Add support for Unity6.5

CHANGES.md

@@ -5,6 +5,7 @@
 ##### Additions :tada:
 
 - Added support for the Linux platform (x86-64 only).
+- Added support for building the package from source in Unity 6.5.
 
 ## v1.24.0 - 2026-07-01
 

Source/Editor/CesiumIonAssetsWindow.cs

@@ -5,6 +5,11 @@
 using UnityEditor;
 using UnityEditor.IMGUI.Controls;
 
+#if UNITY_6000_2_OR_NEWER
+using TreeViewItem = UnityEditor.IMGUI.Controls.TreeViewItem<int>;
+using TreeViewState = UnityEditor.IMGUI.Controls.TreeViewState<int>;
+#endif
+
 namespace CesiumForUnity
 {
     public class CesiumIonAssetsWindow : EditorWindow

Source/Editor/CesiumTreeViewState.cs

@@ -0,0 +1,20 @@
+#if UNITY_EDITOR
+using UnityEditor.IMGUI.Controls;
+
+#if UNITY_6000_2_OR_NEWER
+using TreeViewState = UnityEditor.IMGUI.Controls.TreeViewState<int>;
+#endif
+
+// Class for bridging the gap between templated and non-templated
+// versions of TreeView et al., for the benefit of Reinterop.
+
+namespace CesiumForUnity
+{
+    public  class CesiumTreeViewState : TreeViewState
+    {
+        public CesiumTreeViewState()
+        {
+        }
+    }
+}
+#endif

Source/Editor/ConfigureReinteropEditor.cs

@@ -10,7 +10,6 @@
 using UnityEngine;
 using UnityEngine.Networking;
 
-
 namespace CesiumForUnity
 {
     [Reinterop]
@@ -109,10 +108,7 @@ public void ExposeToCPP()
             string productName = Application.productName;
             string osVersion = System.Environment.OSVersion.VersionString;
 
-            TreeViewItem root = new TreeViewItem(0, -1, "root");
-            int id = root.id;
-
-            TreeViewState treeState = new TreeViewState();
+            CesiumTreeViewState treeState = new CesiumTreeViewState();
             IonAssetsTreeView treeView = new IonAssetsTreeView(treeState);
             treeView.Reload();
 

Source/Editor/IonAssetsTreeView.cs

@@ -5,6 +5,12 @@
 using UnityEditor.IMGUI.Controls;
 using UnityEngine;
 
+#if UNITY_6000_2_OR_NEWER
+using TreeView = UnityEditor.IMGUI.Controls.TreeView<int>;
+using TreeViewItem = UnityEditor.IMGUI.Controls.TreeViewItem<int>;
+using TreeViewState = UnityEditor.IMGUI.Controls.TreeViewState<int>;
+#endif
+
 namespace CesiumForUnity
 {
     public enum IonAssetsColumn

Source/Runtime/ConfigureReinterop.cs

@@ -142,7 +142,6 @@ public void ExposeToCPP()
             mesh.SetIndices(new NativeArray<int>(), MeshTopology.Triangles, 0, true, 0);
             mesh.RecalculateBounds();
             int vertexCount = mesh.vertexCount;
-            int instanceID = mesh.GetInstanceID();
 
             Vector3[] vertices = mesh.vertices;
             Vector3 vertex = vertices[0];
@@ -521,7 +520,7 @@ public void ExposeToCPP()
 
             Mesh.ApplyAndDisposeWritableMeshData(meshDataArray, meshes, MeshUpdateFlags.Default);
 
-            Physics.BakeMesh(mesh.GetInstanceID(), false);
+            Helpers.BakeMeshFromId(Helpers.GetObjectId(mesh));
 
             CesiumCreditComponent creditComponent = new CesiumCreditComponent("text", "link", -1);
             List<CesiumCreditComponent> creditComponents = new List<CesiumCreditComponent>();

