There are currently 6 empty element slots (mostly from all life types being merged into one element) that can be used for temporary elements.

The names are: bran, lote, wind, frg2, frog, star

An example of how to enable one, making it do something interesting is left as an exercise for the reader.
tpt.el.bran.name="BOOM" -- change name, must be at most four letters long, doesn't currently update name in tpt.el.XXXX
tpt.el.bran.enabled=1 -- allow it to be used
tpt.el.bran.menu=1 -- enable display in menu
tpt.el.bran.menusection=1 -- put it in a menu
tpt.el.bran.description="A test element"

(Yes, an API function to do this might be nice, use something similar to the above code for now)

There are some things which don't yet update to reflect changes to tpt.el, they are: graphics cache (so graphics might not change when tpt.el.colour or tpt.el.properties are changed), menu item count (scrolling menus might not work), and can_move (changes to tpt.el.properties and tpt.el.weight don't affect which elements displace which other elements). I'm currently working on fixing these.



Duplicating existing elements wouldn't work well, because some reactions are hardcoded to occur with a specific element ID. For example, RBDM: the reaction is triggered in the water update function when there is a particle with RBDM's element ID nearby. So duplicating RBDM would not correctly duplicate all it's reactions.

It doesn't need to be done in autorun.lua, since autorun.lua is run after everything is initialised anyway.


If PT_NUM is kept a bit higher then the last element ID, then there will continue to be empty element slots that can be used for Lua elements. I think the element limit is actually lower than 255 at the moment - wall numbers will need moving up again at some point.