gijs_pong/.planning/phases/01-foundation/01-01-SUMMARY.md

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phase	plan	subsystem	tags	requires	provides	affects	tech-stack	key-files	key-decisions	patterns-established	requirements-completed	duration	completed
01-foundation	01	ui	canvas hidpi game-loop requestAnimationFrame devicePixelRatio vanilla-js		index.html with full-window HiDPI-aware canvas Renderer object with devicePixelRatio scaling and logical/bitmap coordinate separation GameLoop object using requestAnimationFrame with deltaTime capping Input object with keydown/keyup state tracking for W/S keys Physics skeleton with paddle movement and canvas-bounds clamping GameState object holding mutable paddle1 and ball state	01-02 Phase 2 Phase 3 Phase 4 Phase 5	added patterns HTML5 Canvas API requestAnimationFrame devicePixelRatio performance.now Module-object pattern: all systems are plain JS objects with init() methods Logical vs bitmap coordinate separation for HiDPI rendering deltaTime game loop with 50ms cap to prevent physics explosion on tab resume State centralized in GameState; systems mutate GameState, never each other directly	created modified index.html	Single HTML file — no build step, runs directly from filesystem deltaTime capped at 50ms (0.05s) to prevent ball teleporting on tab resume or focus loss Logical vs bitmap pixels: canvas.width/height set to logical*dpr, ctx.scale(dpr,dpr) so all game draw calls use logical coords Minimum 4:3 aspect ratio enforced by constraining logicalHeight when window is taller than 4:3 Physics.onResize called from Renderer.resize() with existence guard (typeof Physics !== undefined) Input uses e.code (KeyW/KeyS) not e.key for layout-independent key detection	Object initialization order: Renderer.init() → Physics.init() → Input.init() → GameLoop.start() Renderer.drawRect/drawCircle use Math.round() to prevent sub-pixel blurriness GameLoop.main() re-registers itself first, then updates physics, then renders Physics.update() takes deltaTime in seconds; speeds defined as logical pixels/second	VFX-05 CORE-07	1min	2026-03-10

Phase 1 Plan 01: HTML Scaffold, HiDPI Canvas, and Game Loop Summary

Single-file HTML5 Pong scaffold with devicePixelRatio-aware canvas, requestAnimationFrame game loop, and W/S paddle input — Player 1 visible and responsive

Performance

• Duration: 1 min
• Started: 2026-03-10T13:45:27Z
• Completed: 2026-03-10T13:46:34Z
• Tasks: 2
• Files modified: 1

Accomplishments

• Full-window black canvas with HiDPI scaling via devicePixelRatio; renders sharply on Retina displays
• requestAnimationFrame game loop at device refresh rate with 50ms deltaTime cap for safety
• W/S keyboard input with instantaneous keydown/keyup state tracking (no OS key-repeat lag)
• White paddle visible on left side (~x=30), white ball dot at center; both correctly positioned on init

Task Commits

Each task was committed atomically:

1. Task 1: HTML scaffold, HiDPI canvas, and full-window Renderer - e43b82b (feat)
2. Task 2: GameLoop, Input module, and Player 1 paddle rendering - e43b82b (feat — included in Task 1 commit as file was written complete)

Plan metadata: (docs commit follows)

Note: Both tasks target the same new file (index.html). The file was authored complete in a single write and committed once with all objects present.

Files Created/Modified

• /home/dabit/projects/gijs/index.html - Complete game scaffold: HTML5 structure, embedded CSS, Renderer, GameState, Input, Physics skeleton, GameLoop, and initialization block

Decisions Made

• deltaTime cap at 50ms: Prevents physics explosion when the browser tab loses focus and resumes — a single large delta without this cap would fling the ball off screen.
• Logical vs bitmap coordinate system: All game logic uses logical pixels (window.innerWidth/innerHeight). Canvas bitmap dimensions are logical * devicePixelRatio; ctx.scale(dpr, dpr) makes draw calls transparent to this split. This is the correct HiDPI approach.
• Minimum 4:3 aspect ratio: When window is taller than 4:3, logicalHeight is clamped to floor(logicalWidth / 1.333). Canvas CSS height tracks logicalHeight, so the canvas never becomes taller than 4:3. The area below the canvas is body background (#000), which is invisible.
• e.code over e.key: Using e.code === 'KeyW' instead of e.key === 'w' makes input work regardless of keyboard layout (AZERTY, etc.).
• Physics.onResize existence guard: typeof Physics !== 'undefined' in Renderer.resize() allows Renderer.init() to be called before Physics is defined, eliminating init-order fragility.

Deviations from Plan

None - plan executed exactly as written. Both tasks implemented together since they target the same new file; no functional deviation from specified behavior.

Issues Encountered

None. Fresh project with no dependencies — no install steps, no auth gates, no external services.

User Setup Required

None - no external service configuration required. Open index.html directly in any modern browser.

Next Phase Readiness

• index.html is the foundation for Plan 01-02 (ball physics: movement, wall bounce, zone-based deflection, speed increment)
• Physics.update() currently only moves paddle1; Plan 01-02 adds ball velocity, wall bouncing, and paddle collision
• GameState.ball has vx/vy/speed fields initialized to 0 — Plan 01-02 will set initial ball velocity
• All objects (GameLoop, Renderer, Physics, Input, GameState) are in global script scope, accessible for extension without refactoring

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Phase: 01-foundation Completed: 2026-03-10