SDL_KeyMod not present on SDL.EventType.KeyboardButtonUp

[LloydJHowarth]

Using SDL_KeyMod is always None on event SDL.EventType.KeyboardButtonUp

If I use this code:

internal override void OnEvent(SDL.Event e)
{
    switch (e.type)
    {
        // Keyboard Up
        case SDL.EventType.KeyboardButtonUp:
        {
            if (!e.keyboard.repeat)
            {
                var modifier = (Modifier)e.keyboard.keyModifier;
                Debug.Log($"Release {modifier}");
            }
            
            break;
        }
        
        // Keyboard Down
        case SDL.EventType.KeyboardButtonDown:
        {
            if (!e.keyboard.repeat)
            {
                var modifier = (Modifier)e.keyboard.keyModifier;
                Debug.Log($"Press {modifier}");
            }
            
            break;
        }
    }
}

Whenever I check the modifier on KeyboardButtonDown I get the excepted modifier that is pressed for example Alt, Ctrl, etc. However on release it's always none. I would wonder if this is intended behaviour however CapsLock work as expected and is the only SDL_KeyMod that is present on KeyboardButtonUp

Why is this? Is this a bug or intentional behaviour?

[LloydJHowarth]

This probably is intended behaviour since modifiers are typically used in combinations with Keys..

However I do think this functionality would be quite useful to also give events for released Modifier keys since I'd like to be able to custom track modifiers myself. I think for now I'll just have to check the specific SDL_KeyCode against the modifier and assign my own modifiers values instead

[LloydJHowarth]

Managed to solve this using a flag enum system using SDL_GetModState() instead of key event based.

I'll keep it open just in case this isn't intended behaviour or we can get this on KeyboardButtonUp.

Feel free to close!

[DaneelTrevize]

I don't see KeyboardButtonUp as an EventType in SDL2 or SDL3, is this some 3rd party binding's issue?
Pens, Gamepads, Joystick and Mice have Button event types, keyboards don't seem to.

[slouken]

As you noted, the modifier is true while the modifier key is held down and false when it is released. This is expected behavior. CapsLock and NumLock are special in that they toggle the modifier value with each press of the key.

[LloydJHowarth]

@slouken Thanks for the clarification, it's my first time using KeyModifiers in SDL so I was unsure if this was intended.

@DaneelTrevize This is custom bindings written in C# with slightly different naming convention for clarity. This just maps to EventType.SDL_EVENT_KEY_DOWN.. I wrote the bindings so it makes sense to me!