[PATCH 1/2] dinput: Fix phase conversion on periodic effects

[Bruno Jesus]

On Mon, Sep 19, 2016 at 9:11 PM, Matteo Bruni <matteo.mystral at gmail.com> wrote:
>> On Mon, Sep 19, 2016 at 8:12 PM, Matteo Bruni <matteo.mystral at gmail.com> wrote:
>> I have been talking a lot to Elias Vanderstuyft recently, we are aware
>> of precision problems and are working to fix it a in better way. For
>> now I'm sticking the simple changes that I'm able to test in my real
>> hardware. The limit of phase is 35999 because it is related to degrees
>> / 100, more than that would wrap. You are probably right that we need
>> to clamp to max value before calculating.
>
> I don't know if we need to clamp or not. My guess is that it just
> repeats periodically after that, if such values are allowed at all
> (SetParameter might fail). I.e. I would have used something like
> (phase % 36000) instead of clamping.
> That probably means some more tests are required...
>
>> It is important to note that
>> although we are losing precision you can't really notice it in a
>> standard gamepad.
>
> Sure but it still seems like a good idea to do things right when reasonable.
> Notice that I don't mean to blame you or the patch, I had a bit of a
> look at the existing code after all...

Yes, I agree that if we can make it better it should be better. I just
lack the math skills sometimes for things that may look obvious for
other people, I even considered opening questions at
http://math.stackexchange.com to help improve some equations.