WebAssembly: fix the mouse issues when toggling the vsync mode and switching to full screen mode

[oleg-derevenetz]

Related to #9444 (comment)

This PR uses SDL_RenderSetVSync(), which is available since SDL 2.0.18 (that's why the Ubuntu version in the "Linux x86-64 SDL2 Release" workflow has been bumped from 20.04 to 22.04) instead of re-creating the renderer "on the fly" and also it removes a lot of cryptic code related to the SDL rendering.

Also it bumps the emsdk version to 4.0 latest and removes the workaround from our CI that was required to be able to build the multithreaded version of fheroes2.

As usual, you can see this PR running here:

https://oleg-derevenetz.github.io/fheroes2/
https://oleg-derevenetz.github.io/fheroes2/demo/

There are still some issues left - for instance, when trying to change the in-game resolution when the game running in full screen mode, there are some inadequate switching, stretching, etc., but I don't know yet what to do about it anyway.

[ihhub]

Hi @oleg-derevenetz , I put several comments in this pull request. Could you please take a look at them and see if they make sense?

[oleg-derevenetz]

@ihhub what do you think about playability of the wasm version in general (except for some rough edges maybe like the full-screen mode)? Is it good enough to consider this version as "general availability" and publish it on the project's website as a "demo" (in a way)? I'm not talking about the launcher right now, but only about the game itself.

[ihhub]

Hi @Branikolog , please prioritize this pull request.

[ihhub]

Hi @Branikolog , please complete your review by today.

[Branikolog]

Hi!
Everything works fine, but I've noticed a strange thing, once I've switched to window mode and back to Fullscreen. When turning on/off v-sync screen partially shifts (I think it's related to my machine), and the window mode icon switches for a moment.

VID20250207174816.mp4

Not so critical issue, though. There're no any other problems on PC version.

[oleg-derevenetz]

once I've switched to window mode and back to Fullscreen

Full screen is seriously broken in wasm (and it's broken differently in different browsers), and I don't know yet how to cure it in a "cross-platform" way. It may have to be disabled altogether in the wasm version.

[Branikolog]

@oleg-derevenetz , hi.

once I've switched to window mode and back to Fullscreen

Full screen is seriously broken in wasm (and it's broken differently in different browsers), and I don't know yet how to cure it in a "cross-platform" way. It may have to be disabled altogether in the wasm version.

The issue I've filmed is valid for the PC version, since I'm not able to run application with browser.

And I'm convinced, that Fullscreen shouldn't be an option for the browser.

[oleg-derevenetz]

The issue I've filmed is valid for the PC version, since I'm not able to run application with browser.

Yes, I tried to run the game in the "true full-screen" mode (I mean, on Windows with hardware mouse cursor), and yes, when the SDL_RenderSetVSync() is called, there is a single frame rendered with some invalid contents. Sometimes it is apparently some "remembered" contents from the windowed mode, and, if app was never running in the windowed mode - i.e. it was started in the full-screen mode - it is just a black frame. This is especially noticeable during the step-by-step execution in the debugger. To be honest, I do not know if anything can be done about it. This does not happen in windowed mode or in the SDL_WINDOW_FULLSCREEN_DESKTOP ("non-true-fullscreen") mode.

[Branikolog]

@oleg-derevenetz

Yeah, forgot to mention, that the issue occurs for hardware cursor.
From my point it's mostly a cosmetic issue. I just mentioned it just to let you know and to check if nothing is broken there. 👍

Thanks for clarification!

[ihhub]

Hi @oleg-derevenetz , let's merge it after 1.1.6 release.

[ihhub]

@oleg-derevenetz , thank you very much for the changes!