零基础VB教程067期：贪吃蛇游戏开发第三节 撞墙会挂的

Private Type Node '每一节蛇身
    D As Integer '37左38上39右40下
    X As Single 'left
    Y As Single 'top
End Type
Dim W As Integer '每一节蛇身宽度
Dim sno() As Node '声明一条蛇，是动态数组
Dim currentDirect As Integer '代表蛇运动的当前方向

Private WithEvents timer1 As Timer
'初始化一条蛇的各个参数
Function init()
AutoRedraw = True '自动重绘
W = 200
currentDirect = 39 '默认向右运动
ReDim sno(5) As Node

'初始化各个坐标点
Dim i As Long
For i = 0 To UBound(sno) Step 1

    sno(i).D = currentDirect
    sno(i).X = ScaleWidth / 2 + i * W
    sno(i).Y = ScaleHeight / 2
Next i


End Function


'画一条蛇
Function drawSnake()
Cls
Dim i As Long

For i = 0 To UBound(sno) Step 1

    Line (sno(i).X, sno(i).Y)-(sno(i).X + W, sno(i).Y + W), vbBlue, BF

Next i

End Function

Private Sub Form_KeyUp(KeyCode As Integer, Shift As Integer)
If Abs(currentDirect - KeyCode) <> 2 Then currentDirect = KeyCode
End Sub

Private Sub Form_Load()
Call init
Call drawSnake

'对时钟控件进行初始化
Set timer1 = Controls.Add("vb.timer", "timer1")
timer1.Interval = 100
timer1.Enabled = True

End Sub

'运动思路：插入头结点，删除尾节点
Function sport()

Dim i As Long
'将每一个节点数据向前移动一位
For i = 1 To UBound(sno) Step 1
    
    sno(i - 1) = sno(i)
    
Next i

'将头结点，也就是数组的最后一位重新复制
If currentDirect = 37 Then
    sno(UBound(sno)).X = sno(UBound(sno)).X - W
ElseIf currentDirect = 38 Then
    sno(UBound(sno)).Y = sno(UBound(sno)).Y - W
ElseIf currentDirect = 39 Then
    sno(UBound(sno)).X = sno(UBound(sno)).X + W
ElseIf currentDirect = 40 Then
    sno(UBound(sno)).Y = sno(UBound(sno)).Y + W
End If

End Function

Private Sub timer1_Timer()
Call sport
Call drawSnake
'判断是否撞到窗体边缘
If isCrashWall Then
    If MsgBox("GAME OVER ！是否重新开始？", vbYesNo, "游戏结束") = vbYes Then
        Call init
    Else
        End
    End If
End If
End Sub

'是否撞到窗体边缘，撞到返回true，否则就是false
Function isCrashWall() As Boolean

isCrashWall = False

If sno(UBound(sno)).X + W > ScaleWidth _
  Or sno(UBound(sno)).X < 0 _
  Or sno(UBound(sno)).Y < 0 _
  Or sno(UBound(sno)).Y + W > ScaleHeight Then
    isCrashWall = True '撞到了
End If

End Function