1 files changed, 133 insertions, 0 deletions
diff --git a/Plugins/MonoGame.Extended/source/MonoGame.Extended.Tweening/Tweener.cs b/Plugins/MonoGame.Extended/source/MonoGame.Extended.Tweening/Tweener.cs
new file mode 100644
index 0000000..61b55f9
--- /dev/null
+++ b/Plugins/MonoGame.Extended/source/MonoGame.Extended.Tweening/Tweener.cs
@@ -0,0 +1,133 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Reflection;
+using Microsoft.Xna.Framework;
+
+namespace MonoGame.Extended.Tweening
+{
+    public class Tweener : IDisposable
+    {
+        public Tweener()
+        {
+        }
+
+        public void Dispose()
+        {
+            CancelAll();
+            _activeTweens.Clear();
+            _memberCache.Clear();
+        }
+
+        public long AllocationCount { get; private set; }
+
+        private readonly List<Tween> _activeTweens = new List<Tween>();
+
+        public Tween<TMember> TweenTo<TTarget, TMember>(TTarget target, Expression<Func<TTarget, TMember>> expression, TMember toValue, float duration, float delay = 0f)
+            where TTarget : class
+            where TMember : struct
+        {
+            switch (toValue)
+            {
+                case Color toValueColor:
+                    return (Tween<TMember>)(object)TweenTo<TTarget, Color, ColorTween>(target, expression as Expression<Func<TTarget, Color>>, toValueColor, duration, delay);
+                default:
+                    return TweenTo<TTarget, TMember, LinearTween<TMember>>(target, expression, toValue, duration, delay);
+            }
+
+        }
+
+        public Tween<TMember> TweenTo<TTarget, TMember, TTween>(TTarget target, Expression<Func<TTarget, TMember>> expression, TMember toValue, float duration, float delay = 0f)
+            where TTarget : class
+            where TMember : struct
+            where TTween : Tween<TMember>
+        {
+            var memberExpression = (MemberExpression)expression.Body;
+            var memberInfo = memberExpression.Member;
+            var member = GetMember<TMember>(target, memberInfo.Name);
+            var activeTween = FindTween(target, member.Name);
+
+            activeTween?.Cancel();
+
+            AllocationCount++;
+            var tween = (TTween)Activator.CreateInstance(typeof(TTween),
+                BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance, null,
+                new object[]{target, duration, delay, member, toValue}, null);
+            _activeTweens.Add(tween);
+            return tween;
+        }
+
+        public void Update(float elapsedSeconds)
+        {
+            for (var i = _activeTweens.Count - 1; i >= 0; i--)
+            {
+                var tween = _activeTweens[i];
+
+                tween.Update(elapsedSeconds);
+
+                if (!tween.IsAlive)
+                    _activeTweens.RemoveAt(i);
+            }
+        }
+
+        public Tween FindTween(object target, string memberName)
+        {
+            return _activeTweens.FirstOrDefault(t => t.Target == target && t.MemberName == memberName);
+        }
+
+        public void CancelAll()
+        {
+            foreach (var tween in _activeTweens)
+                tween.Cancel();
+        }
+
+        public void CancelAndCompleteAll()
+        {
+            foreach (var tween in _activeTweens)
+                tween.CancelAndComplete();
+        }
+
+        private struct TweenMemberKey
+        {
+#pragma warning disable 414
+            public object Target;
+            public string MemberName;
+#pragma warning restore 414
+        }
+
+        private readonly Dictionary<TweenMemberKey, TweenMember> _memberCache = new Dictionary<TweenMemberKey, TweenMember>();
+
+        private TweenMember<T> GetMember<T>(object target, string memberName)
+            where T : struct
+        {
+            var key = new TweenMemberKey { Target = target, MemberName = memberName };
+
+            if (_memberCache.TryGetValue(key, out var member))
+                return (TweenMember<T>) member;
+
+            member = CreateMember<T>(target, memberName);
+            _memberCache.Add(key, member);
+            return (TweenMember<T>) member;
+        }
+
+        private TweenMember<T> CreateMember<T>(object target, string memberName)
+            where T : struct
+        {
+            AllocationCount++;
+
+            var type = target.GetType();
+            var property = type.GetTypeInfo().GetProperty(memberName);
+
+            if (property != null)
+                return new TweenPropertyMember<T>(target, property);
+
+            var field = type.GetTypeInfo().GetField(memberName);
+
+            if (field != null)
+                return new TweenFieldMember<T>(target, field);
+
+            throw new InvalidOperationException($"'{memberName}' is not a property or field of the target");
+        }
+    }
+}