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Re: XWin can't hold OpenGL picture, has WS_DISABLED and WS_EX_TRANSPARENT styles?
Sorry (I don't know how to you L A Walsh reply so am replying to myself with the same subject)
I think I meant to include this (https://sourceware.org/bugzilla/show_bug.cgi?id=25170) link that
includes this link:
I was too zealous to be brief, and I think now the window styles are a red herring. In any case the
problems arise in "overdraw" scenarios wherein a window passes over the OpenGL windows, that
is when the background is "erased" and the picture is lose (not held) which makes it impossible to
use XWin for anything but one screen demonstrations of graphical effects. Some applications use
multiple windows and do rendering with OpenGL instead of GTK widgets for example. Those can't
use XWin. I think OpenGL doesn't work with MS Windows X servers. I hope it works with Linux ones.
The other X servers available to Windows are in disarray with regard to OpenGL. So it would be good
if one of them could be made to work. XWin is closest since it doesn't crash and does draw correctly
other than it can't hold a picture.
----- Original Message -----
> From: "Mick Pearson" <firstname.lastname@example.org>
> To: "cygwin" <email@example.com>
> Sent: Saturday, November 9, 2019 3:49:12 AM
> Subject: Re: XWin can't hold OpenGL picture, has WS_DISABLED and WS_EX_TRANSPARENT styles?
> P.S. Sorry to add, the WM_ERASEBKGND message occurred to me, or setting the
> class-background to the "null" brush is a likely culprit. It is behaving like
> a front-buffered old-fashioned application somewhat. Clipping and own-DC style
> should prevent damage, but I don't know, something seems to be responding to
> PAINT like events, that don't make sense for OpenGL.
> Below is line formatted version of the old text. I have to do this manually for
> new text, but the > quoted text is already hard-wrapped.
>> XWin has never had a permanent picture with OpenGL. Any movement "damages" all
>> windows. I know I've looked at it before, but I checked its window/class styles
>> with MS's Spy++ tool today. The normal styles that govern clipping and
>> permanence look fine, but it has some weird styles that normally for disabled
>> and transparent windows that I wonder are the cause for its abnormal behavior
>> in this regard. No OpenGL apps that just draw only OpenGL on a window have
>> XWin's problem.
>> To be brief, it has these unnatural window-styles in this mail's subject line.
>> Other than that, I think it may use Direct3D instead of OpenGL, but normally
>> drawing OpenGL or Direct3D onto plain windows doesn't clobber other windows. I
>> mean, you have to work hard to make it do something like that.
>> A second, unrelated, oddity is the window decorations are sometimes classic
>> style, and sometimes current style. It's very odd. It's random in the same
>> session. The windows seem to undergo a transition from classic to current, but
>> get stuck in classic sometimes. Maybe they are using the old "animated" show
>> functions that didn't survive the version of Windows that introduced them.
>> Niggling things like this could be fixed. But I don't know how many people use
>> Cygwin. I've used it a lot over the years myself, to do development work. XWin
>> is the most stable X server. Others don't really get close. But it's kind of
>> too comfortable with its crumminess too. Not that I'm going to shove my work
>> aside to try to remedy it myself.
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