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Hot!MLA GFX: Double buffering does not always work

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Wieschebrock
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2019/02/22 06:56:28 (permalink)
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MLA GFX: Double buffering does not always work

Hi,
I'm using a 320*240 LCD on an PIC24FJ256DA210 design that based on the microchip dev board.
I am using MPLABX 5.15 with XC16 (v1.35) and MLA v2018_11_26 with additional VGDD plugin

The screen works fine with double buffering disabled, but it is flickering on screen update.
With double buffering the flicker goes away but after a while some parts of the screen gets white and more and more parts of the screen vanished away. If I rebuild the screen everything is ok for a while.
 
Pictures attached...
 
 
Any idea?
 
 
 
 
 
 
 
 
post edited by Wieschebrock - 2019/02/22 06:57:51

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#1

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    Mysil
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    Re: MLA GFX: Double buffering does not always work 2019/02/22 07:29:51 (permalink)
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    Hi,
    When double buffering is used, then the same updates must be applied to Both buffers:
     
    When a display update is done in one buffer, and the display is changed to show this buffer,
    then the buffer that is now inactive must also be updated.
    Either by copying whole or part of the active buffer to inactive buffer,
    or performing the same updates again on the now inactive buffer.
     
    Even if double buffering shall give smoother display, it means more processing and more complicated code.
     
        Mysil
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    Wieschebrock
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    Re: MLA GFX: Double buffering does not always work 2019/02/22 07:50:20 (permalink)
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    thanks Mysil for you answer.
     
    We bought VGDD to make it easy to handle the GUI stuff. 
    So I have not dived deep into the MLA GFX code or the GFX stuff created by VGDD
    Unfortunately Fabio (the VGDD guy) is not available any more.
     
    I need to get a an overview who is involved in the buffer stuff.
    I thought it was all on MLA side.
     
    DW
     
     
     
     
     
     
     
    #3
    NKurzman
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    Re: MLA GFX: Double buffering does not always work 2019/02/22 07:57:33 (permalink)
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    You can dig into the code and fix it. They used that code for harmony. I was not impressed with the double buffering code.
    I found if I single buffer, and only updated elements that changed the flickering was minimal.
    #4
    Wieschebrock
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    Re: MLA GFX: Double buffering does not always work 2019/09/20 05:38:51 (permalink)
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    Okay finally found the reason:
    I had to increase  GFX_MAX_INVALIDATE_AREAS from 5 to 10
     
    #define GFX_MAX_INVALIDATE_AREAS 10
     
     
    #5
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