using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using MLEM.Misc;
namespace MLEM.Textures {
///
/// This class represents an atlas of objects that is uniform.
/// Uniform, in this case, means that the texture atlas' size is not determined by the width and height of the texture, but instead by the amount of sub-regions that the atlas has in the x and y direction.
/// Using a uniform texture atlas over a regular texture as an atlas allows for texture artists to create higher resolution textures without coordinates becoming off.
///
public class UniformTextureAtlas : GenericDataHolder {
///
/// The that this uniform texture atlas uses as its basis.
/// In most cases, has the full area of the underlying .
///
public readonly TextureRegion Region;
///
/// The amount of sub-regions this atlas has in the x direction
///
public readonly int RegionAmountX;
///
/// The amount of sub-regions this atlas has in the y direction
///
public readonly int RegionAmountY;
///
/// The width of each region, based on the texture's width and the amount of regions
///
public readonly int RegionWidth;
///
/// The height of reach region, based on the texture's height and the amount of regions
///
public readonly int RegionHeight;
///
/// The texture to use for this atlas.
/// Note that stores the actual area that we depend on.
///
public Texture2D Texture => this.Region.Texture;
///
/// Returns the at this texture atlas's given index.
/// The index is zero-based, where rows come first and columns come second.
///
/// The zero-based texture index
public TextureRegion this[int index] => this[index % this.RegionAmountX, index / this.RegionAmountX];
///
/// Returns the at this texture atlas' given region position
///
/// The region's x and y location
public TextureRegion this[Point point] => this[new Rectangle(point.X, point.Y, 1, 1)];
///
public TextureRegion this[int x, int y] => this[new Point(x, y)];
///
/// Returns the at this texture atlas' given region position and size.
/// Note that the region size is not in pixels, but in region units.
///
/// The region's area
public TextureRegion this[Rectangle rect] => this.GetOrAddRegion(rect);
///
public TextureRegion this[int x, int y, int width, int height] => this[new Rectangle(x, y, width, height)];
private readonly Dictionary regions = new Dictionary();
///
/// Creates a new uniform texture atlas with the given texture region and region amount.
/// This atlas will only ever pull information from the given and never exit the region's bounds.
///
/// The texture region to use for this atlas
/// The amount of texture regions in the x direction
/// The amount of texture regions in the y direction
public UniformTextureAtlas(TextureRegion region, int regionAmountX, int regionAmountY) {
this.Region = region;
this.RegionAmountX = regionAmountX;
this.RegionAmountY = regionAmountY;
this.RegionWidth = region.Width / regionAmountX;
this.RegionHeight = region.Height / regionAmountY;
}
///
/// Creates a new uniform texture atlas with the given texture and region amount.
///
/// The texture to use for this atlas
/// The amount of texture regions in the x direction
/// The amount of texture regions in the y direction
public UniformTextureAtlas(Texture2D texture, int regionAmountX, int regionAmountY) : this(new TextureRegion(texture), regionAmountX, regionAmountY) {}
private TextureRegion GetOrAddRegion(Rectangle rect) {
if (this.regions.TryGetValue(rect, out var region))
return region;
region = new TextureRegion(this.Region,
rect.X * this.RegionWidth, rect.Y * this.RegionHeight,
rect.Width * this.RegionWidth, rect.Height * this.RegionHeight);
this.regions.Add(rect, region);
return region;
}
}
}