Scripting: FindEntityWithName and get script instance

+ Some C# UUID stuff
+ Added some Mono functions
+ ScriptEngine:
  + ID -> ScriptInstance map in ScriptEngine
  + GetManagedInstance

+ Fixed Scene not visible after loading a new scene
  + Renamed OnViewportResize to SetViewportSize for Scene and SceneRenderer

ScriptCore/Core/UUID.cs

@@ -3,4 +3,20 @@ namespace GlitchyEngine.Core;
 public struct UUID
 {
     private ulong _uuid;
+
+    public UUID(ulong uuid)
+    {
+        _uuid = uuid;
+    }
+
+    public static UUID Zero = new UUID(0);
+
+    public static bool operator ==(UUID left, UUID right) => left._uuid == right._uuid;
+
+    public static bool operator !=(UUID left, UUID right) => left._uuid != right._uuid;
+
+    public override string ToString()
+    {
+        return _uuid.ToString();
+    }
 }

ScriptCore/Entity.cs

@@ -1,5 +1,7 @@
 using System;
+using System.Diagnostics;
 using System.Runtime.CompilerServices;
+using System.Xml.Linq;
 using GlitchyEngine.Core;
 using GlitchyEngine.Math;
 
@@ -11,22 +13,22 @@ internal struct EntityHandle
     public uint Index;
 }
 
-public abstract class Entity : EngineObject
+public class Entity : EngineObject
 {
     //private UUID _uuid;
 
     //public UUID UUID => _uuid;
 
-    ///// <summary>
-    ///// Empty constructor not used. Do NOT USE!
-    ///// </summary>
-    //protected Entity()
-    //{}
+    /// <summary>
+    /// Empty constructor not used. Do NOT USE!
+    /// </summary>
+    protected Entity()
+    { }
 
-    //internal Entity(UUID uuid)
-    //{
-    //    _uuid = uuid;
-    //}
+    private Entity(UUID uuid)
+    {
+        _uuid = uuid;
+    }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public bool HasComponent<T>() => HasComponent(typeof(T));
@@ -41,8 +43,6 @@ public abstract class Entity : EngineObject
     /// <returns>The component or null, if the entity doesn't have a component of the specified type.</returns>
     public T GetComponent<T>() where T : Component, new()
     {
-        Log.Info("Trying to get component");
-
         if (HasComponent<T>())
         {
             return new T
@@ -129,10 +129,39 @@ public abstract class Entity : EngineObject
 
     public Transform Transform => GetComponent<Transform>();
 
-    public Vector3 Translation
+    //public Vector3 Translation
+    //{
+    //    get => Transform.Translation;
+    //    set => Transform.Translation = value;
+    //}
+
+    /// <summary>
+    /// Returns the first entity with the given name.
+    /// </summary>
+    /// <param name="name">The name of the entity.</param>
+    /// <returns>The first entity with the given name, or null.</returns>
+    public static Entity FindEntityWithName(string name)
     {
-        get => Transform.Translation;
-        set => Transform.Translation = value;
+        ScriptGlue.Entity_FindEntityWithName(name, out UUID entityId);
+
+        Log.Error($"Found EntityID {entityId}");
+
+        if (entityId == UUID.Zero)
+            return null;
+
+        return new Entity(entityId);
+    }
+
+    /// <summary>
+    /// Returns the script of the given type, or null, if the entity has no script of the given type.
+    /// </summary>
+    /// <typeparam name="T">The type of the script.</typeparam>
+    /// <returns>The script instance or null.</returns>
+    public T As<T>() where T : Entity
+    {
+        object scriptInstance = ScriptGlue.Entity_GetScriptInstance(_uuid);
+
+        return scriptInstance as T;
     }
 
     // Will be executed once after the entity as be created.

ScriptCore/Math/Vector2.cs

@@ -99,7 +99,12 @@ public struct Vector2
     {
         return !(a == b);
     }
-    
+
+    public float Length()
+    {
+        return (float)System.Math.Sqrt(X * X + Y * Y);
+    }
+
     public override int GetHashCode()
     {
         unchecked

ScriptCore/ScriptGlue.cs

@@ -20,7 +20,13 @@ internal static class ScriptGlue
     
     [MethodImpl(MethodImplOptions.InternalCall)]
     internal static extern void Entity_RemoveComponent(UUID entityId, Type componentType);
-
+    
+    [MethodImpl(MethodImplOptions.InternalCall)]
+    internal static extern void Entity_FindEntityWithName(string name, out UUID uuid);
+    
+    [MethodImpl(MethodImplOptions.InternalCall)]
+    internal static extern object Entity_GetScriptInstance(UUID entityId);
+    
 #endregion Entity
 
 #region TransformComponent