Detecting touch....

[CyberCarsten]

How can I detect if a picture touches a line on my form??

[ShIzO]

check the Games Programming Formum on this site!

[ExcalibursZone]

If the picture is dynamically resizing? If the line is moving? If the picture is moving?

You can always check against the positioning values of the objects (top, left, height, width) to determine if they are touching.

Here is a really quick example:

Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
    Select Case KeyCode
        Case 37
            Image1.Left = Image1.Left - Image1.Width
        Case 38
            Image1.Top = Image1.Top - Image1.Height
        Case 39
            Image1.Left = Image1.Left + Image1.Width
        Case 40
            Image1.Top = Image1.Top + Image1.Height
    End Select
    If Image1.Top + Image1.Height > Line1.Y1 Then
        Image1.Top = Line1.Y1 - Image1.Height
    End If
End Sub

To get this to work, on an empty form, place a line (straight line) across the form along the bottom somewhere. Put an Image on the form with a small graphic (I got mine from the common/graphics folder in visual studio).

You move the image around with your cursor keys. It cannot go past the line on the bottom of the form.

Keep in mind this is just a quick hack and doesn't take into account diagonal lines or if a line is above the image.

The properties you need to look for in the line are X1, X2, Y1, and Y2 which correspond to the beginning of the line (X1, Y1) and the end of the line (X2, Y2).

Hope this helps you out.

[CyberCarsten]

Thanx! I'll try it!

[CyberCarsten]

The code worked fine!
Is it possible to do the same, when I have a line that responds to keystrokes, which will jump to the center of the screen, if it touches the edges of the form??

[ExcalibursZone]

Well, it depends on if it is a verticle line or a horizontal line ... but yeah. Just check the X1, X2 and Y1, Y2 and if they hit the ScaleWidth then have them equal Int(ScaleWidth / 2)...

For instance:

    Select Case KeyCode
        Case 37
            Line1.X1 = Line1.X1 - 100
            Line1.X2 = Line1.X2 - 100
        Case 39
            Line1.X1 = Line1.X1 + 100
            Line1.X2 = Line1.X2 + 100
    End Select
    If Line1.X1 >= Me.ScaleWidth Or Line1.X1 <= 0 Then
        Line1.X1 = Int(Me.ScaleWidth / 2)
        Line1.X2 = Line1.X1
    End If

This effect makes a verticle line move left and right (only) and when it gets to the edge of the form, jump to the middle of the form. This looks at both the left and right of the form.

Forgot to add, if you want the line to go up and down the screen, check against ScaleHeight and Y1, Y2 ...

[Edited by ExcalibursZone on 11-03-2000 at 03:32 PM]

[CyberCarsten]

Hi again!
I'm making a game where, a line from the top of the screen falls down on a line that lies down in the bottom of the screen which have to catch the dropping line. When the bottom line catched the top line, the top line must go to the top again.
I have used this code to determine when the lines meet, but even if the two lines don't even meet, the top line goes to the top whenever it gets near the bottom line......

Could you tell me, what I am doing wrong??

Top line: Line2
Bottom line : Line1

Private Sub Timer1_Timer()
Line2.Y1 = Line2.Y1 + 120
Line2.Y2 = Line2.Y2 + 120

If Line1.Y1 = Line2.Y1 Then
Hs = Hs + 1
Score.Caption = "Score: " & Hs
    Timer1.Interval = 0
    Timer1.Enabled = False
    Line2.X1 = 4800
    Line2.X2 = 4800
    Line2.Y1 = 1200
    Line2.Y2 = 1080
    
    Timer1.Interval = 95
    Timer1.Enabled = True
End If
End Sub

[Edited by CyberCarsten on 11-04-2000 at 09:22 AM]

[ExcalibursZone]

change the line:

If Line1.Y1 = Line2.Y1 Then

To

If Line2.Y1 >= Line1.Y1 Then

This will test to make sure that if for some reason line 2 goes beyond line 1, it will trigger properly, of course, if your intent was to show a hit or a miss (miss = beyond) then you test for greater than after this statement, in the same if/then sequence.

[CyberCarsten]

That didn't work.....

What did you mean by this:

This will test to make sure that if for some reason line 2 goes beyond line 1, it will trigger properly, of course, if your intent was to show a hit or a miss (miss = beyond) then you test for greater than after this statement, in the same if/then sequence.

