experiments-monogame/UPWG/UPWG.Main/Animation.cs

using System;
using System.IO;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Elite;

namespace UPWG.Main
{
    internal enum MovementType
    {
        Run,
        Jump,
        Flip,
    }

    internal enum RingPosition
    {
        // these use cardinal directions (picture a compass rose laid over the ring)
        // they will be flipped when animations are reversed
        SouthWest,
        West,
        NorthWest,
        North,
        NorthEast,
        East,
        SouthEast,
        South,
        Center,
    }

    abstract class BattleAnimation
    {
        protected double ElapsedSeconds;
        protected readonly double RunSeconds;

        protected BattleAnimation(double runSeconds)
        {
            ElapsedSeconds = 0;
            RunSeconds = runSeconds;
        }

        public bool Done()
        {
            return ElapsedSeconds > RunSeconds;
        }

        public abstract void Update(double elapsed, ref Vector2 pos, ref float rotation);
    }

    class Run : BattleAnimation
    {
        private Vector2 _start;
        private Vector2 _end;

        public Run(double runSeconds, RingPosition from, RingPosition to) : base(runSeconds)
        {
            _start = RingPositionToVector2(from);
            _end = RingPositionToVector2(to);
        }

        public override void Update(double elapsed, ref Vector2 pos, ref float rotation)
        {
            ElapsedSeconds += elapsed;
            pos = Vector2.Lerp(_start, _end, (float) (ElapsedSeconds / RunSeconds));
        }

        private const float EastRopesX = 200;
        private const float WestRopesX = 500;
        private const float CenterX = (EastRopesX + WestRopesX) / 2;
        private const float NorthRopesY = 100;
        private const float SouthRopesY = 300;
        private const float CenterY = (NorthRopesY + SouthRopesY) / 2;

        public static Vector2 RingPositionToVector2(RingPosition position)
        {
            return position switch
            {
                RingPosition.North => new Vector2(CenterX, NorthRopesY),
                RingPosition.NorthEast => new Vector2(EastRopesX, NorthRopesY),
                RingPosition.East => new Vector2(EastRopesX, CenterY),
                RingPosition.SouthEast => new Vector2(EastRopesX, SouthRopesY),
                RingPosition.South => new Vector2(CenterX, SouthRopesY),
                RingPosition.SouthWest => new Vector2(WestRopesX, SouthRopesY),
                RingPosition.West => new Vector2(WestRopesX, CenterY),
                RingPosition.NorthWest => new Vector2(WestRopesX, NorthRopesY),
                RingPosition.Center => new Vector2(CenterX, CenterY),
                _ => throw new ArgumentOutOfRangeException(nameof(position))
            };
        }
    }

    class Spin : BattleAnimation
    {
        private float _angleFrom;
        private float _angleTo;

        public Spin(double runSeconds, float angleFrom, float angleTo) : base(runSeconds)
        {
            _angleFrom = angleFrom;
            _angleTo = angleTo;
        }

        public override void Update(double elapsed, ref Vector2 pos, ref float rotation)
        {
            ElapsedSeconds += elapsed;
            rotation = MathHelper.Lerp(_angleFrom, _angleTo, (float) (ElapsedSeconds / RunSeconds));
        }
    }

    public class BattleSprite : IBatchDrawable
    {
        private const int Width = 128;
        private const int Height = 128;

        private Texture2D _texture;
        private Vector2 _origin;
        private Vector2 _pos;
        private float _rotation;
        private BattleAnimation[] _animations;
        private int _animationNum;

        public BattleSprite(GraphicsDevice graphicsDevice, string filename)
        {
            var fileStream = new FileStream("Content/jason.jpg", FileMode.Open);
            _texture = Texture2D.FromStream(graphicsDevice, fileStream);
            fileStream.Dispose();

            _pos = new Vector2(100, 200);
            _origin = new Vector2(_texture.Width / 2, _texture.Height / 2);

            _animations = new BattleAnimation[]
            {
                new Run(1, RingPosition.West, RingPosition.East),
                new Run(1, RingPosition.East, RingPosition.West),
                //new Run(1, RingPosition.West, RingPosition.East),
                //new Run(1, RingPosition.East, RingPosition.Center),
                //new Run(0.2, RingPosition.Center, RingPosition.Center),
                new Spin(4, 0, 3.14f),
            };
            _animationNum = 0;
        }

        public void Update(double elapsedSeconds)
        {
            if (_animationNum < _animations.Length)
            {
                _animations[_animationNum].Update(elapsedSeconds, ref _pos, ref _rotation);
                if (_animations[_animationNum].Done())
                    _animationNum += 1;
            }
        }


        public void Draw(SpriteBatch batch)
        {
            batch.Draw(_texture, new Rectangle((int) _pos.X, (int) _pos.Y, Width, Height), null, Color.White,
                _rotation, _origin, SpriteEffects.None, 0);
        }
    }
}