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Dabit 363a798345 docs(phase-02): complete phase execution

2026-03-10 21:23:06 +01:00

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Completed 02-02-PLAN.md

2026-03-10T20:23:01.790Z

total_phases	completed_phases	total_plans	completed_plans
5	2	4	4

STATE: Super Pong Next Gen

Project Reference

Core Value: Pong reimagined with juice and depth — spectacular visuals, rich mechanics, complete game experience
Current Focus: Phase 1 — executing plans
Key Constraint: Coarse granularity (5 phases max), HTML5 Canvas + vanilla JS, static deployment

Current Position

Attribute	Value
Phase	02-core-gameplay
Plan	Plan 2/2 — COMPLETE
Status	Phase 02 COMPLETE — full playable Pong with state machine, scoring, AI, and match-end
Progress	100% (4/4 plans complete; Phase 1 complete, Phase 2 complete)

[██████████] 100% — Phase 2: 2/2 plans complete

Performance Metrics

Metric	Target	Status
Phase Coverage	100% (37/37 requirements mapped)	✓ Complete
Success Criteria	2-5 per phase	✓ Complete
Dependency Chain	Linear (P1 → P2 → P3 → P4 → P5)	✓ Validated
01-01 Duration	—	1 min (2 tasks, 1 file)

| 01-02 Duration | — | 1 min (2 tasks, 1 file) |

Accumulated Context

Key Decisions Made

Coarse Granularity Compression: Research suggested 10 phases; compressed to 5 by merging:
- Game loop + input + physics = Phase 1
- Second paddle + AI = Phase 2
- Menus + audio + pause = Phase 3
- Visual effects + power-ups + arenas = Phase 4
- Performance + testing = Phase 5
Phase 5 (Release) Has No Requirements: All 37 v1 requirements covered by phases 1-4. Phase 5 is purely validation (cross-browser, performance, pitfall mitigation).
Success Criteria Grounded in Research Pitfalls: Each phase's criteria address critical pitfalls from research:
- Phase 1: DPI scaling, game loop timing
- Phase 2: Ball tunneling, input lag, AI balance
- Phase 3: Audio autoplay policy
- Phase 4: Power-up balance
- Phase 5: Performance, memory leaks, cross-browser
deltaTime Cap at 50ms: Game loop caps deltaTime to prevent physics explosion when tab loses focus and resumes — without this a single large delta would fling the ball off screen.
Logical vs Bitmap Coordinate Separation: canvas.width/height = logical * devicePixelRatio; ctx.scale(dpr, dpr) makes all game draw calls use logical pixels — correct HiDPI approach for sharp rendering on Retina displays.
Module-Object Pattern Established: GameLoop, Renderer, Input, Physics, GameState are plain JS objects with init() methods in a single script tag. No classes, no modules, no build step — runs directly from filesystem.
e.code over e.key for Input: Using e.code === 'KeyW' makes W/S detection layout-independent (works on AZERTY and other non-QWERTY keyboards).
Zone angles [-60, -30, 5, 30, 60] degrees: Center zone uses 5 deg not 0 to prevent infinite horizontal ball loops; top/bottom edges at 60 degrees for dramatic deflection.
GameConfig centralizes tunable constants: initialBallSpeed (220px/s), speedIncrement (18px/s), paddleSpeed (400px/s) — all adjustable without touching Physics logic.
vx/vy recomputed from speed+angle each paddle hit: Prevents compound rounding drift from repeated scaling; speed and direction always cleanly separated.
AI uses predictive ray-cast with wall bounce simulation: _predictBallY steps forward in time (up to 500 steps) simulating wall bounces — far more accurate than linear Y interpolation.
AI difficulty presets as config objects: { speed, reactionDelay, errorMargin } in GameConfig — all three dimensions of difficulty tunable without touching AI logic.
AI waits when ball moves toward player (vx < 0): Resets reaction timer and returns early — AI only acts when ball is heading toward its paddle, avoiding premature repositioning.
Physics.onResize() calls init() for full reposition: Ensures paddle2 (and paddle1) are properly repositioned on window resize rather than just updating width/height dimensions.
GameLoop owns scoring/serve, Physics owns physics: Scoring detection is in GameLoop.main() after Physics.update() — Physics no longer auto-resets ball on out-of-bounds. This separation allows GameLoop to increment scores before re-serving.
pauseTime on GameLoop, not GameState: Post-score pause timer is transient per-point timing; storing it on GameLoop (not GameState) keeps GameState clean for restart.
Ball hidden during 'scored' pause: drawCircle guarded by gs.gameState !== 'scored' — gives players a visual signal that a point was scored before the ball re-serves.

Coverage Validation

Total v1 Requirements: 37

CORE (8): All mapped to Phase 1-2
AI (4): All mapped to Phase 2
SCRN (4): All mapped to Phase 3
VFX (5): All mapped to Phase 1 (DPI) and Phase 4 (particles/glow/trails/shake)
PWR (7): All mapped to Phase 4
ARENA (4): All mapped to Phase 4
AUD (5): All mapped to Phase 3

Unmapped Requirements: 0 ✓ Coverage: 100% ✓

Research Alignment

Phase 1 addresses Research Pitfalls: #1 (Game Loop Timing), #2 (Canvas DPI Scaling)
Phase 2 addresses Research Pitfalls: #3 (Ball Tunneling), #4 (Input Lag), #5 (AI Difficulty Balance)
Phase 3 addresses Research Pitfall: #6 (WebAudio Autoplay Policy)
Phase 4 addresses Research Pitfalls: #7 (Power-Up Balance)
Phase 5 addresses Research Pitfall: #8 (Memory Leaks)

Session Continuity

What Just Happened

Phase 02 Plan 02 executed: GameLoop.main() rewritten with full state machine (modeSelect → diffSelect → playing → scored → gameover). Scoring detection added to GameLoop (after Physics.update()). Physics.update() auto-reset removed so GameLoop owns scoring. Mode/difficulty selection screens rendered on canvas. Winner overlay with R-key restart. pauseTime field added to GameLoop for 1s post-score pause. Phase 1 debug speed text removed. Requirements CORE-05, CORE-06 satisfied. Phase 2 complete.

What Comes Next

Execute Phase 3 — menus, audio (WebAudio), pause/resume screen
Continue through phases 4-5 after Phase 3 complete

Known Blockers

None.

Decisions Pending