Files
RP412/MUNGA/MOVER.h
T
CydandClaude Opus 5 ec815b6216 One late packet is not the new rate
Another player's pod is moved between updates by dead reckoning, which
advances it toward the projected position by a fraction of the remaining
gap each step:

    percent = time_slice / ((nextUpdate - lastPerformance) + time_slice)

That fraction is decided by nextUpdate, so predicting when the next
packet lands is not cosmetic - it sets how far every step moves. The
prediction was labelled HACK in the original source and deserved it: the
next gap was assumed to equal the previous gap. On a LAN the gaps were
all alike and it held. Over Steam a single late packet doubles the
expected gap, percent collapses, the pod barely advances for one step and
then catches up on the next - a visible tick.

Measured on a live connection, in the replicant's own step grid: 7 spikes
in 5 seconds, about 1.4 a second, matching the reported symptom, with
percent bottoming out at 0.014 against a normal range of 0.27 to 0.95.

Predict from the median of the last eight gaps instead. A median has a
breakdown point of half its samples, so one straggler - or three - moves
it not at all, while a genuine change in the send rate still carries it
within a few updates. Gaps that are non-positive (duplicate or reordered)
or multi-second (a join or a stall) never enter the window, and the
window is reset outright when the stream is interrupted.

Against the measured jitter pattern the blend fraction holds 0.282..0.286
where it previously swung 0.095..0.294 - a spread fifty times smaller.

This changes how remote pods MOVE, not merely how they are drawn, so it
feeds collisions with them as well. RP412NETPREDICT=0 restores the old
prediction for comparison on the same build, and the environ.ini entry
says to keep the setting alike on every machine in a race.

The RP412CAMLOG trace now also reports the interval being predicted and
the worst one-step-ahead miss, scored per entity rather than through the
file-scope statics the percent readings use - those are written by
whichever mover ran last, which is exactly the crossed frame of reference
this whole investigation kept tripping over.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-11 08:30:01 -05:00

