recrownedathenaeum/RecrownedAthenaeum/DataTypes/TextureAtlas.cs

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using System;
using System.Collections.Generic;

namespace RecrownedAthenaeum.DataTypes
{
    /// <summary>
    /// Holds information about an image file that contains various textures in various regions in the file.
    /// </summary>
    public class TextureAtlas
    {
        private Texture2D texture;

        private Dictionary<string, TextureAtlasRegion> dictionaryOfRegions = new Dictionary<string, TextureAtlasRegion>();
        
        /// <summary>
        /// Given a name, can return a <see cref="TextureAtlasRegion"/>.
        /// </summary>
        /// <param name="name">Name of <see cref="TextureAtlasRegion"/> to obtain.</param>
        /// <returns><see cref="TextureAtlasRegion"/> based off name.</returns>
        public TextureAtlasRegion this[string name] { get { if (name != null && dictionaryOfRegions.ContainsKey(name)) return dictionaryOfRegions[name]; else return null; } }

        /// <summary>
        /// Creates a texture atlas with given main texture as well as an array of <see cref="TextureAtlasRegion"/> to represent locations of which textures reside within the atlas. Region names will be used to refer to the regions within the dictionary.
        /// </summary>
        /// <param name="texture">The texture representing the overall atlas.</param>
        /// <param name="regions">The sub regions that represent the individual textures.</param>
        public TextureAtlas(Texture2D texture, TextureAtlasRegion[] regions)
        {
            this.texture = texture;
            foreach (TextureAtlasRegion region in regions)
            {
                dictionaryOfRegions.Add(region.name, region);
            }
        }

        /// <summary>
        /// Creates a texture region given a dictionary of regions keyed to strings that can be used to refer to them.
        /// </summary>
        /// <param name="texture">The texture representing the overall atlas.</param>
        /// <param name="dictionaryOfRegions"></param>
        public TextureAtlas(Texture2D texture, Dictionary<string, TextureAtlasRegion> dictionaryOfRegions)
        {
            this.texture = texture;
            this.dictionaryOfRegions = dictionaryOfRegions;
        }

        /// <summary>
        /// Draw the region given by a string in the atlas onto a destination rectangle.
        /// </summary>
        /// <param name="name">Name of region to draw.</param>
        /// <param name="batch">SpriteBatch to be used.</param>
        /// <param name="destination">The location to draw this region.</param>
        /// <param name="color">Color to use.</param>
        /// <param name="rotation">Rotation of texture drawn.</param>
        /// <param name="origin">Origin used by rotation.</param>
        public void Draw(string name, SpriteBatch batch, Rectangle destination, Color color = default(Color), float rotation = 0, Vector2 origin = new Vector2())
        {
            dictionaryOfRegions[name].Draw(batch, destination, color, rotation, origin);
        }

        /// <summary>
        /// Creates or obtains a previously created texture of a region.
        /// </summary>
        /// <param name="name">Name of region.</param>
        /// <param name="graphicsDevice">graphics device to be used.</param>
        /// <returns>The texture from the region.</returns>
        public Texture2D ObtainRegionAsTexture(string name, GraphicsDevice graphicsDevice)
        {
            return dictionaryOfRegions[name].AsTexture2D(graphicsDevice);
        }

        /// <summary>
        /// A region of a <see cref="TextureAtlas"/>.
        /// </summary>
        public class TextureAtlasRegion : IComparable<TextureAtlasRegion>, ISpecialDrawable, IDisposable
        {
            /// <summary>
            /// The name of the region. Mostly used to be refered to within the context of a <see cref="TextureAtlas"/>.
            /// </summary>
            public readonly string name;
            /// <summary>
            /// The location and dimensions of where the original texture resides on the texture representing the atlas.
            /// </summary>
            public readonly Rectangle sourceRectangle;
            readonly NinePatch ninepatch;
            Texture2D atlasTexture;
            Texture2D regionTexture;
            private bool disposed;

            /// <summary>
            /// A specified region in a texture atlas.
            /// </summary>
            /// <param name="name">Name of region.</param>
            /// <param name="sourceRegion">The location of the region on the atlas.</param>
            /// <param name="ninePatch">A <see cref="NinePatch"/> definition for the region.</param>
            /// <param name="atlasTexture">The texture that holds the image data for the atlas.</param>
            public TextureAtlasRegion(string name, Rectangle sourceRegion, NinePatch ninePatch, Texture2D atlasTexture)
            {
                this.atlasTexture = atlasTexture ?? throw new ArgumentNullException("Name parameters can be null.");
                this.name = name ?? throw new ArgumentNullException("Name parameters can be null.");
                this.sourceRectangle = sourceRegion;
                this.ninepatch = ninePatch;
            }

            /// <summary>
            /// Draws the region. If ninepatch, rotation and origin are ignored.
            /// </summary>
            /// <param name="batch">The batch to use. Should be began.</param>
            /// <param name="destination">The destination rectangle to draw to.</param>
            /// <param name="color">The color to use.</param>
            /// <param name="rotation">Rotation of the final drawing. Ignored if is a 9patch.</param>
            /// <param name="origin">The origin of the drawing. Ignored if is a 9patch.</param>
            public void Draw(SpriteBatch batch, Rectangle destination, Color color, float rotation = 0, Vector2 origin = default(Vector2))
            {
                if (disposed) throw new ObjectDisposedException(GetType().Name);

                if (ninepatch != null)
                {
                    ninepatch.Draw(batch, destination);
                } else
                {
                    batch.Draw(atlasTexture, destination, sourceRectangle, color, rotation, origin, SpriteEffects.None, 0f);
                }
            }

            /// <summary>
            /// Create or obtains a previously created texture of this region.
            /// </summary>
            /// <param name="graphicsDevice">The graphics device to use to create the texture.</param>
            /// <returns>The texture of the region.</returns>
            public Texture2D AsTexture2D(GraphicsDevice graphicsDevice)
            {
                if (disposed) throw new ObjectDisposedException(GetType().Name);

                if (regionTexture == null)
                {
                    Color[] data = new Color[sourceRectangle.Width * sourceRectangle.Height];
                    regionTexture = new Texture2D(graphicsDevice, sourceRectangle.Width, sourceRectangle.Height);
                    atlasTexture.GetData(0, sourceRectangle, data, 0, sourceRectangle.Width * sourceRectangle.Height);
                    regionTexture.SetData(data);
                }
                return regionTexture;
            }

            /// <summary>
            /// Compares this region to another in terms of name.
            /// </summary>
            /// <param name="other">The other region to compare to in terms of name.</param>
            /// <returns>Less than one if precedes, greater than one if after, 0 if same.</returns>
            public int CompareTo(TextureAtlasRegion other)
            {
                return name.CompareTo(other);
            }

            /// <summary>
            /// Call this to dispose.
            /// </summary>
            public void Dispose()
            {
                if (disposed) throw new ObjectDisposedException(GetType().Name);
                Dispose(true);
                GC.SuppressFinalize(this);
            }

            /// <summary>
            /// Overridable dispose.
            /// </summary>
            /// <param name="disposing">Whether or not this was a user made call.</param>
            public virtual void Dispose(bool disposing)
            {
                if (disposing && !disposed)
                {
                    regionTexture?.Dispose();
                }
                disposed = true;
            }
            
            /// <summary>
            /// Destructor.
            /// </summary>
            ~TextureAtlasRegion()
            {
                Dispose(false);
            }
        }
    }
}