[RESOLVED] [2008] Determine Point Inside Circle.

[masfenix]

Hey I am creating a simple game. But right now all I have is a simple Ball class that creates a filled circle on the screen.

Imports System.Drawing
Public Class Ball
    Private GR As Graphics

    Private _radius As Integer
    Public Property Radius() As Integer
        Get
            Return _radius
        End Get
        Set(ByVal value As Integer)
            _radius = value
        End Set
    End Property


    Private _diameter As Integer
    Public Property Diameter() As Integer
        Get
            Return _diameter
        End Get
        Set(ByVal value As Integer)
            _diameter = value
        End Set
    End Property


    Private _color As Color
    Public Property Color() As Color
        Get
            Return _color
        End Get
        Set(ByVal value As Color)
            _color = value
        End Set
    End Property


    Private _x As Double
    Public Property x() As Double
        Get
            Return _x
        End Get
        Set(ByVal value As Double)
            _x = value
        End Set
    End Property


    Private _y As Double
    Public Property y() As Double
        Get
            Return _y
        End Get
        Set(ByVal value As Double)
            _y = value
        End Set
    End Property



    Public Sub New(ByVal g As Graphics)
        Diameter = 10
        Radius = Diameter / 2
        Color = Drawing.Color.Black
        x = 90
        y = 134
        GR = g
    End Sub

    Public Sub New(ByVal g As Graphics, ByVal d As Integer, ByVal c As Color)
        Diameter = d
        Radius = Diameter / 2
        Color = c
        GR = g
    End Sub

    Public Sub Draw()
        GR.DrawArc(Pens.Blue, Convert.ToInt16(x), Convert.ToInt16(y), Diameter, Diameter, 0, 360)
    End Sub

    Public Sub DrawFill()
        GR.FillEllipse(Brushes.BurlyWood, Convert.ToInt16(x), Convert.ToInt16(y), Diameter, Diameter)
    End Sub

    Public Sub Del()
        GR.FillEllipse(Brushes.White, Convert.ToInt16(x), Convert.ToInt16(y), Diameter, Diameter)
    End Sub

    Public Function InsideBall(ByVal x As Integer, ByVal y As Integer) As Boolean


    End Function

End Class

As you can see my InsideBall class is empty. I am getting the two x and y from the form where its being clicked, but I have no idea how to check if the click is in the circle. Looking for some guidelines on where to start.

Also I tried drawing it on paper, but I am way to tired I guess.

[Harsh Gupta]

Is (X,Y) the center point of circle?

[masfenix]

Umm in the code you see, the X, Y properties are center of the circle. While the X Y parameters in the function "InsideBall" are the click co ordinates.

Bad naming, will change it

[Harsh Gupta]

Find the distance between the radius and the point on which user clicked. If this distance is less than the radius, then it is inside the circle, if equals then on the circle else outside the circle.

'let (mx,my) be coordinates on which user clicked
'(x,y) center of circle, known to you
'radius, known to you.
 
'to find the distance
 
Dim distance As Integer 'whatever
 
distance = Math.Sqrt((mx-x)*(mx-x) + (my-y)*(my-y))
 
If distance < Me.Radius
'Point lies inside circle
'do whatever you want to do
End If

[masfenix]

Duh Distance Formula!
Thankyou