Refactoring Rendering backend

Ghost.Core/Handle.cs

@@ -1,6 +1,10 @@
 namespace Ghost.Core;
 
+public interface IHandleType;
+public interface IIdentifierType;
+
 public readonly struct Handle<T>
+    where T : IHandleType
 {
     public readonly int id;
 
@@ -14,6 +18,8 @@ public readonly struct Handle<T>
 
     public static Handle<T> Invalid => new(-1, -1);
 
+    public bool IsValid => this != Invalid;
+
     public readonly override int GetHashCode()
     {
         return id.GetHashCode();
@@ -46,6 +52,7 @@ public readonly struct Handle<T>
 }
 
 public readonly struct Identifier<T>
+    where T : IIdentifierType
 {
     public readonly int value;
 
@@ -56,6 +63,8 @@ public readonly struct Identifier<T>
 
     public static Identifier<T> Invalid => new(-1);
 
+    public bool IsValid => this != Invalid;
+
     public readonly override int GetHashCode()
     {
         return value.GetHashCode();