The engine freezes when running in Debug mode

[gladiator-hy]

Describe the bug
When debugging the vsgbuilder project, the engine freezes and the window stops responding to any mouse messages.

To Reproduce
Steps to reproduce the behavior:

1. In VSG, I am using shader compilation at runtime.
2. Compile the vsgbuilder project in vsgExamples, set a breakpoint in the main function, and then start debugging.
3. Hit the breakpoint and then continue execution.
4. See error

Expected behavior
The engine runs normally without freezing.

Desktop (please complete the following information):

• OS: [Windows 10]

Additional context

20260410_181810.mp4

[robertosfield]

The VSG is just C++ and Vulkan, the compiler "should" be able to set break points just fine, even if there are bugs in the VSG or the driver.

What might be going on in your case is impossible to say, no one else has reported a similar issue, and all we have to go in your case is a hang, but not stack trace so there is no way for us to guess where the hang is caused by.

I have just tried a debug build of the VSG on my Kubuntu system and I can break vsgbuilder and continue without any issues.

Personally, I'd suspect VisualStudio bug before a VSG one. Could you try another debugging tool?

There is a chance that Vulkan driver/VisualStudio interaction is problematic. What driver and hardware are you using? Could you try another hardware/driver?

[gladiator-hy]

Thank you for your prompt reply. I just got home from work. My graphics card is an NVIDIA RTX 3080, and the Vulkan version is 1.4.341.1. The issue also occurred with the previous Vulkan version 1.3.296.0. I upgraded Vulkan to 1.4.341.1 today. I will try using other debugging tools and other hardware as you suggested.

[gladiator-hy]

I think the issue might be related to shader compilation at runtime. It works fine with teapot.vsgt, and I know that teapot.vsgt contains precompiled shader information.

I also have a question. Your design should use precompiled shader files by default, such as flat_ShaderSet.cpp, phong_ShaderSet.cpp, and pbr_ShaderSet.cpp. But why does running the vsgbuilder project prompt "VulkanSceneGraph not compiled with GLSLang, unable to compile shaders" when VSG_SUPPORTS_ShaderCompiler is disabled?

20260410_214807.mp4

[robertosfield]

My best guess is you're butting up against DLL hell, nothing specific to do with the VSG.

Have a look to see what libraries you are building the VSG/glslang etc. against and what libraries are being picked up at runtime, there's a chance that they aren't compatible so causing Visual Studio to crash.

For discussing for when/what not to use or rely upon runtime shader compilation, it's best to start a thread on the Discussion forum, rather than try to jam it into the Issue tracker which is specifically for reporting VSG bugs, not general user discussion.

[AnyOldName3]

If you press the pause button in Visual Studio once the freeze has happened, you'll be able to investigate what the application is actually doing. The two most likely things are either that it's running a loop that never terminates, which you'll be able to see in the stack view, or that all threads in the process are waiting for an event that never happens, which will be visible by opening the Parallel Stacks view (IIRC, in Debug/Windows), and seeing that the tops of all the stacks are showing waits. They might not show up with obvious names if you've got Just My Code enabled, so if you just see that they're all running functions in NtDll.dll or whatever, try disabling that setting.