Editing Openai/694f5245-1110-800b-b182-7c2accd50046 (section)

==== 你就把這段貼過去（這包專門救你現在兩個痛點）： ====

<syntaxhighlight lang="text">CRITICAL PATCH / Fix broken sprites + bullets not damaging enemies

A) Sprite reliability (no more gray fallback surprises)
* Embed the player sprite into the HTML as a data URL (base64) OR keep a built-in default sprite.
* Do NOT depend on external file paths that can break between runs.
* Add F1 debug overlay showing:
* playerSprite: LOADED / FAILED
* enemySprite: LOADED / FAILED
* If sprite failed, draw fallback BUT also display a warning text “USING FALLBACK SPRITE”.

B) Collision + damage must work (world-space only)
* Ensure BOTH bullets and enemies use the SAME coordinate space: WORLD (x,y).
* Bullet update uses world velocity (vx, vy), not screen coords.
* Collision check in world space:
* Use circle collision for simplicity:
    dist2(bullet.x, bullet.y, enemy.x, enemy.y) < (bullet.r + enemy.r)^2
* On hit:
* enemy.hp -= bullet.damage
* spawn hit effect
* destroy bullet (or mark inactive)
* Ensure enemy.hp is initialized and displayed:
* Add small HP bar above enemy.

C) Debug visualization (toggle F2)
* Draw collision circles:
* bullet radius circle
* enemy radius circle
* Print to console and on-screen when hit occurs:
  “HIT enemyId=.. dmg=.. hpNow=..”
* This is to verify damage logic even if visuals are confusing.

Acceptance criteria:
* Player sprite loads reliably without needing manual re-upload every time.
* Shooting an enemy reduces its HP visibly (HP bar decreases).
* Debug mode proves collisions happen in world space.

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