MouseState.ScrollWheelValue does not change

[captainkidd5]

it does not appear that the mousestate's scrollwheelvalue changes when it does in fact change. Works with my DesktopGL project but not kni

[nkast]

Can you be more specific?
On which platform of KNI it's not working?

I think some platforms like Blazor.GL report MouseWheel only when the window is focused.

[squarebananas]

So with BlazorGL, currently the mouse wheel only works when commenting this section out from the index.html:

window.addEventListener("wheel", function(event)
{
    // Prevent Mousewheel scrolling the outer page
    // when running inside an iframe. e.g: itch.io embedding.
    event.preventDefault();
}, { passive: false });

But that got me thinking, why is this necessary for the mouse but not the keyboard, as there is a similar script to block arrows & space from scrolling the outer page. Then I noticed this with the Window.8.0.10.js code:

window.addEventListener('mousewheel', (event) =>
 {
    DotNet.invokeMethod('nkast.Wasm.Dom', 'JsWindowOnMouseWheel', uid,
        event.deltaX, event.deltaY, event.deltaZ,  event.deltaMode);
});

https://github.com/nkast/Wasm/blob/main/Wasm.Dom/wwwroot/js/Window.8.0.10.js#L176

That is using the event mousewheel and not the event wheel.

Changing this to wheel fixes the issue.

The only issue with this solution is that the wheel event is not supported on Safari apparently.
https://developer.mozilla.org/en-US/docs/Web/API/Element/wheel_event
https://developer.mozilla.org/en-US/docs/Web/API/Element/mousewheel_event

[squarebananas]

Just took another look at the compatibility table and realised it's "Safari on iOS" that is unsupported, not "Safari" for MacOS. If it's a choice between mouse on desktop working or mouse on Apple mobile devices working (if that actually works), then switching to fix desktop platforms seems much more important. I'll do a PR for this.

[nkast]

Thanks @squarebananas .

I see that for some reason the 'wheel' event was masking the 'mousewheel'.

[nkast]

After nkast/Wasm#17 we are getting wheel events. again.

I am worried that we need to convert deltaY values to windows notches (120) based on deltaMode.

kni/Platforms/Input/.Blazor/ConcreteMouse.cs

Line 111 in e0dce13

public void OnMouseWheel(object sender, int deltaX, int deltaY, int deltaZ, int deltaMode)

I think the old event 'mousewheel' was returning 120 per 'notch'.

[squarebananas]

I think the old event 'mousewheel' was returning 120 per 'notch'.

I'm not sure what the old mousewheel event did, but from testing it seems the wheel event has a deltaY of 100 and a wheelDeltaY of 120 for me. The only thing is that wheelDeltaY is deprecated, although it wasn't actually used before.

Initially across Chrome, Edge and Firefox, the deltaMode was always 0 initially for pixel mode. I just found out you can change that in Windows 11 using Mouse Settings > Additional Mouse Settings > Wheel > Vertical Scrolling. That will cause the deltaY to become 1 and the deltaMode to become 2 for page mode.

Also changing the page zoom seems to effect the values by the inverse proportion (at least with Chrome and Edge). So at 50% zoom the deltaY and wheelDeltaY double and at 200% they half. Not sure how that compares to other platform implementations.

[squarebananas]

Not sure how that compares to other platform implementations.

Just had a look at Kni.Platform.SDL2 and that uses const int wheelDelta = 120; :

kni/Platforms/Game/.SDL2/SDLGameWindow.cs

Line 284 in fa34206

const int wheelDelta = 120;

So maybe it's best to just use Math.Sign(deltaY) * 120; to keep it consistent with that?