Recently had been playing around with various IC2 items on my testing range, and when the time came for Item Buffer, I was a little bit confused about what it does.
Due to the color coding I supposed that it works as an intersection between 2 lines of logistic lines (compact item buffers, to be exact): green for vertical transfer, blue for horizontal transfer.
Respectivly colored inventories for each axes with slots for ejecting upgrades in GUI only reinforced my faith in it's presumable function.
During the making of a simple setup to confirm my hypothesis, I found that Item Buffer can be rotated with a wrench, unlike a Compact Item buffer - chests on top and bottom will turn based on it's orientation; though I didn't give it much thought back then.
After adding a stack of crushed iron ore in the Compact Item Buffer in the down left corner, the machines would output 32 iron dust in the top chest and 32 iron ingots in the right one.
And adding I did. Seconds after the process was done and I checked both chests. The results were... confusing, to say the least.
Top chest had 16 iron ingots and 32 iron dust.
Right one had the remaining 16 ingots.
100% confident that I'm either colorblind or just an idiot who can't grasp fundamental concepts of how things work in a cube game, I headed to Wiki. The page for Item Buffer said:
If the destination block is above or below your buffer, then you will be using the GREEN inventory.
If it is on one of the sides, you will be using the BLUE inventory.
Place the ejector upgrade into the bottom slot of the inventory you want to use, and add items to that inventory.
Okay, maybe there was a fault in my setup - I thought. Let's do something very, very basic.
Item Buffer worked as Wiki stated in horizontal plane: macerator ejected iron dust in blue inventory, Item Buffer ejected iron dust in adjacent chest through a blue side. So far so good.
Immediately after though, during the test of vertical axis the game decided that it will be really funny if it would pull a sneaky bamboozle on me, and by that I mean:
to put an item from GREEN input to BLUE inventory. BUT THE SHENANIGANS DON'T END JUST THERE, OH NO!
When I inserted ejector upgrade in GREEN slot, the iron dust went from BLUE invetory into A TOP CHEST, THROUGH A GREEN INPUT.
Moreover, if both item and ejector upgrade (pointed up) are in BLUE inventory, Item Buffer still puts item in a TOP CHEST AS WELL.
So it prioritizes blue inventory no matter what the colors of input and output are. Awesome.
Going back to Wiki: it just restated how I ASSUMED it worked, an assumption that was shattered in pieces after three minutes of in-game double-checking. Desperate, I went on to read the...
And it said literally the same thing as the previous wiki:
Items entered from the blue side can only be output from the blue, and the same is true for green.
End translated quote.
I am completely lost right now, as I'm sure I've missed something here, it defintely should not work like this.
TL;DR: Item buffer only works as intended/described by wikis in 2 out of 16 possible scenarios, please help me understand it.