Fix runtime errors when static batching is enabled

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 - Ensure "ProBuilderize" action is enabled for current selection on opening main window
 - [case: 1258589] Fixed error in runtime sample examples.
+- [case: 1258421] Fixed an issue where GI UV streams would be lost at runtime due to `ProBuilderMesh` assigning a new `Mesh` to the statically combined `MeshFilter`.
 - [case: 1251289] Fixed `m_WireMaterial null reference exception` when re-importing ProBuilder.
 - Fixed `TooltipEditor.Hide` affecting performance linearly with scene size.
 - [case: 1259506] Fixed shortcut not being saved in 2018.4.

Editor/EditorCore/EditorUtility.cs

@@ -193,6 +193,7 @@ public static void SynchronizeWithMeshFilter(ProBuilderMesh mesh)
                 throw new ArgumentNullException("mesh");
 
             mesh.EnsureMeshFilterIsAssigned();
+            mesh.EnsureMeshColliderIsAssigned();
             MeshSyncState state = mesh.meshSyncState;
             bool meshesAreAssets = Experimental.meshesAreAssets;
 

Runtime/Core/ProBuilderMeshFunction.cs

@@ -58,6 +58,7 @@ internal void ClearDrivenProperties()
         void Awake()
         {
             EnsureMeshFilterIsAssigned();
+            EnsureMeshColliderIsAssigned();
 
             if (vertexCount > 0
                 && faceCount > 0
@@ -123,13 +124,13 @@ internal void EnsureMeshFilterIsAssigned()
         {
             if (filter == null)
                 m_MeshFilter = gameObject.AddComponent<MeshFilter>();
+
 #if UNITY_EDITOR
             m_MeshFilter.hideFlags = k_MeshFilterHideFlags;
 #endif
-            filter.sharedMesh = m_Mesh;
 
-            if(mesh && gameObject.TryGetComponent<MeshCollider>(out MeshCollider collider))
-                EnsureMeshColliderIsAssigned();
+            if (!renderer.isPartOfStaticBatch && filter.sharedMesh != m_Mesh)
+                filter.sharedMesh = m_Mesh;
         }
 
         internal static ProBuilderMesh CreateInstanceWithPoints(Vector3[] positions)
@@ -319,6 +320,7 @@ public void ToMesh(MeshTopology preferredTopology = MeshTopology.Triangles)
             }
 
             mesh.name = string.Format("pb_Mesh{0}", id);
+
             EnsureMeshFilterIsAssigned();
         }
 
@@ -388,17 +390,18 @@ public void Refresh(RefreshMask mask = RefreshMask.All)
                 EnsureMeshColliderIsAssigned();
         }
 
-        void EnsureMeshColliderIsAssigned()
+        internal void EnsureMeshColliderIsAssigned()
         {
-            mesh.RecalculateBounds();
-
             if(gameObject.TryGetComponent<MeshCollider>(out MeshCollider collider))
             {
 #if ENABLE_DRIVEN_PROPERTIES
                 SerializationUtility.RegisterDrivenProperty(this, collider, "m_Mesh");
 #endif
-                collider.sharedMesh = null;
-                collider.sharedMesh = mesh;
+                if (collider.sharedMesh != mesh)
+                {
+                    collider.sharedMesh = null;
+                    collider.sharedMesh = mesh;
+                }
             }
         }