[Fix] #20600 : Calling GLFW.setWindowSize with the screen size leads to browser error

[ypujante]

As pointed out in the discussion about this issue, it is very odd that glfwSetWindowSize automatically triggers a fullscreen when the size parameters happen to be the exact size of the screen. When invoking it via code, this triggers the error in browsers because it is not a user event.

If the client code wants to go fullscreen, it should simply call Module.requestFullscreen which is made available to the Module when the Browser library is initialized.

Neither library_sdl.js nor library_glut.js implement such a behavior.

[sbc100]

Can you add something to the ChangeLog about this.

[ypujante]

I added the ChangeLog entry as you suggested. Let me know if the language needs to be tweaked.

Thank you

[sbc100]

What about the Browser.exitFullscreen(); thing... should explictly setting the windows size also not exit fullscreen?

[ypujante]

That is a good question. SDL does not do it. glut does it. In my opinion SDL is right. When Browser.requestFullscreen is called, a fullscreenchange listener is put in place to detect exiting full screen (the user pressing ESC, or whatever key triggers that).

Calling Browser.exitFullscreen(); might trigger an error for the same reason that Browser.requestFullscreen can (if the code calls glfwSetWindowSize while in fullscreen mode but not from a user triggered event).

I believe the proper way for the client code to handle this is to set a Module.onFullScreen callback which gets called whenever the browser goes in/out of fullscreen and then call glfwSetWindowSize.

I actually used this technique in my code this morning:

    EM_ASM(
        {
            RAYLIB = {}; // used to store width/height before fullscreen
            const cb = Module.requestFullscreen;
            Module.requestFullscreen = (pointerLock, resize) => {
                const canvas = document.getElementById('canvas');
                RAYLIB.screenWidth = canvas.clientWidth;
                RAYLIB.screenHeight = canvas.clientHeight;
                cb(pointerLock, resize);
            };
            Module.onFullscreen = Module.cwrap('FullscreenCallback', null, ['boolean']); // called by emscripten
        });

void FullscreenCallback(bool isFullscreen) {
    if(isFullscreen) {
       // ...
    }
    else  {
        glfwSetWindowSize(EM_ASM_INT(return RAYLIB.screenWidth;), EM_ASM_INT(return RAYLIB.screenHeight;));
    }
}

That being said, if you prefer to leave it, I believe the chances of getting an error are lower and probably have less consequences.

[sbc100]

No, I think being consistent with SDL and glut makes more sense.

[ypujante]

Not being lucky with failing tests this morning :(

Connecting to nodejs.org (nodejs.org)|104.20.23.46|:443... connected.
HTTP request sent, awaiting response... 400 Bad Request
2023-11-13 19:50:55 ERROR 400: Bad Request.