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

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using RhythmBullet.Zer01HD.Utilities.UI;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace RhythmBullet.Zer01HD.Game.Screens.Transitions
{
    internal class FadeInTransition : IDisposable
    {
        private const float RATE = 0.3f;
        public readonly Texture2D curtain;
        public Rectangle curtainSize;
        private Color color;
        private float progR, progG, progB, progA;
        private  float rR, rG, rB, rA;
        internal FadeInTransition(GraphicsDevice graphicsDevice, Color startColor)
        {
            curtain = new Texture2D(graphicsDevice, 1, 1);
            curtain.SetData(new[] { Color.White });

            color = startColor;
        }

        internal void Init(Rectangle dimensions)
        {
            curtainSize = dimensions;
            rR = (0 - color.R) / RATE;
            rG = (0 - color.G) / RATE;
            rB = (0 - color.B) / RATE;
            rA = (0 - color.A) / RATE;

            progA = color.A;
            progR = color.R;
            progG = color.G;
            progB = color.B;
        }

        internal bool Fade(float deltaf)
        {
            if (progR > 0 || progG > 0 || progB > 0)
            {
                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;
                return false;
            }
            return false;
        }

        internal void Draw(SpriteBatch batch)
        {
            if (curtain != null)
            {
                batch.Draw(curtain, curtainSize, color);
            }
        }

        public void Dispose()
        {
            curtain.Dispose();
        }
    }
}