[RESOLVED] object collision

[ikdekker]

I want to make a Ball fall and make it stop when it hits the ground. Now I tried this code below, but the ball doesn't move. It thinks the 'collide' is not nothing. But it does not collide. What did I do wrong? Thanks

 Dim objects() As PictureBox
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        objects = New PictureBox() {Ball, Ground}

    End Sub
   
    Private Declare Function GetAsyncKeyState Lib "user32" (ByVal vkey As Integer) As Integer

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick


            Dim collide As PictureBox = objects.FirstOrDefault(Function(o) o.Bounds.IntersectsWith(Ball.Bounds))

            If collide IsNot Nothing Then
        Else
            Ball.top = Ball.top + 2
        End If


    End Sub


End Class

[dday9]

This drops a picturebox straight down and has an if/then statement if hit's the bottom

PictureBox1.Location = New Point(PictureBox1.Location.X, PictureBox1.Location.Y + 1)
        If PictureBox1.Bounds.Bottom > Me.Bounds.Bottom Then
            'It's hit the bottom
        Else
            'It didn't hit the bottom
        End If

[kleinma]

To answer your question, it looks to me like your original code does not work because of the LINQ query you are trying to use.

objects.FirstOrDefault(Function(o) o.Bounds.IntersectsWith(Ball.Bounds))

This code says give me the first (or default) object in the objects array, where the object intersects with the ball object. However since the ball object is part of your array of obects, it will always be returned, since its bounds will intersect with itself technically if you are just comparing bounds. So your collide variable is always going to contain the ball picturebox (it will never be nothing).

Here is intersection checking code that will work:

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick

        Dim collide = Ground.Bounds.IntersectsWith(Ball.Bounds)

        If Not collide Then
            Ball.Top = Ball.Top + 2
        End If

    End Sub