simulation
The purpose of weak_ptr is to avoid performing the simulation on deleted
Actor by promoting it to a shared_ptr via a lock() call. This clutter
the code with a lot of branches, whereas the overwhelmingly common case is for the call to succeed.
Since the simulation is decoupled from the engine state, we can use a shared_ptr instead of a weak_ptr.
This allow us to ignore (ie not handle) the rarer case where the actor is delete from the scene. This means that the simulation
will run for one frame more than before for each actor, whereas the rest of the engine
will be ignorant of this.
MWWorld::Ptr:
- they are equivalent
- btCollisionObject* is readily available from the simulation, it saves
a call to a mutex
- btCollisionObject* is smaller
- compute the swimming state instead of storing it, it changes as part of the simulation and was not updated, so it was wrong anyway.
- store the swim level in ActorFrameData, it is constant per Actor so no need to compute it inside the simulation
ActActorFrameData structure. It makes it easier to reason about the
simulation (and hopefully simplify it).
Remove atomics from Actor class as a side effect.
Rename mFloatToSurface to mInert to make is explicit what it represent, not what it is used for
Store the Actor rotation (1 Vec2) instead of the whole ESM::Position (2 Vec3)
- inline PhysicsSystem::applyQueuedMovements() into PhysicsSystem::stepSimulation()
- rename PhysicsTaskScheduler::moveActors() to PhysicsTaskScheduler::applyQueuedMovements()
- move the actor movement code from World::doPhysics() to
PhysicsSystem::moveActors() (analogically to the projectile manager)
with a TTL of 0 frame. It helps performance when several subsystems
request the same LOS in the same frame (combat, headtracking, etc).
Except it doesn't work if the cache is never trimmed.
- default to 1 thread
- default to always use defered aabb update, remove option
- always keep a cache of LOS request for at least the current frame.
This decreases number of raycast, especially when a lot of actors are
involved and "NPCs avoid collisions" is on
In this case, the actor mPreviousPosition is not updated, so the actor
position is interpolated between an old (stucked) position and the new
(unstucked) position. The new position is most likely "stucked", so the
unstuck code strikes again, making the actor "vibrates".
That's exactly what the sync code path does, and it doesn't exhibit this
behavior.
What happened is that the last handle to an Actor shared_ptr was a
promoted weak_ptr. When the shared_ptr goes out of scope, the Actor dtor
is invoked. That involves removing the Actor collision object after
exclusively locking mCollisionWorldMutex. In this case, the lock was
already held in the outter scope of the promoted weak_ptr.
Reduce the scope of the mCollisionWorldMutex to never encompass the
lifetime of a promoted weak_ptr.
One of the issue since the introduction of async physics is the quirky
handling of scripted moves. Previous attempt to account for them was
based on detecting changes in actor position while the physics thread is
running. To this end, semantics of Actor::updatePosition() (which is
responsible for set the absolute position of an actor in the world) was
toned down to merely store the desired position, with the physics system
actually responsible for moving the actor. For the cases were complete
override of the physics simulation was needed, I introduced
Actor::resetPosition(), which actually have same semantics as
original updatePosition(). This in turn introduced a loads of new bugs
when the weakened semantics broke key assumptions inside the engine
(spawning, summoning, teleport, etc).
Instead of tracking them down, count on the newly introduced support for
object relative movements in the engine (World::moveObjectBy) to
register relative movements and restore original handling of absolute positionning.
Changes are relatively small:
- move resetPosition() content into updatePosition()
- call updatePosition() everywhere it was called before
- remove all added calls to the now non-existing resetPosition()
tldr; ditch last month worth of bug introduction and eradication and redo
it properly
This gives finer control over reseting positions (switch off tcl is no
longer glitchy) and solve most of the erroneous usage of stale World::Ptr
indicated by:
"Error in frame: moveTo: object is not in this cell"
its current position.
Use it in relevant MWScripts opcode (move and moveworld).
Remove the fragile detection of scripted translation from PhysicsTaskScheduler.
No user visible change, just a more robust mechanism.
position being used under heavy load, I introduced a regression that
prevented the position to be updated in case of teleport.
Move the logic in its own function and decide in PhysicsSystem whether a
reset is needed.
be sure the simulation is over. Otherwise, if the simulation is too slow
the position is wrong, and the actors would jump back and forth between
old and new position instead of actually moving.
