Post your modding questions here

[Gerald]

Why is player:getpos() returning nil? Whenever I try to use player:getpos() the game crashes with `attempt to call getpos a nil value`

on_use has three arguments: itemstack, user, pointed_thing. Therefore player is the itemstack, which does not have getpos().
I would recommend to use the pointed position instead of the player position to spawn something.
Normally you want to remove the item after using it.

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Code: Select all

on_use = function(itemstack, player, pointed_thing)
  if pointed_thing.type == "node" then
    minetest.spawn_tree(pointed_thing.above, treedef)
    itemstack:take_item()
  end
  return itemstack
end


[Cerapter]

How would I go about replacing default:stone in mapgen(s) with my owns?

What I mean is that, let's say, I have 4 different blocks, mymod:mystone1 to mymod:mystone4. From y=0 to y=-800, I want a layer of all four of mymod's stones, so, from 0 to -200, I'd have a layer of mystone1, then from -200 to -400, a layer of mystone2, etc.

I looked into the mapgen.lua file, and saw that there is even a node_stone variable, that almost does what I want. In fact, I managed to get biomes full of my nodes as a test, going down to y=-32 or so.

But what I'd want to is to replace default:stone in every biome with my own, and besides that, I also want to switch it off every 200 nodes downwards.

I looked at the biomes, and while there is an 'underground' biome, it seems to not have a set node_stone; the game seems to just accept that the 'filler' node for underground is going to be default:stone.

So, basically, can I somehow get what are basically geological layers? I've even tried dissecting other mods that seem to try to do the same, but I really can't wrap my head around the codes.

Really, I think the 'underground' biome is the biggest problem here. Well, I just have a feeling if that I replaced those with different "biomes" of layers of different stones, I could get what I want. But I'd like to only make a mod as of yet, not a subgame.

[KCoombes]

If you don't care what name it's called in debug mode (f5), use minetest.override_item - you still have to define your nodes (create a nodes.lua file for this), define your biomes (create a mapgen.lua file for this), then lastly an overrides.lua file to declare your overrides. Add a depends.txt file (containing the word "default") to these and dump everything in a folder called 'mymod' (or whatever), plus put your textures in a folder called 'textures' in the mymod folder. Oh a new thing I've seen in 0.4.14 - add a mod.config file with just "name = (insert modname here)" to your main folder (without the ()'s or the ""'s).

Create a new world, enable your mod in 'configure' and test it out (go mining).

[Cerapter]

I don't think that is what I want or need, but thanks anyway. It seems override_item cannot override biomes, or at least, that's what the wiki says.

But even if it does, I want to turn off the 'underground' biome, not override it, unless I could somehow get it to never appear — I wonder if setting the minimal y larger than the maximal y would make it never appear, as technically, no placement would fill those requirements, right?

Also, I love how you explained how to set up a mod folder, but chose to not elaborate on minetest.override_item — one would think you would explain the thing not detailed in every tutorial about Minetest modding. Not picking on you here, just found it funny.

[KCoombes]

Oh sorry - I thought you wanted to create your own biomes (hence the detailed how-to) - if all you want is to not have the underground biome, find the mapgen.lua file in the minetest/games/minetest_game/mods/default folder and find the entry for register.biome "underground" (around line 825) and comment the entry out (825 through 841 or so)

As for why I detailed setting up custom biomes but did not define override_item : loads of modding resources/lua.api resources cover it, but not one resource for explaining exactly how to make it all work together.

[Cerapter]

Ah, again, that solution is not good; I can't really tell people to comment out something in their games if they want to use my mod.

But anyways, I managed to get what I wanted to by just having my stones be generated as sheet-style ores in default:stone. Granted, that still leaves default:stone around, but eh, it's not that big of a deal.

[TumeniNodes]

I was hoping to write recipes for TumeniNodes' angledstairs mod; I was wondering if there was an easier way to write it without listing every single variant.

I saw how 'stairs' has one recipe with 'subname' and "recipeitem" but I don't understand how it works.

I'll take a look at this and see if I can help.
I am no good at coming up with recipes though...

[teh_newbz]

How can I get the direction the player is facing as X+/X-/Z+/Z-?

I looked into get_look_dir() but I couldn't find any examples.

