+ plugins project

1 files changed, 58 insertions, 0 deletions

diff --git a/Plugins/MonoGame.Extended/source/MonoGame.Extended/Screens/Transitions/Transition.cs b/Plugins/MonoGame.Extended/source/MonoGame.Extended/Screens/Transitions/Transition.cs
new file mode 100644
index 0000000..8336a04
--- /dev/null
+++ b/Plugins/MonoGame.Extended/source/MonoGame.Extended/Screens/Transitions/Transition.cs
@@ -0,0 +1,58 @@
+using System;
+using Microsoft.Xna.Framework;
+
+namespace MonoGame.Extended.Screens.Transitions
+{
+    public enum TransitionState { In, Out }
+
+    public abstract class Transition : IDisposable
+    {
+        private readonly float _halfDuration;
+        private float _currentSeconds;
+        
+        protected Transition(float duration)
+        {
+            Duration = duration;
+            _halfDuration = Duration / 2f;
+        }
+
+        public abstract void Dispose();
+
+        public TransitionState State { get; private set; } = TransitionState.Out;
+        public float Duration { get; }
+        public float Value => MathHelper.Clamp(_currentSeconds / _halfDuration, 0f, 1f);
+
+        public event EventHandler StateChanged;
+        public event EventHandler Completed;
+
+        public void Update(GameTime gameTime)
+        {
+            var elapsedSeconds = gameTime.GetElapsedSeconds();
+
+            switch (State)
+            {
+                case TransitionState.Out:
+                    _currentSeconds += elapsedSeconds;
+
+                    if (_currentSeconds >= _halfDuration)
+                    {
+                        State = TransitionState.In;
+                        StateChanged?.Invoke(this, EventArgs.Empty);
+                    }
+                    break;
+                case TransitionState.In:
+                    _currentSeconds -= elapsedSeconds;
+
+                    if (_currentSeconds <= 0.0f)
+                    {
+                        Completed?.Invoke(this, EventArgs.Empty);
+                    }
+                    break;
+                default:
+                    throw new ArgumentOutOfRangeException();
+            }
+        }
+
+        public abstract void Draw(GameTime gameTime);
+    }
+}
\ No newline at end of file