update Tue 07/14/2026 12:21:23.58

public/js/ar/pose.js

@@ -10,6 +10,13 @@ import * as THREE from 'three';
 const _m = new THREE.Matrix4();
 const _q = new THREE.Quaternion();
 
+/* Input convention (matches the v1-validated fix): raw centered image coords are
+ * passed to POS-IT — NO Y pre-flip. The -t[1]/-t[2] negation below is what converts
+ * to the Three.js camera frame. Pre-flipping Y here double-flips the vertical axis
+ * and inverts pitch response (ghosts move opposite when tilting the phone).
+ * If tilt ever reads inverted on a device, toggle this for a quick A/B test. */
+const FLIP_INPUT_Y = false;
+
 export class PoseEstimator {
   constructor(focalLength) {
     this.focal = focalLength;
@@ -26,7 +33,7 @@ export class PoseEstimator {
   /** corners: aruco marker corners, image-space; cx/cy: image center.
    *  Returns { position: THREE.Vector3 (mm, marker->camera), quaternion, error } */
   estimate(markerId, corners, cx, cy, sizeMM) {
-    const centered = corners.map(c => ({ x: c.x - cx, y: (cy - c.y) }));
+    const centered = corners.map(c => ({ x: c.x - cx, y: FLIP_INPUT_Y ? (cy - c.y) : (c.y - cy) }));
     const pose = this.positFor(sizeMM).pose(centered);
     if (!pose) return null;