FrameLimiter being ignored for D3D rendering backends

[CG-SS]

This is more of a question, but it seems that, if using RenderBackend::D3D12 or RenderBackend::D3D11, the frames are always limited, that is, currently, for me on a 144 Hz monitor, it can only get up to 144 FPS, but with RenderBackend::OpenGL or RenderBackend::Vulkan, the frames are indeed unlimited, I can reach around >700 FPS.

Is that intentional?

[eugeneko]

Frame limiting above vsync is not often used so the code may be funky.
I would say it is a bug and it would be nice to have the ability to disable all limits, but it's not something I care too much.
Do you happen to have vsync enabled? If so, it's another bug that OpenGL does not respect it.

[CG-SS]

It seems OpenGL and Vulkan are working as intended, as I had VSync disabled

[eugeneko]

@CG-SS I did a bit of investigation, and this behavior is caused by Diligent implementation:

https://github.com/DiligentGraphics/DiligentCore/blob/bb098aea024f3dd321ecb9620245adfd9f287d29/Graphics/GraphicsEngineD3DBase/include/SwapChainD3DBase.hpp#L282-L298

Diligent for DX11 and DX12 does not allow application to submit any new frames if the frame queue is already full.
I am not sure if it can be disabled easily, I couldn't find a way.

If you really need this behavior, please request it explicitly and I will push the issue to Diligent maintainers.

[CG-SS]

Altho not critical, as a game engine user, I would like to be able to at least have a FPS cap that is higher than the monitor refresh rate, I'm surprised they don't allow this, as it's standard for any game engine in order to allow the user to have better perfomance for lag spikes and some other competitive gaming use cases

[eugeneko]

@CG-SS This is related diligent issue: DiligentGraphics/DiligentEngine#279
AFAIU windows compositor causes application to wait until display is ready, no matter what we do.
Only DX11 and DX12 in window are affected. Native fullscreen should not be affected.