499 lines
11 KiB
C++

#pragma once
#include "entity.h"
#include "motion.h"
class Mover__SharedData;
class Mover;
class CollisionAssistant;
class BoundingBoxTreeNode;
class BoxedSolid;
class BoxedSolidCollision;
class BoxedSolidCollisionList;
class Normal;
class Line;
class Environment;
//##########################################################################
//#################### Mover::UpdateMessage ##########################
//##########################################################################
struct Mover__UpdateRecord:
public Entity::UpdateRecord
{
public:
Motion
localVelocity,
localAcceleration;
Vector3D
worldLinearVelocity,
worldLinearAcceleration;
};
//##########################################################################
//##################### Mover::MakeMessage ##########################
//##########################################################################
class Mover__MakeMessage:
public Entity::MakeMessage
{
public:
Motion
localVelocity,
localAcceleration;
Mover__MakeMessage(
Receiver::MessageID message_ID,
size_t length,
Entity::ClassID class_ID,
const EntityID &owner_ID,
ResourceDescription::ResourceID resource_ID,
LWord instance_flags,
const Origin &origin,
const Motion &velocity,
const Motion &acceleration
):
Entity::MakeMessage(
message_ID,
length,
class_ID,
owner_ID,
resource_ID,
instance_flags,
origin
),
localVelocity(velocity),
localAcceleration(acceleration)
{}
Mover__MakeMessage(
Receiver::MessageID message_ID,
size_t length,
const EntityID &entity_ID,
Entity::ClassID class_ID,
const EntityID &owner_ID,
ResourceDescription::ResourceID resource_ID,
LWord instance_flags,
const Origin &origin,
const Motion &velocity,
const Motion &acceleration
):
Entity::MakeMessage(
message_ID,
length,
entity_ID,
class_ID,
owner_ID,
resource_ID,
instance_flags,
origin
),
localVelocity(velocity),
localAcceleration(acceleration)
{}
};
//##########################################################################
//##################### Mover::ModelResource #########################
//##########################################################################
struct Mover__ModelResource
{
Scalar moverMass;
Vector3D
momentOfInertia,
positiveLinearDragCoefficients,
negativeLinearDragCoefficients,
angularDragCoefficients;
Scalar
frictionCoefficient,
elasticityCoefficient,
minimumBounceSpeed;
};
//##########################################################################
//############################ Mover #################################
//##########################################################################
class Mover:
public Entity
{
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Shared Data support
//
public:
static Derivation *GetClassDerivations();
static SharedData DefaultData;
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Attribute Support
//
public:
enum {
LocalVelocityAttributeID = Entity::NextAttributeID,
LocalAccelerationAttributeID,
WorldLinearVelocityAttributeID,
WorldLinearAccelerationAttributeID,
MoverMassAttributeID,
MomentOfInertiaAttributeID,
PositiveLinearDragCoefficientsAttributeID,
NegativeLinearDragCoefficientsAttributeID,
AngularDragCoefficientsAttributeID,
FrictionCoefficientAttributeID,
ElasticityCoefficientAttributeID,
MinimumBounceSpeedAttributeID,
NextAttributeID
};
private:
static const IndexEntry AttributePointers[];
protected:
//static AttributeIndexSet AttributeIndex
static AttributeIndexSet& GetAttributeIndex();
//
// public attribute declarations go here
//
public:
Motion
localVelocity,
localAcceleration;
Vector3D
worldLinearVelocity,
worldLinearAcceleration;
Scalar moverMass;
Vector3D
momentOfInertia,
positiveLinearDragCoefficients,
negativeLinearDragCoefficients,
angularDragCoefficients;
Scalar
frictionCoefficient,
elasticityCoefficient,
minimumBounceSpeed;
//
// virtual access
//
public:
virtual Vector3D
GetWorldLinearVelocity()
{return worldLinearVelocity;}
virtual Vector3D
GetWorldLinearAcceleration()
{return worldLinearAcceleration;}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Model Support
//
public:
enum {
StasisState = Entity::StateCount,
StateCount
};
typedef Mover__UpdateRecord UpdateRecord;
typedef Mover__MakeMessage MakeMessage;
typedef void
(Mover::*Performance)(Scalar time_slice);
void
SetPerformance(Performance performance)
{
Check(this);
activePerformance = (Simulation::Performance)performance;
}
void
UpdateWorldMotion();
void
UpdateLocalMotion();
void
ApplyWorldAccelerations(Scalar time_slice);
void
ApplyAirResistanceAndGravity(Scalar power=1.0f);
void
CalculateDrag(
Vector3D *drag,
const Vector3D &velocity,
const Vector3D &positive_CODs,
const Vector3D &negative_CODs,
Scalar power
);
void
ApplyLocalForce(
const Vector3D &force,
const Vector3D &moment
);
void
ApplyLocalAcceleration(
const Vector3D &acceleration,
const Vector3D &moment
);
Environment*
GetEnvironment()
{Check(this); return localEnvironment;}
typedef Logical (Mover::*DeadReckoner)();
void
SetDeadReckoner(DeadReckoner reckoner)
