# 贪食蛇 > 原文： [http://zetcode.com/gui/vbwinforms/nibbles/](http://zetcode.com/gui/vbwinforms/nibbles/) 在 Mono Winforms 编程教程的这一部分中，我们将创建贪食蛇游戏克隆。 ## 贪食蛇游戏 贪食蛇是较旧的经典视频游戏。 它最初是在 70 年代后期创建的。 后来它被带到 PC 上。 在这个游戏中，玩家控制蠕虫。 目的是尽可能多地吃苹果。 蠕虫每次吃一个苹果，它的身体就会长大。 它必须避开墙壁和自己的身体。 ## 开发 蠕虫每个关节的大小为 10 像素。 蠕虫由光标键控制。 最初，蠕虫具有三个关节。 通过按下光标键之一开始游戏。 如果游戏结束，我们将在棋盘中间显示`Game Over`消息。 `board.vb` ```vb Imports System Imports System.Collections Imports System.ComponentModel Imports System.Drawing Imports System.Data Imports System.Windows.Forms NameSpace BoardSpace public class Board Inherits UserControl Const WIDTH As Integer = 300 Const HEIGHT As Integer = 300 Const DOT_SIZE As Integer = 10 Const ALL_DOTS As Integer = 900 Const RAND_POS As Integer = 27 Const DELAY As Integer = 140 Dim x(ALL_DOTS) As Integer Dim y(ALL_DOTS) As Integer Dim dots As Integer Dim apple_x As Integer Dim apple_y As Integer Dim left As Boolean = False Dim right As Boolean = True Dim up As Boolean = False Dim down As Boolean = False Dim inGame As Boolean = True Private Dim timer As Timer Private Dim dot As Bitmap Private Dim apple As Bitmap Private Dim head As Bitmap Private Dim components As IContainer Public Dim BORDER_WIDTH As Integer Public Dim TITLEBAR_HEIGHT As Integer Public Sub New components = New Container Me.BackColor = Color.Black Me.DoubleBuffered = True Me.ClientSize = New Size(WIDTH, HEIGHT) Try dot = New Bitmap("dot.png") apple = New Bitmap("apple.png") head = New Bitmap("head.png") Catch e As Exception Console.WriteLine(e.Message) Environment.Exit(1) End Try Me.InitGame End Sub Private Sub InitGame dots = 3 For z As Integer = 0 To dots-1 x(z) = 50 - z*10 y(z) = 50 Next Me.LocateApple AddHandler Me.KeyUp, AddressOf Me.OnKeyUp timer = New Timer(Me.components) timer.Enabled = True timer.Interval = DELAY AddHandler timer.Tick, AddressOf Me.OnTick AddHandler Me.Paint, AddressOf Me.OnPaint End Sub Private Sub OnPaint(ByVal sender As Object, _ ByVal e As PaintEventArgs) Dim g As Graphics = e.Graphics If inGame Me.DrawObjects(g) Else Me.GameOver(g) End If End Sub Private Sub DrawObjects(ByVal g As Graphics) g.DrawImage(apple, apple_x, apple_y) For z As Integer = 0 To dots-1 If z = 0 g.DrawImage(head, x(z), y(z)) Else g.DrawImage(dot, x(z), y(z)) End If Next End Sub Private Sub GameOver(ByVal g As Graphics) Dim msg As String = "Game Over" Dim rectF As RectangleF = RectangleF.op_Implicit(Me.ClientRectangle) Dim format As New StringFormat format.Alignment = StringAlignment.Center format.LineAlignment = StringAlignment.Center g.DrawString(msg, Font, Brushes.White, rectF , format) timer.Stop End Sub Private Sub CheckApple If x(0) = apple_x And y(0) = apple_y dots += 1 Me.LocateApple End If End Sub Private Sub Move For z As Integer = dots To 1 Step -1 x(z) = x(z - 1) y(z) = y(z - 1) Next If left x(0) -= DOT_SIZE End If If right x(0) += DOT_SIZE End If If up y(0) -= DOT_SIZE End If If down y(0) += DOT_SIZE End If End Sub Private Sub CheckCollision For z As Integer = dots To 1 Step -1 If z > 4 And x(0) = x(z) And y(0) = y(z) inGame = False End If Next If y(0) >= HEIGHT - DOT_SIZE - TITLEBAR_HEIGHT inGame = False End If If y(0) < 0 inGame = False End If If x(0) >= WIDTH - DOT_SIZE - BORDER_WIDTH: inGame = False End If If x(0) < 0 inGame = False End If End Sub Private Sub LocateApple Dim rand As New Random Dim r As Integer = rand.Next(RAND_POS) apple_x = r * DOT_SIZE r = rand.Next(RAND_POS) apple_y = r * DOT_SIZE End Sub Private Sub OnTick(ByVal sender As Object, ByVal e As EventArgs) If inGame Me.CheckApple Me.CheckCollision Me.Move End If Me.Refresh End Sub Private Sub OnKeyUp(ByVal sender As Object, ByVal e As KeyEventArgs) Dim key As Integer = e.KeyCode If key = Keys.Left And Not right left = True up = False down = False End If If key = Keys.Right And Not left right = True up = False down = False End If If key = Keys.Up And Not down up = True right = False left = False End if If key = Keys.Down And Not up down = True right = False left = False End If End Sub End Class End Namespace ``` 首先，我们将定义游戏中使用的常量。 `WIDTH`和`HEIGHT`常数确定电路板的大小。 `DOT_SIZE`是苹果的大小和蠕虫的点。 `ALL_DOTS`常数定义了板上可能的最大点数。 （`900 = 300 * 300 / 10 * 10`）`RAND_POS`常数用于计算苹果的随机位置。 `DELAY`常数确定游戏的速度。 ```vb Dim x(ALL_DOTS) As Integer Dim y(ALL_DOTS) As Integer ``` 这两个数组存储蠕虫的所有关节的 x，y 坐标。 在`Move`方法中，我们有游戏的关键算法。 要了解它，请查看蠕虫如何移动。 您控制蠕虫的头部。 您可以使用光标键更改其方向。 其余关节在链上向上移动一个位置。 第二关节移动到第一个关节的位置，第三关节移动到第二个关节的位置，依此类推。 ```vb For z As Integer = dots To 1 Step -1 x(z) = x(z - 1) y(z) = y(z - 1) Next ``` 该代码将关节向上移动。 ```vb If left x(0) -= DOT_SIZE End If ``` 将头向左移动。 在`CheckCollision`方法中，我们确定蠕虫是否已经击中自己或撞墙之一。 ```vb For z As Integer = dots To 1 Step -1 If z > 4 And x(0) = x(z) And y(0) = y(z) inGame = False End If Next ``` 如果蠕虫用头撞到关节之一，就结束游戏。 ```vb If y(0) >= HEIGHT - DOT_SIZE - TITLEBAR_HEIGHT inGame = False End If ``` 如果蠕虫到达了棋盘的底部，我们就结束了游戏。 下图有助于了解蠕虫对象与板子底部的碰撞。  图：碰撞 `locateApple`方法在表格上随机定位一个苹果。 ```vb Dim rand As New Random Dim r As Integer = rand.Next(RAND_POS) ``` 我们得到一个从 0 到`RAND_POS-1`的随机数。 ```vb apple_x = r * DOT_SIZE ... apple_y = r * DOT_SIZE ``` 这些行设置了`apple`对象的 x，y 坐标。 在`OnKeyUp`方法中，我们确定了键击玩家击键的时间。 ```vb If key = Keys.Left And Not right left = True up = False down = False End If ``` 如果我们按左光标键，则将`left`变量设置为`True`。 在`Move`方法中使用此变量来更改蠕虫对象的坐标。 还要注意，当蠕虫向右移动时，我们不能立即向左转。 `nibbles.vb` ```vb ' ZetCode Mono Visual Basic Winforms tutorial ' ' In this program, we create ' a Nibbles game clone ' ' author jan bodnar ' last modified May 2009 ' website www.zetcode.com Imports System Imports System.Drawing Imports System.Windows.Forms Public Class WinVBApp Inherits Form Public Sub New Me.Text = "Nibbles" Me.FormBorderStyle = FormBorderStyle.FixedSingle Dim borderWidth As Integer = (Me.Width - Me.ClientSize.Width) / 2 Dim titleBarHeight As Integer = Me.Height - Me.ClientSize.Height - borderWidth Dim board As New BoardSpace.Board board.BORDER_WIDTH = borderWidth board.TITLEBAR_HEIGHT = titleBarHeight Me.Controls.Add(board) Me.CenterToScreen End Sub Public Shared Sub Main Application.Run(New WinVBApp) End Sub End Class ``` 这是主要的类。  图：贪食蛇 这是使用 Mono Winforms 库和 Visual Basic 语言编写的贪食蛇游戏。