feat(anim): Phase L.1c select combat maneuvers

src/AcDream.Core/Combat/CombatManeuverSelector.cs

@@ -0,0 +1,89 @@
+using DatReaderWriter.DBObjs;
+using DatMotionCommand = DatReaderWriter.Enums.MotionCommand;
+using DatMotionStance = DatReaderWriter.Enums.MotionStance;
+using DatAttackHeight = DatReaderWriter.Enums.AttackHeight;
+using DatAttackType = DatReaderWriter.Enums.AttackType;
+
+namespace AcDream.Core.Combat;
+
+/// <summary>
+/// Selects combat swing motions from the retail <c>CombatTable</c> DBObj.
+///
+/// Retail evidence:
+/// - <c>CombatManeuverTable::Get</c> (0x0056AB60) loads DB type
+///   <c>0x1000000D</c> for a 0x30xxxxxx combat table id.
+/// - ACE <c>CombatManeuverTable.GetMotion</c> indexes maneuvers by
+///   stance, attack height, and attack type, returning all matching motions.
+/// - ACE <c>Player_Melee.GetSwingAnimation</c> then chooses
+///   <c>motions[1]</c> when more than one motion exists and power is below
+///   the subdivision threshold; otherwise it uses <c>motions[0]</c>.
+/// </summary>
+public static class CombatManeuverSelector
+{
+    public const float DefaultSubdivision = 0.33f;
+    public const float ThrustSlashSubdivision = 0.66f;
+
+    public static CombatManeuverSelection SelectMotion(
+        CombatTable table,
+        DatMotionStance stance,
+        DatAttackHeight attackHeight,
+        DatAttackType attackType,
+        float powerLevel,
+        bool isThrustSlashWeapon = false)
+    {
+        var motions = FindMotions(table, stance, attackHeight, attackType);
+        if (motions.Count == 0)
+            return CombatManeuverSelection.None;
+
+        float subdivision = isThrustSlashWeapon
+            ? ThrustSlashSubdivision
+            : DefaultSubdivision;
+
+        var motion = motions.Count > 1 && powerLevel < subdivision
+            ? motions[1]
+            : motions[0];
+
+        return new CombatManeuverSelection(
+            Found: true,
+            Motion: motion,
+            Candidates: motions,
+            EffectiveAttackType: attackType,
+            Subdivision: subdivision);
+    }
+
+    public static IReadOnlyList<DatMotionCommand> FindMotions(
+        CombatTable table,
+        DatMotionStance stance,
+        DatAttackHeight attackHeight,
+        DatAttackType attackType)
+    {
+        var result = new List<DatMotionCommand>();
+
+        foreach (var maneuver in table.CombatManeuvers)
+        {
+            if (maneuver.Style == stance
+                && maneuver.AttackHeight == attackHeight
+                && maneuver.AttackType == attackType)
+            {
+                result.Add(maneuver.Motion);
+            }
+        }
+
+        return result;
+    }
+}
+
+public readonly record struct CombatManeuverSelection(
+    bool Found,
+    DatMotionCommand Motion,
+    IReadOnlyList<DatMotionCommand> Candidates,
+    DatAttackType EffectiveAttackType,
+    float Subdivision)
+{
+    public static CombatManeuverSelection None { get; } = new(
+        Found: false,
+        Motion: DatMotionCommand.Invalid,
+        Candidates: Array.Empty<DatMotionCommand>(),
+        EffectiveAttackType: DatAttackType.Undef,
+        Subdivision: 0f);
+}