problem when losing focus...

Brice Manuel · Post by **Brice Manuel** » Mon Jul 11, 2005 1:02 am

I am porting a windowed game I had started in IBasic and I ran into a snag. Anytime it loses focus, the screen goes white. I thought it was my shoddy programming, but then I tried the "Lady" game by Paul and the same problem happens with "Lady". What can I do to prevent this?

MrMat · Post by **MrMat** » Mon Jul 11, 2005 2:14 am

Do you have a WindowEvent() or WaitWindowEvent() in your main loop?

Brice Manuel · Post by **Brice Manuel** » Mon Jul 11, 2005 2:49 am

umm... No, I don't. And I am not sure how to properly use them (still somewhat new to PB.

Here is the main loop for Lady's Garden, which exhibits the same problem as my game. Is there any chance you could show me how to properly fix this so it doesn't become corrupted when the window loses focus?

Code: Select all

;--------------------
;-MAINLOOP
mainloop:
  Gosub init_data
  Gosub load_maze
  Gosub load_data
  
  If level=1 And bugs=1
    hold=0
    While hold=0
      DisplaySprite(4,0,0)
      text(80,90,"GUIDE BUMBLE THROUGH")
      text(80,115,"THE HEDGE MAZE AND")
      text(80,140,"PICK ALL THE FLOWERS")
      text(80,215,"IF LADY CATCHES YOU")
      text(80,240,"ITS GAME OVER")
      text(130,350,"PRESS SPACEBAR")
      frmbee=frmbee+1
      If frmbee>9:frmbee=0:EndIf
      DisplayTransparentSprite(frmbee+50,30,90)
      DisplayTransparentSprite(8,30,220)
      FlipBuffers()
      ExamineKeyboard()
      If KeyboardPushed(#PB_Key_Space) Or KeyboardPushed(#PB_Key_Escape):hold=1:EndIf
    Wend
  EndIf 
  If useAudio:PlaySound(4):EndIf 
  
  While quit=0
    If flower=0:quit=1:EndIf        
    ExamineKeyboard()
    If KeyboardPushed(#PB_Key_Escape):Gosub draw_credits:End:EndIf
    If KeyboardPushed(#PB_Key_Left):mm=1:EndIf
    If KeyboardPushed(#PB_Key_Right):mm=2:EndIf
    If KeyboardPushed(#PB_Key_Up):mm=3:EndIf
    If KeyboardPushed(#PB_Key_Down):mm=4:EndIf    
    Select mm
      Case 1 
        If mve=0 And maze(cpxpos-1,cpypos)>2
       cx=-2:cy=0:cpdir=1:cpxpos=cpxpos-1:mve=32
       Gosub check_flower
       EndIf
      Case 2 
        If mve=0 And maze(cpxpos+1,cpypos)>2
       cx=2:cy=0:cpdir=3:cpxpos=cpxpos+1:mve=32
       Gosub check_flower
       EndIf
      Case 3 
        If mve=0 And maze(cpxpos,cpypos-1)>2
       cx=0:cy=-2:cpdir=2:cpypos=cpypos-1:mve=32
       Gosub check_flower
       EndIf
      Case 4 
        If mve=0 And maze(cpxpos,cpypos+1)>2
       cx=0:cy=2:cpdir=4:cpypos=cpypos+1:mve=32
       Gosub check_flower
       EndIf      
    EndSelect
    If mve<>0:cpx=cpx+cx:cpy=cpy+cy:mve=mve-2:EndIf

    Gosub move_lady
    Gosub draw_board
    Gosub draw_bugs
    Gosub set_score    

    If quit>0
       If quit=1
          tmpy=480
          If useAudio:PlaySound(3):EndIf 
          For nextlevel=0 To 190
            Gosub draw_board
            Gosub set_score
            DisplaySprite(10,134,tmpy)
            FlipBuffers()
            tmpy=tmpy-3
          Next
       EndIf
       If quit=2:If useAudio:PlaySound(2):EndIf:EndIf
    EndIf

    FlipBuffers()
  Wend

  If quit=2
    diz=0
    Restore level1
    For hold=1 To 400
      Gosub draw_board
      Gosub set_score
      Gosub draw_diz
      DisplaySprite(11,134,110)  
      Delay(50)
      ExamineKeyboard()
      If KeyboardPushed(#PB_Key_Space):hold=400:Delay(500):EndIf
      If KeyboardPushed(#PB_Key_Escape)    
        Gosub draw_credits
        End    
      EndIf
      FlipBuffers() 
    Next
    level=0
    bugs=0
    score=0
  EndIf
  level=level+1
  bugs=bugs+1
  If bugs>4:bugs=4:EndIf
  If level>4:level=1:Restore level1:EndIf
Goto mainloop

Thank you in advance for any help.

MrMat · Post by **MrMat** » Mon Jul 11, 2005 3:20 am

Try putting

Code: Select all

WindowEvent()

after the line

Code: Select all

While quit=0

and most people put a small delay e.g.

Code: Select all

Delay(5)

after the

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FlipBuffers()

The WindowEvent() line processes window messages so events like dragging the window are handled. You can also get the result of WindowEvent() e.g. event = WindowEvent() and respond to windows events (e.g. if the close button has been clicked you could quit your game).

The delay is recommended to prevent the loop from using all the CPU so your desktop should be a little more responsive with that in place.

Brice Manuel · Post by **Brice Manuel** » Mon Jul 11, 2005 3:57 am

Thank you VERY much. Fixed the issue perfectly!

MrMat · Post by **MrMat** » Mon Jul 11, 2005 3:59 am

My pleasure. Good luck with your game!