BitBlt....Please Help!

[Mike Downing]

Not sure if it will help but if you try http://www.codearchive.com there's a vb project that use this technique - One entitled picanimate (I think) moves a spaceship sprite around a screen using a timer in response to a mouse click.

[BLiNDPiG]

I'm making a hunting game in VB6, and I'm trying to figure out how to implement BitBlt into it.
I have some sample source that I found from vb-world, but I need to figure out how to make it so that I can use a timer to move the mask/picsource to a new destination every second or so. Here's what I have for code, please somebody help:

[Form1 code]
Dim xdest As Long
Dim ydest As Long

Sub refreshscreen()
Form1.Cls
Call BitBlt(picbuf.hDC, 0, 0, 214, 161, picback.hDC, 0, 0, SRCCOPY)
Call BitBlt(picbuf.hDC, xdest, ydest, 32, 32, picMask.hDC, 0, 0, SRCAND)
Call BitBlt(picbuf.hDC, xdest, ydest, 32, 32, picsource.hDC, 0, 0, SRCINVERT)
Call BitBlt(Form1.hDC, 0, 0, 214, 161, picbuf.hDC, 0, 0, SRCCOPY)
End Sub


Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
Select Case KeyCode

Case vbKeyRight
xdest = xdest + 5
refreshscreen

Case vbKeyLeft
xdest = xdest - 5
refreshscreen

Case vbKeyUp
ydest = ydest - 5
refreshscreen

Case vbKeyDown
ydest = ydest + 5
refreshscreen

End Select

If xdest < 10 Then xdest = 10
If xdest > 170 Then xdest = 170
If ydest < 10 Then ydest = 10
If ydest > 120 Then ydest = 120

End Sub

Private Sub Form_Load()
Dim leftd, topd
leftd = Int(Rnd * picback.Width)
topd = Int(Rnd * picback.Height)
xdest = 100
ydest = 100
refreshscreen
End Sub

Private Sub picsource_Click()

End Sub

Private Sub Timer1_Timer()
picbuf.Left = leftd
picsource.Left = picbuf.Left
picbuf.Top = topd
picsource.Top = picbuf.Top
End Sub


[Module code]
Public Declare Function BitBlt Lib "gdi32" (ByVal hDestDC As Long, ByVal X As Long, ByVal Y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal dwRop As Long) As Long

Global Const White = 16777215
Global Const SRCAND = &H8800C6
Global Const SRCCOPY = &HCC0020
Global Const SRCINVERT = &H660046
Global Const srcpaint = vbSrcPaint


What am I doing wrong? I'm trying to move the picture to a new spot every second, and it doesn't move. (I also have the keyboard input, where it moves using the arrow keys, but how do I get it to work like I want it to?)

Thanks for any help I get.
-BLiNDPiG

[Fox]

Hi there again!

I read the code and saw somehting you made not the best way . First you don't have to declare the consts (drawing method). You can directly use vbSrcCopy, vbSrcPaint, ...

Next is that you don't have to move the buffer coz you're drawing the whole picture *out* the buffer, so it doesn't matter where it is.

Last is how you're blitting it, try this:

-
BitBlt( Buffer.hdc, 0, 0, BackW, BackH, Back.hdc, 0, 0, vbSrcCopy )
BitBlt( Buffer.hdc, 0, 0, PicW / 2, PicH, Back.hdc, PicW / 2, 0, vbSrcPaint )
BitBlt( Buffer.hdc, 0, 0, PicW / 2, PicH, Back.hdc, 0, 0, vbSrcAnd )
BitBlt( Front.hdc, 0, 0, FrontW, FrontH, Buffer.hdc, 0, 0 vbSrcCopy )
-

Note that your Picture must have a same-sized mask on the right side (Original pic: White background, Mask picture: White object on black background)

Good luck!

------------------
[email protected]
...
Every program can be reduced to one instruction which doesn't work.



[This message has been edited by Fox (edited 01-26-2000).]