4bbc4589e7
The pathing and step-cache comments had accumulated as development notes rather
than documentation: internal phase jargon ("Tier 4", "the Phase-2 synthesizer"),
change narration aimed at a reviewer ("which the old ComputeStandingZ anchor
missed", "legacy behavior"), benchmark anecdotes ("benchmarked as near-optimal",
"a ~20 ns lookup"), and multi-paragraph blocks restating what the code says.
Rewritten to keep the rationale a reader cannot derive from the code - why the
source-Z guard cannot be loosened, why multis fall through, why the promotion gate
counts Finds instead of calls, why the fingerprint hashes files rather than the
live tile tables - and to drop the history that got us there.
Also corrects comments that had gone stale:
- CacheEvictionTimer and CacheStats documented a class named
StaticWalkabilityCache, which no longer exists; it is StepCache.
- StepCacheFile's header said "File layout v8" while FormatVersion is 9, and the
body called the current record layout "the v6 layout" throughout. The layout
descriptions are now unversioned, since they describe whatever FormatVersion
currently is.
- StepProbe.ComputeStandingZ claimed StepCache uses it to bake SourceZ. It hasn't
since the baker moved to the clearance-aware ComputeStandableSurfaceZs; only a
parity test calls it now.
Two small code changes came along with the comment work, both behavior-preserving:
_lazyReaders now uses a collection expression like its neighbours, and
TryLoadFromLazyReader collapses to an expression body once its inline comment moved
to the doc comment.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
85 lines
2.8 KiB
C#
85 lines
2.8 KiB
C#
namespace Server.Engines.Pathing.Cache;
|
|
|
|
/// <summary>
|
|
/// Per-cell, per-direction walkability baked by <see cref="StepProbe"/> and stored by
|
|
/// <see cref="StepCache"/>. Two rule sets travel together: WalkMask + WalkZ_* for a default
|
|
/// walker (cantWalk=false, canSwim=false), WetMask + SwimZ_* for a swim-only mob
|
|
/// (cantWalk=true, canSwim=true). Callers overlay whichever applies to the mobile.
|
|
/// </summary>
|
|
public readonly struct StepMask(
|
|
byte walkMask,
|
|
byte wetMask,
|
|
sbyte walkZN,
|
|
sbyte walkZNE,
|
|
sbyte walkZE,
|
|
sbyte walkZSE,
|
|
sbyte walkZS,
|
|
sbyte walkZSW,
|
|
sbyte walkZW,
|
|
sbyte walkZNW,
|
|
sbyte swimZN,
|
|
sbyte swimZNE,
|
|
sbyte swimZE,
|
|
sbyte swimZSE,
|
|
sbyte swimZS,
|
|
sbyte swimZSW,
|
|
sbyte swimZW,
|
|
sbyte swimZNW,
|
|
CacheHitKind hitKind = CacheHitKind.Hit
|
|
)
|
|
{
|
|
public readonly byte WalkMask = walkMask;
|
|
public readonly byte WetMask = wetMask;
|
|
public readonly sbyte WalkZ_N = walkZN;
|
|
public readonly sbyte WalkZ_NE = walkZNE;
|
|
public readonly sbyte WalkZ_E = walkZE;
|
|
public readonly sbyte WalkZ_SE = walkZSE;
|
|
public readonly sbyte WalkZ_S = walkZS;
|
|
public readonly sbyte WalkZ_SW = walkZSW;
|
|
public readonly sbyte WalkZ_W = walkZW;
|
|
public readonly sbyte WalkZ_NW = walkZNW;
|
|
public readonly sbyte SwimZ_N = swimZN;
|
|
public readonly sbyte SwimZ_NE = swimZNE;
|
|
public readonly sbyte SwimZ_E = swimZE;
|
|
public readonly sbyte SwimZ_SE = swimZSE;
|
|
public readonly sbyte SwimZ_S = swimZS;
|
|
public readonly sbyte SwimZ_SW = swimZSW;
|
|
public readonly sbyte SwimZ_W = swimZW;
|
|
public readonly sbyte SwimZ_NW = swimZNW;
|
|
public readonly CacheHitKind HitKind = hitKind;
|
|
|
|
/// <summary>
|
|
/// True when the cache produced a usable answer. False on any Fallthrough_*, where the
|
|
/// payload is all zeroes and the caller must resolve this cell via the slow path.
|
|
/// </summary>
|
|
public bool IsHit => HitKind <= CacheHitKind.Miss_DirtyRebuild;
|
|
|
|
public bool IsWalkable(Direction d) => (WalkMask & (1 << (int)d)) != 0;
|
|
public bool IsSwimmable(Direction d) => (WetMask & (1 << (int)d)) != 0;
|
|
|
|
public sbyte GetWalkZ(Direction d) => d switch
|
|
{
|
|
Direction.North => WalkZ_N,
|
|
Direction.Right => WalkZ_NE,
|
|
Direction.East => WalkZ_E,
|
|
Direction.Down => WalkZ_SE,
|
|
Direction.South => WalkZ_S,
|
|
Direction.Left => WalkZ_SW,
|
|
Direction.West => WalkZ_W,
|
|
Direction.Up => WalkZ_NW,
|
|
_ => 0
|
|
};
|
|
|
|
public sbyte GetSwimZ(Direction d) => d switch
|
|
{
|
|
Direction.North => SwimZ_N,
|
|
Direction.Right => SwimZ_NE,
|
|
Direction.East => SwimZ_E,
|
|
Direction.Down => SwimZ_SE,
|
|
Direction.South => SwimZ_S,
|
|
Direction.Left => SwimZ_SW,
|
|
Direction.West => SwimZ_W,
|
|
Direction.Up => SwimZ_NW,
|
|
_ => 0
|
|
};
|
|
}
|