Calibration updates

public/js/exhibit.js

@@ -84,16 +84,31 @@ function markerToCameraMatrix(m) {
   return { M, err: pose.bestError, dist: Math.hypot(t[0], t[1], t[2]) };
 }
 
-// anchor world placement -> matrix (world coords of the marker's centre + yaw).
-// The marker lies flat-ish on the build; we treat its plane with the anchor yaw
-// about the vertical (Y) axis. Anchor.position is the marker centre in world mm.
+// anchor world placement -> matrix mapping the MARKER's local frame (as POS-IT
+// sees it: marker in its XY plane, +Z out of the printed face) into WORLD space.
+//
+// A crest lying flat on the table has its face pointing UP, so the marker's
+// local +Z must map to world +Y. That's a -90 deg rotation about X. On top of
+// that we apply the anchor's yaw (spin on the table) and its world position.
+//
+//   mount 'flat' (default): marker lies on the table, face up   -> rotX(-90) then yaw about Y
+//   mount 'wall':           marker stands vertical, face outward -> yaw about Y only
+//
+// The order matters: worldFromMarker = T(pos) * Ry(yaw) * planeTilt.
 function anchorToWorldMatrix(anchor) {
   const p = anchor.position || { x: 0, y: 0, z: 0 };
   const yaw = THREE.MathUtils.degToRad(anchor.rotationDeg?.y || 0);
-  const m = new THREE.Matrix4();
-  m.makeRotationY(yaw);
-  m.setPosition(p.x, p.y, p.z);
-  return m;
+  const mount = anchor.mount || 'flat';
+
+  const planeTilt = new THREE.Matrix4();
+  if (mount === 'wall') planeTilt.identity();          // face already points sideways
+  else planeTilt.makeRotationX(-Math.PI / 2);           // flat: tip face up to +Y
+
+  const spin = new THREE.Matrix4().makeRotationY(yaw);
+  const trans = new THREE.Matrix4().setPosition(p.x, p.y, p.z);
+
+  // trans * spin * planeTilt
+  return trans.multiply(spin).multiply(planeTilt);
 }
 
 // Given a detected marker with a known anchor, compute world->camera and apply