Handles converting between 1D, 2D, and 3D indexes

PackedConvert.cs

public readonly struct BitData {
    public readonly int Size;
    public readonly int BitSize;
    public readonly int BitSizePow2;
    public readonly int BitMask;
    
    public BitData(uint size) {
        BitSize = (int)Mathf.Sqrt(size);
        Size = 1 << BitSize;
        BitSizePow2 = BitSize * 2;
        BitMask = Size - 1;
    }
}

public static class PackedConvert {
    public static Vector2Int Convert1Dto2D(BitData bitData, int index1D) {
        return new Vector2Int(
            index1D & bitData.BitMask,
            (index1D >> bitData.BitSize) & bitData.BitMask
        );
    }

    public static Vector3Int Convert1Dto3D(BitData bitData, int index1D) {
        return new Vector3Int(
            (index1D >> bitData.BitSizePow2) & bitData.BitMask,
            (index1D >> bitData.BitSize) & bitData.BitMask,
            index1D & bitData.BitMask
        );
    }

    public static Vector3Int Convert1Dto3D(int index1D, int maxX, int maxY) {
        return new Vector3Int(
            index1D % maxX,
            (index1D / maxX) % maxY,
            index1D / (maxX * maxY)
        );
    }

    public static int Convert2Dto1D(BitData bitData, Vector2Int index2D) {
        return index2D.x | index2D.y << bitData.BitSize;
    }

    public static int Convert3Dto1D(BitData bitData, Vector3Int index3D) {
        return index3D.z | (index3D.y << bitData.BitSize) | (index3D.x << bitData.BitSizePow2);
    }

    public static int Convert3Dto1D(Vector3Int index3D, int size) {
        return index3D.x + index3D.y * size + index3D.z * size * size;
    }
}