EightBitNet/LR35902/CharacterDefinition.cs

// <copyright file="CharacterDefinition.cs" company="Adrian Conlon">
// Copyright (c) Adrian Conlon. All rights reserved.
// </copyright>
namespace EightBit.GameBoy
{
    public sealed class CharacterDefinition
    {
        private readonly Ram vram;
        private readonly ushort address;

        public CharacterDefinition(Ram vram, ushort address)
        {
            this.vram = vram;
            this.address = address;
        }

        public int[] Get(int row)
        {
            var returned = new int[8];

            var planeAddress = (ushort)(this.address + (row * 2));

            var planeLow = this.vram.Peek(planeAddress);
            var planeHigh = this.vram.Peek(++planeAddress);

            for (var bit = 0; bit < 8; ++bit)
            {
                var mask = 1 << bit;

                var bitLow = (planeLow & mask) != 0 ? 1 : 0;
                var bitHigh = (planeHigh & mask) != 0 ? 0b10 : 0;

                returned[7 - bit] = bitHigh | bitLow;
            }

            return returned;
        }
    }
}