SpriteGridSplitter.cs

// ReSharper disable PossibleLossOfFraction

using JetBrains.Annotations;
using UnityEngine;

namespace Kogane
{
    /// <summary>
    /// スプライトをグリッド上に分割して返すクラス
    /// </summary>
    public static class SpriteGridSplitter
    {
        //================================================================================
        // 関数(static)
        //================================================================================
        /// <summary>
        /// スプライトをグリッド上に分割して返します
        /// </summary>
        [MustUseReturnValue]
        public static Sprite[] Split
        (
            Sprite         sprite,
            int            column,
            int            row,
            SpriteMeshType meshType,
            float?         overridePixelsPerUnit = null
        )
        {
            var count         = column * row;
            var texture       = sprite.texture;
            var width         = texture.width;
            var height        = texture.height;
            var unitWidth     = ( float )width / column;
            var unitHeight    = ( float )height / row;
            var pivot         = sprite.pivot;
            var pixelsPerUnit = sprite.pixelsPerUnit;
            var sprites       = new Sprite[ count ];
            var spriteCount   = sprites.Length;

            for ( var i = 0; i < spriteCount; i++ )
            {
                var rect = new Rect
                (
                    x: unitWidth * ( i % column ),
                    y: unitHeight * ( row - 1 - i / column ),
                    width: unitWidth,
                    height: unitHeight
                );

                sprites[ i ] = Sprite.Create
                (
                    texture: texture,
                    rect: rect,
                    pivot: pivot / new Vector2( width, height ),
                    pixelsPerUnit: overridePixelsPerUnit ?? pixelsPerUnit,
                    extrude: 0,
                    meshType: meshType
                );
            }

            return sprites;
        }
    }
}