8e39da2810
### Summary
Fixes the long-standing reports of monsters losing track of players who run around a corner ("Is monster AI not using pathfinding? It seems to be LOS blocked by statics"). Root-cause investigation compared current behavior against RunUO line-by-line and traced the regressions through the AI overhaul era (#2232, #2246, #2379, #2401, #2461).
### Root causes and fixes
1. **Movement contract** — `MoveTo`/`ApproachTarget` returned false on every healthy mid-chase tick (true only on arrival), so MeleeAI's RunUO-inherited *"move failed and beyond RangePerception+1 → Guard"* clause — which RunUO only evaluated on genuine blockage — fired **every tick of every chase**. A mounted player trivially opens 17 tiles at a corner, the monster guards, Guard nulls the combatant, and re-acquisition is LOS-gated — unrecoverable through a wall. Movement now reports failure only on genuine failure (no step taken with no working path, or approach give-up). ArcherAI's equivalent clause moves to the hard leash.
2. **Last-known-position pursuit** — while a combatant is in LOS its position is recorded each think tick. When the target vanishes (corner, hiding, recall), the creature walks to the last-seen spot, stands guard there ~10s (restoring RunUO's guard grace, which had decayed to a single tick since #2246), and **re-engages instantly** if the same target re-enters view — bypassing the 10s reacquire throttle.
3. **`ChaseLeashRange`** — new virtual on BaseCreature (default `RangePerception * 2` = 32 tiles) replaces the inline `RangePerception * 3` (48) in Melee/Mage/Archer AI. Per-creature tunable via `[props`.
4. **Group movement demoted to a crowding refinement** — previously any uncontrolled creature with one ally within 8 tiles on the same target used greedy ring-stepping for the *entire* chase, with wall-slides counted as success, never invoking the pathfinder — the "aggroed but won't come around the corner" symptom for spawn groups. It now engages only near the target when allies actually contest the ring, and blocked/wall-slid steps escalate to the pathfinding approach primitive.
5. **Mages close distance on broken LOS** — a mage within casting range but LOS-blocked by geometry stood at the wall holding a spell target until the 60s combatant expiry (ProcessTarget short-circuits Think and its RunTo stands off at RangeFight). Geometry-blocked mages now close in until LOS returns, both pre-cast and while holding a target. Hidden targets (CanSee) and poison-cure priority unchanged. The new movement contract also stops the constant spurious `OnFailedMove` teleport rolls mid-chase.
6. **Move budget: one actual step per AI tick** — nothing advanced `NextMove` on a normal step (RunUO's `m_NextMove` budget was lost), so code paths attempting several moves in one think tick could cross multiple tiles at once — visible as "warping" when crowded creatures jockey for position. A successful step now consumes a half-step budget (floor 50ms): blocks intra-tick double moves, stays safely below the timer interval so legitimate next-tick moves are never jitter-throttled, and does not reintroduce `TransformMoveDelay` inflation. Blocked attempts consume nothing, so retry ladders (repath-and-step, the collision fan) are unaffected. `CanMoveNow` is also wraparound-safe now.
### Reference behavior
RunUO requires LOS to *acquire* a target and to *land* a hit or spell — never to *continue* a chase (its MeleeAI LOS bail-out is literally commented out in stock code). Chases drop only on: target hidden, target dead/off-map, beyond `RangePerception * 3`, 60s without combat interaction, or blocked movement while far away. This PR restores those semantics while adding the last-known-position investigation on top. NPC run flags are untouched — pace is AI-timer-driven and most NPC art has no run animation.
