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Solved
VB .Circle GDI Alternative
Posted on 2006-11-30
Hey
For my game I am using VB6's .Circle and .Line - but I wondered if these were slow as I have made a basic "particle engine" - and it appears to be quite slow when dealing with 300+ particles (even though fps is reported as 114). I lack expertise in directx and opengl, and due to the time span I really don't want to go down that road of learning either of them.
I read that .NET GetPixel and SetPixel is about 12x faster than .Point - So maybe the same for .Circle and .Line? - Also could you please supply code that will generate a circle (ellipse as I think it is known in GDI)
thanks a lot :D
garreh
For my game I am using VB6's .Circle and .Line - but I wondered if these were slow as I have made a basic "particle engine" - and it appears to be quite slow when dealing with 300+ particles (even though fps is reported as 114). I lack expertise in directx and opengl, and due to the time span I really don't want to go down that road of learning either of them.
I read that .NET GetPixel and SetPixel is about 12x faster than .Point - So maybe the same for .Circle and .Line? - Also could you please supply code that will generate a circle (ellipse as I think it is known in GDI)
thanks a lot :D
garreh
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10 Comments
There are several overloads that allow you to call them in different ways.
Here is one way:
Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.Paint
e.Graphics.DrawEllipse(Pen
e.Graphics.DrawLine(Pens.R
End Sub
Here is one way:
Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.Paint
e.Graphics.DrawEllipse(Pen
e.Graphics.DrawLine(Pens.R
End Sub
Here ya go...
Private Declare Function GetDC Lib "user32" (ByVal hWnd As Long) As Long
Private Declare Function MoveToEx Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long, lpPoint As Any) As Long
Private Declare Function LineTo Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long) As Long
Private Declare Function Ellipse Lib "gdi32" (ByVal hdc As Long, ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Private Declare Function ReleaseDC Lib "user32" (ByVal hWnd As Long, ByVal hdc As Long) As Long
Private Sub Command1_Click()
Dim DC As Long
DC = GetDC(Me.hWnd)
MoveToEx DC, 25, 25, ByVal 0&
LineTo DC, 50, 50
Ellipse DC, 25, 25, 50, 50
ReleaseDC Me.hWnd, DC
End Sub
Private Declare Function GetDC Lib "user32" (ByVal hWnd As Long) As Long
Private Declare Function MoveToEx Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long, lpPoint As Any) As Long
Private Declare Function LineTo Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long) As Long
Private Declare Function Ellipse Lib "gdi32" (ByVal hdc As Long, ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Private Declare Function ReleaseDC Lib "user32" (ByVal hWnd As Long, ByVal hdc As Long) As Long
Private Sub Command1_Click()
Dim DC As Long
DC = GetDC(Me.hWnd)
MoveToEx DC, 25, 25, ByVal 0&
LineTo DC, 50, 50
Ellipse DC, 25, 25, 50, 50
ReleaseDC Me.hWnd, DC
End Sub
:O it works good Idle_Mind! But one more question.. how would I go about changing the colour of the circle or line? And maybe even like its thickness.
You have to create a new Pen. Then you set the current Pen, keeping a reference to the old pen so that you can put it back when you are done.
Have to pick up the kids from school...will post an example when I get back.
Have to pick up the kids from school...will post an example when I get back.
Option Explicit
Private Declare Function MoveToEx Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long, lpPoint As Any) As Long
Private Declare Function LineTo Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long) As Long
Private Declare Function Ellipse Lib "gdi32" (ByVal hdc As Long, ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Private Declare Function CreatePen Lib "gdi32" (ByVal nPenStyle As Long, ByVal nWidth As Long, ByVal crColor As Long) As Long
Private Declare Function CreateSolidBrush Lib "gdi32" (ByVal crColor As Long) As Long
Private Declare Function SelectObject Lib "gdi32" (ByVal hdc As Long, ByVal hObject As Long) As Long
Private Declare Function DeleteObject Lib "gdi32" (ByVal hObject As Long) As Long
Private Const PS_SOLID = 0
Private Sub Command1_Click()
Dim myBrush As Long
Dim myPen As Long
Dim prevBrush As Long
Dim prevPen As Long
myBrush = CreateSolidBrush(RGB(255, 0, 0)) ' Red Brush
myPen = CreatePen(PS_SOLID, 3, RGB(0, 0, 255)) ' Blue Pen
' Select the new Pen/Brush KEEPING references to the previous ones
prevBrush = SelectObject(Me.hdc, myBrush)
prevPen = SelectObject(Me.hdc, myPen)
Ellipse Me.hdc, 25, 25, 50, 50
MoveToEx Me.hdc, 25, 25, ByVal 0&
LineTo Me.hdc, 50, 50
' Put the previous Pen/Brush back
SelectObject Me.hdc, prevBrush
SelectObject Me.hdc, prevPen
' Clean-up our Pen/Brush
DeleteObject myBrush
DeleteObject myPen
End Sub
Private Declare Function MoveToEx Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long, lpPoint As Any) As Long
Private Declare Function LineTo Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long) As Long
Private Declare Function Ellipse Lib "gdi32" (ByVal hdc As Long, ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Private Declare Function CreatePen Lib "gdi32" (ByVal nPenStyle As Long, ByVal nWidth As Long, ByVal crColor As Long) As Long
Private Declare Function CreateSolidBrush Lib "gdi32" (ByVal crColor As Long) As Long
Private Declare Function SelectObject Lib "gdi32" (ByVal hdc As Long, ByVal hObject As Long) As Long
Private Declare Function DeleteObject Lib "gdi32" (ByVal hObject As Long) As Long
Private Const PS_SOLID = 0
Private Sub Command1_Click()
Dim myBrush As Long
Dim myPen As Long
Dim prevBrush As Long
Dim prevPen As Long
myBrush = CreateSolidBrush(RGB(255, 0, 0)) ' Red Brush
myPen = CreatePen(PS_SOLID, 3, RGB(0, 0, 255)) ' Blue Pen
' Select the new Pen/Brush KEEPING references to the previous ones
prevBrush = SelectObject(Me.hdc, myBrush)
prevPen = SelectObject(Me.hdc, myPen)
Ellipse Me.hdc, 25, 25, 50, 50
MoveToEx Me.hdc, 25, 25, ByVal 0&
LineTo Me.hdc, 50, 50
' Put the previous Pen/Brush back
SelectObject Me.hdc, prevBrush
SelectObject Me.hdc, prevPen
' Clean-up our Pen/Brush
DeleteObject myBrush
DeleteObject myPen
End Sub
hehe okay sure... thanx for ur help so far btw, really appreciate it :)
so far i have found
hPen = CreatePen(PS_SOLID, 0, RGB(0, 255, 0))
hOldPen = SelectObject(picBuffer.hdc
and it is working fine.. strange that when i change 0 value to being higher it gets much much slower in drawing... but anyway
thinking about it i was hoping for a more elegant approach as i'm going to be changing the colour every frame (its fading to black) and creating a new pen everytime might be slow?
so far i have found
hPen = CreatePen(PS_SOLID, 0, RGB(0, 255, 0))
hOldPen = SelectObject(picBuffer.hdc
and it is working fine.. strange that when i change 0 value to being higher it gets much much slower in drawing... but anyway
thinking about it i was hoping for a more elegant approach as i'm going to be changing the colour every frame (its fading to black) and creating a new pen everytime might be slow?
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