-- [ Picked text/plain from multipart/alternative ] Oh I see what Vino was getting at now. Indeed, that is odd. Especially with Ryans tests.
On 4/8/06, Jorge Rodriguez <[EMAIL PROTECTED]> wrote: > > Ryan Desgroseilliers wrote: > > >I think a great many people seem to be ignoring his actual > >question/issue in order to add completely irrelevant details and > >digressions, or to defend Valve's coding practices against some > >perceived criticism that just isn't there. The suggestion that *every* > >use of Vector::Normalize() was a reassignment of the result back to > >the original vector is silly; just do a search of the 2.3 SDK and > >you'll find plenty of counter-examples. > > > >The member function from HL1 he's referring to, Vector::Normalize(), > >was a simple inline constant member function that has *no effect* on > >the vector it is called with. It has nothing to do with code speed and > >everything to do with reducing the quantity of code verbiage that > >needed to be written for quick, one-off uses of normalized vectors. > >Basically, it's a question of: > > > >Vector vecTempNormalized = vecUseful; > >VectorNormalize(vecTempNormalized); // can also use NormalizeInPlace() > >FunctionUsingNormalVector(vecTempNormalized, [...]); > >// Additional code requiring vecUseful in its original form > > > >versus > > > >FunctionUsingNormalVector(vecUseful->Normalize(), [...]); > >// Additional code requiring vecUseful in its original form > > > >With regards to speed, I did a quick test run using two stripped-down > >vector classes, with allocation being done before starting the time > >count and the test vector being kept constant to avoid the square-root > >causing a bias. The net result was that the global function method was > >only about 7% faster after 50000000 loops of each. Given the amount of > >other stuff happening in the game, and the fact that the engine can > >use whatever method it wants, I suspect that the occasional call to a > >member function of this kind for expediency from the game DLL would > >have an utterly negligible effect on game performance. > > > >The advantage increases to about 11% if the vector is reassigned to > >itself instead of a separate variable, but [a] you can still (and > >should!) use NormalizeInPlace() for that, and [b] once again, it is > >overwhelmed by the amount of other stuff going on in the game. If you > >consider the direct passing as a function argument (i.e. the example I > >suggested above), the member function method is actually about 22% > >faster, and a bit lighter on memory. > > > >Adding a nonvirtual Normalize() function to the Vector class should > >not affect the vtables -- the function will have a valid address > >defined for any pointer to the class regardless of the object it > >points to (you can even call the function from a NULL pointer, with > >predictably undefined results), and its presence should not require > >additional storage. So yes, as Tony said you can probably add it > >without any problems. > > > >==================== > >Ryan Desgroseilliers > >Project Director, Half-Life: Nightwatch > > > > > WOW! > > Finally, somebody who understands me! A thoughtful, intelligent, > relevant and useful response! I never thought one of those would appear > from this thread. > > This is all good to know. I believed it's possible to add a Normalize() > when Tony said it, but was too upset with all the cruft to say so. I'll > be sure to put this information to good use. > > Still, none of this answers the original question about why the method > was removed in the first place, but I suppose that's all academic now. > It was probably removed by a misinformed Valve employee years ago who > doesn't remember doing it. Either way, adding it back is no big problem. > > Thanks, Tony and Ryan. > > -- > Jorge "Vino" Rodriguez > > > _______________________________________________ > To unsubscribe, edit your list preferences, or view the list archives, > please visit: > http://list.valvesoftware.com/mailman/listinfo/hlcoders > > -- Programmer for RnL www.resistanceandliberation.com -- _______________________________________________ To unsubscribe, edit your list preferences, or view the list archives, please visit: http://list.valvesoftware.com/mailman/listinfo/hlcoders
