[FIX] Undefined behaviour on comparison of NaN and float at particlemgr.cpp

[celisej567]

At particlemgr.cpp in class CParticleEffectBinding there is a variable named float m_flParticleCullRadius that (as i think valve expected to happen) are 0.0f -ed in constructor by calling SetParticleCullRadius(0.0f), but looks like they didnt know that if ( m_flParticleCullRadius != flMaxParticleRadius ) that happens in SetParticleCullRadius working with float NaN, which is Undefined Behaviour, and results of this thing are declared by individual compilers realization. Even differend msvc versions can handle this differendly.

As the result of the problem some particles like explosions, sparks, smoke and dust may not appear at all. There even where no drawcall at this conditions.

Hopefully it can be fixed easely, by manually 0.0f -ing m_flParticleCullRadius in constructor.

Also, it can be forced to happen every time. Just instead of m_flParticleCullRadius = 0.0f; put m_flParticleCullRadius = nanf(""); in constructor.

If you want to actually see how this looks like, ive recorded it in hl2 here. Exactly same happends in alien swarm.

Ive made same push request in mapbase and it was approved.

[BenLubar]

Thanks!