Released: Chess System Tal GUI

[chrisw]

will have some space/time to look at this in a couple of days. tested the download on a different PC here, worked. Possibly it demands avx2 minimum, but not anything else as far as I know.

No, avx2 is definitely not the problem, because I've many avx2 chess engines running here without problems, so it must be something else.

Okay. Give me something to work on. You download the latest 220Mb(?) zip, unzip it, and what do you get?

[F.Huber]

Okay. Give me something to work on. You download the latest 220Mb(?) zip, unzip it, and what do you get?

Well, as I already wrote: I get nothing at all - no program window, no error message, no entry in the taskmanager, it's just as if I won't have started it at all.
I guess it has something to do with the new 3D mode, because the previous 2D version worked without problems.

[chrisw]

Okay. Give me something to work on. You download the latest 220Mb(?) zip, unzip it, and what do you get?

Well, as I already wrote: I get nothing at all - no program window, no error message, no entry in the taskmanager, it's just as if I won't have started it at all.
I guess it has something to do with the new 3D mode, because the previous 2D version worked without problems.

When you unzip you have an empty folder?

[Bart Weststrate]

Chris sorry for the off-topic: I am trying to build a own framework around the Strong Malt NNUE. Can you please give some specifics about the layout of the NNUE file (about 66,6 MB after uci option save NNUE). There seems to be a PST also and maybe a material table, i am not sure.

My gratitude would be infinite for some insight.

Shouldn't be in this specific topic but Talkchess is so slow that i couldn't reach page 2...

[MMarco]

Okay. Give me something to work on. You download the latest 220Mb(?) zip, unzip it, and what do you get?

Well, as I already wrote: I get nothing at all - no program window, no error message, no entry in the taskmanager, it's just as if I won't have started it at all.
I guess it has something to do with the new 3D mode, because the previous 2D version worked without problems.

When you unzip you have an empty folder?

If that can help:

I have a laptop with Zen 3 and nvidia 3700. It runs every game I installed on it.

In my case I get a black window ans CSTAL GUI showing in the task manager.

The CST-GUI-2.07.zip file weights 202 Mo (212 076 189 octets), unzip weights 407 Mo (427 432 030 octets).

image: https://ibb.co/prwtwbVp

[F.Huber]

Okay. Give me something to work on. You download the latest 220Mb(?) zip, unzip it, and what do you get?

Well, as I already wrote: I get nothing at all - no program window, no error message, no entry in the taskmanager, it's just as if I won't have started it at all.
I guess it has something to do with the new 3D mode, because the previous 2D version worked without problems.

When you unzip you have an empty folder?

Hmm? Where did I say anything about an empty folder? Do you really think I'm not able to unzip your CST-GUI-2.07.zip ???
I get nothing when I start CST-GUI.exe !

[chrisw]

Okay. Give me something to work on. You download the latest 220Mb(?) zip, unzip it, and what do you get?

Well, as I already wrote: I get nothing at all - no program window, no error message, no entry in the taskmanager, it's just as if I won't have started it at all.
I guess it has something to do with the new 3D mode, because the previous 2D version worked without problems.

When you unzip you have an empty folder?

Hmm? Where did I say anything about an empty folder? Do you really think I'm not able to unzip your CST-GUI-2.07.zip ???
I get nothing when I start CST-GUI.exe !

I am not there looking over your shoulder. Rather than guess I try to get you to be specific.

[chrisw]

Okay. Give me something to work on. You download the latest 220Mb(?) zip, unzip it, and what do you get?

Well, as I already wrote: I get nothing at all - no program window, no error message, no entry in the taskmanager, it's just as if I won't have started it at all.
I guess it has something to do with the new 3D mode, because the previous 2D version worked without problems.

When you unzip you have an empty folder?

If that can help:

I have a laptop with Zen 3 and nvidia 3700. It runs every game I installed on it.

In my case I get a black window ans CSTAL GUI showing in the task manager.

The CST-GUI-2.07.zip file weights 202 Mo (212 076 189 octets), unzip weights 407 Mo (427 432 030 octets).

image: https://ibb.co/prwtwbVp

From our friend Mr Claude:


❯ enduser report who ran the zip file in release: If that can help:

I have a laptop with Zen 3 and nvidia 3700. It runs every game I installed on it.

