BT5-Dev #38: Layer 16(JumpThrough) + 동적 IgnoreLayerCollision 토글 (PD 제안 채택)

PD 보고: 발판 통과 X 여전 (BT35 PlatformEffector2D+Composite 영역 동작 X)
PD 제안: 충돌 로직 바꿔서 해결

표준 Drop-Through 패턴:
- Tilemap·Alien Layer 16 변환 (BT38)
- 기본: Player(13) ↔ JumpThrough(16) 충돌 ON = 정상 착지
- PlayerController.Update: velocity.y > 0.05 (상승) → IgnoreLayerCollision(13, 16, true) = 모든 발판 통과
- velocity.y <= 0.05 (하강·정지) → IgnoreLayerCollision(13, 16, false) = 충돌 ON = 착지

폐기:
- PlatformEffector2D·CompositeCollider2D·Rigidbody2D Static (BT35 영역)
- Layer 8·PlatformDropThrough Raycast (BT27·BT31 영역)

동작 (PD 의도 정합):
- Player 점프 상승 → 발판 모두 통과
- Player 하강 → 발판 위 착지
- 옆·아래에서 점프 → 통과 (상승 영역 모든 Layer 16 OFF)

Assets/Scripts/Mechanics/GameOptimizer.cs

@@ -30,9 +30,8 @@ namespace Platformer.Mechanics
         [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.AfterSceneLoad)]
         static void SetupJumpThroughPlatforms()
         {
-            // BT5-Dev #34 — Unity 표준 OneWay Platform = PlatformEffector2D + useOneWay + surfaceArc 180.
-            // 모든 일반 Collider(Tilemap 포함) PlatformEffector2D 적용. Layer 영역 무관 (기본 Layer 0 유지).
-            // 동작: 위에서 떨어지면 충돌(착지) / 옆·아래·점프 상승 시 통과
+            // BT5-Dev #38 — 표준 Drop-Through 패턴: Layer 16(JumpThrough) + 동적 IgnoreLayerCollision 토글
+            // 점프 상승 = IgnoreLayerCollision(13, 16, true) 통과 / 하강 = false 충돌 ON
             int applied = 0, excluded = 0;
             var allColliders = Object.FindObjectsByType<Collider2D>(FindObjectsSortMode.None);
             var appliedNames = new System.Collections.Generic.List<string>();
@@ -51,45 +50,20 @@ namespace Platformer.Mechanics
                     continue;
                 }
 
-                if (c.gameObject.layer == 8) c.gameObject.layer = 0;
-
-                // BT5-Dev #35 — TilemapCollider2D 영역 표준 패턴 (CompositeCollider2D + Rigidbody2D Static + PlatformEffector2D)
-                var tilemapCollider = c.GetComponent<UnityEngine.Tilemaps.TilemapCollider2D>();
-                if (tilemapCollider != null)
-                {
-                    tilemapCollider.compositeOperation = Collider2D.CompositeOperation.Merge;
-                    var composite = c.GetComponent<CompositeCollider2D>();
-                    if (composite == null) composite = c.gameObject.AddComponent<CompositeCollider2D>();
-                    var rb = c.GetComponent<Rigidbody2D>();
-                    if (rb == null) rb = c.gameObject.AddComponent<Rigidbody2D>();
-                    rb.bodyType = RigidbodyType2D.Static;
-                    composite.usedByEffector = true;
-                    var compositeEffector = c.GetComponent<PlatformEffector2D>();
-                    if (compositeEffector == null) compositeEffector = c.gameObject.AddComponent<PlatformEffector2D>();
-                    compositeEffector.useOneWay = true;
-                    compositeEffector.surfaceArc = 180f;
-                    compositeEffector.rotationalOffset = 0f;
-                    compositeEffector.useSideFriction = false;
-                    compositeEffector.useSideBounce = false;
-                    applied++;
-                    if (appliedNames.Count < 8) appliedNames.Add($"{c.gameObject.name}(Tilemap+Composite)");
-                    continue;
-                }
-
-                // 일반 Collider — PlatformEffector2D 직접 적용
-                c.usedByEffector = true;
+                // BT38 — PlatformEffector2D·CompositeCollider2D·Rigidbody2D 영역 영역 영역 폐기
                 var effector = c.GetComponent<PlatformEffector2D>();
-                if (effector == null) effector = c.gameObject.AddComponent<PlatformEffector2D>();
-                effector.useOneWay = true;
-                effector.surfaceArc = 180f;
-                effector.rotationalOffset = 0f;
-                effector.useSideFriction = false;
-                effector.useSideBounce = false;
+                if (effector != null) Object.Destroy(effector);
+                c.usedByEffector = false;
+
+                // Layer 16(JumpThrough) 변환
+                c.gameObject.layer = 16;
                 applied++;
                 if (appliedNames.Count < 8) appliedNames.Add($"{c.gameObject.name}({c.GetType().Name})");
             }
-            Debug.Log($"[BT35-OneWay] applied={applied} excluded={excluded} total={allColliders.Length}");
-            Debug.Log($"[BT35-OneWay] appliedSamples=[{string.Join(", ", appliedNames)}]");
+            Debug.Log($"[BT38-DropThrough] applied={applied} excluded={excluded} total={allColliders.Length}");
+            Debug.Log($"[BT38-DropThrough] appliedSamples=[{string.Join(", ", appliedNames)}]");
+            // 기본 = Player(13) ↔ JumpThrough(16) 충돌 ON. PlayerController.Update에서 점프 시 동적 토글
+            Physics2D.IgnoreLayerCollision(13, 16, false);
         }
     }
 }

Assets/Scripts/Mechanics/PlayerController.cs

@@ -155,6 +155,11 @@ namespace Platformer.Mechanics
 
             // PD 지시 2026-05-07 — 낙사 시 복귀할 안전 위치 추적
             if (IsGrounded) LastGroundedPosition = transform.position;
+
+            // BT5-Dev #38 — 표준 Drop-Through: 점프 상승(velocity.y > 0) Layer 16 통과·하강(≤0) 충돌 ON
+            const int JUMP_THROUGH_LAYER = 16;
+            bool rising = velocity.y > 0.05f;
+            Physics2D.IgnoreLayerCollision(13, JUMP_THROUGH_LAYER, rising);
         }
 
         void UpdateJumpState()