Post your modding questions here

[Hybrid Dog]

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Code: Select all

    local player_inv = player:get_inventory()
    local list = player_inv:get_list("main")
    local retval = {}
    for _, stack in pairs(list) do
        retval[#retval + 1] = stack:to_string()
    end
    local data_base = minetest.serialize(retval)


Can an item in list be nil?
Even if not, l'd use the index from the list:

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 player_inv = player:get_inventory()
    local list = player_inv:get_list("main")
    local retval = {}
    for n, stack in pairs(list) do
        retval[n] = stack:to_string()
    end
    local data_base = minetest.serialize(retval)


Are you sure that get_list returns a copy?

l guess else there wouldn't be the set_item and remove_item

[kaeza]

I'm pretty sure it doesn't return nil items, at least it doesn't when you do print(dump(list)). Are you sure that get_list returns a copy?

Looked at the sources, and indeed the items are guaranteed to be `ItemStack`s. Also, a new table is created on the spot to hold the items, so editing it in-place has no side-effects.

Edit: Clarification.

[BrunoMine]

Thanks! Another learning experience for me.

[Byakuren]

Are detached inventories persistent like player and node inventories?

[rubenwardy]

Are detached inventories persistent like player and node inventories?

No. They're deleted on shutdown.

[BrunoMine]

I want to save memory.
This is correct?

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Code: Select all

mytable = {}
table.insert(mytable,"a string")
table.insert(mytable,"another string")
[...]
mytable[1] = nil


[qwertymine3]

I want to save memory.
This is correct?

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

mytable = {}
table.insert(mytable,"a string")
table.insert(mytable,"another string")
[...]
mytable[1] = nil


Yes this is the correct way, however...
The String
Strings in lua are references to a table of all strings, if the string "a string" is stored anywhere else (in any other variable in your mod or other mods), the interpreter won't be able to delete the global copy to free memory.
The Table
Tables in lua are only dynamically re-sized in memory when they are full - this means that setting only one of the indexes to nil won't cause it to re-size and reduce it's memory consumption

PS: Setting only [1] to nil means that you can no longer use ipairs() or # on the table - you may want to use...

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Code: Select all

table.remove(mytable,1) 
mytable[1] == "another string" --this is now true


This is much slower but it shuffles the entries in the table down to fill the hole in
or, if it work with what you are trying to do

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Code: Select all

mytable[1] = mytable[#mytable]
mytable[#mytable] = nil


This is faster, but messes up the order of the table

[Evergreen]

How can I add an item to a nodes inventory when it is thrown into said node? This is the code I have for it, but it seems to only remove the item and not add it to the specified list within the nodes inventory.

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Code: Select all

-- Store the old on_step function for __builtin:item so it can be called at the
-- end of the new on_step function.
local old_on_step = minetest.registered_entities["__builtin:item"].on_step
-- Register a new on_step function for __builtin:item
minetest.registered_entities["__builtin:item"].on_step = function(self, dtime)
   local item_pos = self.object:getpos()
   -- If the item is sitting in the same node as trash_can:trash_can_wooden,
   -- then continue.
   if minetest.get_node(item_pos).name == "trash_can:trash_can_wooden" then
      -- Get the ItemStack from the itemstring contained in this
      -- __builtin:item.
      local item_stack = ItemStack(self.itemstring)
      -- Get inventory of the trash_list:trash_can_wooden the item is sitting
      -- in
      local inv = minetest.get_inventory({type="node", pos=item_pos})
      -- Add the item to trash_list (a list defined in the formspec for
      -- trash_can_wooden
      inv:add_item("trash_list", item_stack)

      -- Remove the item itself
      self.object:remove()
      return
   end
   -- Call old on_step function.  This has the effect of simply adding this
   -- code to the beginning of the old on_step function.
   old_on_step(self, dtime)
end


[rubenwardy]

How can I add an item to a nodes inventory when it is thrown into said node? This is the code I have for it, but it seems to only remove the item and not add it to the specified list within the nodes inventory.

