[CLOSED]menus  flickering with OpenGLControl
lazarus / 31-LCL

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AlexVinS · 2013-03-24 16:30

How to avoid flickering of menus overlapping active Openglcontrol?

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User137 · 2013-03-24 20:10

They're not flickering at all for me. You might need to provide a
simple project to see where it flickers.

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AlexVinS · 2013-03-25 12:16

For me its reproducible with opengl example (from Lazarus
distribution). And there they not just flickering but decrease FPS to
0.

PS in real code I invalidate glcontrol only as needed.

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User137 · 2013-03-25 14:16

I see now, AppPropertiesIdle() event stops when menu is active (it
will still draw a new frame everytime you move mouse). You may need to
use another way to make the main drawing loop. For example TTimer with
interval 1 made it smooth. It's also possible to create a thread, or
find some more high precision timers etc.

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AlexVinS · 2013-03-25 14:33

Adding timer fixes issue with FPS, thanks (only in example; in real
code I already use timer+forced invalidate). But flickering persists.

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AlexVinS · 2013-03-30 11:26

This is not LCL issue, it`s related to GDI and OpenGL. Forcing VSYNC
made flickering not annoying (but Its not a real solution).