[BUG]: DAW UI Freeze when multiple instances are open

[Franiac]

Thanks for taking the time to fill out this bug report!

• I have read the plugin manual and searched the existing issues.

What happened?

- Plugin version & format:

0.4.5 / VST 3

- A clear and concise description of what the bug is:

I found issue #137 and it is marked as 'not planned'. Well, I really enjoy ZL Equalizer a lot but if I open up more than 2 instances, the UI of the entire DAW (Reaper) gets laggy, 3 and 4 are like PowerPoint and the 5th instance completely kills Reaper and it is not coming back.

This seems like a serious issue in my eyes. Sure, there is the option to go 'Software Rendering' but I don't think that is the way to go in the otherwise functional OpenGL world of VST's.

The weird thing in my eyes is that neither the CPU or GPU spike to 100% so that it would make sense that the UI locks up. When I kill Reaper with ZL, the CPU is at 10% and the GPU at like 15%, so it's not an issue of overloading the GPU. Since nothing reacts anymore, my wild guess is that something blocks the event loop of the GUI thread.

I am a software dev myself. If you need debug info or anything, just tell me. If I can help, I gladly do. This is definitely a show-stopper for me and it could have a negative impact on new users (like me). I really want this plugin to blow up, it's just that good.

- A clear and concise description of what you expected to happen:

No matter the count of open ZL instances, the UI of the DAW should remain usable.

Additional information

- Operating system (& version if applicable):

Windows 11 Pro 24H2

- Hardware (CPU & GPU if applicable):

AMD Ryzen 9 5950X / Nvidia Quadro P4000

- DAW:

Reaper v7.28

Relevant log output

No response

Code of Conduct

• I agree to follow the Code of Conduct.

[zsliu98]

I found issue #137 and it is marked as 'not planned'. Well, I really enjoy ZL Equalizer a lot but if I open up more than 2 instances, the UI of the entire DAW (Reaper) gets laggy, 3 and 4 are like PowerPoint and the 5th instance completely kills Reaper and it is not coming back.

As I said in the release note here https://github.com/ZL-Audio/ZLEqualizer/releases/tag/0.4.5, JUCE team is aware of this issue and they are working hard on a fix. Even some commercial plugins have to roll back to the software rendering because of the bad performance (on some machines). More details are available at this JUCE forum post: https://forum.juce.com/t/direct2d-causes-considerable-performance-drop/64009.

Sure, there is the option to go 'Software Rendering' but I don't think that is the way to go in the otherwise functional OpenGL world of VST's.

Currently software rendering is the best solution if you are encountering the freezing issue.

The weird thing in my eyes is that neither the CPU or GPU spike to 100% so that it would make sense that the UI locks up. When I kill Reaper with ZL, the CPU is at 10% and the GPU at like 15%, so it's not an issue of overloading the GPU. Since nothing reacts anymore, my wild guess is that something blocks the event loop of the GUI thread.

You are totally correct. JUCE 8 Direct2D painting takes too much time on the CPU, which finally blocks the GUI thread.

[Franiac]

I did not recognize the hint in the release notes. That said, I will wait for the JUCE team to fix the issue. After browsing through the forum post it seems like they really made a pretty big opsie. Can I leave this issue open to track whenever you are able to merge a fixed JUCE build?

[zsliu98]

Sure. I will leave this issue open until the fix is merged.