[D00Med]

Is this what you are looking for?:
get_look_dir()

[teh_newbz]

Is this what you are looking for?:
get_look_dir()

Can you provide an example of get_look_dir()? I'm having a bit of trouble understanding how to use it

[paramat]

Cerapter.

> while there is an 'underground' biome, it seems to not have a set node_stone

The line is commented out so that it falls back to the default of stone.

You need to write a mod (depending on default) that at the start does 'minetest.clear_registered_biomes'
Then copy-paste all the biome registrations from default/mapgen.lua and edit to what you want.

For every surface biome: replace (or add) 'node stone' with your own stone and change ymin to y = -200.
Change the 'underground biome' to have ymax = -200 ymin = -400 and add your own 'node stone'.
Add additional underground biomes each 200 thick, each with chosen stone.

This won't work in mgv6 though, biomes are hardcoded, use sheet ore instead for that.

[D00Med]

Can you provide an example of get_look_dir()? I'm having a bit of trouble understanding how to use it

Ok, here is what I use it for:

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Code: Select all

   on_use = function(itemstack, placer, pointed_thing)
         local dir = placer:get_look_dir();
         local playerpos = placer:getpos();
         local obj = minetest.env:add_entity({x=playerpos.x+dir.x,y=playerpos.y+1.5+dir.y,z=playerpos.z+0+dir.z}, "scifi_mobs:bfg_shot")
         local vec = {x=dir.x*6,y=dir.y*6,z=dir.z*6}

[Cerapter]

'minetest.clear_registered_biomes'

Ah right, there is that thing too!
Totally forgot about that, even though default.register_biomes() starts with it. I suppose I have just always skimmed over that.

I'll try fiddling around with that to see what happens.

EDIT: Nevermind, this fucks me over.

> Do I have to define biomes in such a way that only ONE biome type can match any given combination of altitude, temp, and humidity?

Yes.

I think this might be way out of my league for now, and should start with something simpler.

[burli]

Is it possible to get only walkable nodes or how can I check for walkable nodes?

[Hybrid Dog]

Is it possible to get only walkable nodes or how can I check for walkable nodes?

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Code: Select all

local def = minetest.registered_nodes[node.name]
if not def then
-- unknown node
return
end
local walkable = def.walkable


[burli]

Thanks, but walkable is only defined if a node is not walkable.

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Code: Select all

minetest.register_node("default:stone", {
   description = "Stone",
   tiles = {"default_stone.png"},
   groups = {cracky = 3, stone = 1},
   drop = 'default:cobble',
   legacy_mineral = true,
   sounds = default.node_sound_stone_defaults(),
})

So I have to assume that walkable = nil means walkable = true?

[Krock]

So I have to assume that walkable = nil means walkable = true?

No, because it uses the default value 'true' when it's not defined in the node def.

[Mad Alchemist]

How to add a new liquid to minetest? I have added a sulphur, which can be used as fuel or crafted to acid. But when I place acid from bucket on solid block, it appears like block and don't flow :(
This works fine:

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Code: Select all

bucket.register_liquid(
    "nether:acid_source",
    "nether:acid_flowing",
    "nether:acid_bucket",
    "bucket_acid.png",
    "Acid bucket")


I think problem is here, but can't find it:

