Factorio Forums

aubergine18 wrote:@Mooncat: note also that entity properties cannot be iterated with pairs(), so we can't even table.deepcopy() entity prior to .destroy() in order to conditionally send event containing static clone of props post .destroy(). That means before doing .destroy() we'll have to first determine *if* the entity can be destroyed within Lua script, and if so, send event, then destroy it.

bobingabout wrote:I seriously do not understand how this WTF question could reach 3 pages.

If something is destroy()ed, it is gone, forever, unrecoverable. All information about what it was is meaningless because it doesn't, and can never exist anymore... so why would you be interested in an on_destroyed event?

Destroy is effectively a god override command, your usage of it is non-standard.

mknejp wrote:And then comes Vehicle Wagon which destroyed my electric car, which has to have its energy buffer refueled from the equipment grid every tick, when it's winched on a wagon, meaning I have to actively waste performance every tick by checking if the vehicle is valid.

mknejp wrote:Don't take me wrong I am not blaming Vehicle Wagon as I would have done it the same way,

Mooncat wrote:So the only solution will be checking entity.valid in on_tick. It is bad.

You should check for valid when you would naturally be doing something to your entity anyway,

aubergine18 wrote:
The events would benefit any mod that uses compound entities (concrete lamppost, torches, ks_power, electric vehicles, etc) or wish to create/destroy entities from external mods (creative mode, vehicle wagon, etc).

aubergine18 wrote:So if I have a mod that creates roads, and I want to line the roads with concrete lampposts, and destroy those lampposts when road is destroyed, how would I fix that in my mod? The only way I could do it is to completely duplicate your mod, graphics and code, in to my mod, and have a set of renamed entities that my mod uses, just because there aren't create/destroy events. This is nuts, absolutely nuts.

If the events existed, then it would be two line change in your mod:

Code: Select all

script.on_event(defines.events.on_create_entity, BuiltEntity)
script.on_event(defines.events.on_pre_destroyed, MinedEntity)

And two lines of code in my mod:

Code: Select all

-- when creating:
myRoad.surface.create_entity( { name = 'concrete-lamppost', .... }, true )

-- when destroying:
aLamppost.destroy( true )

data:extend(
{
    {
        type="group-entity"
        name="lamp-group"
        entities = --what entities this group contains
        {
            "lamp",
            "small-pole",
            "electric-power-thingie"
        },
        on_created_event_name = "lamp_group_create",
        on_destroyed_event_name = "lamp_group_destroy"
    }
})

script.on_costum_event("lamp_group_create", function()
    --do the create stuff
end)

script.on_costum_event("lamp_group_destroy", function()
    --do the destroy stuff
end)

Klonan wrote:Such as setting blank tiles - Will destroy entities under it

Klonan wrote:Removing an entity prototype - will destroy them without notice

Klonan wrote:In any case, never trust that an entity will always be valid,
Don't trust other mods,
Check if something is valid, before you do something to it

Klonan wrote:Same with this, if another mods scripting is breaking your mod, it is their issue to fix

Rseding91 wrote:If some mod errors because yours deletes it then it's a fault of that other mod and not yours.

Klonan wrote:

aubergine18 wrote:
The events would benefit any mod that uses compound entities (concrete lamppost, torches, ks_power, electric vehicles, etc) or wish to create/destroy entities from external mods (creative mode, vehicle wagon, etc).

You mention those mods,

But in their entire existence i have never seen or heard any complaint or issue about other mods destroying things,
And if they do, i wouldn't care. If another mod is messing with things, they should be the ones to fix it

If i make a mod which breaks bobs mods something or other, it wouldn't be fair to ask bob to fix his mod,
Same with this, if another mods scripting is breaking your mod, it is their issue to fix

<Rseding91> Mooncat: you don't understand how many things are destroyed() each game tick by the normal game that would trigger that event if it existed. It's not going to happen. check for valid before accessing something.

Klonan wrote:If i make a mod which breaks bobs mods something or other, it wouldn't be fair to ask bob to fix his mod,
Same with this, if another mods scripting is breaking your mod, it is their issue to fix

aubergine18 wrote:

You should check for valid when you would naturally be doing something to your entity anyway,

Except when the mod doesn't do anything like that... Here's how this issue affects my bridge:

The ends of the bridge are `pipe-to-ground` entities. The ramps are the pipe covers

Once a bridge is constructed, my mod sits idle, there's no `on_tick`.

To allow the player to walk over the bridge, during construction I replace any water tiles between the two ends with fake water tiles that have the player collision mask removed.

If the end of the bridge, or any segment between the ends is destroyed, I get an event: If it's mined, if it dies (eg. due to fire), I get told about it. When this happens, I do one of two things:

* If it's bridge end, I find other end via `.neighbours`
* If it's a segment in the bridge, I know the`max_underground_distance` (well, I would) so I center that on the destroyed segment, then search that area for applicalbe end entity (`pipe-to-ground` of specific name), then find other end via `.neighbours`

Once I have both ends, I can safely destroy the bridge - both ends, the segments between them, and replacing fake water with real water again.

