Post your modding questions here

[Joz]

What is the best method to determine if the actual node has been initialised?

Themes: world generating, singlenode

When my lua map generators write nodes into an uninitialised chunk (for example trees, special caves, big pyramids…) the changes will be overridden when the on_register function of that chunk is called. There will be cut trees and leaf hanging in the air decaying.

So I have to know which nodes have been placed by a map generator. Is this possible? I tried it with testing if a node's id is not == minetest.get_content_id("ignore") but no node had this id. I also tried the same with …content_id("air") but there were still many empty chunks.

Thanks in advance!

[ArguablySane]

Does anyone know of a fast way to hash 2 or more numbers together in Lua such that the result is deterministic, depends on the order of the parameters, and has a reasonably low probability of collisions?
Almost any standard hash function would be fine, but Lua 5.1 doesn't even support bitwise operators which rather limits my options.

The reason I need this is that I want to generate deterministic seeds from xyz coordinates and edges in a graph. It was incredibly easy to throw together a proof-of-concept cave generator in Python, but now that I'm trying to port it to Lua I'm fighting against awkward syntax and missing features.

The best idea I have had so far is to use minetest's PRNG with a function like:

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all

local function hash(n1,n2)
  local prng = PseudoRandom(n1)
  local n3 = prng.next() + n2
  prng = PseudoRandom(n3)
  return prng.next()
end


but creating a new PRNG object for every number I want to hash just seems horribly inefficient.

[rubenwardy]

Isn't Minetest. Serialise position for this purpose?

[ArguablySane]

Isn't Minetest. Serialise position for this purpose?

Is it? Can PseudoRandom(seed) accept a string as its seed, and will it use the entire string rather than just truncating it? If so, that would simplify things massively.

[rubenwardy]

wrong name, it's minetest.hash_node_position({x=,y=,z=})

http://rubenwardy.com/minetest_modding_ ... .html#misc

[Hybrid Dog]

How can l make a function which can change a inventory image of an item by adding the image onto the old one modifying the formspec?

[ArguablySane]

wrong name, it's minetest.hash_node_position({x=,y=,z=})

http://rubenwardy.com/minetest_modding_ ... .html#misc

That's perfect, thanks. I'll remember to use that site (or lua_api.txt) in future instead of relying on the wiki.

[Sane]

Hi there,

the minetest.find_path() function has an parameter to set the searching algorithm ("A*_noprefetch", "A*", "Dijkstra"),
I am wondeing what the differences are. Is there a documentation on them somewhere?

[ArguablySane]

Hi there,

the minetest.find_path() function has an parameter to set the searching algorithm ("A*_noprefetch", "A*", "Dijkstra"),
I am wondeing what the differences are. Is there a documentation on them somewhere?

Wikipedia has articles on both Dijkstra's Algorithm and the A* Algorithm. In simple terms, the A* algorithm is usually a lot faster and more efficient than Dijkstra's algorithm, especially in cases where there are a large number of possible paths you could take to get from A to B (eg. A and B are on opposite sides of a large field). Dijkstra's might be faster in certain designs of maze though.
I'm not sure what A*_noprefetch is though.

[Joz]

With what NodeID are nodes initialised in singlenode?

[ArguablySane]

With what NodeID are nodes initialised in singlenode?

By default, it's air (minetest.get_content_id("air")). I believe there's a way to customise it from within a mapgen mod though.

[Don]

I have a number of tables set up.

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all

local chis1 = stuff
local chis2 = stuff
local hori1 = stuff
local hori2 = stuff
local vert1 = stuff
local vert2 = stuff
etc


Then I have another table set up.

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all

local modes = {
   {"chiseled", "Chiseled", chis},
   {"horizontal", "Horizontal", hori},
   {"vertical", "Vertical", vert},
   {"cross", "Cross", cross},
   }
for i in ipairs (modes) do
local mode = modes [i][1]
local mdesc = modes [i][2]
local typ = modes [i][3]


How do I join them? I want to make it so that it puts the type then a number so it is read as vert1 or hori1.

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all

node_box = typ.."1",
node_box = typ.."2"


[JasonGrace246]

I am using the Cart Mod of PilzAdams (https://forum.minetest.net/viewtopic.php?id=2451) and its not working.
First it gave the characters not allowed error, so I changed the folder's name to "carts".
But now it gives me this error-

error.JPG

Brief Description Of Error-
The init.lua file in the mod throws an error saying- "Attempt to concatenate a nil value"
then its says "in main chunk" "check debug.txt for details"

PLEASE HELP
How To Get This Mod Working?

