Allow "input-output" fluid arrows for crafting machines

[Wiwiweb]

Here's the "casting machine" from Space Exploration and the "greenhouse" from Krastorio 2:

fluid-arrows.jpg (171.49 KiB) Viewed 3358 times

These entities have fluid boxes with `production-type = "input"` and some `pipe_connections` of type `"input-output"`. So they can pass-through fluids and be chained together.

But it's difficult to convey that to players because players expect "in-and-out" fluid arrows on the pipe connections, just like the boilers and steam engines. So every day we get people going "Wait you can chain those?!!".

It'd be great if we could have the same "in-and-out" arrows for crafting machines too. I'm not sure internally how that'd work, but probably one of those:

a) Allow `production_type = "input-output"` for crafting machines for the purpose of the fluid arrows. Currently this causes a load error: "Error ModManager.cpp Error while loading entity prototype "se-casting-machine" (assembling-machine): Crafting machine fluidboxes must be input or output types."

b) Add a parameter on Types/PipeConnectionDefinition to override which arrow gets drawn. none/input/output/input-output. As a bonus I could see some use in being able to remove the fluid arrows for some composite entities.

Thanks!

[Stringweasel]

+1 for b!

It could indirectly help clean up Fluidic Power where the input-output arrows are shown while the entity is in the cursor. It's already possible to remove it when placed with 'hide-alt-info', but that might hide more than you really want.

For reference: 97809

[Anachrony]

This would be great for the Nullius overhaul as well. The chemical plant there has a pair of input-output pipe connections that allow fluid to pass through it, but a lot of players never realize it because the arrows are rendered as input only. If players know about this feature it can allow much cleaner layouts, but it's awkward to inform them about it when the mechanism they normally rely on fails to show the correct information. I could add my own arrow icons as a separate layer to the image itself, but then it wouldn't behave like a real arrow and only show up some of the time. It's currently discovered mainly by reading the FAQ or by word of mouth lore, often too late. I've thought about cramming an explanation into the tooltip description or adding a tips & tricks just for this, but really it should just be an option to show the arrows differently.

[Anachrony]

It would be ideal if this could be a new property of each pipe_connection that you could override the arrow it displays, regardless of prototype. If the field isn't set then it does whatever it thinks it should do now. But setting it makes it display as a particular type of arrow regardless of the fluid box production type or prototypes, including a setting to disable the arrow if someone wants that. For example storage tanks don't seem to show these arrows, but for some modded storage tanks it may not always be as obvious as the vanilla graphic and it would be good to allow it to opt into rendering the arrow for each possible connection.

[Anachrony]

Thanks, I can confirm that this is implemented in the latest game update. In Nullius the passthrough slots on chemical plants are displayed with the double arrows, and the arrows on storage tanks make it easier to tell where the North connection is on small or large storage tanks.