GetEntityState is a performance-critical function in the GUI when a
large number of units are selected. The goal of this patch is to
increase the efficiency of it without modifying the returned states
visible to rest of the GUI in any way (it renames a few properties of
entities states or moves them around, but the information they contain
and the way to access it remain the complete same)
As explained the comments, certain parts (the template data) of an
entity state are "predictable" and can be reused between entities with
the same template.
What one has to account for, however, is that values of the template
data can be modified. This happens on two different levels:
Firstly, player-wide modifications, which apply to all entities owned
by that player. This includes stuff like bonuses from researched techs,
civs bonuses, team bonuses. And secondly, entity-local modifications,
which apply to individual entities. This includes buffs or debuffs from
status effects or auras (of other entities).
So we can construct a whole entity state by first just computing the
dynamic state (stuff like current hitpoints, which differs from entity
to entity) and then adding the (potentially already cached) template
data to it, which can be reused between entities with the same template
and owning player. And then overwrite the values affected by
entity-local modifications, which are usually just a few and even they
can be cached and reused for entities with the same owning player,
template, and entity-local modifications (identified by the
"modifications ID").
This saves the effort of retrieving/computing a ton of data each turn
and also saves the time it takes the engine to clone the data from the
simulation to the GUI (as the return value of the GUI interface call),
which previously took just as long as retrieving the entity states
themselves.
Since only the dynamic state is read from the components, a number of
small getter methods have become unused; they are kept (for now at
least) since they might be useful again in the future or for mods.
This patch is primarily meant as preparation in order to be able to
reuse this logic for GetEntityState calls in the future.
Key changes:
- Clearer API by providing different functions for different purposes.
- Slight performance optimisation by storing parameters in a context
object and pulling the info from there instead of redeclaring a lambda
each time, which it seems Spidermonkey struggled to optimise well.
- Allow computing only partial template data, specified by passing a
list of desired components. (to be used more in the future)
- Make it so the naming and structure of template data and matches 1:1
with the data in entity states. This makes accessing values from them
more consistent and would also allow e.g. adopting data between the two
in the future.
It is possible to modify sizes by setting the properties directly.
(Without having to create a copy of it)
This allows to shorten those passages quite a bit without any functional change.
("Variant" in this case means a template that is functionally the same
as its
base template - but is a different promotion level, requires a
technology to
unlock (that the base template doesn't), is an upgrade of its base, or
is a
trainable version.)
Should fix concern raised on b2842e8021.
Accepted by: Angen
Differential Revision: https://code.wildfiregames.com/D3347
This was SVN commit r25260.
