Help With Pixel Scanning

Public Class Form1

Private _targetColor As Color '' yay for global variables
Private _screenShot As Bitmap = New Bitmap(Screen.PrimaryScreen.WorkingArea.Width, Screen.PrimaryScreen.WorkingArea.Height) '' no dual monitor support here
Private _forceStop As Boolean = False '' thread loop control
Private _isRunning As Boolean = False '' thread loop control
Private _wThread As Threading.Thread '' background worker thread

Private Sub cmdSetColor_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSetColor.Click
_targetColor = modPublic.GetPixelColor(Cursor.Position.X, Cursor.Position.Y)
Panel1.BackColor = _targetColor ''update gui so user can see the color
lblScanColorRGB.Text = "rgb " & _targetColor.R & ", " & _targetColor.G & ", " & _targetColor.B '' should call .ToString() on them : too long/verbose.
End Sub

Private Sub cmdOnOff_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdOnOff.Click
If cmdOnOff.Text = "Turn On" Then
If _isRunning Then
MsgBox("Thread is still busy, please wait a moment for the thread to end and try again.")
Else
_forceStop = False '' sanity check
_isRunning = True
_wThread = New Threading.Thread(AddressOf BotOn)
_wThread.Start()
cmdOnOff.Text = "Turn Off"
End If
Else
_forceStop = True
cmdOnOff.Text = "Turn On"
End If
End Sub

Private Sub BotOn()
Do Until _forceStop = True
_screenShot = modPublic.GetScreenShot()
''loop over each pixel (left to right, top to bottom) and check for target color
Dim _tmpPixelColor As Color
For xx As Int32 = 1 To (_screenShot.Width - 1)
For yy As Int32 = 1 To (_screenShot.Height - 1)
_tmpPixelColor = _screenShot.GetPixel(xx, yy)
If _tmpPixelColor.R = _targetColor.R And _tmpPixelColor.G = _targetColor.G And _tmpPixelColor.B = _targetColor.B Then
''the pixel matches our color. Success.
Cursor.Position = New Point(xx, yy) ''move cursor to the color's location
Threading.Thread.Sleep(500) '' wait a moment because the game may store the cursor's position and it needs to be refreshed.
If chkBeep.Checked Then
Beep() '' single small beeping noise from pc's on-board speaker. why not.
End If

modPublic.LeftClick()
Threading.Thread.Sleep(CInt(numSleepTime.Value * 1000))
Continue Do
End If
Next
If _forceStop Then Exit For '' 1 line IF statment. awk but doesn't deserve 3 lines..
Next
Loop
_forceStop = False '' we left then loop because it was true, now set it back to false.
_isRunning = False
End Sub

Private Sub chkHideColorBox_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chkHideColorBox.CheckedChanged
Panel1.Visible = Not chkHideColorBox.Checked ' aka below
'If chkHideColorBox.Checked Then
'Panel1.Visible = False
'Else
'Panel1.Visible = True
'End If
End Sub


End Class

Module modPublic
''Windows API
Private Declare Function GetDesktopWindow Lib "user32" () As IntPtr
Private Declare Function GetPixel Lib "gdi32" (ByVal hDC As IntPtr, ByVal x As Integer, ByVal y As Integer) As Integer
Private Declare Function GetWindowDC Lib "user32" (ByVal hWnd As IntPtr) As IntPtr
Private Declare Function ReleaseDC Lib "user32" (ByVal hWnd As IntPtr, ByVal hDC As IntPtr) As Integer
Private Declare Function mouse_event Lib "user32" (ByVal dwflags As Integer, ByVal dx As Integer, ByVal dy As Integer, ByVal dwData As Integer, ByVal dwExtraInfo As Integer) As Boolean

Private Const mouse_leftDown As Integer = 2
Private Const mouse_leftUp As Integer = 4

Public Sub LeftClick()
mouse_event(mouse_leftDown, 0, 0, 0, 0) '' left click down
Threading.Thread.Sleep(250)
mouse_event(mouse_leftUp, 0, 0, 0, 0) '' left click release
End Sub
Public Function GetPixelColor(ByVal x As Int32, ByVal y As Int32) As Color
Dim hWnd As IntPtr = GetDesktopWindow()
Dim hDC As IntPtr = GetWindowDC(hWnd)
Dim lColor As Int32 = GetPixel(hDC, x, y)
ReleaseDC(hWnd, hDC)
Return System.Drawing.ColorTranslator.FromWin32(lColor) '' color struct is like 20+ bytes :/
End Function
Public Function GetScreenShot() As Bitmap
Dim _rtnBmp As New Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, System.Drawing.Imaging.PixelFormat.Format32bppRgb)
Dim _gr As Graphics = Graphics.FromImage(_rtnBmp)
_gr.CopyFromScreen(0, 0, 0, 0, Screen.PrimaryScreen.Bounds.Size, CopyPixelOperation.SourceCopy)
_gr.Dispose()
Return _rtnBmp
End Function
End Module