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

-- Store the old on_step function for __builtin:item so it can be called at the
-- end of the new on_step function.
local old_on_step = minetest.registered_entities["__builtin:item"].on_step
-- Register a new on_step function for __builtin:item
minetest.registered_entities["__builtin:item"].on_step = function(self, dtime)
   local item_pos = self.object:getpos()
   -- If the item is sitting in the same node as trash_can:trash_can_wooden,
   -- then continue.
   if minetest.get_node(item_pos).name == "trash_can:trash_can_wooden" then
      -- Get the ItemStack from the itemstring contained in this
      -- __builtin:item.
      local item_stack = ItemStack(self.itemstring)
      -- Get inventory of the trash_list:trash_can_wooden the item is sitting
      -- in
      local inv = minetest.get_inventory({type="node", pos=item_pos})
      -- Add the item to trash_list (a list defined in the formspec for
      -- trash_can_wooden
      inv:add_item("trash_list", item_stack)

      -- Remove the item itself
      self.object:remove()
      return
   end
   -- Call old on_step function.  This has the effect of simply adding this
   -- code to the beginning of the old on_step function.
   old_on_step(self, dtime)
end


You may need to floor the position, maybe?

Also, add_item won't necessarily add the whole stack.
You should check with inv:room_for_item(listname, stack).
See http://rubenwardy.com/minetest_modding_ ... -to-a-list

[Evergreen]

How can I add an item to a nodes inventory when it is thrown into said node? This is the code I have for it, but it seems to only remove the item and not add it to the specified list within the nodes inventory.

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

-- Store the old on_step function for __builtin:item so it can be called at the
-- end of the new on_step function.
local old_on_step = minetest.registered_entities["__builtin:item"].on_step
-- Register a new on_step function for __builtin:item
minetest.registered_entities["__builtin:item"].on_step = function(self, dtime)
   local item_pos = self.object:getpos()
   -- If the item is sitting in the same node as trash_can:trash_can_wooden,
   -- then continue.
   if minetest.get_node(item_pos).name == "trash_can:trash_can_wooden" then
      -- Get the ItemStack from the itemstring contained in this
      -- __builtin:item.
      local item_stack = ItemStack(self.itemstring)
      -- Get inventory of the trash_list:trash_can_wooden the item is sitting
      -- in
      local inv = minetest.get_inventory({type="node", pos=item_pos})
      -- Add the item to trash_list (a list defined in the formspec for
      -- trash_can_wooden
      inv:add_item("trash_list", item_stack)

      -- Remove the item itself
      self.object:remove()
      return
   end
   -- Call old on_step function.  This has the effect of simply adding this
   -- code to the beginning of the old on_step function.
   old_on_step(self, dtime)
end


You may need to floor the position, maybe?

Also, add_item won't necessarily add the whole stack.
You should check with inv:room_for_item(listname, stack).
See http://rubenwardy.com/minetest_modding_ ... -to-a-list

It seems that for one reason or another the inventory for the trash can is not being retrieved correctly. Any ideas as to why that may be?

EDIT:
I found out that the formspec isn't reloaded on the node unless you dig and replace it. I suppose this makes sense since forsmpecs are metadata. Whoops. The reason this messed things up was that the old formspec contained in that trash can didn't have the list I was trying to access.

[rubenwardy]

Try print(dump(inv:get_lists()))?

[Evergreen]

Solved, see last post.

[BrunoMine]

This is faster, but messes up the order of the table

but if it is not an ordinary table?
For example:

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Code: Select all

database = {}
-- Keeps a value when the player connect
minetest.register_on_joinplayer(function(player)
   local name = player:get_player_name()
   database[name] = {<data_of_mod>}
end)
-- Remove the value when the player leaves
minetest.register_on_leaveplayer(function(player)
   local name = player:get_player_name()
   database[name] = nil
end)


This saves no memory?

[qwertymine3]

but if it is not an ordinary table?
For example:

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

database = {}
-- Keeps a value when the player connect
minetest.register_on_joinplayer(function(player)
   local name = player:get_player_name()
   database[name] = {<data_of_mod>}
end)
-- Remove the value when the player leaves
minetest.register_on_leaveplayer(function(player)
   local name = player:get_player_name()
   database[name] = nil
end)


This saves no memory?

I would recommend reading this http://www.lua.org/gems/sample.pdf - this is my main reference for lua specific optimisations

+ My Attempt at an Answer

That should save memory as the {<data_of_mod>} can now be removed from memory.

If {<data_of_mod>} contained a string stored else where, that string will not be removed from memory - but the rest of the table will be.

