From 4154563d8397fade35d674c7a4f12a39870281c6 Mon Sep 17 00:00:00 2001
From: Pierre Tremblay <pierre.tremblay@autodesk.com>
Date: Tue, 26 Mar 2024 11:52:06 -0400
Subject: [PATCH] Avoid Maya Hydra registration for mayaUsdPlugin if not
 loaded.

---
 .../hydraExtensions/sceneIndex/registration.cpp        | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/mayaHydra/hydraExtensions/sceneIndex/registration.cpp b/lib/mayaHydra/hydraExtensions/sceneIndex/registration.cpp
index 85c17a2a4d..db61074e41 100644
--- a/lib/mayaHydra/hydraExtensions/sceneIndex/registration.cpp
+++ b/lib/mayaHydra/hydraExtensions/sceneIndex/registration.cpp
@@ -42,6 +42,8 @@
 #include <maya/MItDag.h>
 #include <maya/MMessage.h>
 #include <maya/MNodeMessage.h>
+#include <maya/MFnPlugin.h>
+#include <maya/MGlobal.h>
 
 #include <ufeExtensions/Global.h>
 
@@ -201,10 +203,16 @@ PXR_NAMESPACE_OPEN_SCOPE
 // Remove this once the code has been moved to the MayaHydra namespace.
 using namespace MayaHydra;
 
-// MayaHydraSceneIndexRegistration is used to register a scene index for a given dag node type.
+// MayaHydraSceneIndexRegistration is used to register a scene index for
+// mayaUsdPlugin proxy shape nodes.
 MayaHydraSceneIndexRegistry::MayaHydraSceneIndexRegistry(const std::shared_ptr<Fvp::RenderIndexProxy>& renderIndexProxy)
     : _renderIndexProxy(renderIndexProxy)
 {
+    if (!MFnPlugin::isNodeRegistered(kMayaUsdProxyShapeNode)) {
+        MGlobal::displayWarning("mayaUsdPlugin not loaded, cannot be registered to Maya Hydra.  Please load mayaUsdPlugin, then switch back to a Maya Hydra viewport renderer.");
+        return;
+    }
+
     MCallbackId id;
     MStatus     status;
     id = MDGMessage::addNodeAddedCallback(