Source/Runtime/Helpers.cs

@@ -209,5 +209,23 @@ public static double Mod(double m, double n)
             }
             return ((m % n) + n) % n;
         }
+
+        public static ulong GetObjectId(UnityEngine.Object o)
+        {
+#if UNITY_6000_4_OR_NEWER
+            return EntityId.ToULong(o.GetEntityId());
+#else
+            return (ulong)o.GetInstanceID();
+#endif
+        }
+
+        public static void BakeMeshFromId(ulong id)
+        {
+#if UNITY_6000_4_OR_NEWER
+            Physics.BakeMesh(EntityId.FromULong(id), false);
+#else
+            Physics.BakeMesh((int)id, false);
+#endif
+        }
     }
 }

native~/src/Editor/IonAssetsTreeViewImpl.h

@@ -6,7 +6,6 @@
 
 #include <DotNet/CesiumForUnity/IonAssetsColumn.h>
 #include <DotNet/System/String.h>
-#include <DotNet/UnityEditor/IMGUI/Controls/TreeViewItem.h>
 #include <DotNet/UnityEngine/Rect.h>
 
 #include <memory>

native~/src/Runtime/CesiumMetadataImpl.cpp

@@ -9,9 +9,11 @@
 #include <CesiumGltf/PropertyTablePropertyView.h>
 #include <CesiumGltf/PropertyTableView.h>
 
+#include <DotNet/CesiumForUnity/Helpers.h>
 #include <DotNet/System/Array1.h>
 #include <DotNet/UnityEngine/GameObject.h>
 #include <DotNet/UnityEngine/Mesh.h>
+#include <DotNet/UnityEngine/Object.h>
 #include <DotNet/UnityEngine/Transform.h>
 
 using namespace DotNet;
@@ -58,14 +60,14 @@ CesiumMetadataImpl::CesiumMetadataImpl(
 CesiumMetadataImpl::~CesiumMetadataImpl() {}
 
 void CesiumMetadataImpl::addMetadata(
-    int32_t instanceID,
+    uint64_t objectId,
     const CesiumGltf::Model* pModel,
     const CesiumGltf::MeshPrimitive* pPrimitive) {
-  this->_pModels.insert({instanceID, {pModel, pPrimitive}});
+  this->_pModels.insert({objectId, {pModel, pPrimitive}});
 }
 
-void CesiumMetadataImpl::removeMetadata(int32_t instanceID) {
-  auto find = this->_pModels.find(instanceID);
+void CesiumMetadataImpl::removeMetadata(uint64_t objectId) {
+  auto find = this->_pModels.find(objectId);
   if (find != this->_pModels.end()) {
     this->_pModels.erase(find);
   }
@@ -78,7 +80,8 @@ CesiumForUnityNative::CesiumMetadataImpl::GetFeatures(
     const DotNet::CesiumForUnity::CesiumMetadata& metadata,
     const DotNet::UnityEngine::Transform& transform,
     int triangleIndex) {
-  auto find = this->_pModels.find(transform.GetInstanceID());
+  auto find =
+      this->_pModels.find(CesiumForUnity::Helpers::GetObjectId(transform));
   if (find == this->_pModels.end()) {
     return DotNet::System::Array1<DotNet::CesiumForUnity::CesiumFeature>(0);
   }

native~/src/Runtime/CesiumMetadataImpl.h

@@ -29,11 +29,11 @@ class CesiumMetadataImpl : public CesiumImpl<CesiumMetadataImpl> {
   ~CesiumMetadataImpl();
 
   void addMetadata(
-      int32_t instanceID,
+      uint64_t objectId,
       const CesiumGltf::Model* pModel,
       const CesiumGltf::MeshPrimitive* pPrimitive);
 
-  void removeMetadata(int32_t instanceID);
+  void removeMetadata(uint64_t objectId);
 
