Properly set IsPrecise for SDL scroll events

[Susko3]

Continuation of #5186 (comment).

Tested on a windows precision touchpad, and with a regular mouse.

[peppy]

I guess this method of detection will mean the flag could be incorrect if the first event to arrive is from a precision source but exactly 1.00. Very very unlikely in practice, but just confirming.

[bdach]

I guess this method of detection will mean the flag could be incorrect if the first event to arrive is from a precision source but exactly 1.00

This was touched on previously. The windows APIs don't seem to be designed to let you know what the scrolling resolution of the device is, they just report back raw values. If you happen to receive a multiple of SCROLL_DELTA, which is supposed to be a 1 notch on a "normal scroll", there looks to be no easy way of knowing if it was "precise" or not.

[Susko3]

I guess this method of detection will mean the flag could be incorrect if the first event to arrive is from a precision source but exactly 1.00. Very very unlikely in practice, but just confirming.

Correct, could be false for the first scroll, but I expect the following deltas to be precise.

Also, due to how the debounce is implemented, any scroll within 100 ms of SDL_Init will be considered precise, not worth mentioning as the window is not created/visible in the first 100 ms.

[peppy]

I've tested this on windows and it works as expected (did not test transitioning to mouse from precision, but I think the code is sound enough).