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Code: Select all

minetest.register_node("nether:acid_source", {
    description = "Acid Source",
    drawtype = "liquid",
    tiles = {
      {
          name = "acid_source_animated.png",
          animation = {
            type = "vertical_frames",
            aspect_w = 16,
            aspect_h = 16,
            length = 2.0,
          },
      },
    },
    special_tiles = {
      -- New-style lava source material (mostly unused)
      {
         name = "acid_source_animated.png",
         animation = {
            type = "vertical_frames",
            aspect_w = 16,
            aspect_h = 16,
            length = 3.0,
         },
         backface_culling = false,
      },
   },
   alpha = 160,
   paramtype = "light",
   walkable = false,
   pointable = false,
   diggable = false,
   buildable_to = true,
   is_ground_content = false,
   drop = "",
   drowning = 1,
   liquidtype = "flowing",
   liquid_viscosity = 1,
   liquid_renewable = false,
   liquid_range = 2,
  damage_per_second = 4,
   post_effect_color = {a = 103, r = 30, g = 76, b = 90},
   groups = {liquid = 2, puts_out_fire = 1},
})
minetest.register_node("nether:acid_flowing", {
   description = "Flowing Acid",
   drawtype = "flowingliquid",
   tiles = {"acid.png"},
   special_tiles = {
      {
         name = "acid_flowing_animated.png",
         backface_culling = false,
         animation = {
            type = "vertical_frames",
            aspect_w = 16,
            aspect_h = 16,
            length = 0.8,
         },
      },
      {
         name = "acid_flowing_animated.png",
         backface_culling = true,
         animation = {
            type = "vertical_frames",
            aspect_w = 16,
            aspect_h = 16,
            length = 0.8,
         },
      },
   },
   alpha = 160,
   paramtype = "light",
   paramtype2 = "flowingliquid",
   walkable = false,
   pointable = false,
   diggable = false,
   buildable_to = true,
   is_ground_content = false,
   drop = "",
   drowning = 1,
   liquidtype = "flowing",
   --liquid_alternative_flowing = "default:river_water_flowing",
   --liquid_alternative_source = "default:river_water_source",
   liquid_viscosity = 1,
   liquid_renewable = false,
   liquid_range = 2,
  damage_per_second = 4,
  post_effect_color = {a = 103, r = 30, g = 76, b = 90},
   groups = {liquid = 2, puts_out_fire = 1,
      not_in_creative_inventory = 1},
})


Code is mostly copypasted from lava and water code.

[everamzah]

I'm guessing, but maybe it's the commented out alternative stuff, where river water is defined.

[Mad Alchemist]

I'm guessing, but maybe it's the commented out alternative stuff, where river water is defined.

Yes, now acid flows.
But I still can't ignite sulphur block with flint and steel.

[everamzah]

Flint & Steel checks for a node below with a flammable group rating. I don't know if that's what you want, but I guess you could try making the liquid flammable. You'll likely want to remove the 'puts_out_fire' group rating.

[Mad Alchemist]

But I want to make flammable sulphur block, not acid. (bucket_acid = bucket_water + nether:sulphur)

[everamzah]

Again, flint & steel checks for a `flammable' group rating. If you want flammable sulfur - and it is not already flammable - then add `flammable = 1' (or such) to groups = {} in the node definition for sulfur.

[Mad Alchemist]

Ok, now all works fine. I have also created mod "glowwater"- harmless glowing liquid made from nether:acid and nether:glowstone, and glowwater lamps made from glass and glowwater.
I want to create one big mod with alchemy and magic, but don't know how to move "sulphur" from "nether" mod to new mod, because it is in map generation code (see attachment).

[Sirmentio]

Hello! Is it possible to have player specific variables that affect said players?

[everamzah]

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Code: Select all

local players = {}
minetest.register_on_joinplayer(function(player)
    players[player:get_player_name()] = 1
end)
minetest.register_on_leaveplayer(function(player)
    players[player:get_player_name()] = nil
end)
minetest.register_on_dieplayer(function(player)
    players[player:get_player_name()] = players[player:get_player_name()] + 1
    player:set_physics_override({speed = players[player:get_player_name()]})
end)


Go faster every time you die?

[Sirmentio]

That would work, thanks for the example!

EDIT: I do have one question, would it be possible to save the speeds in minetest.conf?

[KCoombes]

That would work, thanks for the example!

EDIT: I do have one question, would it be possible to save the speeds in minetest.conf?

I wouldn't save it there, but create a player database file for that (search the mod forums for one called "db")

[Krock]

would it be possible to save the speeds in minetest.conf?

Yes, see lua_api.txt

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Code: Select all

minetest.setting_set("setting_name", value)
Save: minetest.setting_set("speed_".. player_name, tostring(players[player_name]))
Get:  players[player_name] = tonumber(minetest.setting_get("speed_".. player_name))


But that will flood your minetest.conf file with settings that actually don't belong there. Better create a new file in the world directory, like I did with the last rewrite of "flatgen". With "minetest.serialize" and "minetest.deserialize" you can easily save and load an entire table.

[burli]

I want to create a simple lua entity cube. What are the minimum properties to spawn a cube?

The cube should not have a collision box or anything else. The cube should be able to move through nodes