   DotNet::System::Array1<DotNet::CesiumForUnity::CesiumFeature> GetFeatures(
       const DotNet::CesiumForUnity::CesiumMetadata& metadata,
@@ -42,7 +42,7 @@ class CesiumMetadataImpl : public CesiumImpl<CesiumMetadataImpl> {
 
 private:
   std::unordered_map<
-      int32_t,
+      uint64_t,
       std::pair<const CesiumGltf::Model*, const CesiumGltf::MeshPrimitive*>>
       _pModels;
 };

native~/src/Runtime/UnityPrepareRendererResources.cpp

@@ -34,6 +34,7 @@
 #include <DotNet/CesiumForUnity/CesiumPointCloudRenderer.h>
 #include <DotNet/CesiumForUnity/CesiumPrimitiveFeatures.h>
 #include <DotNet/CesiumForUnity/CesiumPropertyTable.h>
+#include <DotNet/CesiumForUnity/Helpers.h>
 #include <DotNet/System/Array1.h>
 #include <DotNet/System/Collections/Generic/List1.h>
 #include <DotNet/System/Object.h>
@@ -55,7 +56,6 @@
 #include <DotNet/UnityEngine/MeshRenderer.h>
 #include <DotNet/UnityEngine/MeshTopology.h>
 #include <DotNet/UnityEngine/Object.h>
-#include <DotNet/UnityEngine/Physics.h>
 #include <DotNet/UnityEngine/Quaternion.h>
 #include <DotNet/UnityEngine/Rendering/CullMode.h>
 #include <DotNet/UnityEngine/Rendering/IndexFormat.h>
@@ -992,9 +992,9 @@ UnityPrepareRendererResources::prepareInLoadThread(
             if (shouldCreatePhysicsMeshes) {
               // Baking physics meshes takes awhile, so do that in a
               // worker thread.
-              const std::int32_t len = meshes.Length();
-              std::vector<std::int32_t> instanceIDs;
-              for (int32_t i = 0; i < len; ++i) {
+              const std::uint64_t len = meshes.Length();
+              std::vector<std::uint64_t> objectIds;
+              for (uint64_t i = 0; i < len; ++i) {
                 // Don't attempt to bake a physics mesh from points, lines, or
                 // an invalid triangle mesh.
                 switch (primitiveInfos[i].mode) {
@@ -1007,21 +1007,22 @@ UnityPrepareRendererResources::prepareInLoadThread(
                   }
                 }
 
-                instanceIDs.push_back(meshes[i].GetInstanceID());
+                objectIds.push_back(
+                    CesiumForUnity::Helpers::GetObjectId(meshes[i]));
               }
 
-              if (instanceIDs.size() > 0) {
+              if (objectIds.size() > 0) {
 #ifndef __EMSCRIPTEN__
                 return asyncSystem.runInWorkerThread(
 #else
                 // Unity Wasm can only access managed code from the main thread.
                 return asyncSystem.runInMainThread(
 #endif
                     [workerResult = std::move(workerResult),
-                     instanceIDs = std::move(instanceIDs),
+                     objectIds = std::move(objectIds),
                      meshes = std::move(meshes)]() mutable {
-                      for (std::int32_t instanceID : instanceIDs) {
-                        UnityEngine::Physics::BakeMesh(instanceID, false);
+                      for (std::uint64_t objectID : objectIds) {
+                        CesiumForUnity::Helpers::BakeMeshFromId(objectID);
                       }
 
                       LoadThreadResult* pResult = new LoadThreadResult{
@@ -1628,7 +1629,8 @@ void* UnityPrepareRendererResources::prepareInMainThread(
         // For backwards compatibility.
         if (metadataComponent != nullptr) {
           metadataComponent.NativeImplementation().addMetadata(
-              primitiveGameObject.transform().GetInstanceID(),
+              CesiumForUnity::Helpers::GetObjectId(
+                  primitiveGameObject.transform()),
               &gltf,
               &primitive);
         } else {
@@ -1680,7 +1682,7 @@ void freePrimitiveGameObject(
   // Kept for backwards compatibility.
   if (metadataComponent != nullptr) {
     metadataComponent.NativeImplementation().removeMetadata(
-        primitiveGameObject.transform().GetInstanceID());
+        CesiumForUnity::Helpers::GetObjectId(primitiveGameObject.transform()));
   } else {
     freePrimitiveFeatures(primitiveGameObject);
   }