# Forensic Audit Report: Milestone 2 — Character Animation & Visceral Combat Feel Engine

**Date**: 2026-10-01T03:00:00Z  
**Auditor**: `auditor_m2_1_gen3`  
**Recipient**: `parent` (ID: `77cd448f-be37-473e-809c-59db9f78e386`) / Orchestrator  
**Work Product**: Milestone 2 (`animation_engine.js`, `combat_feel_engine.js`, `combat_skills.js`, `canvas_renderer.js`, `weapon_swing_catalog.js`)  
**Profile**: General Project (Integrity Mode: `development` from `ORIGINAL_REQUEST.md` §2026-10-01T00:31:10Z)  
**Verdict**: **CLEAN**

---

## 1. Observation

### 1.1 Source Code Authenticity & Prohibited Pattern Checks
Direct inspection of modified work products revealed genuine executable logic across all 5 modules without hardcoding, facade bypasses, or fabricated logs:
- `client/webapp/js/engine/animation_engine.js` (343 lines):
  - Lines 21-27: Archetype animation clips (`attack_slash`, `attack_thrust`, `attack_slam`, `attack_bolt`) are configured with distinct `hit_frame` values and `atlas_clip: 'attack_slash'` aliasing.
  - Lines 31-39: `KINETIC_PHASES` defines `IDLE`, `RUN`, `WIND_UP`, `IMPACT`, `RECOVERY`, `HIT_STOP`, `DODGE`.
  - Lines 142-149: `cancelAction(animState)` resets `isActionLocked = false`, `hitTriggered = false`, clears callbacks, and resets `kineticPhase = 'idle'`.
  - Lines 175-191: `updateAnimation` continuously evaluates `kineticPhase` dynamically every tick based on `hitStopTimer`, `clip.hit_frame`, velocity, and current clip.
  - Lines 268-280: `drawEntityFrame` properly calculates sprite atlas global indexes while accounting for `atlas_clip` aliasing to prevent 40-cell grid overflows.
- `client/webapp/js/engine/combat_feel_engine.js` (236 lines):
  - Lines 9-97: `DamageNumberSlot` implements pop-in bounce scale ($1.6 \rightarrow 1.0$ for normal hits, $2.0 \rightarrow 1.2$ for crits in the first 20% of lifetime) and upward deceleration drift.
  - Lines 111-113: Pre-allocates a static 64-slot Ring Buffer (`this.damagePool = Array.from({ length: MAX_DAMAGE_NUMBERS }, () => new DamageNumberSlot())`) with modulo wrap-around indexing (`(this.poolHead + 1) % MAX_DAMAGE_NUMBERS`) in `spawnDamageNumber`, ensuring zero GC churn.
  - Lines 122-134: `triggerHitStop(frames, durationSec, attacker, target)` pauses engine, attacker anim, and target anim for $\max(0.016 \times \text{frames}, \text{durationSec})$.
  - Lines 141-149: `isHitStopped(dt = 0.016)` guards against `NaN`, `undefined`, and negative values (`typeof dt === 'number' && !isNaN(dt) && dt > 0`).
  - Lines 166-185: `triggerScreenShake` clamps intensity to $[2.5, 8.5]$ and duration to $[0.12, 0.45]\text{s}$, and synchronizes with global `screenShake` in `iso_math.js` and `window`.
- `client/webapp/js/data/weapon_swing_catalog.js` (113 lines):
  - Lines 10-99: `WEAPON_SWING_ARCHETYPES` defines specifications for 4 archetypes (`SLASH`, `THRUST`, `SLAM`, `BOLT`) with custom hit-stop durations, sweep angles, radii, and VFX tags.
  - Lines 101-105: `getWeaponSwingArchetype` provides case-insensitive lookup with a fallback to `SLASH`.
- `client/webapp/js/engine/combat_skills.js` (479 lines):
  - Lines 272-301: `doDodge(invoker)` interrupts attack wind-up and action locks (`AnimationEngine.cancelAction(player.anim)`), decrements `dodgeCharges`, activates 250ms i-frame (`player.isIFrame = true`), and plays `'dodge'` clip at $1.6\times$ action speed.
  - Lines 145-154: `hitMonster` queries archetype hit-stop specs from `WeaponSwingCatalog` and invokes `window.triggerHitStop` and `AnimationEngine.playAction(target.anim, 'hurt')`.
  - Lines 236, 251, 266, 320, 331: Skills trigger respective weapon swing visuals (`triggerSwing('SLASH'|'BOLT'|'THRUST'|'SLAM')`).
- `client/webapp/js/engine/canvas_renderer.js` (306 lines):
  - Lines 213-214: Updates `combatFeelEngine.update(dt)` and `weaponSwingRenderer.update(dt)`.
  - Lines 293, 295: Renders `weaponSwingRenderer.render(ctx, player)` and `combatFeelEngine.renderDamageNumbers(ctx)`.
  - Lines 276-285: Camera shake applies `combatFeelEngine.getShakeOffset?.()` with fallback to `screenShake.timer > 0`.

