We do this by using the GImpact shapes. These work, but are resource
intensive. So make sure you don't use too many of these in free mode.
This isn't thouroughly researched though. It might be worth looking into
btCollisionHull, or to alter some of the parameters to fine tune the
simulation.
To allow for better performance when scaling to larger worlds we can't keep
iterating though all entities when checking visibility.
Instead we now have the PhysicalDomain keep track of all entities that are
either observering something, or being observed.
Since Bullet already contains efficient structures for doing space partioning and
collision detections we'll resuse that for visibility checks.
Each entity now has a sphere of "visibility" with which each perceptive entity does
checks against.
The Inventory domain is meant for all characters, i.e. those than can have
an "inventory".
It's a non physical domain, which means that entities contained in it won't
be affected by any physical constraints, or have physics applied to them.
Visibility for outside entities are by default forbidden unless an entity is
outfitted or wielded.
The idea is that other playes shouldn't see what's in the inventory of another
player, unless things are outfitted or wielded.
In some cases you want to store property data for each instance. Often
you'll use member data on the entities themselves for this. But in some
cases you don't want to bloat the entity class with data for seldomly
used properties.
In these cases you can instead use the PropertyInstanceState class, and
keep a static instance of this per property.
As any world can contain multiple domains, we let the domain handle the
sights calculations.
This is a change from how this previously was done, as previously
sight checks were only done for the top level World entity. This has
changes however, so that sights checks now are done for all entities.
When determining whether an entity can be seen, the system first checks
the size of the entity against the distance from the observer. If this
check fails, the system makes exceptions if the entity in case is
outfitted or wielded.
