feat(viz): fixed default viz mode (voronoi on t)

VIZ_DEFAULT_MODE=<name> boots the viz on that mode and disables the
auto-openpos switch entirely, so the mode is truly always active (user
request: the t-key voronoi effect permanent). Concert launcher defaults
to voronoi; "auto" keeps the historical behavior.

data_only_viz/config.py

@@ -44,6 +44,7 @@ ARKIT_FULL_SKELETON         "1"       bool   draw full 91-joint ARKit body (!=0
 VIZ_HUD                     "0"       bool   show debug HUD overlay
 VIZ_SOURCE_KEYS             "0"       bool   wxcvbn + 0-9 source-bundle shortcuts (off: perf safety)
 VIZ_AUDIO_KEYS              "0"       bool   qsdfghjkl audio-scene shortcuts (off: perf safety; m stays)
+VIZ_DEFAULT_MODE            "auto"    str    fixed boot viz mode (e.g. voronoi); disables auto-openpos
 IPHONE_OSC_PORT             57128     int    UDP port for iPhone ARBodyTracker /body3d/kp
 CONCERT_MIRROR              "1"       bool   mirror video horizontally (!=0 = True)
 ICP_FUSION                  "0"       bool   enable ICP LiDAR fusion (only "1" = True)
@@ -141,6 +142,11 @@ class VizConfig:
     # Audio-scene row (qsdfghjkl): same perf-safety gate, same date. The
     # special m key (matrix mode: scene stop + openpos viz) stays active.
     viz_audio_keys: bool = False
+    # Fixed viz mode at boot (a viz_mode_names entry, e.g. "voronoi").
+    # "auto" = historical behavior (mode 0 + auto-openpos when persons
+    # appear). A fixed mode also DISABLES the auto-openpos timer so it is
+    # truly always on (user request live 2026-07-02: t/voronoi permanent).
+    viz_default_mode: str = "auto"
 
     # ---- iPhone OSC ------------------------------------------------------
     iphone_osc_port: int = 57128
@@ -290,6 +296,7 @@ class VizConfig:
             viz_hud=_bool_std("VIZ_HUD", False),
             viz_source_keys=_bool_std("VIZ_SOURCE_KEYS", False),
             viz_audio_keys=_bool_std("VIZ_AUDIO_KEYS", False),
+            viz_default_mode=_str("VIZ_DEFAULT_MODE", "auto"),
             iphone_osc_port=_int("IPHONE_OSC_PORT", 57128),
             concert_mirror=_bool_ne0("CONCERT_MIRROR", True),
             # ICP_FUSION / MULTIHMR_AUTOCAST use strict "1" convention

data_only_viz/main.py

@@ -206,9 +206,19 @@ class AppDelegate(NSObject):
         # 2d) Auto-engage du mode openpos (#9) quand des personnes sont
         # detectees. Si l'utilisateur a force un mode au clavier dans
         # les 8 dernieres secondes, on n'override pas (lock manuel).
+        # VIZ_DEFAULT_MODE=<name> fixes the boot mode and DISABLES the
+        # auto-switch entirely (user request: t/voronoi always active).
         self._user_viz_lock_t = 0.0   # set par _on_key, lu par autoOpenpos
-        self._autoOpenposTimer = NSTimer.scheduledTimerWithTimeInterval_target_selector_userInfo_repeats_(
+        from .config import VizConfig as _VC
-            0.5, self, "autoOpenpos:", None, True)
+        _vmode = _VC.from_env().viz_default_mode
+        self._autoOpenposTimer = None
+        if _vmode != "auto" and _vmode in self._state.viz_mode_names:
+            with self._state.lock():
+                self._state.viz_mode = self._state.viz_mode_names.index(_vmode)
+            LOG.info("[viz] fixed default mode %s (auto-openpos disabled)", _vmode)
+        else:
+            self._autoOpenposTimer = NSTimer.scheduledTimerWithTimeInterval_target_selector_userInfo_repeats_(
+                0.5, self, "autoOpenpos:", None, True)
 
         if self._opts.fullscreen:
             self._window.toggleFullScreen_(None)

data_only_viz/tests/test_config.py

@@ -419,3 +419,9 @@ def test_viz_audio_keys_default_off():
     cfg = VizConfig.from_env({})
     assert cfg.viz_audio_keys is False
     assert VizConfig.from_env({"VIZ_AUDIO_KEYS": "1"}).viz_audio_keys is True
+
+
+def test_viz_default_mode():
+    assert VizConfig.from_env({}).viz_default_mode == "auto"
+    assert VizConfig.from_env(
+        {"VIZ_DEFAULT_MODE": "voronoi"}).viz_default_mode == "voronoi"

launcher/concert/launch_concert.sh

@@ -29,6 +29,9 @@ export PINCH_ENABLE="${PINCH_ENABLE:-1}"
 # displayed video ccw. The 2D landmark streams arrive already uprighted
 # (see iphone_usb_source) and are not rotated.
 export VIDEO_ROTATE="${VIDEO_ROTATE:-ccw}"
+# Fixed viz mode: voronoi (the t-key effect) always active — the auto
+# openpos switch is disabled by data_only_viz when a mode is fixed.
+export VIZ_DEFAULT_MODE="${VIZ_DEFAULT_MODE:-voronoi}"
 # Gestures use the iPhone Vision hands exclusively (stable, rotation-invariant);
 # the Mac MediaPipe hand detector is skipped under --iphone-usb (multi.py).
 export FINGER_SOURCE="${FINGER_SOURCE:-iphone}"