I have some ItemStack capabilities that need to be updated every tick. Is there any way I can add tick updates to the vanilla chest, with events or capabilities or something? I'd like to avoid having to completely re-create chests just to add this one change.

3 minutes ago, diesieben07 said:

Ticking items in inventories is a pretty bad idea from a performance perspective (plus there isn't an easy way to achieve it). Why do you need this exactly? What are you trying to achieve?

I have food items which decay over time, so they have a tick counter that tracks their decay level.

8 minutes ago, diesieben07 said:

Use world time instead. Store the "begin" world time (World::getTotalWorldTime on the overworld dimension) in the ItemStack's NBT then you can always calculate how much time has elapsed without having to constantly update the ItemStack.

 

I'm using the durability bar to represent the decay level when the item is in a GUI, so it will often be called every tick for rendering purposes anyway - will it still make a significant performance difference to use the total world time instead of a counter?

 

Edit: also, I want the item to turn into a different item (representing rot) when it reaches the end of its shelf life. That can only be achieved using a tick update though, right? Otherwise the item won't turn into rot until its age is checked some other way.

Edited February 18, 20178 yr by Jay Avery

1 minute ago, diesieben07 said:

Using the world time makes it possible for your item to age continuously, even when it is in an inventory or even an unloaded chunk, since the age is always calculated on the fly from the creation time and the current time. This is simply not possible to achieve with a counter.

Fair enough. I'll give this a try.

1 minute ago, diesieben07 said:

 

Yes, you would have to do that in onUpdate on the Item class, which means the Item will rot as soon as the player picks it up. This is the best you can do.

I just realised I could maybe get away with keeping the ItemStack unchanged, but add a predicate to the model so that it uses a different texture when it's fully decayed (like with broken elytra).

 

Thanks for the ideas. 

2 hours ago, diesieben07 said:

Use world time instead. Store the "begin" world time (World::getTotalWorldTime on the overworld dimension) in the ItemStack's NBT then you can always calculate how much time has elapsed without having to constantly update the ItemStack.

 

Follow-up question - where should I get the world from? The initCapabilities method only takes an ItemStack and NBTTagCompound as parameters. Should I just do Minecraft.getMinecraft().world?

Because initCapabilities is where I add the capability to my decaying items. Where else would I do it?

2 minutes ago, diesieben07 said:

Yes, that's where you add the capability. But when do you want the items to start decaying?

I want the timer to start as soon as the item starts to exist. With my previous method using a tick counter, starting it in initCapabilities has worked in the way I wanted it to.

As soon as the item is first created, either from a crafting recipe, furnace recipe, or drop from a block or entity. I'm saving information about the age to NBT, so it should persist through splitting etc - i.e. if a stack is split in two then both new stacks will have the same 'birth time' as the original stack did.

Similarly the creative menu will bypass it.

23 hours ago, Jay Avery said:

Follow-up question - where should I get the world from? The initCapabilities method only takes an ItemStack and NBTTagCompound as parameters. Should I just do Minecraft.getMinecraft().world?

I need to revisit this question. I can't use Minecraft.getMinecraft().world because it's client-side only. Where should I get a world object from in initCapabilities?

2 minutes ago, diesieben07 said:

You don't. Why do you need to?

Because I need to get the world time when I construct the capability.

Okay I see. It's working now because when the stack is copied/split/etc it then gets read from NBT anyway - so if it's *not* a brand new stack it gets its birth time from its parent stack straight away. I guess that's not the best way to do it though. But the alternative is to manually hook into every place where a new stack of my decayable item might be created, and set the capability data there?