From d770b5578f84d875329a47836a01dd730018b03b 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

---
 .../include/cesium/omniverse/FabricResourceManager.h  |  5 +++++
 src/core/src/FabricGeometry.cpp                       |  3 +++
 src/core/src/FabricMaterial.cpp                       | 11 ++++++++---
 src/core/src/FabricResourceManager.cpp                |  9 +++++++++
 4 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/src/core/include/cesium/omniverse/FabricResourceManager.h b/src/core/include/cesium/omniverse/FabricResourceManager.h
index 6808e7872..fbcdac4d4 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>
 
@@ -70,6 +71,8 @@ class FabricResourceManager {
     void setTexturePoolInitialCapacity(uint64_t texturePoolInitialCapacity);
     void setDebugRandomColors(bool debugRandomColors);
 
+    void retainPath(const omni::fabric::Path& path);
+
     void clear();
 
   protected:
@@ -117,6 +120,8 @@ 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/FabricGeometry.cpp b/src/core/src/FabricGeometry.cpp
index f94f13656..09eb99d03 100644
--- a/src/core/src/FabricGeometry.cpp
+++ b/src/core/src/FabricGeometry.cpp
@@ -2,6 +2,7 @@
 
 #include "cesium/omniverse/FabricAttributesBuilder.h"
 #include "cesium/omniverse/FabricMaterial.h"
+#include "cesium/omniverse/FabricResourceManager.h"
 #include "cesium/omniverse/FabricUtil.h"
 #include "cesium/omniverse/GltfUtil.h"
 #include "cesium/omniverse/Tokens.h"
@@ -46,6 +47,8 @@ FabricGeometry::FabricGeometry(
         return;
     }
 
+    FabricResourceManager::getInstance().retainPath(path);
+
     initialize();
     reset();
 }
diff --git a/src/core/src/FabricMaterial.cpp b/src/core/src/FabricMaterial.cpp
index 79b6e95ca..f5ccf6cc6 100644
--- a/src/core/src/FabricMaterial.cpp
+++ b/src/core/src/FabricMaterial.cpp
@@ -2,6 +2,7 @@
 
 #include "cesium/omniverse/Context.h"
 #include "cesium/omniverse/FabricAttributesBuilder.h"
+#include "cesium/omniverse/FabricResourceManager.h"
 #include "cesium/omniverse/FabricUtil.h"
 #include "cesium/omniverse/Tokens.h"
 #include "cesium/omniverse/UsdUtil.h"
@@ -67,15 +68,19 @@ void FabricMaterial::initialize() {
     const auto shaderPath = FabricUtil::joinPaths(materialPath, FabricTokens::Shader);
     const auto baseColorTexturePath = FabricUtil::joinPaths(materialPath, FabricTokens::baseColorTexture);
 
-    createMaterial(materialPath);
     _materialPath = materialPath;
+    _shaderPath = shaderPath;
+    _baseColorTexturePath = baseColorTexturePath;
+
+    FabricResourceManager::getInstance().retainPath(materialPath);
+    FabricResourceManager::getInstance().retainPath(shaderPath);
+    FabricResourceManager::getInstance().retainPath(baseColorTexturePath);
 
+    createMaterial(materialPath);
     createShader(shaderPath, materialPath);
-    _shaderPath = shaderPath;
 
     if (hasBaseColorTexture) {
         createTexture(baseColorTexturePath, shaderPath, FabricTokens::inputs_base_color_texture);
-        _baseColorTexturePath = baseColorTexturePath;
     }
 }
 
diff --git a/src/core/src/FabricResourceManager.cpp b/src/core/src/FabricResourceManager.cpp
index 76f1f8ab4..59a1755d8 100644
--- a/src/core/src/FabricResourceManager.cpp
+++ b/src/core/src/FabricResourceManager.cpp
@@ -268,6 +268,15 @@ 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 a future Kit release at which point we can remove
+    // this workaround.
+    _retainedPaths.push_back(path);
+}
+
 int64_t FabricResourceManager::getNextGeometryId() {
     return _geometryId++;
 }