
+        from tracker import list_cameras
         w = QWidget()
         lay = QFormLayout(w)
         lay.setContentsMargins(0, 4, 0, 4)
 
-        self._s_cam = QSpinBox()
-        self._s_cam.setRange(0, 9)
-        self._s_cam.setValue(
-            self._win.get_camera_index() if self._win else 0)
-        self._s_cam.setObjectName("traceWidthSpin")
-        self._s_cam.valueChanged.connect(self._sync_cam_to_window)
-        lay.addRow("Camera index:", self._s_cam)
+        cam_row = QHBoxLayout()
+        self._s_cam = QComboBox()
+        self._s_cam.setObjectName("channelPickerCb")
+        self._s_cameras: list = []
+        self._s_refresh_btn = QPushButton("⟳")
+        self._s_refresh_btn.setObjectName("configButton")
+        self._s_refresh_btn.setFixedWidth(28)
+        self._s_refresh_btn.setToolTip("Rescan cameras")
+        self._s_refresh_btn.clicked.connect(lambda: self._populate_settings_cam(list_cameras))
+        cam_row.addWidget(self._s_cam, 1)
+        cam_row.addWidget(self._s_refresh_btn)
+        lay.addRow("Camera:", cam_row)
+
+        self._populate_settings_cam(list_cameras)
+        self._s_cam.currentIndexChanged.connect(self._sync_cam_to_window)
 
         self._s_pxmm = QDoubleSpinBox()
         self._s_pxmm.setRange(0.01, 100_000)
@@ -168,9 +178,25 @@ class MotionCapturePlugin(LabPlugin):
         if self._toolbar_btn is not None:
             self._toolbar_btn.setChecked(False)
 
-    def _sync_cam_to_window(self, v: int) -> None:
+    def _populate_settings_cam(self, list_cameras_fn) -> None:
+        current = self._win.get_camera_index() if self._win else 0
+        self._s_cam.blockSignals(True)
+        self._s_cam.clear()
+        self._s_cameras = list_cameras_fn()
+        for _, label in self._s_cameras:
+            self._s_cam.addItem(label)
+        for i, (idx, _) in enumerate(self._s_cameras):
+            if idx == current:
+                self._s_cam.setCurrentIndex(i)
+                break
+        self._s_cam.blockSignals(False)
+
+    def _sync_cam_to_window(self, combo_i: int) -> None:
+        if not self._s_cameras:
+            return
+        idx = self._s_cameras[combo_i][0]
         if self._win:
-            self._win.set_camera_index(v)
+            self._win.set_camera_index(idx)
 
     def _sync_pxmm_to_window(self, v: float) -> None:
         if self._win: