Tetris/ViewsModels/GameViewModel.cs

using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Threading;
using Tetris.Models;
using Color = System.Drawing.Color;

namespace Tetris.ViewsModels;

public class GameViewModel : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler? PropertyChanged;
    
    private const int RendererHertz = 5;
    private const int GameRendererHertz = (1 / RendererHertz) * 1000;
    private const int Width = 25;
    private const int Height = 50;
    private readonly WriteableBitmap _writeableBitmap;

    private const int GridWidth = 25;
    private const int GridHeight = 50;
    private static readonly Grid Grid = new(new Color[GridWidth, GridHeight]);
    private readonly Tetrominoe _currentTetrominoe = new(Grid, "J", new Point(25 / 2, 0), 0, Color.Aqua);

    public GameViewModel()
    {
        _writeableBitmap = BitmapFactory.New(Width, Height);
        
        var dispatcherRenderTimer = new DispatcherTimer
        {
            Interval = new TimeSpan(0, 0, 0, 0, GameRendererHertz)
        };
        
        dispatcherRenderTimer.Tick += Render;
        dispatcherRenderTimer.Start();
        
        var dispatcherUpdateTimer = new DispatcherTimer
        {
            Interval = new TimeSpan(0, 0, 0, 0, 100)
        };
        
        dispatcherUpdateTimer.Tick += Update;
        dispatcherUpdateTimer.Start();
    }
    
    public ImageSource Source => _writeableBitmap;
    public Tetrominoe CurrentTetrominoe => _currentTetrominoe;

    private void Render(object? sender, EventArgs eventArgs)
    {
        _writeableBitmap.Lock();
        _writeableBitmap.Clear(Colors.Black);

        for (var x = 0; x < GridWidth; x++)
        {
            for (var y = 0; y < GridHeight; y++)
            {
                var color = Grid.CGrid[x, y];
                _writeableBitmap.SetPixel(x, y, color.R, color.G, color.B);
            }
        }

        var tetrominoeWidth = _currentTetrominoe.Shape.GetLength(0);
        var tetrominoeHeight = _currentTetrominoe.Shape.GetLength(1);

        for (int x = 0; x < tetrominoeWidth; x++)
        {
            for (int y = 0; y < tetrominoeHeight; y++)
            {
                if (!_currentTetrominoe.Shape[x, y]) continue;
                var color = _currentTetrominoe.Color;
                _writeableBitmap.SetPixel(_currentTetrominoe.Coordinates.X + x, _currentTetrominoe.Coordinates.Y + y, color.R, color.G, color.B);
            }
        }

        _writeableBitmap.Unlock();
    }
    
    private void Update(object? sender, EventArgs eventArgs)
    {
        _currentTetrominoe.GoDown();
    }
}