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

Phase 1: Foundation - Context

Gathered: 2026-03-10 Status: Ready for planning

## Phase Boundary

Build the technical foundation: game loop, HiDPI-aware canvas rendering, Player 1 keyboard input (W/S), ball physics (continuous movement, wall bouncing, zone-based angle deflection, per-hit speed increase). No scoring, no AI, no UI screens yet.

## Implementation Decisions

File Structure

• Single HTML file — everything embedded (JS + CSS in one .html file)
• JavaScript organized into a module pattern: GameLoop, Physics, Renderer, Input objects within a single <script> tag
• No build tooling; runs directly from the filesystem

Canvas Sizing

• Full-window canvas — fills the entire browser window
• Resizes immediately on window resize
• Maintains aspect ratio during resize; minimum 4:3 aspect ratio enforced
• No maximum size cap — grows unbounded to fill any screen
• Must be HiDPI/Retina aware (devicePixelRatio scaling)

Ball Physics Feel

• Zone-based deflection: paddle divided into 5 zones
  • Top edge → ~60° angle upward
  • Upper zone → ~30° angle
  • Center → ~5° angle (nearly flat)
  • Lower zone → ~30° angle
  • Bottom edge → ~60° angle downward
• Speed increases per paddle hit (small increment each rally)
• Speed resets on each point scored
• No maximum speed cap — ball accelerates indefinitely through long rallies

Claude's Discretion

• Exact speed increment value per hit (tune for feel)
• Precise zone boundary definitions and angle values (within the ~5°–60° range)
• Game loop timing implementation (requestAnimationFrame + delta time)
• Serve direction and initial ball velocity for dev testing
• Input handling internals (keydown/keyup state tracking)

## Specific Ideas

• No specific requirements — open to standard approaches

<code_context>

Existing Code Insights

Reusable Assets

• None — fresh project, no existing code

Established Patterns

• None yet — Phase 1 establishes the patterns all subsequent phases follow

Integration Points

• Phase 2 will add scoring, Player 2 input, and AI — the game loop and physics module must be structured to accommodate adding a second paddle and score tracking without refactoring

</code_context>

## Deferred Ideas

• None — discussion stayed within phase scope

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Phase: 01-foundation Context gathered: 2026-03-10