[osg-users] Change to Optimizer OptimizationOptions

Peter Hrenka p.hrenka at science-computing.de
Tue Nov 3 01:17:00 PST 2009


Hi,

Paul Martz schrieb:
> Hi Robert -- The code submission by Wojciech and I for MSFBO has opened 
> a small can of worms on declaring bits and bitmasks. I hope you can 
> weigh in and put an end to the debate.

Has anybody had a look at Qt's QFlags? 
http://doc.trolltech.com/4.5/qflags.html

They provide a type-safe way of dealing with bit-mask-style enums.
The implementation is mostly a template class with overloaded
operators. Once you have the idea, it should be rather trivial
to reimplement this from scratch and tailor it OSG's requirements.

Cheers,

Peter

> Originally, my submission followed the Optimizer's OptimizationOptions 
> pattern of declaring bit values in an enum, but declaring the bitmask 
> variable as an unsigned int.
> 
> In Wojciech's modified submission, he changed the bitmask variable to a 
> signed int, with the reasoning that enum values are also signed ints, 
> and this eliminates the need for a typecast to get rid of compiler 
> warnings.
> 
> This caused me to weigh in with the workaround of declaring the bit 
> values as static const unsigned int, and keeping the bitmask unsigned. 
> But this goes against the OSG precedent set with the Optimizer.
> 
> The ensuing discussion has covered the merits, or lack thereof 
> (depending on the poster) of declaring bitmasks as signed or unsigned.
> 
> What this really boils down to is: If we decide that the MSFBO 
> bit/bitmask declarations should be different from the Optimizer pattern 
> for bits and bitmasks, then we should change the Optimizer to follow the 
> new standard, and also do the same for any other classes that followed 
> the Optimizer's current pattern.
> 
> If you could post with "do it this way" or "do it that way", I (for one) 
> could get back to work and stop prodding everyone with my code style 
> opinions. :-)




> Thanks,

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