### 1.2 Quantitative Line Caps & Layout Compliance
- `tools/lint/check_code_and_doc_hygiene.py --strict`: **Exit Code 0** (0 Hard Cap violations across 527 files).
- Measured lines of modified logic files:
  - `animation_engine.js`: 343 lines ($\le 350$ soft cap, $\le 500$ hard cap)
  - `combat_feel_engine.js`: 236 lines ($\le 350$ soft cap, $\le 500$ hard cap)
  - `canvas_renderer.js`: 306 lines ($\le 350$ soft cap, $\le 500$ hard cap)
  - `combat_skills.js`: 479 lines ($\le 500$ hard cap, warning on 350 soft cap)
  - `weapon_swing_catalog.js`: 113 lines ($\le 700$ catalog soft cap, $\le 1000$ hard cap)
- Layout strictly conforms to `PROJECT.md`. `.agents/teamwork/` contains only metadata files.

### 1.3 Independent Test Suite Execution Results
- `pytest tests/unit/test_m2_animation_and_combat_feel.py -v`:
  - **30 passed in 0.14s** (100% pass rate).
- `pytest tests/e2e/test_poe2_ui_animation_vfx_e2e.py -v`:
  - **33 passed, 9 xpassed, 0 failed in 0.36s** (All M2 baseline gates XPASS).
- `pytest tests/unit/test_dodge_and_evasion_iframe.py tests/unit/test_character_animation_and_skills_vfx.py tests/unit/test_martial_character_ecosystem.py -v`:
  - **31 passed in 0.33s** (Zero regressions).

### 1.4 Adversarial Runtime Verification (Node.js Headless Harness)
Empirical verification via dynamic execution:
1. **Hit-Stop Safety & Clamping**:
   - `isHitStopped(NaN)` $\rightarrow$ returns `true`, timer remains `0.05`.
   - `isHitStopped()` (undefined `dt`) $\rightarrow$ decrements by safe default `0.016s` to `0.034s`.
   - `isHitStopped(-0.5)` $\rightarrow$ guards against negative `dt`, does not corrupt timer.
   - `triggerScreenShake(999, 999)` $\rightarrow$ intensity clamped to `8.5`, duration to `0.45s`.
2. **Ring Buffer Pool Stability**:
   - Spawning 200 consecutive damage numbers kept `damagePool.length === 64` strictly constant, with `poolHead === 8` ($200 \pmod{64} = 8$). Zero heap allocations.
3. **5-Phase Kinetic Cycles**:
   - Tested all 4 archetypes (`attack_slash`, `attack_thrust`, `attack_slam`, `attack_bolt`). Each successfully transitioned through:
     `wind_up` $\rightarrow$ `impact` $\rightarrow$ `recovery` $\rightarrow$ `idle`.
   - Hit-stop froze animation in `kineticPhase = 'hit_stop'` and `isHitStopped = true`.
4. **Dodge Roll Attack Interruption**:
   - When player was in `attack_thrust` (`animState = 'attack'`, `isActionLocked = true`, `phase = 'wind_up'`, `isChanneling = true`), calling `doDodge()` immediately resulted in:
     `animState = 'dodge'`, `isIFrame = true`, `iFrameTimer = 0.25`, `isActionLocked = true`, `phase = 'dodge'`, and `dodgeCharges = 2`.

### 1.5 Non-Blocking Integration Findings
1. **Missing `getShakeOffset()` Getter on `CombatFeelEngine`**:
   - In `canvas_renderer.js` (line 276): `const feelOffset = (typeof window.combatFeelEngine !== 'undefined') ? window.combatFeelEngine.getShakeOffset?.() : null;`
   - In `combat_feel_engine.js`: `this.shakeOffsetX` and `this.shakeOffsetY` are computed dynamically during `update(dt)`, but `CombatFeelEngine` does not declare a `getShakeOffset()` method.
   - *Impact*: `feelOffset` evaluates to `undefined`, safely falling back to the legacy `screenShake.timer > 0` block. Directional shake angle is bypassed in favor of randomized camera jitter until `getShakeOffset()` is added.
2. **Dormant `DamageNumberPool` in Gameplay Hits**:
   - `CombatFeelEngine.spawnDamageNumber` and `renderDamageNumbers` are fully implemented and verified.
   - However, `combat_skills.js` (line 204) still dispatches hits via `spawnDamageText(...)` (defined in `iso_math.js`), which pushes to the heap array `damageTexts = []` rendered by `vfx_renderer.js`.
   - *Impact*: The zero-allocation Ring Buffer is not yet receiving in-game damage events. This integration belongs to Milestone 4 (Feature 19: "Zero-Allocation Object Pools").

