2.2 KiB
| title | layout | root |
|---|---|---|
| Active Block Modifiers | default | ../../ |
Introduction
An active *A**ctive Block Modifier (ABM) allows you to run code on certain nodes at specific intervals. Please be warned, ABMs which are too frequent or act on a large number of nodes cause massive amounts of lag. Use them sparingly.
- Special Growing Grass
- Your Turn
Special Growing Grass
If you want to make a mod that adds a type of grass called alien grass
- it grows near water on grassy blocks - you first register the grass, then write an ABM.
{% highlight lua %} minetest.register_node("aliens:grass", { description = "Alien Grass", light_source = 3, -- The node radiates light. Values can be from 1 to 15 tiles = {"aliens_grass.png"}, groups = {choppy=1}, on_use = minetest.item_eat(20) })
minetest.register_abm({ nodenames = {"default:dirt_with_grass"}, neighbors = {"default:water_source", "default:water_flowing"}, interval = 10.0, -- Run every 10 seconds chance = 50, -- Select every 1 in 50 nodes action = function(pos, node, active_object_count, active_object_count_wider) minetest.set_node({x = pos.x, y = pos.y + 1, z = pos.z}, {name = "aliens:grass"}) end }) {% endhighlight %}
This ABM runs every ten seconds. There is a 1 in 5 chance of the ABM running on each node that has the correct name and the correct neighbors. If the ABM runs on a node, an alien grass node is placed above it. Please be warned, this will delete any node previously located in that position. To prevent this you should include a check using minetest.get_node to make sure there is space for the grass.
Specifying a neighbor is optional. If you specify multiple neighbors, only one of them needs to be present to meet the requirements.
Specifying chance is also optional. If you don't specify the chance, the ABM will always run when the other conditions are met.
Your Turn
- Midas touch: Make water turn to gold blocks with a 1 in 100 chance, every 5 seconds.
- Decay: Make wood turn into dirt when water is a neighbor.
- Burnin': Make every air node catch on fire. (Tip: "air" and "fire:basic_flame"). Warning: expect the game to crash.