Mobile Compat Checker — 5-Item Lint

Generated games are desktop-only by default. This skill checks and patches 5 properties that make or break mobile playability. Each item is a 1-2 line change; the refiner is overkill for these.

When to use

After codesmith, before playtester. Re-run after any refiner pass that touches config.js or index.html.

The 5 checks

1. roundPixels: true in Phaser config (src/config.js)

Without it, sub-pixel rendering blurs pixel art on Retina displays.

// config.js should contain:
roundPixels: true,

2. image-rendering: pixelated on <canvas> (index.html)

Without it, the browser bilinear-filters the upscaled canvas, making pixel art look blurry even when the canvas is sharp.

/* index.html should contain: */
canvas { image-rendering: pixelated; image-rendering: crisp-edges; }

3. devicePixelRatio canvas sizing (src/config.js or index.html)

Without it, games render at CSS resolution instead of physical pixels, halving effective sharpness on Retina.

// config.js should contain:
zoom: Math.floor(Math.min(window.innerWidth, window.innerHeight) / 240) || 1,
// or explicit devicePixelRatio scaling

4. Touch / virtual d-pad input (src/scenes/Game.js)

Without it, mobile players have no control at all. Minimum: four directional buttons and one action button.

Acceptable patterns:

• this.input.addPointer(2) (multi-touch)
• this.add.zone(...) based virtual d-pad
• this.input.on('pointerdown', ...) with directional zones

5. AudioContext unlock on user gesture

Safari iOS suspends AudioContext until a tap or keydown event. Any audio that auto-plays on create() will fail silently.

Acceptable patterns:

• AudioManager.init(this) from the audio-composer skill (handles this)
• this.input.once('pointerdown', () => audioCtx.resume())
• Any call to .resume() inside a pointer/keyboard event handler

Output contract

{
  "ok": false,
  "checks": [
    { "id": "roundPixels",          "pass": true,  "file": "src/config.js" },
    { "id": "image-rendering",      "pass": false, "file": "index.html",    "fix": "add canvas CSS" },
    { "id": "devicePixelRatio",     "pass": true,  "file": "src/config.js" },
    { "id": "touch-input",          "pass": false, "file": "src/scenes/Game.js", "fix": "add virtual d-pad" },
    { "id": "audio-context-unlock", "pass": true,  "file": "src/audio/AudioManager.js" }
  ],
  "failCount": 2
}

Auto-patch mode (--fix)

Patches checks 1, 2, and 3 automatically (mechanical text changes). Checks 4 and 5 are flagged for codesmith / refiner since they require game-aware positioning.

• Check 2 fix: appends canvas { image-rendering: pixelated; image-rendering: crisp-edges; } to the <style> block in index.html.
• Check 1 fix: adds roundPixels: true, after pixelArt: true, in config.js.
• Check 3 fix: wraps canvas width/height with Math.floor(... * (window.devicePixelRatio || 1)) and adds CSS size properties.

Process

1. Run scripts/check_mobile.mjs <project-dir> after codesmith.
2. With --fix: auto-patches checks 1, 2, 3; reports 4 and 5 as manual items.
3. Feed check 4 and 5 failures to refiner as mobile-missing-touch and mobile-no-audio-unlock.

Scripts

• scripts/check_mobile.mjs <project-dir> [--fix] — lint and optionally patch.