jump-and-game-loop

name	jump-and-game-loop
description	Add beginner-friendly jump physics and a minimal frame loop to the Dino teaching project. Use when students need stage-2 style help for input handling, gravity, landing clamps, and requestAnimationFrame without overengineering.

Skill: jump-and-game-loop

What This Skill Is

A minimal pattern for adding jump physics and a frame loop without overengineering.

Why It Matters in This Project

This stage teaches core real-time update logic: input, physics, render.

Files Usually Touched

• main.js

Common Bugs

• Multiple jump triggers while in air
• Gravity applied with wrong sign
• Missing requestAnimationFrame

Debugging Checklist

1. Log y and vy values during jump
2. Verify jump only starts when on ground
3. Clamp landing at ground level
4. Confirm loop still draws every frame

How Students Should Ask Codex

"Stage 2 only: add jump with gravity in main.js, avoid refactor, and include 3 manual test steps."

Done Looks Like

• Dino jumps and lands predictably
• No double-jump bug in base stage
• Code remains compact in one file