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feat: derive the Running bit from the step pace and fix step-pacing bursts (#2599)

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Stacked on #2594. Fixes jerky creature movement (lich / Fast-bucket melee chases) by choosing the client animation flag from the actual step pace instead of a caller-supplied `run` argument, and fixes three step-pacing defects in the move budget found while verifying it with paired server/client traces.

### Why

The `Direction.Running` bit does nothing for creatures server-side (`Mobile.OnMove` reads it only for the player throttle and stealth reveal). Its whole effect is on the client, which animates each step over a fixed time selected by that bit: walk 400 ms / run 200 ms on foot, 200 / 100 ms mounted. ClassicUO queues up to 5 steps and *drops* the sixth, so a creature stepping every 300 ms while flagged as walking backs the queue up until it snaps forward — the observed jerk.

The `run` argument never carried the one fact that matters (the step interval). RunUO passed `true` in combat / `false` for pets and gated it on `dist > 5`; #2271 flipped every combat site to `false`; pets passed `currentDistance > 2`. None of that is a coherent signal.

### What

**Pace-derived run flag**
- `BaseAI.ShouldRun()`: run iff the effective step delay (move clock + badly-hurt inflation) is shorter than `Movement.WalkFootDelay` / `WalkMountDelay` (mounted or flying) — with a continuity rule: an *isolated* step (taken after standing at least a walk interval) goes out as a walk, because the client renders each step alone and a lone run-flagged step is a 200 ms dart. Only a continuing cadence flags run; a true sprinter (pace under the run interpolation) always runs, since a walk-rendered first step would flood the client's 5-step queue. This reproduces RunUO's close-in feel (its `dist > 5` gate) from first principles.
- `DoMoveImpl` stamps the bit; it is the single place the flag is set.
- `run` removed from `MoveTo`, `WalkMobileRange`, `ApproachTarget`, `MoveToPoint`, `MoveToWithGroup`, `MoveToWithCollisionAvoidance`, the move intent, and `PathFollower.Follow`. All 35 call sites updated. **API change** for custom scripts — documented in the RunUO migration docs (`09-items-mobiles-creatures.md`, `11-api-reference.md`) and `content-patterns.md` § Creature Speeds.

**Move-budget pacing fixes** (each confirmed by UTC-aligned server/client step traces)
- A stall no longer banks catch-up steps: the budget's snap-to-now released up to three steps in ~300 ms when a creature resumed chasing after standing beside its target — rendered as a teleport.
- Debt accrual removed entirely: a step landing sub-period late (think-grid vs budget misalignment during reactive mirroring) kept the remainder and fired a follow-up ~100 ms later — a dart pair. `ConsumeMoveBudget` now paces every step from when it was actually taken; in continuous pursuit the move-wake lands within wheel resolution of the deadline, so the cost is single-digit-ms drift.
- Net effect: a creature can never step faster than its pace, verified across a full chase session (zero sub-pace steps; metronomic 350 ms cadence for a 0.3 s lich).

- Test fixture now runs `Movement.Configure()` (the walk delays were 0 in tests).

### Accepted trade-off

Animal (LOW group) bodies without a run animation slide on their stand frames when flagged as running. Most are slow enough to stay flagged as walking; the client-side fallback is in ClassicUO/ClassicUO#1930.

### Tests

`RunFlagTests`: foot thresholds (0.3 / 0.125 run; 0.4 / 0.45 / 1.05 walk), flying uses the mount threshold, badly-hurt inflation flips a 0.35 s creature back to walk, a real `DoMove` stamps the bit, isolated steps drop to walk (sprinters keep running), a stall restarts the cadence with no banked steps, and a late step earns no quicker follow-up. Full suite: 837 Server + 747 UOContent green.
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Kamron Batman 2026-08-30 16:48:52 -07:00 • committed by GitHub
parent 4420872b22
commit e07416902a
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26 changed files with 294 additions and 84 deletions
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1
Projects/UOContent.Tests/Fixtures/TestServerInitializer.cs
View file

@ -103,6 +103,7 @@ internal static class TestServerInitializer
// Registers the Accounts entity persistence; without it no test can construct an Account.
Server.Accounting.Accounts.Configure();
RaceDefinitions.Configure();
Server.Movement.Movement.Configure();
MovementImpl.Configure();
PathFollower.Configure();
World.Load();

10
Projects/UOContent.Tests/Tests/Mobiles/AI/ApproachTargetTests.cs
View file

@ -40,7 +40,7 @@ public class ApproachTargetTests
for (var i = 0; i < maxTicks; i++)
{
ai.NextMove = 0;
ai.WalkMobileRange(target, 1, false, 1, 2);
ai.WalkMobileRange(target, 1, 1, 2);
if (bc.InRange(target, arriveDist))
{
return true;
@ -123,7 +123,7 @@ public class ApproachTargetTests
for (var i = 0; i < 200; i++)
{
ai.NextMove = 0;
ai.MoveTo(target, false, 1);
ai.MoveTo(target, 1);
if (bc.InRange(target, 1))
{
arrived = true;
@ -154,7 +154,7 @@ public class ApproachTargetTests
for (var i = 0; i < 60; i++)
{
ai.NextMove = 0;
ai.MoveTo(target, true, 1);
ai.MoveTo(target, 1);
// Target walks west every other tick for its first several steps, then stops,
// so a same-speed chaser eventually closes the gap.
@ -214,7 +214,7 @@ public class ApproachTargetTests
for (var i = 0; i < 120; i++)
{
ai.NextMove = 0;
ai.MoveTo(target, false, 1);
ai.MoveTo(target, 1);
}
// After giving up, the creature must idle (not oscillate) while the goal is still.
@ -223,7 +223,7 @@ public class ApproachTargetTests
for (var i = 0; i < 20; i++)
{
ai.NextMove = 0;
ai.MoveTo(target, false, 1);
ai.MoveTo(target, 1);
if (bc.Location != idleStart)
{
stayedIdle = false;

