Statistics GUI Klonan, Oxyd The statistics GUI (electric network stats, production stats, etc.) is one of the GUIs that has been in the game for a very long time, and has had its functionality fleshed out reasonably over the years. It was not long ago when Twinsen added hovering and highlighting to the graphs. Given that, and the relatively short timeframe for 1.0 release, the update of the statistics GUI has really just been a style update, no new features or heavy logic rewriting. Oxyd has most of the work done, so we are happy to show some real in-game screenshots of how it looks: A notable change with the electric stats is that the Satisfaction/Production/Accumulator charge are next to each other in a single row, as opposed to each in a separate row. The label for the exact amount has also been moved to inside of the progress bar, which itself is much thicker. The production stats are pretty much the same functionality wise. One new button you might spot is the search button. However there are some problems with the search feature. As you can see, production and consumption frames have a different search box independent from each other. The main problem is when pressing CTRL+F to perform a regular search: How do we know which frame to open? Of course this could lead to different solutions like the use of a cycle for the focus of the search, in which the second time you press CTRL+F the other frame gets the focus. Or both of the search boxes open at the same time but only one gets the focus. Or only one frame gets the focus and the other one works only by pressing the button. But let's face it, these "solutions" are not solid at all and create inconsistency in the main design. To solve this issue we decided that the simplest way to go is the use of just one search box on the header of the panel. This new location works as a general feature for the entire panel. One single search gives you 2 results, one on each frame. This solution is used in the new character window -to come soon- making it consistent with the whole design of the GUI. You can also see we took this opportunity to integrate the Kill statistics in with the rest, instead of being its own window with its own hotkey. The Statistics GUIs will need a few tweaks and polishings here and there before it is ready for release, but unless something unexpected happens you can expect it coming out in a release soon.

Hello, this is the last Friday of 2017, and as such, the last Friday facts of this year.

Hello, long time no see! Today we are going to talk about the expansion which is called Factorio: Space Age.

Fluid mixing saga Dominik Hello Factorians, Today I would like to talk to you about my favourite subject - fluid mixing and its prevention. It is a new mechanic introduced in 0.17 that seemed quite simple at first, but has been giving me nightmares ever since. A while ago I took on the task of updating the fluid system (FFF-260). The way it works in 0.16 is that the fluid boxes (the thing that holds the fluid and is contained in entities like pipes or refineries) had no organisation whatsoever except their connections. They would sit there and do nothing and then once per update send fluid somewhere. It had it's issues especially with symmetry, and when you happened to put some fluid where it did not belong, you could end up requiring major demolition works. My task was to develop a better algorithm to move the fluids, and a very very optional side task I had in mind was to do something about the fluids getting to wrong places and mixing. We started by organizing the fluid boxes into systems (connected FBs make a system) managed by a special fluid manager, and optimizing the heck out of it (FFF-271). Soon after, I started working on the new algorithm and anti fluid-mixing. Until then nobody really considered preventing the fluid mixing seriously as it did not seem possible. But when I thought about it, it did not seem that hard. The idea is to simply not allow any action that would lead to fluids getting where they are not supposed to go. When you build a steam pipeline, you should not need nor want it to touch another fluid. In principle, it would only require a few quite realistic mechanisms: A connected block of fluid boxes would either be fluid-free, or it would be locked to one fluid. Two such blocks can connect only if they are compatible - either one has no fluid lock, or they have the same fluid. An assembler can only set a recipe if it is compatible with the fluid locks on its fluid boxes. Have a migration from old saves that can contain mixing. By creating the fluid systems right before, number 1 was almost finished and we only needed to assign the lock. It would be set either by a fluid, or by a 'filter', which is a fluidbox that is set to use a fluid - such as a water pump using water, or assembler having some inputs/outputs given by a recipe. After a while I had both the fluid algorithm and the mixing done (FFF-274). The mixing was not that easy (like 5x more complicated) but it worked pretty well. As for the fluid algorithm, V453000 and Twinsen found some issues with waves on a macro scale, and because it was right before releasing the 0.17 experimental, we decided to hold it off on it for the time being (we have a new version now that seems okay, but has to wait for 0.17 becoming stable first). The mixing made it through though and seemed quite finished. It turned out that the work on it was at most one tenth complete. Some difficulties appeared already before the initial release, but that was only a hint of what would come later. One by one, then ten by ten, bugs started coming. The problem is that as often as not, they were not just little issues with simple fixes. Instead, over and over, they turned the current solution on its head and the code had to be completely rewritten in order to account for the new case. As of now, almost exactly half a year and many rewrites later, it is still not fully bug free. The number one issue was with Assembling machines. It turned out that their code was pretty messy and does not simply allow the checks I needed, so it had to be refactored. The next problem was that the check was not only required when setting a recipe on an existing assembler - as I naively thought - but in about one million different situations I would not dream existed. Building a fixed recipe assembler. Reviving an assembler. Rotating. Blueprint of an assembler. Blueprint with a recipe and a rotation placed over a ghost with a non-default rotation during a full moon. Teleport. Script building. Copy-paste settings. Any combination of these. Pretty much every case would go through different paths in the code and behave entirely differently. Fixing one would break another and so tons of tests had to be written. When these cases finally worked, it turned out that doing these operations when they fail (e.g. can’t rotate because it would cause mixing) brings another wave of issues. And then mods come and the complexity multiplies. All this, although in a more simple form, had to be done for all other entities that can use fluid too, such as inserters (mods...). Another number one issue are underground connections. When playing, you would not think twice about them but on a closer look they are all but simple. They have this (cough) uncomfortable feature (want to shoot myself) that you can build another underground pipe between them (or take it out) and a complex reconnection logic jumps in. It means that based on building order, connections are established and reestablished differently. This is a big thing when building a blueprint with many pipes, or loading a save game. But the largest issue is one tiny corner case with huge implications. Have two underground pipes that have different fluids, but are split by a third, and it gets removed. Until now mixing was theoretically completely avoidable, but here it was and there was nothing to stop it. As a result, a new concept is introduced - a blocked connection. An underground connection that would normally connect but can’t. Establishing it is the easier part. But when does it get fixed? An entity miles away gets rotated, that splits a fluid system, disconnecting the blocked connection from a fluid filter on the other side, and the connection should unblock. But even something as simple as a rotation contains fluid fixes and re-establishing of fluid boxes and if it fails, it still fixes the blocked connection in the process and it can’t be undone... You get the picture. And we are still talking about underground pipes, while anything can have underground connections, including said assemblers, which the previous code did not consider at all. The complexity just goes deeper and deeper, and Rseding is probably right that we should have never gone this way at all. So the bug fixing has been basically running in circles - clearing one batch of bugs, thinking that those were the last ones and the ordeal is finally over, only to find another batch (ideally from some bizzare modder idea) a few days later. Many times I wished that mods never existed. Nor multiplayer, or any players at all for that matter. About two months ago all seemed really fine, with basically no reports and just a few crashes in the automated crash reports. At that moment another nightmare materialized in the form of a talented volunteer bug tester named boskid, who took on a personal crusade to break the fluids to dust (I actually imagine him sitting in his dark room with evil laughter, dreaming about making my next day worse than the previous). In all seriousness, he has done a great deal of work with his bug testing, creating bizzare modded cases and testing scripts, and deserves a big thanks. He is actually coming to our offices next week, so follow the news for reports of developers falling out of windows. An example of a nice configuration he found (and I can’t fix). The whole time we were taking the offensive approach to mixing - crash the game when it happens - so that we know about bugs to fix them. Recently we have decided to put a stop to it and have the mixing automatically fix itself once it is detected, eyeing the end of this episode. Right now I have 3 mixing bugs on the list and I am sure those are the last, and mixing will be done (lying to myself is a way to cope with it) and the new fluid algorithm can come soon after :).

