Add SceneObjectsOnly attriute

Editor.Extras/Validators/SceneObjectsOnlyValidator.cs

@@ -0,0 +1,36 @@
+using TriInspector;
+using TriInspector.Validators;
+using UnityEditor;
+using UnityEngine;
+
+[assembly: RegisterTriAttributeValidator(typeof(SceneObjectsOnlyValidator))]
+
+namespace TriInspector.Validators
+{
+    public class SceneObjectsOnlyValidator : TriAttributeValidator<SceneObjectsOnlyAttribute>
+    {
+        public override TriExtensionInitializationResult Initialize(TriPropertyDefinition propertyDefinition)
+        {
+            if (!typeof(Object).IsAssignableFrom(propertyDefinition.FieldType))
+            {
+                return "AssetsOnly attribute can be used only on Object fields";
+            }
+
+            return TriExtensionInitializationResult.Ok;
+        }
+
+        public override TriValidationResult Validate(TriProperty property)
+        {
+            var obj = property.TryGetSerializedProperty(out var serializedProperty)
+                ? serializedProperty.objectReferenceValue
+                : (Object) property.Value;
+
+            if (obj == null || !AssetDatabase.Contains(obj))
+            {
+                return TriValidationResult.Valid;
+            }
+
+            return TriValidationResult.Error($"{obj} cannot be an asset.");
+        }
+    }
+}

Editor.Extras/Validators/SceneObjectsOnlyValidator.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 98948bb92a504f87abeda6e500dc22b2
+timeCreated: 1657621306

Editor.Samples/Validators/Validators_SceneObjectsOnlySample.cs

@@ -0,0 +1,8 @@
+using TriInspector;
+using UnityEngine;
+
+public class Validators_SceneObjectsOnlySample : ScriptableObject
+{
+    [SceneObjectsOnly]
+    public GameObject obj;
+}

Editor.Samples/Validators/Validators_SceneObjectsOnlySample.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 7bd709dcdda44927b14c8a77ffebf843
+timeCreated: 1657621668

README.md

@@ -171,6 +171,15 @@ private bool VisibleInEditMode => !Application.isPlaying;
 public GameObject obj;
 ```
 
+#### SceneObjectsOnly
+
+![SceneObjectsOnly](https://user-images.githubusercontent.com/26966368/178470605-618c9796-054f-40bb-9c09-2d9c6f342faf.png)
+
+```csharp
+[SceneObjectsOnly]
+public GameObject obj;
+```
+
 ### Decorators
 
 #### Dropdown

Runtime/Attributes/SceneObjectsOnlyAttribute.cs

@@ -0,0 +1,11 @@
+using System;
+using System.Diagnostics;
+
+namespace TriInspector
+{
+    [AttributeUsage((AttributeTargets.Field | AttributeTargets.Property))]
+    [Conditional("UNITY_EDITOR")]
+    public sealed class SceneObjectsOnlyAttribute : Attribute
+    {
+    }
+}

Runtime/Attributes/SceneObjectsOnlyAttribute.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 908b02bc0b5d4cdd88e952625ce0cbc7
+timeCreated: 1657621281