[PATCH] CmpRangeManager optimisation

[wraitii]

Following some recent profiling, I have noticed that a big part of PerformQuery is checking each entity for the existence of a given interface in TestEntity.

The attached patch is rather barebones, but stores a pointer to the component cache in the entity data and thus makes this computation much much faster.

Would like some other people to confirm or infirm the results. I personally tested over an MP replay.

NB: fairly sure 64-bit systems will need the struct size to be 36 and not 32, should have used 28 + sizeof(void*).

[wraitii]

In 18344:

Re-use the same vector for the range manager spatial subdivision queries to cut down on allocations and memory fragmentation. Refs #4045

[wraitii]

fewercopy.patch changes the way we iterate the subdivision query results. Instead of copying the subdivision vectors in a larger vector, we copy a pointer to the first member of that vector and a size. Then we iterate in two steps, first over the returned vectors, then over the size (recasting everything properly). Data locality should be pretty good still.

This should be a bigger optimization if there are many entities in subdivisions.

Additionally hadn't noticed but we could probably skip the "empty" verification, since size would be 0.

[wraitii]

Updated to remove the empty check and the misplaced auto

[wraitii]

Saner version passing a vector thanks to sanderd

[elexis]

See comments in irc (​http://irclogs.wildfiregames.com/2016-06-14-QuakeNet-%230ad-dev.log)

[elexis]

Only one comment I think:

17:12 <@leper> #4045 not sure I like all that leaking of internal data structures all over the place