Collision Detection in vb.net

J

jusanthermemory

Newcomer
Joined
Dec 12, 2005
Messages
7
Im trying to get my collision detection to work and the picture boxes move in certain directions when they hit each other. Is there anyway to change this code so that It specifies a certain side?

If Me.linkviewer.Bounds.IntersectsWith(enemyviewer.Bounds) Then
Me.linkviewer.Left = Me.linkviewer.Left + 100
Me.enemyviewer.Left = Me.enemyviewer.Left - 100
End If

so if linkviewer hit enemyviewer on the right, linkviewer would go left and enemyviewer would go right and vice versa. same for top

Thanks for any help
 
Never used that function...but you could trick it into just checking a certain side...by creating a new bounds rectangle 1 pixel thick on whichever side you want to check.


For example the left side:

Rectangle rec = new Rectangle(this.Bounds.X, this.Bounds.Y, this.Bounds.X+1, this.Bounds.Bottom)


That's one idea
 
I'm sry but I don't really understand how to use that code. If you dont mind could you please give me a sample of how to use it?

thanks for your help and sry its taken so long to reply
 
You would use that code like this, but I'm not sure it's the best way to achieve what you want....

Visual Basic: 
        Dim rectOne As Rectangle = New Rectangle(0, 0, 100, 100)
        Dim rectTwo As Rectangle = New Rectangle(100, 100, 100, 100)

        If rectOne.IntersectsWith(New Rectangle(rectOne.Left, rectOne.Top, 1, rectOne.Height)) Then
            ' Left side
        ElseIf rectOne.IntersectsWith(New Rectangle(rectOne.Left, rectOne.Bottom - 1, rectOne.Width, 1)) Then
            ' Bottom side
        ElseIf rectOne.IntersectsWith(New Rectangle(rectOne.Right - 1, rectOne.Top, 1, rectOne.Height)) Then
            ' Right side
        ElseIf rectOne.IntersectsWith(New Rectangle(rectOne.Left, rectOne.Top, rectOne.Width, 1)) Then
            ' Top side
        End If

rectOne & rectTwo would be the bounds of your two picture boxes.
 
The trick to doing it is to perform two collision checks: once after the image moves horizontally and again, after the image moves vertically.

Obj.Left = Obj.Left + 100
If Obj.Bounds.IntersectsWith(enemyviewer.Bounds) Then
'collided on left or right side.
End If
Obj.Top = Obj.Top + 100
If Obj.Bounds.IntersectsWith(enemyviewer.Bounds) Then
'collided on top or bottom side.
End If

To determine which of the sides you actually collided on within the If blocks, look at the sign of the object's velocity (i.e. the 100 that you add to the left/top positions.

This method is not foolproof, especially if you have small objects moving large distances. :)
 
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