Sokoban changes

[nickgirardo]

This pr was meant to just add undo support to the sokoban game, but as I was digging around I ended up being inspired to do a bit more

Changes

• Gameplay
  • Undo support (buffer holds 512 moves)
  • Added noclip triggered by a secret code
  • Added a final GG level which cannot be beaten
  • You can no longer fail to finish a level by pushing the barrel over the final goal
• Audio
  • Added noise sfx for undo
  • Added noise sfx for noclip walk
• Build process
  • Fixed a glitch in the sokoban conversion script which miscalculated remaining available space
  • Moved grass foliage generation from sokoban script to runtime. This allows significantly better compression (level data ~16k -> ~8k)
  • Related to above: this removal of build time randomization is a step towards reproducibility
  • Added package-lock.json files to repo. This is best practice and also helps with reproducibility
• Other
  • Added a function weak_rnd in random.c to reduce the amount of shuffling done by the lsfr. This will produce less apparently random results but for the sake of randomizing grass foliage it is sufficient and significantly reduces lag when generating levels
  • scan_level now exits early when finding a starting position for the player. This should be faster but would change behavior for levels with multiple start positions set (none of the current set have multiple start positions)
  • Changed how checking for level completion is done. Previously there was a goals_remaining counter which tracked how many goals did not have barrels covering them. Because undo support somewhat complicated keeping this value synced I removed it and instead just scan the level for open goals once per frame. A potentially faster method I have not tried: at level start time put all goal locations into a buffer and only check those tiles.

Work which remains to be done

• Bgm
• I want to add a special sfx for enabling noclip, currently it uses the yee song

[clydeshaffer]

Very exciting updates! Thanks!