Add function to query nodes by distance for spatial queries

bridge/src/lib.rs

@@ -1,3 +1,30 @@
+#[no_mangle]
+pub extern "C" fn sdxr_query_nodes_by_distance(
+    center_x: f32,
+    center_y: f32,
+    center_z: f32,
+    radius: f32,
+    out_ids: *mut u64,
+    max_count: usize,
+) -> usize {
+    if !STARTED.load(Ordering::SeqCst) { return 0; }
+    let ctrl = CTRL.lock().unwrap();
+    let mut found = 0;
+    let center = glam::Vec3::new(center_x, center_y, center_z);
+    for (id, node) in ctrl.nodes.iter() {
+        let (_scale, _rot, trans) = node.transform.to_scale_rotation_translation();
+        let pos = glam::Vec3::new(trans.x, trans.y, trans.z);
+        if (pos - center).length() <= radius {
+            if found < max_count {
+                unsafe { *out_ids.add(found) = *id; }
+                found += 1;
+            } else {
+                break;
+            }
+        }
+    }
+    found
+}
 // Rust C-ABI bridge for StardustXR client integration.
 
 mod model_downloader;