Avatar works seated: only shoulders required, bust mode without hips

Sitting at a desk the hips are rarely visible, which made the avatar
never appear. The pelvis is now synthesized below the shoulders when
hidden (torso/head/arms as a bust; legs return when actually visible).
The output also reports diagnostics to the panel: pose tracker failed,
or avatar active with no body detected for 5s.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/interactive.js

@@ -1027,15 +1027,20 @@ class InteractiveSim {
     // tracked skeleton 1:1 — raise your arm and the robot raises its arm.
     if (mode === 'avatar') {
       const L = this.lmsRaw;
-      const ok = this.modelSim && L && L[11] && L[11].vis > 0.5 && L[12].vis > 0.5
-        && L[23].vis > 0.4 && L[24].vis > 0.4;
+      // Only the shoulders are required: seated at a desk the hips are often
+      // hidden, so the pelvis is synthesized and the robot shows as a bust.
+      const ok = this.modelSim && L && L[11] && L[11].vis > 0.5 && L[12].vis > 0.5;
       if (!ok) { this._drawField(7, e, audio, canvas, 0); return; }
       const S = 2.6;
       const W = (i) => [(L[i].x - 0.5)*S, (0.5 - L[i].y)*S, -(L[i].z || 0)*1.2];
       const mid = (p, q) => [(p[0]+q[0])/2, (p[1]+q[1])/2, (p[2]+q[2])/2];
-      const sh1 = W(11), sh2 = W(12), hp1 = W(23), hp2 = W(24);
-      const neck = mid(sh1, sh2), pelvis = mid(hp1, hp2);
+      const sh1 = W(11), sh2 = W(12);
+      const neck = mid(sh1, sh2);
       const shw = Math.max(0.15, Math.hypot(sh1[0]-sh2[0], sh1[1]-sh2[1], sh1[2]-sh2[2]));
+      const hipsVis = L[23].vis > 0.4 && L[24].vis > 0.4;
+      const hp1 = hipsVis ? W(23) : [neck[0]-shw*0.28, neck[1]-shw*1.25, neck[2]];
+      const hp2 = hipsVis ? W(24) : [neck[0]+shw*0.28, neck[1]-shw*1.25, neck[2]];
+      const pelvis = mid(hp1, hp2);
       const t = shw;
       const metal = [0.60, 0.64, 0.72], dark = [0.28, 0.30, 0.36];
       const acc = e.colorB || [0.2, 1, 1];
@@ -1063,9 +1068,9 @@ class InteractiveSim {
       };
       arm(sh1, 13, 15); arm(sh2, 14, 16);
       ball(sh1, t*0.16, dark); ball(sh2, t*0.16, dark);
-      // legs with feet
+      // legs with feet (only when actually visible: seated = bust only)
       const leg = (h, knI, anI) => {
-        if (L[knI].vis < 0.4 || L[anI].vis < 0.4) return;
+        if (!hipsVis || L[knI].vis < 0.4 || L[anI].vis < 0.4) return;
         const kn = W(knI), an = W(anI);
         limb(h, kn, t*0.16, metal);
         limb(kn, an, t*0.13, metal);

src/output.js

@@ -549,7 +549,7 @@ function avTick(now) {
   djv.report({ type: 'autoVj', on: true, name: e.name, mood, bpm: audio.bpm || 0 });
 }
 
-let camErrReported = false;
+let camErrReported = false, poseErrReported = false, avatarHintAt = 0, avatarHinted = false;
 function frame() {
   const t = (performance.now() - startTime) / 1000;
   audio.update();
@@ -564,6 +564,24 @@ function frame() {
     djv.report({ type: 'error', message: 'Camera non disponibile (' + viz.inter.camErr +
       ') — l’effetto Interattivo funziona comunque con il mouse sull’output' });
   }
+  // Body-tracking diagnostics: tracker failed, or avatar active with no body.
+  const now2 = performance.now();
+  if (viz.inter && viz.inter.poseState === 'error' && !poseErrReported) {
+    poseErrReported = true;
+    djv.report({ type: 'error', message: 'Tracking corpo non disponibile: le famiglie ' +
+      'Interattivo usano solo il movimento (Avatar non può funzionare)' });
+  }
+  if (viz.effect && viz.effect.interactiveMode === 'avatar' && viz.inter) {
+    if (viz.inter.lmsRaw) { avatarHintAt = 0; avatarHinted = true; }
+    else if (!avatarHinted) {
+      if (!avatarHintAt) avatarHintAt = now2;
+      else if (now2 - avatarHintAt > 5000) {
+        avatarHinted = true;
+        djv.report({ type: 'error', message: 'Avatar: nessun corpo rilevato — mettiti davanti ' +
+          'alla camera (almeno il busto ben inquadrato e illuminato)' });
+      }
+    }
+  } else { avatarHintAt = 0; }
 
   // Report beat rising-edges so the control window can auto-cycle effects.
   if (a.beat > 0.6 && prevBeat <= 0.6) djv.report({ type: 'beat' });