Fix exception in animations

src/Alex.ResourcePackLib/Json/Bedrock/Entity/Animation.cs

@@ -6,6 +6,11 @@
 
 namespace Alex.ResourcePackLib.Json.Bedrock.Entity
 {
+	public class LoopElement
+	{
+		public bool IsString { get; set; }
+		public bool IsExpression { get; set; }
+	}
 	/// <summary>
 	///		Defines a model's animations.
 	/// </summary>
@@ -22,8 +27,23 @@ static Animation()
 		///		Determines whether the animation should go back to T0 when finished.
 		/// </summary>
 		[JsonProperty("loop")]
-		public IExpression Loop { get; set; } = new BooleanExpression(false);
+		public string Loop { get; set; } 
 
+		/// <summary>
+		///		 How long to wait in seconds before playing this animation.
+		///		Note that this expression is evaluated once before playing, and only re-evaluated if asked to play from the beginning again.
+		///		A looping animation should use 'loop_delay' if it wants a delay between loops.
+		/// </summary>
+		[JsonProperty("start_delay")]
+		public IExpression StartDelay { get; set; }
+
+		/// <summary>
+		///		How long to wait in seconds before looping this animation.
+		///		Note that this expression is evaluated after each loop and on looping animation only.
+		/// </summary>
+		[JsonProperty("loop_delay")]
+		public IExpression LoopDelay { get; set; }
+
 		/// <summary>
 		///		How does time pass when playing the animation.
 		///     Defaults to "query.anim_time + query.delta_time" which means advance in seconds.
@@ -45,8 +65,7 @@ static Animation()
 		public float AnimationLength { get; set; } = 0f;
 
 		/// <summary>
-		///		Should this animation override the rotation etc?
-		///		If set to true, all animations applied before this one don't have any effect.
+		///	 reset bones in this animation to the default pose before applying this animation
 		/// </summary>
 		[JsonProperty("override_previous_animation")]
 		public bool OverridePreviousAnimation { get; set; } = false;

src/Alex/Graphics/Models/Entity/Animations/EntityAnimation.cs

@@ -6,6 +6,7 @@
 using Alex.ResourcePackLib.Json.Bedrock.MoLang;
 using ConcreteMC.MolangSharp.Runtime;
 using ConcreteMC.MolangSharp.Runtime.Exceptions;
+using ConcreteMC.MolangSharp.Runtime.Value;
 using Microsoft.Xna.Framework;
 using NLog;
 
@@ -25,6 +26,10 @@ public class EntityAnimation : IAnimation
 		private readonly Animation _definition;
 		private bool _loop;
 
+		public bool HoldOnLastFrame { get; set; } = false;
+		private double _startDelay = -1;
+		private double _loopDelay = -1;
+		private bool _isFirstLoop = true;
 		public EntityAnimation(AnimationComponent parent, Animation definition, string name)
 		{
 			_parent = parent;
@@ -38,7 +43,20 @@ public EntityAnimation(AnimationComponent parent, Animation definition, string n
 			{
 				if (definition.Loop != null)
 				{
-					_loop = parent.Execute(definition.Loop).AsBool();
+					var loop = definition.Loop;
+
+					if (loop == "hold_on_last_frame")
+					{
+						HoldOnLastFrame = true;
+						_loop = false;
+					}
+					else
+					{
+						if (bool.TryParse(loop, out _loop))
+						{
+
+						}
+					}
 				}
 				else
 				{
@@ -59,6 +77,9 @@ public EntityAnimation(AnimationComponent parent, Animation definition, string n
 
 		public bool CanPlay()
 		{
+			if (HoldOnLastFrame && !_isFirstLoop)
+				return false;
+
 			return true;
 		}
 
@@ -71,6 +92,18 @@ public void Tick()
 			if (!Playing)
 				return;
 
+			if (_startDelay > 0d)
+			{
+				if (_timeSinceStart.Elapsed.TotalSeconds < _startDelay)
+					return;
+			}
+
+			if (_loopDelay > 0d && !_isFirstLoop)
+			{
+				if (_timeSinceLastLoop.Elapsed.TotalSeconds < _loopDelay)
+					return;
+			}
+
 			try
 			{
 				var entity = _parent.Entity;
@@ -92,7 +125,7 @@ public void Tick()
 
 					bone.Tick(
 						_parent.Runtime, _elapsedTimer.Elapsed.TotalSeconds, _animationTime,
-						anim.OverridePreviousAnimation);
+						false);
 				}
 			}
 			finally
@@ -102,9 +135,17 @@ public void Tick()
 
 			if (_animationLength > 0 && _animationTime >= _animationLength)
 			{
+				_isFirstLoop = false;
 				if (_loop)
 				{
 					_animationTime = 0;
+
+					if (_definition.LoopDelay != null)
+					{
+						var loopDelay = _parent.Execute(_definition.LoopDelay);
+						_loopDelay = loopDelay.AsDouble();
+					}
+					_timeSinceLastLoop.Restart();
 				}
 				else
 				{
@@ -124,22 +165,31 @@ public void UpdateBindings(ModelRenderer renderer)
 				}
 			}
 		}
-
+		
 		public void Play()
 		{
 			if (Playing)
 				return;
-
+
+			if (_definition.StartDelay != null)
+			{
+				var startDelay = _parent.Execute(_definition.StartDelay);
+				_startDelay = startDelay.AsDouble();
+			}
+
+			_timeSinceStart.Restart();
 			foreach (var bone in _components)
 			{
-				bone.Start();
+				bone.Start(_definition.OverridePreviousAnimation);
 			}
 
 			Playing = true;
 			_animationTime = 0d;
 			_elapsedTimer.Restart();
 		}
 
+		private Stopwatch _timeSinceLastLoop = new Stopwatch();
+		private Stopwatch _timeSinceStart = new Stopwatch();
 		public void Stop()
 		{
 			if (Playing)
@@ -176,7 +226,7 @@ public BoneComp(string name, EntityAnimation animation, AnimationBoneElement ele
 		private Vector3 _startPosition = Vector3.Zero;
 		private Vector3 _startScale = Vector3.Zero;
 
-		public void Start()
+		public void Start(bool reset = false)
 		{
 			if (_started) return;
 

src/Alex/Utils/ItemExtensions.cs

@@ -67,7 +67,7 @@ public static Item ToAlexItem(this MiNET.Items.Item item, [CallerMemberName] str
 			{
 				if (!ItemFactory.TryGetBedrockItem(item.Name, item.Metadata, out result))
 					Log.Warn(
-						$"Failed to convert MiNET item to Alex item. (MiNET={item}, CallingMethod={source}{(item == null ? "" : $", Name={item.Name}")})");
+						$"Failed to convert MiNET item to Alex item. ({(item == null ? "" : $"Name={item.Name}, ")} CallingMethod={source}, MiNET={item})");
 			}
 
 			if (result == null)