157 lines
4.2 KiB
C#
157 lines
4.2 KiB
C#
namespace Server.Mobiles;
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public class MeleeAI : BaseAI
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{
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public MeleeAI(BaseCreature m) : base(m)
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{
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}
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public override double FleeHealthThreshold => 0.2; // 20% is default
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public override double FleeChance => 0.1; // 10% is default
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public override bool DoActionWander()
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{
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if (AcquireFocusMob(Mobile.RangePerception, Mobile.FightMode, false, false, true))
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{
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this.DebugSayFormatted($"I have detected {Mobile.FocusMob.Name}, attacking");
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Mobile.Combatant = Mobile.FocusMob;
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Action = ActionType.Combat;
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}
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else
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{
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DebugSay("I am wandering");
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Mobile.Warmode = false;
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base.DoActionWander();
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}
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return true;
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}
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public override bool DoActionCombat()
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{
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var combatant = Mobile.Combatant;
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if (!IsValidCombatant(combatant))
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{
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DebugSay("My combatant is gone, so my guard is up");
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Action = ActionType.Guard;
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return true;
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}
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if (!Mobile.InRange(combatant, Mobile.RangePerception))
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{
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if (!HandleOutOfRangeCombatant(combatant))
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{
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return true;
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}
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combatant = Mobile.Combatant;
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}
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if (!AttemptMoveToCombatant(combatant))
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{
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return true;
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}
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if (Core.TickCount - Mobile.LastMoveTime > 400)
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{
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Mobile.Direction = Mobile.GetDirectionTo(combatant);
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}
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if (Mobile.TriggerAbility(MonsterAbilityTrigger.CombatAction, combatant))
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{
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DebugSay("I used my abilities!");
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}
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return true;
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}
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private bool IsValidCombatant(Mobile combatant)
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{
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return combatant?.Deleted == false
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&& combatant.Map == Mobile.Map
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&& combatant.Alive
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&& !combatant.IsDeadBondedPet;
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}
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private bool HandleOutOfRangeCombatant(Mobile combatant)
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{
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if (AcquireFocusMob(Mobile.RangePerception, Mobile.FightMode, false, false, true))
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{
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Mobile.Combatant = Mobile.FocusMob;
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Mobile.FocusMob = null;
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return true;
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}
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if (!Mobile.InRange(combatant, Mobile.ChaseLeashRange))
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{
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Mobile.Combatant = null;
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}
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if (Mobile.Combatant == null)
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{
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DebugSay("My combatant has fled, so I am on guard.");
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Action = ActionType.Guard;
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return false;
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}
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return true;
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}
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private bool AttemptMoveToCombatant(Mobile combatant)
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{
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if (MoveTo(combatant, false, Mobile.RangeFight))
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{
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return true;
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}
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if (AcquireFocusMob(Mobile.RangePerception, Mobile.FightMode, false, false, true))
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{
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this.DebugSayFormatted($"My move is blocked, so I am going to attack {Mobile.FocusMob.Name}.");
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Mobile.Combatant = Mobile.FocusMob;
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Action = ActionType.Combat;
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return true;
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}
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if (Mobile.GetDistanceToSqrt(combatant) > Mobile.RangePerception + 1)
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{
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this.DebugSayFormatted($"I cannot find {combatant.Name}, so my guard is up.");
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Action = ActionType.Guard;
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return false;
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}
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this.DebugSayFormatted($"I cannot reach {combatant.Name} but continuing to try.");
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return true;
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}
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public override bool DoActionGuard()
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{
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if (AcquireFocusMob(Mobile.RangePerception, Mobile.FightMode, false, false, true))
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{
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this.DebugSayFormatted($"I have detected {Mobile.FocusMob.Name}, attacking.");
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Mobile.Combatant = Mobile.FocusMob;
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Action = ActionType.Combat;
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}
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else
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{
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base.DoActionGuard();
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}
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return true;
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}
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public override bool DoActionFlee()
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{
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if (Mobile.Hits > Mobile.HitsMax * FleeHealthThreshold)
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{
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DebugSay("I am stronger now, so I will continue fighting.");
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Action = ActionType.Combat;
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}
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else
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{
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Mobile.FocusMob = Mobile.Combatant;
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base.DoActionFlee();
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}
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return true;
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}
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}
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