Factorio Forums

Rseding91 wrote:I would implement this but there's no simple way to fire the event that wouldn't cause catastrophic issues with the rest of Factorio.

Closing a GUI can be triggered from almost anywhere during the update loop and when firing events into the Lua state the mod(s) are able to do any actions which can completely invalidate the calling section of code.

A simple example:

1. The player has a blueprint open to edit that's contained in a chest.
2. A biter destroys the chest which goes through and clears every item in the chest 1 by 1
3. In reaction to the blueprint being destroyed the GUI is closed
4. In reaction to being closed the event is fired
5. The mod does some stuff and one of the things it does is delete the chest that's being killed
6. Returning back to the biter destroying the chest: it's now in-process of destroying items but they're all already destroyed and it's in an invalid state and crashes

You take that same scenario and apply it pretty much everywhere except the player pressing "E" to close the GUI and there's just no simple answer to making this work yet.

binbinhfr wrote:I do not really understand, because for the moment we are all polling with on_tick the player.opened object to open or close our additive GUI. We could already destroy chest or whatever stupid thing, if we wanted it. Modders already have the possibility to do nasty things, but we are simply not doing it, because we want our mod to work correctly... So I do not see the difference between polling player.opened or having a on_opened event that would simplify our work and avoid this cpu consuming polling.

1. The player has a blueprint open to edit that's contained in a chest.
2. A biter destroys the chest which goes through and clears every item in the chest 1 by 1
3. In reaction to the blueprint being destroyed the GUI is closed
4. In reaction to being closed the event is fired
5. The mod does some stuff and one of the things it does is delete the chest that's being killed
6. Returning back to the biter destroying the chest: it's now in-process of destroying items but they're all already destroyed and it's in an invalid state and crashes

binbinhfr wrote:

1. The player has a blueprint open to edit that's contained in a chest.
2. A biter destroys the chest which goes through and clears every item in the chest 1 by 1
3. In reaction to the blueprint being destroyed the GUI is closed
4. In reaction to being closed the event is fired
5. The mod does some stuff and one of the things it does is delete the chest that's being killed
6. Returning back to the biter destroying the chest: it's now in-process of destroying items but they're all already destroyed and it's in an invalid state and crashes

returning to your example, I still do not get it.
in step 2, the biter destroys the chest.
then in step 5, if the mod tries to destroy the chest, it won't work because the chest is not valid anymore, so there will be a lua error "object invalid", no ? No crash.

binbinhfr wrote:you said before : "All events that I know of are safe from mods doing "interesting" things."
So I supposed you already encounter this problem and you did what was needed to secure that (i.e. you did all that was need before firing the event and letting modder do their stuff).

So why factorio won't do all the stuff needed (correctly destroy the chest in our example) before firing on_closed this event ?

Another question : when do you update this famous player.opened to nil ? When you update this variable, I supose that everything is safe. So you could fire the on_closed event just at the moment where you update this variable, no ?

aubergine18 wrote:All this being the case, if I want to provide a complete custom UI for my entity, what would be the way to achieve that? (other than checking every tick to see if the player opened something)

Supercheese wrote:Your best bet might be the Wrench/WrenchFu library (if it's updated for 0.13).

Rseding91 wrote:Some events are fired from specific places and those have guards in place. Closing the GUI can happen from almost everywhere in code because it works automatically when the GUI target is removed.

if (player.guiTarget != null && DistanceBetween(player.character, player.guiTarget) > range)
    player.guiTarget = null;

foreach (var player in game.players)
{
    if (player.guiTarget == entity)
        player.guiTarget = null;
}

if (player.guiTarget != null)
    player.guiTarget = null;
else
    OpenSelfOrMenu(player)

foreach (var player in game.players)
{
    if (player.guiTarget == null)
        CloseGUIForPlayer(payer);
}