created new fade in transition

RhythmBullet/Zer01HD/Game/Screens/Transitions/FadeInTransition.cs

@@ -0,0 +1,65 @@
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+using RhythmBullet.Zer01HD.Utilities.UI;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace RhythmBullet.Zer01HD.Game.Screens.Transitions
+{
+    internal class FadeInTransition : IDisposable
+    {
+        public readonly Texture2D curtain;
+        Rectangle curtainSize;
+        Color color;
+        private float progR, progG, progB, progA;
+        private float rR, rG, rB, rA;
+        private bool recorded;
+
+        internal FadeInTransition(GraphicsDevice graphicsDevice, Color startColor, Vector2 dimensions)
+        {
+            curtain = new Texture2D(graphicsDevice, 1, 1);
+            curtain.SetData(new[] { startColor });
+            curtainSize.Width = (int)dimensions.X;
+            curtainSize.Height = (int)dimensions.Y;
+            color = startColor;
+        }
+
+
+        internal void Fade(SpriteBatch batch, float deltaf)
+        {
+            if (progR > 0 || progG > 0 || progB > 0)
+            {
+                if (!recorded)
+                {
+                    rR = (0 - color.R) / 1f;
+                    rG = (0 - color.G) / 1f;
+                    rB = (0 - color.B) / 1f;
+                    rA = (0 - color.A) / 1f;
+                    recorded = true;
+                }
+
+                progR += rR * deltaf;
+                progR = Math.Max(progR, 0);
+                progG += rG * deltaf;
+                progG = Math.Max(progG, 0);
+                progB += rB * deltaf;
+                progB = Math.Max(progB, 0);
+                progA += rA * deltaf;
+                progA = Math.Max(progA, 0);
+                color.R = (byte)progR;
+                color.G = (byte)progG;
+                color.B = (byte)progB;
+                color.A = (byte)progA;
+            }
+            batch.Draw(curtain, curtainSize, color);
+        }
+
+        public void Dispose()
+        {
+            curtain.Dispose();
+        }
+    }
+}