[ArguablySane]

Don, am I right in thinking that you want to assign the value of chis1/hori1/etc (in this case "stuff"), to node_box?
You're going to have to iterate over a table of references to each type, but it would be helpful to know exactly what you're going to be using this code for. If I know the context I might be able to suggest a much simpler way of doing it.

JasonGrace, please post the full error message. It should say which line of init.lua the error is occurring on.


Oh, and I have a question of my own. If I'm writing a mapgen, is there a way to make sure the mapgen runs before any other mods? I know depends.txt lets me specify other mods which have to run before mine, but I'd like to make sure that my mod has a chance to actually create the terrain before other mods add things to it.

[swordpaint12]

Nevermind, I was right.

[Don]

I remember reading somewhere that a special file was required to make something a modpack. I think was modpack.txt, but I'm not sure. What is the title supposed to be?

I am trying to bundle a couple of the mods I have downloaded together so they are easier to enable. It's just for some worlds I'm working on.

Just put an empty file called modpack.txt

[Sokomine]

Oh, and I have a question of my own. If I'm writing a mapgen, is there a way to make sure the mapgen runs before any other mods? I know depends.txt lets me specify other mods which have to run before mine, but I'd like to make sure that my mod has a chance to actually create the terrain before other mods add things to it.

There's no such option. At least I don't know of any other than the depends.txt approach.

[Hybrid Dog]

Oh, and I have a question of my own. If I'm writing a mapgen, is there a way to make sure the mapgen runs before any other mods? I know depends.txt lets me specify other mods which have to run before mine, but I'd like to make sure that my mod has a chance to actually create the terrain before other mods add things to it.

There's no such option. At least I don't know of any other than the depends.txt approach.

you could try table.insert(minetest.registered_on_generateds, 1, function(minp,maxp,seed)
[…]
end)
l guess ores and mgv6 would still be generated before that.

Edit: l just used it myself: https://github.com/HybridDog/fractured/ ... 53e79d30c6

[ArguablySane]

you could try table.insert(minetest.registered_on_generateds, 1, function(minp,maxp,seed)
[…]
end)

Oohhh, that's clever. Thanks for the idea.

[swordpaint12]

Is there any way to create a block that is basically a vertical slab? If so, how do I do that?

[ArguablySane]

Is there any way to create a block that is basically a vertical slab? If so, how do I do that?

You can set the drawtype to nodebox to create blocks which don't fill the entire volume.
You'll need to set paramtype2 == "facedir" in your nodedef to be able to make it rotate to any of the 4 (or 6) possible alignments.

[Hybrid Dog]

Is there any way to create a block that is basically a vertical slab? If so, how do I do that?

you could use the screwdriver

[TenPlus1]

Slabs *can* be placed on the side of a node so that it stands UP...

[Hybrid Dog]

Slabs *can* be placed on the side of a node so that it stands UP...

When l place a slab on the side of a node it doesn't stand up.
If they did, building roofs with slabs would become far more annoying.

[TenPlus1]

Apologies, I use a different version of Stairs mod that allows for on_rotate functions so that you can place slabs on floor or wall and have a different rotation with both (or hold shift and place on wall to place flat/normal)...

I've attached it here if you wish to use it:

[Hybrid Dog]

Apologies, I use a different version of Stairs mod that allows for on_rotate functions so that you can place slabs on floor or wall and have a different rotation with both (or hold shift and place on wall to place flat/normal)...

I've attached it here if you wish to use it:

no, thanks, l try to build bigger, e.g. to get more details, instead of e.g. using slabs to build thin walls

[Don]

Slabs made from the saw in moreblocks rotate on place.
viewtopic.php?id=509

[Hybrid Dog]

Slabs made from the saw in moreblocks rotate on place.
viewtopic.php?id=509

l know, that's extremely annoying in my opinion.

[Don]

Slabs made from the saw in moreblocks rotate on place.
viewtopic.php?id=509

l know, that's extremely annoying in my opinion.

I love it. No need for the screwdriver.

[swordpaint12]

If they did, building roofs with slabs would become far more annoying.

Actually, that's WHY I asked. I'm trying to make a tall roof using 'walls.'