🚀 go-pugleaf

In alt.lang.basic, bdwheele@silver.ucs.indiana.edu (Brian Wheeler) writes:

>Is there anyway for VB to simulate sprites?  I tried using a picture box on 
>top of another picture box, but the unpainted portion of the top box blocks
>out the background picture.  The reason why I'm wanting this is so I can write
>a game...and its no fun if everything has to be rectangular!

>	Thanks in advance
>	Brian Wheeler

>-- 

You can either use "oddpicture" a control from MicroHelp (1-800-922-3383 or 
404/594-1185)  or create your own "transparent pictures" using a BitBlt call
to the Windows API:

The API declarations are:

Declare Function BitBlt Lib "Gdi" (ByVal HDestDC As Integer, ByVal X As Integer,
 ByVal Y As Integer, ByVal nWidth As Integer, ByVal nHeight As Integer, 
 ByVal hSrcDC As Integer, ByVal Xsrc As Integer, ByVal Ysrc As Integer, 
 ByVal dwRop As Long) As Integer    '****NOTE: all on one line!!!! ****

Global Const SRCCOPY = &HCC0020
Global Const SRCAND = &H8800C6
Global Const SRCINVERT = &H660046

The idea here is to create two picture controls- one with your icon (see thru
areas are black), the other a "mask" of your icon (see thru areas white, all 
others black).  Set the visibility property of the "mask" to false.  You then
You then BitBlt the form (or "background") area covered by the "icon" and the
and the "mask" to your "icon" picture control.  This makes the picture control
essentially transparent. 

In your program the code looks something like:

Done% = BitBlt(Mask1.Hdc,0,0,32,32,Form1.Hdc,Icon1.Left,Icon1.Top,SRCAND)
Done% = BitBlt(Icon1.Hdc,0,0,32,32,Mask1.Hdc,0,0,SRCINVERT)

Have fun...
- Galen -