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 texture to use for this atlas
///
public readonly Texture2D Texture;
///
/// 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;
///
/// 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, new Point(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 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.Texture = texture;
this.RegionAmountX = regionAmountX;
this.RegionAmountY = regionAmountY;
this.RegionWidth = texture.Width / regionAmountX;
this.RegionHeight = texture.Height / regionAmountY;
}
private TextureRegion GetOrAddRegion(Rectangle rect) {
if (this.regions.TryGetValue(rect, out var region))
return region;
region = new TextureRegion(this.Texture,
rect.X * this.RegionWidth, rect.Y * this.RegionHeight,
rect.Width * this.RegionWidth, rect.Height * this.RegionHeight);
this.regions.Add(rect, region);
return region;
}
}
}