Re: Other Quesa concerns/suggestions

[Stefan H. <st...@to...>]

>Stefan Huber wrote:
>  >>> At least nan, inf, etc. do not work (correctly) when __FAST_MATH__ is on.
>>>  Please tell me more.  How do they work differently when it is off?
>>
>>  About two years ago I ported an app that relies on nan, etc. from CW
>>  to Xcode. The main problem is (as far as I remember) that isnan,
>>  isinf and similar functions always return false if __FAST_MATH__ is
>>  on. Quesa does not use these functions.
>>
>>  BTW CWs "Relaxed IEEE Floating Point" setting works perfectly well with nan.
>
>Quesa does use isfinite, and I'm sure I would have noticed if it wasn't
>working... rendering with shadows requires an infinite yon, and
>E3ViewAngleAspectCamera::GetFrustumMatrix uses isfinite to do the right
>thing in that case.


I've tested __FAST_MATH__ is on for floats again (Xcode 2.4.1):

you are right :
isfinite and isinf work correctly for std::numeric_limits<float>::infinity()

but:
isnan returns 0 (instead of 1) and isfinite returns 1 (instead of 0) 
for std::numeric_limits<float>::quiet_NaN()

It seems that inf works but nan does not.


   Stefan
   http://www.topoi.ch