The SDL_GL_SetSwapInterval function in the example_sdl2_opengl3 project sometimes does not work

[capp-adocia]

Version/Branch of Dear ImGui:

Version v1.91.8, Branch: master

Back-ends:

imgui_impl_sdl2.cpp + imgui_impl_opengl3.cpp

Compiler, OS:

Windows10 + MSVC 2019

Full config/build information:

No response

Details:

When I run the example_sdl2_opengl3 project on Windows, I found that when I enabled the vertical synchronization function, that is, set SDL_GL_SetSwapInterval to 1, the frame rate should be limited to the screen refresh rate. Before this, I also tested it on a laptop. This function worked on my laptop and it was limited to 60 frames. But when I changed the device, this SDL_GL_SetSwapInterval function did not work. What is the reason?

Screenshots/Video:

Minimal, Complete and Verifiable Example code:

SDL_GL_SetSwapInterval(1); // Enable vsync

[ocornut]

I believe it may be overridden (globally or per executable) in some drivers settings.
Either way, take note that this is a SDL question, not a Dear ImGui question. I agree that in principle it would be nice if our example apps were more battle-tested for all situations, but it would make them much more complicated too.

[capp-adocia]

我相信它可能在某些驱动程序设置中被覆盖（全局或每个可执行文件）。 无论如何，请注意这是一个 SDL 问题，而不是 Dear ImGui 问题。我同意，原则上如果我们的示例应用程序在所有情况下都经过更严格的测试，那就太好了，但这也会使它们变得更加复杂。

Thanks for your answer. You mentioned the driver, which is a good direction. I paid special attention to the vertical synchronization option of the local NVIDIA graphics card. When I saw this option, it was turned off. When it was enabled, the frame rate was limited to 60 regardless of whether I used SDL_GL_SetSwapInterval. At this point, I feel that things are somewhat clear. I guess that the priority of the driver configuration item is higher than what I set here. The problem I mentioned before also makes sense, because I disabled vertical synchronization in the driver at the beginning, which made it meaningless whether I turned on SDL_GL_SetSwapInterval or not.