sy_digger

sys_digger/CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Running the game
+
+Open `index.html` directly in a browser — no build step, no server required.
+
+```bash
+open index.html
+```
+
+There are no tests, no linter, and no package manager.
+
+## Architecture
+
+Pure vanilla JS/HTML/CSS game. No frameworks, no modules — all files are loaded as classic `<script>` tags and share a single global scope. **Load order matters**:
+
+```
+constants.js  →  atom.js  →  render.js  →  game.js
+```
+
+### File responsibilities
+
+| File | Role |
+|---|---|
+| `constants.js` | Single source of truth for every tunable value (speeds, counts, radii, timing). Edit here first when tweaking gameplay feel. |
+| `atom.js` | `IncomingAtom` class — construction, per-frame movement, docking logic, self-draw. Reads globals from `game.js` (`canvas`, `CX`, `CY`, `anchorPoints`, `docks`, `gameOver`) and calls `burst()`, `updateCystinstein()`, `triggerGameOver()` from `render.js`/`game.js`. |
+| `render.js` | All canvas drawing: background, central molecule, anchor points, particles, click effects, and the Cystinstein side-panel. Also owns `burst()` (particle spawner) and `updateCystinstein()`. Reads `ctx`, `cysCtx`, `CX`, `CY`, `anchorPoints`, `particles`, `clickEffects`, `docks` from `game.js`. |
+| `game.js` | Game state, `requestAnimationFrame` loop, input handling, leaderboard (localStorage), screen transitions (intro → game → game-over → intro). Declares all shared mutable globals consumed by the other files. |
+| `index.html` | CSS + HTML structure only. Houses the intro screen, attract screen, game-over overlay, leaderboard table, and the kidney-shaped Cystinstein side panel (inline SVG border). |
+
+### Global state (declared in `game.js`, used everywhere)
+
+`canvas`, `ctx`, `cysCanvas`, `cysCtx`, `CX`, `CY`, `score`, `docks`, `gameOver`, `gameStarted`, `incomingAtoms`, `anchorPoints`, `particles`, `clickEffects`, `stars`.
+
+### Screen flow
+
+```
+Boot → Intro  ──(30 s idle)──→  Attract (highscore)
+              ←─(any key/click)─
+  │
+  └─(START clicked)──→  Game loop
+                            │
+                        (6 docks)──→  Game-over overlay
+                                          │
+                                      (Play Again)──→  Intro
+```
+
+### Leaderboard persistence
+
+Stored in `localStorage` under key `sysdigger_leaderboard` as a JSON array of `{name, score}` objects, capped at 10 entries, sorted descending by score.
+
+### Key design constraints
+
+- Anchor points activate (turn red) only when the incoming atom **enters the visible viewport**, not at spawn time — see `IncomingAtom.update()` in `atom.js`.
+- Difficulty ramps automatically: `spawnInterval` decreases by `SPAWN_DIFFICULTY_STEP` each spawn, floored at `SPAWN_INTERVAL_MIN`.
+- The custom cursor is a data-URL SVG pill embedded directly in CSS on the `canvas` selector.
+- The Cystinstein side panel uses an inline SVG with a bezier kidney path for its border; the interior atom-cluster is drawn on a separate `<canvas id="cystinstein-canvas">` by `updateCystinstein()` in `render.js`.