An opengl regression

[Duane Clark]

The patch for dynamic loading of opengl,
http://www.winehq.com/hypermail/wine-cvs/2002/11/0151.html

has caused a (apparently minor) regression in the program earthquake
http://www.navagent.com/products/earthquake/

That is a small app (250K download) with a spinning globe that shows 
current earthquakes; actually a pretty cool little app. The regression 
is that now when the oceans are turned on (via the settings dialog), the 
land gets flooded.

[Duane Clark]

Duane Clark wrote:
> The patch for dynamic loading of opengl,
> http://www.winehq.com/hypermail/wine-cvs/2002/11/0151.html
>
> has caused a (apparently minor) regression in the program earthquake
> http://www.navagent.com/products/earthquake/

And as a bit more information, this is the chunk that does it.

--- wine/dlls/x11drv/x11drv_main.c:1.64	Mon Nov 25 19:04:54 2002
+++ wine/dlls/x11drv/x11drv_main.c	Mon Nov 25 19:04:54 2002
@@ -313,8 +317,11 @@
      }
      else screen_depth = DefaultDepthOfScreen( screen );

+    /* Initialize OpenGL */
+    X11DRV_OpenGL_Init(display);
+
      /* If OpenGL is available, change the default visual, etc as 
necessary */
-    if ((desktop_vi = X11DRV_setup_opengl_visual( display )))
+    if (desktop_dbl_buf && (desktop_vi = X11DRV_setup_opengl_visual( 
display )))
      {
          visual       = desktop_vi->visual;
          screen       = ScreenOfDisplay(display, desktop_vi->screen);

[Lionel Ulmer]

> - /* Initialize OpenGL */
> - X11DRV_OpenGL_Init(display);
> -

Well, by removing this, you will disable all OpenGL in X11...
>   /* If OpenGL is available, change the default visual, etc as 
>
> necessary */
> - if ((desktop_vi = X11DRV_setup_opengl_visual( display )))
> - if (desktop_dbl_buf && (desktop_vi = X11DRV_setup_opengl_visual(
>
> display )))
>       {
>           visual       = desktop_vi->visual;
>           screen       = ScreenOfDisplay(display, desktop_vi->screen);

Out of curiosity, do you have the 'DesktopDoubleBuffered' option set in your
Wine config file ?

Lionel

[Duane Clark]

Lionel Ulmer wrote:
> ...
> >  /* If OpenGL is available, change the default visual, etc as 
> >
> > necessary */
> > - if ((desktop_vi = X11DRV_setup_opengl_visual( display )))
> > - if (desktop_dbl_buf && (desktop_vi = X11DRV_setup_opengl_visual(
> >
> > display )))
> >      {
> >          visual       = desktop_vi->visual;
> >          screen       = ScreenOfDisplay(display, desktop_vi->screen);
>
> Out of curiosity, do you have the 'DesktopDoubleBuffered' option set in your
> Wine config file ?

I did notice and try that (after posting), and it also fixes it. So I 
guess the issue becomes whether it should also work without double 
buffering, as that is the default in the sample config file.

[Lionel Ulmer]

> I did notice and try that (after posting), and it also fixes it. So I 
> guess the issue becomes whether it should also work without double 
> buffering, as that is the default in the sample config file.

Well, before my patch, in one of the X11DRV rewrite, the option got somehow
lost and was enabled by default whatever the value of the entry in the
config file. So that it was working before was a 'feature' :-)

Now let's try to explain the reason of this option : in Windows, you first
create the Window and then only tell it that one wants to do OpenGL drawing
in it (single or double buffered). Now, in X11, if you plan to use a window
to do OpenGL drawings, you first need to be sure that the visual you choose
for it is compatible with OpenGL (ie does it support double buffering ? has
it a stencil buffer ? ...). The problem is that when Wine detects that the
application wants to do double buffered OpenGL drawings in that window, it's
too late as the window was already created with the default visual => hence
the option to have the default visual used by all windows be double buffered.

I do not think putting it as default is such a good idea as it may lead to
performance problems to all the people not using OpenGL... And the gamerz
just have to read the config file (if they know how to read, sometimes we
wonder when doing 'support' on #WineHQ 8-) ).

As to why it's called 'DesktopDoubleBuffered' and not something else, it's
also historic : at the beginnings, OpenGL only worked properly in Desktop
mode :-)

Finally, Alexandre (if you read this :-) ), now that you rewrote most of the
internal Windows handling code (ie with the Wine window == X11 window
stuff), would it be possible to somehow recreate the X11 window when we
detect OpenGL attaching to it and replace the old window in Wine's window
hierarchy ?

Lionel

[Alexandre Julliard]

Lionel Ulmer  writes:
> Finally, Alexandre (if you read this :-) ), now that you rewrote most of the
> internal Windows handling code (ie with the Wine window == X11 window
> stuff), would it be possible to somehow recreate the X11 window when we
> detect OpenGL attaching to it and replace the old window in Wine's window
> hierarchy ?

Possible, yes. Easy, definitely not ;-)