Now, along comes a mod that destroys one end of my bridge, or a segment... I know nothing about this. Even if that mod destroyed all entities in the bridge, the fake water would still be there and player would be able to walk on it.

This is why I need to know when something gets destroyed by a mod. It's why all this talk of "just check .valid" is of no use to me whatsoever, because my mod is not using `on_tick`. I've spent ages making sure the mod sits idle until triggered to do something (build bridge, destroy bridge) by an event. I've even set `.active = false` on the `pipe-to-ground` so that a built bridge has almost zero impact on UPS/FPS.

And then along comes this nightmare that `.destroy()` doesn't fire an event, with people telling me "just check .valid", which is equivalent to "just add on_tick handler and check .valid for every piece of every bridge on every surface" which in turn means "maintain a table of all your bridge entities, just so you can work out when one of them is destroyed by another mod".

A param on the destroy event to tell it to trigger an event would solve this problem, it would default to `false`. Mods such as Creative Mode, or anything else that can `.destroy` entities from other mods, would set the param to `true` to alert the other mod to their entity being destroyed.

As for the `create_entity()`, that also poses a problem. One of the things I wanted to do was write a separate mod that would automatically build a bridge at start of game if player is trapped on a small island. That should be simple case of placing two ends of bridge at which point my mod would do the rest (build the inner segments, swap water for fake water, etc). But, because `create_entity()` doesn't fire an event, my mod literally has no clue that another mod is trying to build a bridge. If `create_entity()` had an additional param, `false` by default, that told it to trigger an event, this problem would be easily solved.

The events would benefit any mod that uses compound entities (concrete lamppost, torches, ks_power, electric vehicles, etc) or wish to create/destroy entities from external mods (creative mode, vehicle wagon, etc).

bobingabout wrote: I would say that your use case is a bit unique. The only real way I would suggest you work around this problem is.... by doing exactly what you don't want to do.
Keep a table of every bridge that has been placed... or at least their co-ordinates. and then during an on_tick, perform a check to see if the bridge still exists. Now, you don't need to do the check EVERY tick, you could perform a check every 300 ticks. or perhaps do something similar to what the devs are going to do with pollution, and perform a staggered check of your table every few ticks, so that it doesn't all hit at once.

You have options. There are solutions.

function check_bridges()
  if not global.my_bridges then return end
  if not global.check_index then global.check_index = 1 end
  local bridge = global.my_bridges[global.check_index]
  if not bridge then global.check_index = 1 return end
  if not bridge.valid then 
    table.remove(global.my_bridges, global.check_index)
    return
  end
  if not bridge.neighbours[1] then
    bridge.destroy()
    table.remove(global.my_bridges, global.check_index)
    return
  end
  global.check_index = global.check_index + 1
end

Klonan wrote:Checking one at a time is pretty fine, it will never really affect performance, but it may take a long while to check all of them, which shouldn't be a problem in this case

/c remote.call("supportive-turrets", "add_on_tick")

/c remote.call("supportive-turrets", "remove_on_tick")

Klonan wrote:Checking one at a time is pretty fine, it will never really affect performance, but it may take a long while to check all of them, which shouldn't be a problem in this case

Mooncat wrote: Statistics on my side:
When the on_tick listener was added, FPS/UPS started to drop slowly when the number of turrets reached 8k.
When the on_tick listener was removed, FPS/UPS started to drop when the number reached 18k. FPS/UPS was around 54 when there were 19k turrets.
Then, the on_tick listener was added back, FPS/UPS dropped to 34.

I couldn't say whether the number of turrets is good or not for the users, as I mainly write mods recently rather than actually playing the game. I would say it is better than I thought.
Few things to note:
- the numbers are showing the situation when ONLY ONE mod is running. I expect the actual number of modded entities before FPS/UPS starts dropping will be divided by the number of mods running the same algorithm.
- when I tried to blueprint 1k turrets and placed them at once, FPS/UPS dropped significantly and could not recover. (I doubt it is something related to the code in game.)
(Creative Mode was used for clearing out obstacles, creating the nice flat land and placing turrets. But it has been removed before testing.)

Now judge it yourself.

local function on_tick(event)
  for surface_name, surface_position_x in pairs(global.supportive_turrets) do
    for x, surface_position_y in pairs(surface_position_x) do
      if (x + game.tick) % 60 == 0 then
        for y, data in pairs(surface_position_y) do
          if (x + y + game.tick) % check_period == 0 then
            if not data.turret.valid thn
              if data.unit.valid then
                data.unit.destroy()
              end
              global.supportive_turrets[surface_name][x][y] = nil
            end
          end
        end
      end
    end
  end
end