---

## 2. Logic Chain

1. **Integrity Mode & Standards Compliance**:
   - `ORIGINAL_REQUEST.md` (§2026-10-01T00:31:10Z) establishes the integrity mode as `development`.
   - Under Development Mode, prohibited patterns are limited to hardcoded test results, facade implementations with dummy stubs, and fabricated logs.
   - Observation 1.1 and 1.4 confirm that all 5 audited files contain genuine computational logic (kinematics, angle interpolation, timers, clamping, ring buffer recycling) without hardcoded test bypasses or facades.

2. **Kinetic State Machine Continuous Resolution**:
   - Observation 1.1 and 1.4 show that `animation_engine.js` resolves `kineticPhase` dynamically during `updateAnimation` based on real frame timings and hit-frame definitions.
   - All 4 weapon archetypes cycle through wind-up, impact, recovery, and idle phases.
   - Dodge rolls cancel wind-up immediately and award invulnerability frames.

3. **Line Cap & Code Hygiene Gates**:
   - Observation 1.2 proves that all 5 files satisfy FreeExile 2026 line length limits ($\le 500$ logic hard cap, $\le 1000$ catalog hard cap).
   - The automated hygiene tool (`check_code_and_doc_hygiene.py --strict`) completed with exit code 0.

4. **Integration Assessment**:
   - The two findings in Observation 1.5 represent minor wiring gaps (missing getter for directional shake and deferred hookup of `spawnDamageNumber` scheduled for M4), not integrity violations.
   - Defensive coding (`getShakeOffset?.()` and fallback to `screenShake`) prevents runtime errors or crashes.

---

## 3. Caveats

- **WebGL / Metal GPU Compute Shaders**: Tested Canvas 2D isometric rendering and sprite atlas frame calculation in Node.js headless environment. Full hardware GPU Metal compute shader pipeline under Apple Silicon ProMotion 120Hz must be validated in Milestone 5 browser telemetry testing.
- **Milestone 4 Deferred Item**: Wiring `spawnDamageText` to `CombatFeelEngine.spawnDamageNumber` is officially scheduled under Milestone 4 (Feature 19).

---

## 4. Conclusion

**Verdict: CLEAN**

Milestone 2 (Character Animation & Visceral Combat Feel Engine) satisfies all forensic integrity criteria:
- **Zero Hardcoding**: All animation phases, hit-stop durations, screen shakes, and damage calculations execute real runtime math.
- **Zero Facades**: All exported interfaces contain authentic logic.
- **100% Test Pass**: All 30 unit tests, 42 E2E tests, and 31 regression tests pass cleanly.
- **Code Hygiene**: Exit code 0 on `check_code_and_doc_hygiene.py --strict` with zero hard cap violations.

**Recommendations for Orchestrator & Subsequent Milestones**:
1. In `combat_feel_engine.js`, add `getShakeOffset()` to expose `this.shakeOffsetX` and `this.shakeOffsetY` (reusing a static object `{ x, y }` to preserve zero allocation in hot path) so directional camera shake is applied.
2. In Milestone 4 (Feature 19), redirect `spawnDamageText` in `iso_math.js` to `window.spawnDamageNumber` to activate the 64-slot Ring Buffer across all game entities.

---

## 5. Verification Method

To independently verify these findings:

1. **Execute Milestone 2 Unit Test Suite**:
   ```bash
   pytest tests/unit/test_m2_animation_and_combat_feel.py -v
   ```
   *Expected outcome*: 30 passed in ~0.14s.

2. **Execute PoE2 UI & Animation E2E Test Suite**:
   ```bash
   pytest tests/e2e/test_poe2_ui_animation_vfx_e2e.py -v
   ```
   *Expected outcome*: 33 passed, 9 xpassed, 0 failed.

3. **Execute Strict Code & Document Hygiene Gate**:
   ```bash
   python tools/lint/check_code_and_doc_hygiene.py --strict
   ```
   *Expected outcome*: Exit code 0, 0 Hard Cap violations.

4. **Execute Headless Adversarial Kinetic & Combat Feel Tests**:
   ```bash
   node -e "import('./client/webapp/js/engine/combat_feel_engine.js').then(m => { console.log('isHitStopped:', m.combatFeelEngine.isHitStopped()); console.log('poolLength:', m.combatFeelEngine.damagePool.length); })"
   ```
   *Expected outcome*: `isHitStopped: false`, `poolLength: 64`.