Re: dinput: Move gain support from effect to device

[Vitaliy Margolen]

Vincent Pelletier wrote:
> Hi.
>
> Windows supports setting force feedback effect gain at 2 levels:
> - device
> - effect
> There is support for the former on Linux, but not for the latter.
>
> +	DWORD				ff_gain;
>  };
> ...
> +      This->ff_gain = max(0, (int) pd->dwData);
> First why do you typecase DWORD to (int) to assign to DWORD? Second DWORD
> will always be > 0. If you want to check it against limit then just check it
> being <= 10000 otherwise return error.
> +      if (This->joyfd != -1) {
> You should be checking This->base.acquired instead of fd.
> +        event.value = This->ff_gain * 0xFFFF / 10000;
> You should use MulDiv instead because this can be optimized out by compiler
> into something that won't be as accurate.

Vitaliy.

dinput: Move gain support from effect to device

[Vincent Pelletier]

Le Friday 30 January 2009 02:58:34 Vitaliy Margolen, vous avez écrit :
> First why do you typecase DWORD to (int) to assign to DWORD? Second DWORD
> will always be > 0. If you want to check it against limit then just check
> it being <= 10000 otherwise return error.
> [...]
> You should use MulDiv instead because this can be optimized out by compiler
> into something that won't be as accurate.

I store internaly as a DWORD because of those accuracy problems.
Thanks for pointing out this function, attached patch is now more homogeneous 
with existing code, and does not do any casting magic.
> You should be checking This->base.acquired instead of fd.

Right, fixed.

Also fixed in test:
- test vs. message incoherent
- typo in test message

-- 
Vincent Pelletier