On Mon, 23 Feb 2026 19:24:34 GMT, Sergey Bylokhov <[email protected]> wrote:

> The OGL pipeline on Linux passes raw X11 window id to GLX. This is allowed by 
> the spec but is a deprecated compatibility path. Mesa has a 
> [bug](https://gitlab.freedesktop.org/mesa/mesa/-/issues/1001) where 
> glXMakeContextCurrent() drops the buffers of the previously bound drawable 
> when switching to a different window, corrupting its content.
> 
> The fix creates GLXWindow objects via glXCreateWindow() and uses them instead 
> of raw window id for all GLX calls. The question is where to store the 
> GLXWindow. It could be stored in the java in XWindow and passed around, but 
> that would pollute "shared xawt code" with OGL specific state even when OGL 
> is not enabled. Instead, the GLXWindow is managed entirely on the native OGL 
> side using a map keyed by the X window id. This keeps one GLXWindow per X 
> window, creates it only when GLX surfaces are actually used, and uses 
> reference counting so it is destroyed when the last surface releases it.
> 
> Also fixes [JDK-8369561](https://bugs.openjdk.org/browse/JDK-8369561) — wrong 
> pixel colors in DrawBitmaskImage on Linux, same root cause.
> 
> Two tests added:
> - MultiWindowFillTest — reproduces the bug: paints two windows different 
> colors, switches context between them, verifies the first window's content 
> survives
> - FlipCoexistTest — verifies that direct rendering and flip BufferStrategy 
> coexist on the same window. This test will fail if the implementation creates 
> a separate GLXWindow per Java OGL surface instead of sharing one per X window

I'm getting a build failure on both linux aarch64 and x64
src/java.desktop/unix/native/common/java2d/opengl/GLXSurfaceData.c: In function 
'acquireGLXWindow':
src/java.desktop/unix/native/common/java2d/opengl/GLXSurfaceData.c:71:28: 
error: implicit declaration of function 'XrmUniqueQuark' 
[-Wimplicit-function-declaration]
    71 |         glxWindowContext = XUniqueContext();

We build on OL 8 (although using  a OL 6.4 devkit)

-------------

PR Comment: https://git.openjdk.org/jdk/pull/29886#issuecomment-3980776848

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