162
Projects/UOContent.Tests/Tests/Mobiles/AI/RunFlagTests.cs Normal file
View file

@ -0,0 +1,162 @@
using System.Collections.Generic;
using Server;
using Server.Mobiles;
using Xunit;
namespace UOContent.Tests.Mobiles.AI;
// The Running bit is derived from the step pace: a step shorter than the client's walk
// interpolation (400ms on foot, 200ms mounted/flying) is flagged as a run.
[Collection("Sequential Pathfinding Tests")]
public class RunFlagTests : System.IDisposable
{
private readonly List<Mobile> _created = new();
private PetTestStub Spawn(double activeMove)
{
var pet = new PetTestStub();
pet.MoveToWorld(new Point3D(1000, 1000, 0), Map.Felucca);
pet.AIObject.AITimer?.Stop();
pet.SetMoveSpeed(activeMove, activeMove * 3);
pet.SetCurrentSpeedToActive();
pet.LastMoveTime = Core.TickCount; // mid-cadence unless a test says otherwise
_created.Add(pet);
return pet;
}
public void Dispose()
{
foreach (var m in _created)
{
m?.Delete();
}
_created.Clear();
}
[Theory]
[InlineData(0.3, true)]
[InlineData(0.125, true)]
[InlineData(0.4, false)]
[InlineData(0.45, false)]
[InlineData(1.05, false)]
public void FootCreature_RunsOnlyWhenFasterThanWalk(double activeMove, bool expected)
{
var pet = Spawn(activeMove);
Assert.Equal(activeMove, pet.CurrentMoveSpeed);
Assert.Equal(expected, pet.AIObject.ShouldRun());
}
[Theory]
[InlineData(0.3, false)]
[InlineData(0.15, true)]
public void FlyingCreature_UsesMountThresholds(double activeMove, bool expected)
{
var pet = Spawn(activeMove);
pet.Flying = true;
Assert.Equal(expected, pet.AIObject.ShouldRun());
}
[Fact]
public void BadlyHurt_SlowsBelowWalk_DropsToWalk()
{
var pet = Spawn(0.35);
Assert.True(pet.AIObject.ShouldRun());
// The hurt inflation is on the observed step pace, so the flag follows it.
pet.SetHits(100);
pet.Hits = 5;
pet.SetStam(100);
pet.Stam = 5;
Assert.False(pet.AIObject.ShouldRun());
}
[Theory]
[InlineData(0.3, true)]
[InlineData(0.45, false)]
public void DoMove_StampsRunningBit(double activeMove, bool expected)
{
var map = Map.Maps[1];
Assert.NotNull(map);
map.GetAverageZ(1500, 1600, out _, out var z, out _);
var pet = Spawn(activeMove);
pet.MoveToWorld(new Point3D(1500, 1600, (sbyte)z), map);
var ai = pet.AIObject;
ai.NextMove = 0;
var start = pet.Location;
Assert.True(ai.DoMove(Direction.West));
Assert.NotEqual(start, pet.Location);
Assert.Equal(expected, (pet.Direction & Direction.Running) != 0);
}
// An isolated step (after standing at least a walk interval) renders alone and darts
// if run-flagged, so it walks; continuing cadences and true sprinters keep the flag.
[Fact]
public void IsolatedStep_DropsToWalk()
{
var pet = Spawn(0.3);
pet.LastMoveTime = Core.TickCount - 1000;
Assert.False(pet.AIObject.ShouldRun());
}
[Fact]
public void IsolatedStep_SprinterStillRuns()
{
var pet = Spawn(0.125);
pet.LastMoveTime = Core.TickCount - 1000;
Assert.True(pet.AIObject.ShouldRun());
}
[Fact]
public void StallDoesNotBankCatchUpSteps()
{
var map = Map.Maps[1];
Assert.NotNull(map);
map.GetAverageZ(1500, 1600, out _, out var z, out _);
var pet = Spawn(0.3);
pet.MoveToWorld(new Point3D(1500, 1600, (sbyte)z), map);
var ai = pet.AIObject;
ai.NextMove = Core.TickCount - 1000;
Assert.True(ai.DoMove(Direction.West));
// A stall must restart the cadence at full pace: banked catch-up steps
// release as a burst the client renders as a sprint/teleport.
Assert.False(ai.CanMoveNow(out _));
Assert.True(ai.NextMove - Core.TickCount > 250);
}
[Fact]
public void LateStepDoesNotEarnAQuickerFollowUp()
{
var map = Map.Maps[1];
Assert.NotNull(map);
map.GetAverageZ(1500, 1600, out _, out var z, out _);
var pet = Spawn(0.3);
pet.MoveToWorld(new Point3D(1500, 1600, (sbyte)z), map);
pet.Warmode = true; // keep the active move clock through the step
var ai = pet.AIObject;
// The step lands 200ms past the budget — under one period, the reactive
// mirroring case (think grid vs budget deadline misalignment).
ai.NextMove = Core.TickCount - 200;
Assert.True(ai.DoMove(Direction.West));
// The debt must not be repaid: a sub-period catch-up step follows ~100ms
// behind and renders as a dart pair beside the player.
Assert.True(ai.NextMove - Core.TickCount > 250);
}
}