The database[] table will not get smaller in memory though i.e. if it had 2 people and you removed one, it would still have 2 'slots' of memory reserved to be able to put a person in

Overall:

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 annoying_extra_string = "stored string"
local constant = 5
local do_generic_stuff Longer= function() return nil; end

database = { --this table will have enough 'slots' to store the largest no. people you had in it (and a few extra)
    template = {

        string_one = "stored_string", --this string is stored by annoying_extra_string - when the table is deleted only the
                                      --memory used for the 'slot' will be saved
        string_two = "unique_string", --this is unique - when the table is deleted both the memory for the string and slot
                                      --will be saved

        --What I think would happen with numbers and functions - These are educated guesses however
        number = 5, --when the table is deleted I think any memory used by this can be freed
        another_number = constant, --same as above

        do_stuff = function() return nil; end, --when the table is deleted I assume that all the memory can be
                                         -- freed
        do_more_stuff = do_generic_stuff -- when the table is deleted I assume that only memory from the
                                         -- 'slot' is saved as the function is still stored by do_generic_stuff
    },
}


[Merlin]

Hi,

I've run into a problem when exporting DirectX files for mobs.
I tried to create a .x file like the ones PilzAdam uses in his SimpleMobs-Mod, but my .x just doesn't look like his and I am rather new to all that stuff and have no idea why.
I posted the whole story over here http://blenderartists.org/forum/showthread.php?390252-How-to-make-these-x-files-look-alike with all important files attached.
As no one yet answered there, I thought I'd try my luck here.

Thanks in advance!

[iangp]

Hi,

I've run into a problem when exporting DirectX files for mobs.
I tried to create a .x file like the ones PilzAdam uses in his SimpleMobs-Mod, but my .x just doesn't look like his and I am rather new to all that stuff and have no idea why.
I posted the whole story over here http://blenderartists.org/forum/showthread.php?390252-How-to-make-these-x-files-look-alike with all important files attached.
As no one yet answered there, I thought I'd try my luck here.

Thanks in advance!

Did you have checked out the Export animation field before your exportation?
And did you have selected all objects of your model?

[Merlin]

Yes and yes. I did an export with all options checked. It's more about the structure of the files. There are differences in the .blend files which are responsible for the differences of the .x files I guess, but as total noob, I'm unable to spot them.

[iangp]

hmmm probably is because you have checked all options... (PilzAdam, maybe, only checked out some of them) and so that's can be the difference... got it?
but, why do you want this? planning some script for create .x files from zero in lua? or is a problem in-game?

[Hybrid Dog]

For calculating those nether trees, would it work faster or slower if l used minetest.hash_node_position instead of the functions from vector.extras?

[Byakuren]

How is set_attach's rotation argument supposed to be formatted? Is it rotation per axis?

[ABJ]

I am trying to do this.
Say I have a craft recipe that crafts 9 item1 when 1 item2 is placed in grid. Now I want to make a function that, when called, automatically creates a reverse recipe where 9 item1 goes into 1 grid each to create 1 item2. Anyone have any ideas?

[BrunoMine]

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

player:setpos(pos)

player:moveto(pos)


These two perform exactly the same task?
What is the difference?

[iangp]

setpos -> teleport/magic
moveto -> the player will walk from where he are to this point "pos"
(But I haven't tested this yet)

[BrunoMine]

In 'moveto' the player is teleported.

[iangp]

our savior archive: lua_api.txt

* `setpos(pos)`; `pos`=`{x=num, y=num, z=num}`
* `moveto(pos, continuous=false)`: interpolated move

check out this option "continuous" (turn it true and after that false) and see what happens with the player...
I really don't know why moveto are, by default, the same as setpos...

[BrunoMine]

check out this option "continuous" (turn it true and after that false) and see what happens with the player...

I did not realize the difference.

[iangp]

that's a strange issue... I will finally make some simple script to test this (how do you implemented that?)
Are your minetest version the 0.4.13 one?
Well that can be a too new function... In rubenwardy's documentation (read it as: "nicer formatted version of lua_api.txt, the documentation that came with minetest.") there's a callback called on_secondary_use
that are called when the player left-click pointing to air (nothing) [I wanted this for my starwars mod] I tried and didn't worked... but I just downloaded the latest github code of minetes and then it worked...
Your situation can be similar to mine...

[rubenwardy]

It's not my documentation you're refering to.

The page on my website is just a nicer formatted version of lua_api.txt, the documentation that came with minetest.

[iangp]

I'm getting the same... I think this should be reported as an issue...
@rubenwardy do you know something about that?

[iangp]

It's not my documentation you're refering to.

The page on my website is just a nicer formatted version of lua_api.txt, the documentation that came with minetest.

yes yes :D sorry about that...