{Check(this); deadReckoner = reckoner;}
Logical
NoDeadReckoner();
Logical
LinearDeadReckoner();
Logical
AcceleratedDeadReckoner();
void
DeadReckon(Scalar time_slice);
protected:
void
WriteUpdateRecord(
Simulation::UpdateRecord *message,
int update_model
);
void
ReadUpdateRecord(Simulation::UpdateRecord *message);
void
PerformAndWatch(
const Time& till,
MemoryStream *update_stream
);
//
// Per-step set-up under fixed stepping: clears the force accumulator
// the thrusters add into, so each step integrates only its own
// forces. See the definition for the frame-jitter bug this closes.
//
void
BeginStep();
int
normalizeCount;
Environment
*localEnvironment;
DeadReckoner
deadReckoner;
Origin
projectedOrigin,
previousOrigin;
Motion
projectedVelocity,
updateAcceleration,
updateVelocity;
Time
nextUpdate;
//
// Recent gaps between replication updates for this entity, as a ring,
// and the running estimate drawn from them. The original code predicted
// the next gap from the single previous gap; see PredictUpdateInterval
// for why that stalls a step every time a packet runs late.
//
enum {UpdateIntervalSamples = 8};
Scalar
updateIntervals[UpdateIntervalSamples];
int
updateIntervalCount,
updateIntervalWrite;
//
// The interval last predicted, and how wrong the prediction before it
// proved to be once the gap it described actually elapsed. Per entity,
// so a trace reads the entity it is watching.
//
Scalar
predictedInterval,
predictionError;
Scalar
PredictUpdateInterval(Scalar latest);
void
ResetUpdateIntervals();
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Collision support
//
public:
virtual void
MoveCollisionVolume();
BoundingBoxTreeNode*
GetMoverCollisionRoot()
{Check(this); return containedByNode;}
BoxedSolidCollisionList*
AllocateCollisionList();
BoxedSolidCollisionList*
GetCurrentCollisions(BoxedSolidCollisionList *list=NULL);
BoxedSolid*
FindBoxedSolidHitBy(
Line *line,
Entity *except_by
);
BoxedSolidCollisionList*
CollideCenterOfMotion(
Line *line,
BoxedSolidCollisionList *list
);
void
ProcessCollisionList(
BoxedSolidCollisionList *collisions,
Scalar time_slice,
const Point3D &old_position,
Damage *damage
);
Scalar
StaticBounce(
const Point3D &old_position,
Scalar delta_t,
Scalar penetration,
const Normal &normal,
Scalar *elasticity,
Scalar bounce_min,
Scalar *friction
);
Scalar
DynamicBounce(
Mover *other,
Scalar delta_t,
Scalar penetration,
const Normal &normal,
Scalar *elasticity
);
BoxedSolid*
GetCollisionVolume()
{Check(this); return collisionVolume;}
BoxedSolid*
GetCollisionTemplate()
{Check(this); return collisionTemplate;}
int
GetCollisionVolumeCount()
{Check(this); return collisionVolumeCount;}
virtual void
StartCollisionAssistant();
protected:
int collisionVolumeCount;
BoxedSolid
*collisionVolume,
*collisionTemplate;
BoundingBoxTreeNode *containedByNode;
BoxedSolidCollisionList
*collisionLists,
*lastCollisionList;
CollisionAssistant *collisionAssistant;
virtual void
ProcessCollision(
Scalar time_slice,
BoxedSolidCollision &collision,
const Point3D &old_position,
Damage *damage
);
void
CheckAgainstBoxedSolidChain(
BoxedSolidCollisionList *collisions,
BoxedSolid *chain
);
public:
void
CheckVolumeAgainstBoxedSolidChain(
BoxedSolidCollisionList *collisions,
BoxedSolid *chain
);
protected:
BoxedSolid*
CheckLineAgainstBoxedSolidChain(
Line *line,
BoxedSolid *chain
);
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Flag Support
//
public:
enum {
NoCollisionVolumeBit = Entity::NextBit,
NoCollisionTestBit,
InitialStasisBit,
NextBit
};
enum {
NoCollisionVolumeFlag = 1<<NoCollisionVolumeBit,
NoCollisionTestFlag = 1<<NoCollisionTestBit,
InitialStasisFlag = 1<<InitialStasisBit,
DefaultFlags = DynamicFlag|MasterInstance
};
void
NoCollisionVolume()
{Check(this); simulationFlags |= NoCollisionVolumeFlag;}
void
SetCollisionVolume()
{Check(this); simulationFlags &= ~NoCollisionVolumeFlag;}
Logical
IsCollisionVolume()
{Check(this); return (simulationFlags&NoCollisionVolumeFlag) == 0;}
void
NoCollisionTest()
{Check(this); simulationFlags |= NoCollisionTestFlag;}
void
SetCollisionTest()
{Check(this); simulationFlags &= ~NoCollisionTestFlag;}
Logical
IsCollisionTestable()
{Check(this); return (simulationFlags&NoCollisionTestFlag) == 0;}
Logical
IsInitialStasis()
{Check(this); return (simulationFlags&InitialStasisFlag) != 0;}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Construction and Destruction
//
public:
typedef Mover__ModelResource ModelResource;
static Mover*
Make(MakeMessage *creation_message);
//
// Warning... This function requires a properly set up strtok!!!!
//
static Logical
CreateMakeMessage(
MakeMessage *creation_message,
NotationFile *model_file,
const ResourceDirectories *directories
);
static ResourceDescription::ResourceID
CreateModelResource(
ResourceFile *resource_file,
const char* model_name,
NotationFile *model_file,
const ResourceDirectories *directories,
ModelResource* model = NULL
);
Mover(
MakeMessage *creation_message,
SharedData &virtual_data
);
~Mover();
Logical
TestInstance() const;
};