[plt-scheme] Double buffer (scheme/gui)

Yes, But I have 2 bitmaps, because both of my objects have to move  
independently, the tunnel has to be able to move to the left, without  
moving the Copter, and the Copter has to move Up and Down without  
moving the tunnel...

Marc



On Apr 11, 2009, at 8:47 PM, Robby Findler wrote:

> Oh! I misread the code. You need to create a single bitmap containing
> the whole thing and then draw it. Don't draw two bitmaps (that's
> what's causing your flicker).
>
> Robby
>
> On Sat, Apr 11, 2009 at 12:59 PM, CHAMLY <marc.chamly at gmail.com>  
> wrote:
>> Well I already put the 'no-autoclear  to the canvas, my BITMAP-DC-1  
>> (tunnel)
>> doesn't flicker only my BITMAP-DC-2(Object) flickers, I will try to  
>> put the
>> 'no-autoclear somewhere else, and see if it works.
>>
>> Thank you.
>>
>> On Apr 11, 2009, at 7:31 PM, Robby Findler wrote:
>>
>>> Probably you want to pass the 'no-autoclear style to the canvas%
>>> object when you create it (I may have got the precise name wrong,  
>>> but
>>> it is listed in the docs for the initialization arguments to canvas 
>>> %).
>>>
>>> But you also probably want to only recreate the bitmaps when their
>>> content changes, not every time the window is refreshed. In other
>>> words, all but the last line below should be somewhere else, not in
>>> the on-paint method.
>>>
>>> Robby
>>>
>>> On Sat, Apr 11, 2009 at 12:25 PM, CHAMLY <marc.chamly at gmail.com>  
>>> wrote:
>>>>
>>>> HI!
>>>>
>>>> I am programming a game on scheme using #lang scheme/gui, the  
>>>> game is
>>>>  made
>>>> of:
>>>> 1) an object (copter) that when you click moves up, otherwise it  
>>>> falls
>>>> down,
>>>> and does not move horizontaly.
>>>> 2) a tunnel that moves from right to left, giving the impression  
>>>> that the
>>>> object is moving forward (moving to the right reaching the end of  
>>>> the
>>>> tunnel).
>>>>
>>>>
>>>> I have a little problem with my double buffer,
>>>> I'm using two bitmaps one to draw the copter, and one to draw my  
>>>> tunnel
>>>>
>>>> Here is what i have in the paint-callback of my canvas:
>>>>
>>>>            (send BITMAP-DC-1 clear)              ; i move my tunnel
>>>>            (send TUNNEL draw-tunnel1  BITMAP-DC-1  y1)
>>>>            (send dc draw-bitmap BITMAP-1  (- x-canvas) 0 'solid))
>>>>
>>>>
>>>>            (send BITMAP-DC-2 clear)     ; i move my copter
>>>>            (send BITMAP-DC-2 draw-bitmap copterUp  0 0 'solid)
>>>>
>>>>            (send dc draw-bitmap BITMAP-2  150 (send COPTER get-y- 
>>>> copter)
>>>>  'solid))
>>>>
>>>> The problem is that my copter still flickers, and i don't know  
>>>> why??
>>>> (i don't draw my copter in BITMAP-DC-1 because afterwords i also  
>>>> use
>>>> other
>>>> bitmaps to draw my tunnel)
>>>>
>>>> thanks
>>>>
>>>>
>>>> Marc
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>>>>
>>
>>