In my case I get a black window ans CSTAL GUI showing in the task manager.

The CST-GUI-2.07.zip file weights 202 Mo (212 076 189 octets), unzip weights 407 Mo (427 432 030 octets).

image: https://ibb.co/prwtwbVp

Searched for 3 patterns, read 5 files, listed 3 directories, ran 5 shell commands

What the screenshot already rules out

The title bar reads "CST-GUI — Chess System Tal 2.07 51019". That string is only ever set at mainwindow.py:572, inside the engine-ready handler — after QApplication started, after MainWindow fully constructed, after the event loop turned over (QTimer.singleShot(0, self._autoload_engine)), and after the bundled engine spawned and completed its UCI handshake.

So this is not a crash, not a hang, not a missing DLL, and not an engine problem. The app is alive and working. Only the painting is dead — and it's dead for the entire window: there's no menu bar in that shot either, just uniform black.

The likely cause

One thing in Qt 6 blacks out a whole window while leaving the app running: a QOpenGLWidget in the widget hierarchy. Parenting a texture-backed widget flips the top-level window's backingstore from the plain software blit to RHI/OpenGL compositing for everything in that window. If the GL context can't be created, every flush is a no-op and you get an alive, black, unpainted window — menu bar included.

cst_gui/ui/mainwindow.py:72:

self.board2d = BoardWidget(self)
self.board3d = Board3DGLWidget(self) # constructed unconditionally

The 3D board defaults to off (view/board3d, False, line 287), so this end user never asked for 3D. The widget merely existing is enough to put the whole window on the GL path. Their Zen 3 + RTX 3070 laptop is hybrid graphics — the classic case where the process lands on the wrong adapter or the 3.3-core/4×MSAA format request fails. "Runs every game I installed" is consistent: games pick the dGPU explicitly, a Qt desktop app doesn't.

Before I fix anything — one thing I can't check

I don't know which commit the shipped zip was built from (there are no tags, and __version__ is still 0.1.0; the 2.07 in the title is the engine). The 3D board landed in 4c150b2, 2026-07-20. If the release predates that, this diagnosis is wrong and I'd look elsewhere.

Quick self-check on the unzipped folder — the GL build has _internal\PySide6\Qt6OpenGLWidgets.dll and a numpy folder. If those aren't there, tell me and I'll start over.

Test to send the end user

In a cmd window, in the unzipped folder:

set QT_OPENGL=software
CST-GUI.exe

If the board appears, it's confirmed — and it also gives them a working app today. (This needs opengl32sw.dll in the folder; the spec says it's deliberately kept, worth confirming it's actually there.) Note they won't see any error text either way: the release is built CONSOLE = False, so stderr goes nowhere. Getting real Qt logs out of them needs a CONSOLE = True build.

The fix I'd make

Construct Board3DGLWidget lazily, only when 3D is switched on, and probe GL first — a throwaway QOpenGLContext.create() — falling back to the 2D board with a status-bar message if it fails. That takes every 2D user off the RHI compositing path entirely, and turns "unusable black window" into "3D board unavailable on this GPU" for the rest.

Two caveats on my end: I can't test it here (this machine has only Python 3.9 — the project needs 3.10+ and PySide6, and there's no ComfyUI, so it isn't the 5080 laptop), and it needs a rebuilt release to reach the user.

Want me to write that fix now, or wait for the QT_OPENGL=software result first?

[PHILOCHESS]

Congratulations on the release, Chris, and thank you for sharing CST-GUI. I have already downloaded it and will begin using it in my tests. I look forward to becoming familiar with it.

Best regards

[F.Huber]

I am not there looking over your shoulder. Rather than guess I try to get you to be specific.

I've found the problem: my notebook has 2 graphic cards, an integrated Intel HD Graphics and a Nvidia GeForce.
By default Windows uses the Intel graphics, and automatically switches to the more powerful GeForce graphics when a program requires it.
This automatic switching usually works for all my other 3D programs (and I have a lot of them), but not for CST-GUI - I've no idea why!?
So CST-GUI works if I manually change the graphics card to the Nvidia GeForce.