update exe GUI build

examples/viz/mesh_camera.py

@@ -38,6 +38,12 @@ def resolve_viz_pose_path(path: str | Path | None = None) -> Path:
         Path.cwd() / raw,
         here.parents[2] / raw,
     ]
+    try:
+        from app_paths import app_root
+
+        candidates.insert(0, app_root() / raw)
+    except ImportError:
+        pass
     for candidate in candidates:
         if candidate.is_file():
             return candidate.resolve()
@@ -74,6 +80,79 @@ def camera_look_at_from_world_to_cam(
     return lookat, eye, up
 
 
+def default_look_at_view(
+    mesh_vertices: np.ndarray,
+    lookat: np.ndarray,
+) -> tuple[np.ndarray, np.ndarray, np.ndarray]:
+    """Fallback look_at triple when no world_to_cam pose is available."""
+    center = np.asarray(lookat, dtype=np.float64).reshape(3)
+    extent = np.ptp(np.asarray(mesh_vertices, dtype=np.float64), axis=0)
+    span = float(np.max(extent))
+    eye = center + np.array([0.0, 0.0, span * 2.0], dtype=np.float64)
+    up = np.array([0.0, 1.0, 0.0], dtype=np.float64)
+    return center, eye, up
+
+
+def _rotation_matrix(axis: np.ndarray, angle_rad: float) -> np.ndarray:
+    axis = np.asarray(axis, dtype=np.float64).reshape(3)
+    norm = float(np.linalg.norm(axis))
+    if norm < 1e-12:
+        return np.eye(3, dtype=np.float64)
+    axis = axis / norm
+    x, y, z = axis
+    cross = np.array(
+        [[0.0, -z, y], [z, 0.0, -x], [-y, x, 0.0]],
+        dtype=np.float64,
+    )
+    return np.eye(3, dtype=np.float64) + np.sin(angle_rad) * cross + (1.0 - np.cos(angle_rad)) * (cross @ cross)
+
+
+def orbit_eye_about_target(
+    target: np.ndarray,
+    eye: np.ndarray,
+    up: np.ndarray,
+    dx_deg: float,
+    dy_deg: float,
+) -> tuple[np.ndarray, np.ndarray]:
+    """Orbit ``eye`` around ``target``; dx/dy are drag deltas in degrees."""
+    target = np.asarray(target, dtype=np.float64).reshape(3)
+    eye = np.asarray(eye, dtype=np.float64).reshape(3)
+    up = np.asarray(up, dtype=np.float64).reshape(3)
+
+    offset = eye - target
+    if float(np.linalg.norm(offset)) < 1e-9:
+        offset = np.array([0.0, 0.0, 1.0], dtype=np.float64)
+
+    world_up = up.copy()
+    if float(np.linalg.norm(world_up)) < 1e-9:
+        world_up = np.array([0.0, 1.0, 0.0], dtype=np.float64)
+    world_up /= np.linalg.norm(world_up)
+
+    if abs(dx_deg) > 1e-9:
+        rot = _rotation_matrix(world_up, np.deg2rad(dx_deg))
+        offset = rot @ offset
+        up = rot @ up
+
+    forward = -offset
+    forward_norm = float(np.linalg.norm(forward))
+    if forward_norm > 1e-9:
+        forward = forward / forward_norm
+        right = np.cross(forward, up)
+        right_norm = float(np.linalg.norm(right))
+        if right_norm > 1e-9:
+            right = right / right_norm
+            if abs(dy_deg) > 1e-9:
+                rot = _rotation_matrix(right, np.deg2rad(dy_deg))
+                offset = rot @ offset
+                up = rot @ up
+
+    new_eye = target + offset
+    up_norm = float(np.linalg.norm(up))
+    if up_norm > 1e-9:
+        up = up / up_norm
+    return new_eye, up
+
+
 def apply_view_from_world_to_cam(vis, world_to_cam: np.ndarray, *, lookat: np.ndarray) -> None:
     """Apply Blender-exported world_to_cam as the Open3D default view."""
     world_to_cam = np.asarray(world_to_cam, dtype=np.float64)