## Levels:

- ignore comments in lvl files

- Grid Observer:
  https://github.com/mlange-42/arche/issues/374

- Add shaders for animation (player destruction etc)

- Start New game starts with last played level, better add a Resume
  Game menu item for this and use Start New always for level 1.

- for finding caller:
	pc := make([]uintptr, 10)
	n := runtime.Callers(0, pc)
	pc = pc[:n]
	fs := runtime.CallersFrames(pc)
	source, _ := fs.Next()
	source, _ = fs.Next()
	source, _ = fs.Next()

	slog.Debug("get observer", "minmoves", observer.LevelScore,
		"file", source.File, "line", source.Line)

- Turn menu button in hud_system (events in level_scene!) into ebitenui button

- On level loose, do not offer "next level"

- Moving obstacles don't kill the player when they hit him, they just stop there.

- use grid/collider.CheckGridCollision() for players AND
  obstacles. Currenty if I use it with obstacles, the don't move
  anymore when a player bumps into it, for whatever strange reasons.
  Maybe add a func argument to it so that the function can respond to
  the event as the entity wishes.

## Collider Rework [abandoned: see branch collider-system, fails]

- do not use the map anymore for collision detection
- central collision_system
- add Collider component with callback funcs to call on certain events
- callback types:
  - rect intersect (== future collision)
  - collision resolve (set new position)
  - pass over foreign rect (to e.g. change sprite while flying over sprite)
  - pass over done (switch sprite)
- check  for all  moving objects against  non-moving ones  like moving
  obstacle, player, bullet, laser
- check if executing callbacks within query loop is allowed
- callback  function needs to be  able to modify other  components, so
  possibly use observers for them, e.g.:
  Collider.IntersectResolve => func(newpos) {player.pos = newpos; player.vel = stop}
- in the end it must be  possible to add new entities without the need
  to write a collision check for them, but have collision detection anyway!