Fix rotate issue

src/core/commands/CreatePrimCommand.cpp

@@ -1,9 +1,42 @@
 #include "CreatePrimCommand.h"
 #include "../../utils/Logger.h"
 #include <pxr/usd/usd/prim.h>
+#include <pxr/usd/usdGeom/xformCommonAPI.h>
+#include <pxr/usd/usdGeom/metrics.h>
+#include <pxr/usd/usdGeom/tokens.h>
 
 namespace UsdLayerManager {
 
+// ---------------------------------------------------------------------------
+// ApplyCameraDefaultOrientation
+//
+// USD cameras always use +Y-up / look-down-−Z in their own local frame.
+// For a Y-up stage that is already the standard world forward direction, so
+// the identity transform is fine.
+//
+// For a Z-up stage the identity transform would point the camera straight
+// DOWN (world −Z = −up), which produces wrong orientation when the viewport
+// switches to the prim, and wrong tumble/roll directions when navigating.
+//
+// Fix: rotate the camera +90° around its local X axis so that:
+//   camera local +Y (up)   → world +Z  (stage up axis)   ✓
+//   camera local −Z (view) → world +Y  (horizontal "forward") ✓
+// ---------------------------------------------------------------------------
+static void ApplyCameraDefaultOrientation(pxr::UsdPrim& prim,
+                                           pxr::UsdStageRefPtr stage)
+{
+    if (!prim.IsValid() || !stage) return;
+
+    bool isZUp = (pxr::UsdGeomGetStageUpAxis(stage) == pxr::UsdGeomTokens->z);
+    if (!isZUp) return;   // Y-up default (identity) is already correct
+
+    pxr::UsdGeomXformCommonAPI xformAPI(prim);
+    // +90° around X: camera up aligns with world Z, view direction becomes +Y
+    xformAPI.SetRotate(pxr::GfVec3f(90.f, 0.f, 0.f),
+                       pxr::UsdGeomXformCommonAPI::RotationOrderXYZ,
+                       pxr::UsdTimeCode::Default());
+}
+
 CreatePrimCommand::CreatePrimCommand(pxr::UsdStageRefPtr stage,
                                      const pxr::SdfPath&  primPath,
                                      const pxr::TfToken&  typeName)
@@ -18,8 +51,16 @@ void CreatePrimCommand::Execute() {
     if (!m_stage) return;
     try {
         pxr::UsdPrim prim = m_stage->DefinePrim(m_primPath, m_typeName);
-        if (!prim.IsValid())
+        if (!prim.IsValid()) {
             LOG_ERROR("CreatePrimCommand: failed to define prim " + m_primPath.GetString());
+            return;
+        }
+
+        // Camera-specific initialisation: orient the prim so the camera looks
+        // in the correct "forward" direction for the stage's up-axis.
+        if (m_typeName == pxr::TfToken("Camera"))
+            ApplyCameraDefaultOrientation(prim, m_stage);
+
     } catch (const std::exception& e) {
         LOG_ERROR(std::string("CreatePrimCommand::Execute error: ") + e.what());
     }