PS:
This is the code for the game:

Dim Hs
Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
Select Case KeyCode
Case vbKeyRight: GoRight
Case vbKeyLeft: GoLeft
Case vbKeyEscape: End
End Select

End Sub


Sub GoRight()
Line1.X1 = Line1.X1 + 120
Line1.X2 = Line1.X2 + 120

End Sub
Sub GoLeft()
Line1.X1 = Line1.X1 - 120
Line1.X2 = Line1.X2 - 120

End Sub

Private Sub Form_Load()
Dim Hs As Integer
Hs = 0
End Sub

Private Sub Timer1_Timer()
Line2.Y1 = Line2.Y1 + 120
Line2.Y2 = Line2.Y2 + 120

If Line2.Y1 >= Line1.Y1 Then
Hs = Hs + 1
Score.Caption = "Score: " & Hs
    Timer1.Interval = 0
    Timer1.Enabled = False
    Line2.X1 = 4800
    Line2.X2 = 4800
    Line2.Y1 = 1200
    Line2.Y2 = 1080
    
    Timer1.Interval = 65
    Timer1.Enabled = True
End If
End Sub

Private Sub TitleTim1_Timer()
Title.ForeColor = &HFFFF&
TitleTim1.Enabled = False
TitleTim2.Enabled = True
End Sub

Private Sub TitleTim2_Timer()
Title.ForeColor = &HFF&
TitleTim1.Enabled = True
TitleTim2.Enabled = False

End Sub

[Edited by CyberCarsten on 11-04-2000 at 11:51 AM]

[ExcalibursZone]

Ahhh, ok. I re-read your post ... sorry for the confusion.

To make sure that you catch the falling line:

Private Sub Timer1_Timer()
    Line2.Y1 = Line2.Y1 + 120
    Line2.Y2 = Line2.Y2 + 120
    
    If CheckCatch = True Then
        
        Hs = Hs + 1
        Score.Caption = "Score: " & Hs
        Timer1.Interval = 0
        Timer1.Enabled = False
        Line2.X1 = 4800
        Line2.X2 = 4800
        Line2.Y1 = 1200
        Line2.Y2 = 1080
        
        Timer1.Interval = 65
        Timer1.Enabled = True
    End If
End Sub

Private Function CheckCatch() As Boolean
    If Line2.Y1 >= Line1.Y1 Then
        If Line2.Y1 > Line1.Y1 Then
            CheckCatch = False
            Exit Function
        End If
        If (Line2.X1 >= Line1.X1 And Line2.X1 <= Line1.X2) Or _
           (Line2.X2 >= Line1.X1 And Line2.X2 <= Line1.X2) Then _
           CheckCatch = True
    End If
End Function

This should allow you to check if they touch. it can be 1 twip overlap on either end, which would allow for the line to pass right by, or go back to the top of the form. With a little modification of this code, you can definately add more precision.

[CyberCarsten]

Yes!!! It worked!!! Thank you VERY much!!!

Only one question left.....

When the timer has looped 3 times, the dropping stays away for a few seconds, and the reapear, but then the HS variable, which holds the highscore is being reduced by 1...why is that.....here is the "new code":

Dim Hs
Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
Select Case KeyCode
Case vbKeyRight: GoRight
Case vbKeyLeft: GoLeft
Case vbKeyEscape: End
End Select

End Sub


Sub GoRight()
Line1.X1 = Line1.X1 + 120
Line1.X2 = Line1.X2 + 120

End Sub
Sub GoLeft()
Line1.X1 = Line1.X1 - 120
Line1.X2 = Line1.X2 - 120
End Sub

Private Sub Timer1_Timer()
RndGenCoord = Int((12000 * Rnd) + 240)
Line2.Y1 = Line2.Y1 + 120
Line2.Y2 = Line2.Y2 + 120
    
    If CheckCatch = True Then
        
        Hs = Hs + 1
        Score.Caption = "Score: " & Hs
        Timer1.Interval = 0
        Timer1.Enabled = False
        Line2.X1 = Line1.X1 + RndGenCoord
        Line2.X2 = Line1.X1 + RndGenCoord
        
        If Line2.X1 >= Me.ScaleWidth Or Line2.X1 <= 0 Then
        Line2.X2 = Int(Me.ScaleWidth / 2)
        Line2.X2 = Line2.X1
        
        End If
        Line2.Y1 = 2280
        Line2.Y2 = 2280
        
        Timer1.Interval = 25
        Timer1.Enabled = True
    End If
If Line2.Y2 > Line1.Y1 Then
    Hs = Hs - 1
    Score.Caption = "Score: " & Hs
        Timer1.Interval = 0
        Timer1.Enabled = False
        Line2.X1 = 4800
        Line2.X2 = 4800
        Line2.Y1 = 2280
        Line2.Y2 = 2280
        
        Timer1.Interval = 25
        Timer1.Enabled = True
End If
End Sub

Private Function CheckCatch() As Boolean
    If Line2.Y1 >= Line1.Y1 Then
        If Line2.Y1 > Line1.Y1 Then
            CheckCatch = False
            Exit Function
        End If
        If (Line2.X1 >= Line1.X1 And Line2.X1 <= Line1.X2) Or _
           (Line2.X2 >= Line1.X1 And Line2.X2 <= Line1.X2) Then _
           CheckCatch = True
    End If
End Function

Private Sub TitleTim1_Timer()
Title.ForeColor = &HFFFF&
TitleTim1.Enabled = False
TitleTim2.Enabled = True
End Sub

Private Sub TitleTim2_Timer()
Title.ForeColor = &HFF&
TitleTim1.Enabled = True
TitleTim2.Enabled = False

End Sub

[Edited by CyberCarsten on 11-04-2000 at 05:50 PM]