From 35e823190e3825557b0b581a0057c072ee94033a Mon Sep 17 00:00:00 2001
From: Sean Lilley <lilleyse@gmail.com>
Date: Fri, 18 Aug 2023 10:13:28 -0400
Subject: [PATCH] Fix crash when reloading tileset

---
 .../cesium/omniverse/FabricResourceManager.h       |  4 ++++
 src/core/src/FabricResourceManager.cpp             | 14 ++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/src/core/include/cesium/omniverse/FabricResourceManager.h b/src/core/include/cesium/omniverse/FabricResourceManager.h
index 6808e7872..f51d4bf31 100644
--- a/src/core/include/cesium/omniverse/FabricResourceManager.h
+++ b/src/core/include/cesium/omniverse/FabricResourceManager.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <omni/fabric/IPath.h>
 #include <pxr/usd/sdf/assetPath.h>
 #include <pxr/usd/sdf/path.h>
 
@@ -86,6 +87,7 @@ class FabricResourceManager {
     std::shared_ptr<FabricMaterialPool>
     createMaterialPool(const FabricMaterialDefinition& materialDefinition, long stageId);
     std::shared_ptr<FabricTexturePool> createTexturePool();
+    void retainPath(const omni::fabric::Path& path);
 
     int64_t getNextGeometryId();
     int64_t getNextMaterialId();
@@ -117,6 +119,8 @@ class FabricResourceManager {
 
     std::unique_ptr<omni::ui::DynamicTextureProvider> _defaultTexture;
     pxr::TfToken _defaultTextureAssetPathToken;
+
+    std::vector<omni::fabric::Path> _retainedPaths;
 };
 
 } // namespace cesium::omniverse
diff --git a/src/core/src/FabricResourceManager.cpp b/src/core/src/FabricResourceManager.cpp
index 76f1f8ab4..864eb8c0c 100644
--- a/src/core/src/FabricResourceManager.cpp
+++ b/src/core/src/FabricResourceManager.cpp
@@ -66,6 +66,7 @@ std::shared_ptr<FabricGeometry> FabricResourceManager::acquireGeometry(
     if (_disableGeometryPool) {
         const auto pathStr = fmt::format("/fabric_geometry_{}", getNextGeometryId());
         const auto path = omni::fabric::Path(pathStr.c_str());
+        retainPath(path);
         return std::make_shared<FabricGeometry>(path, geometryDefinition, _debugRandomColors, stageId);
     }
 
@@ -79,6 +80,8 @@ std::shared_ptr<FabricGeometry> FabricResourceManager::acquireGeometry(
 
     auto geometry = geometryPool->acquire();
 
+    retainPath(geometry->getPath());
+
     return geometry;
 }
 std::shared_ptr<FabricMaterial>
@@ -88,6 +91,7 @@ FabricResourceManager::acquireMaterial(const MaterialInfo& materialInfo, bool ha
     if (_disableMaterialPool) {
         const auto pathStr = fmt::format("/fabric_material_{}", getNextMaterialId());
         const auto path = omni::fabric::Path(pathStr.c_str());
+        retainPath(path);
         return std::make_shared<FabricMaterial>(path, materialDefinition, _defaultTextureAssetPathToken, stageId);
     }
 
@@ -101,6 +105,8 @@ FabricResourceManager::acquireMaterial(const MaterialInfo& materialInfo, bool ha
 
     auto material = materialPool->acquire();
 
+    retainPath(material->getPath());
+
     return material;
 }
 
@@ -268,6 +274,14 @@ std::shared_ptr<FabricTexturePool> FabricResourceManager::createTexturePool() {
         std::make_shared<FabricTexturePool>(getNextPoolId(), _texturePoolInitialCapacity));
 }
 
+void FabricResourceManager::retainPath(const omni::fabric::Path& path) {
+    // This is a workaround for https://github.com/CesiumGS/cesium-omniverse/issues/425.
+    // By retaining a reference to the path we avoid a crash deep in the Sdf library
+    // that's triggered by loading a tileset, removing the tileset, and reloading the tileset.
+    // It's possible this will be fixed in future Kit releases.
+    _retainedPaths.push_back(path);
+}
+
 int64_t FabricResourceManager::getNextGeometryId() {
     return _geometryId++;
 }