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

==== 把下面整段貼給 GEMINI： ====

<syntaxhighlight lang="text">PATCH 2.1 / Regression Fix: Facing reversed + Room AREA broken (Isometric)

Goal:
* Prevent recurring regressions by enforcing a strict rule:
  ALL gameplay logic uses WORLD or TILE coordinates only.
  Screen/isometric projection is rendering-only.

A) Fix facing reversal (mouse aim)
* Do NOT decide facing using mouseX screen coords directly.
* Convert mouse screen position to aimWorld (inverse isometric projection), then:
  faceLeft  if (aimWorld.x < playerWorld.x)
  faceRight otherwise
* Inverse iso (with camera offset):
  sx = mouseX - camX
  sy = mouseY - camY
  worldX = ( sy/(tileH/2) + sx/(tileW/2) ) / 2
  worldY = ( sy/(tileH/2) - sx/(tileW/2) ) / 2
* Ensure sprite mirroring is applied in ONE place only (avoid double-flip):
  e.g., drawImage with scaleX = -1 OR choose mirrored frame, not both.

Debug (F2):
* Show: playerWorld.x, playerWorld.y
* Show: aimWorld.x, aimWorld.y
* Show: facing = LEFT/RIGHT
Acceptance:
* Aim mouse left of player => mech faces left (always).
* Aim mouse right of player => mech faces right (always).

B) Fix room AREA / exit trigger (after isometric changes)
* Exit triggers MUST be computed in WORLD/TILE coords, never screen coords.
* Best practice: define room size in TILE grid:
  roomTilesW, roomTilesH
  playerTile = worldToTile(playerWorld)
* Exit margins in tiles (e.g. 1~2 tiles):
  if playerTile.x <= 0 + margin => LEFT exit
  if playerTile.x >= roomTilesW-1 - margin => RIGHT exit
  if playerTile.y <= 0 + margin => UP exit
  if playerTile.y >= roomTilesH-1 - margin => DOWN exit
* Only render exit indicators for exits that exist in the room graph.

Debug (F1):
* Show current room coords (rx, ry)
* Show playerTile (tx, ty)
* Show roomTilesW/H and margin
* Print when trigger fires: "ENTER EXIT: LEFT/RIGHT/UP/DOWN"
Acceptance:
* Walking to an exit edge triggers transition reliably within 3 seconds.
* Indicators match actual exits (no fake arrows).

C) Regression guardrails (important)
* Never mix screenX/screenY into collision, exit, or facing logic.
* Keep a single source of truth:
  playerWorld, enemyWorld, bulletWorld, roomGraph in world/tile space.

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