Things I want to change for 0.3

Combating infestation

• Make walls/gates the only thing that can block direct spread.

• Make bricks/concrete block leap spread.

• Make bricks/concrete slow direct spread.

Spread

• Use a chunk-iterator instead of using random chunks for spread.

• Maybe add a 'breach' effect, which would briefly focus spread in an area where an alien killed a player structure. (But spread would still be limited to its budget though.)

Fixes

• Need to fix/change the way borders of concrete/bricks are rendered adjacent to infestation tiles.

• Need to fix an issue where tile-ghosts are removed when the underlaying tile is changed.

Something I want to experiment with for a bit, is using entities.

I want to see if I can replace the current tile-based infestation, with an entity-based one. That would mean normal weapons would be able to remove it.

Bug Fix

• Fixed the issue causing tile ghosts to disappear when tiles bordering them get built on with bricks/concrete.

Version 0.2.3 (Bug fix)

• Fixed an issue where biters could cause infestation under walls if they died close enough to them.

Version 0.2.2 (Crash fix)

• Fixed an issue where placing any tile that did not cause a hidden tile to be under it caused a crash.

Version 0.2.1

Oops, I forgot to include a thumbnail. And since Factorio does not allow me to re-upload an existing version of my mod (with the only change being the including of a thumbnail), I had to make it a new version.

Version 0.2

Current version 0.2 is a complete rebuild of the same idea as 0.1, hopefully improved in all aspects. Currently, the mod may be highly unbalanced due to lack of play-testing. Please feel free to give the current version a try!

Changes:

• Spaghetti code patchwork replaced with a more reasonable code form.

• Infestation spread information/status is no longer stored directly by the mod.
  Instead, the physical tiles themselves have become the information needed to correctly and efficiently spread.

• All artificial hard surface tiles (bricks, concrete, etc.) should now block infestation spread onto their tiles. But beware, infestation can still leap-spread over them if the distance is short enough.

• Added multi-line messages.
  These can be triggered by events, and will print their lines into the chat over a short time. Currently only one such message is used. It is triggered the first time a tile becomes infested and provides some information to the player about infestation.

Version 0.1 (Outdated)

Hello World! Welcome to my first ever Factorio mod!

This mod is still (very) incomplete, but this version should be play-testable now.
Feel free to give it a try, and please give feedback to help me find issues and improve this mod.

This mod adds infestation, a dangerous tile-based alien threat. Infestation originates from alien corpses. Once it is on the surface, it tries to spread wherever it can, damaging/destroying nearly everything it comes into contact with. The only things that can block its spread are water, and bricks.

Please know that this mod:
hasn't been tested outside of singleplayer, and there may be issues in multiplayer
hasn't been tested past 1,5 hours, and there may be late-game performance issues