More particle optimisations Allaizn Rseding's recent optimisations of the particle system (FFF-322) made particles much more lightweight than they were before, but it still left particles as rather complex beasts. A quick summary of the possible actions a particle can make during it's update: Move their own position. Advance their animation to another frame. Land in water and apply a trigger. Apply another trigger with a certain frequency. Remove themselves from the game world once their life time ends. What makes this complex is that triggers are general purpose systems that can do all kinds of things, including creating and destroying entities, fire, smoke and other particles as well as playing sounds or recursively applying even more triggers. In other words: applying a trigger is an "anything can happen" situation and thus totally unpredictable, which in turn makes optimisations extremely hard.

Team production changes Improving the Team production challenge was prompted by this Reddit post. Team production was made back in 2016 to test the multiplayer networking of the 0.14 update with a larger number of players without the overhead of having a large factory. Since then it has not really had much love. So after 4 years of accruing wisdom, I started making some general improvements.

A week in the office This week is another week of typical bug fixing, so I thought we would make a one-time change of style and do a day-by-day account of what exactly that means for us.

Hello, we had a small Factorio 0.17 LAN party this weekend. The purpose was to try and test some of the new features and play the game properly as I haven't had time for that for quite a while. I used this opportunity to think about all the smaller or bigger decisions, features or change of plans in the context of playing the game for many hours.

The many lessons learned from testing the new tutorial We have already pointed out, that we are trying to make a new campaign (FFF-245), and part of it is the core beginning, the NPE/tutorial. The tutorial is one of the very critical parts of the game, as if the first 15 minutes of a game feels shitty, there is big chance that the player will not play any further. I had this experience in many games myself. So the challenge could be articulated like this: "The current tutorial is okay, but can we make it great?" The approach in the current tutorial is to feed the player with the basic knowledge of how to control the basics of the game (the first mission and the start of the second mission) in the fastest way possible. The player is even given descriptive info like this, to diminish the chance of not understanding how the basic entities work. After few steps in the 2nd level, the player can start exploring his first self-feeding loop (make iron to make more iron). The tools used to this is mainly: The message dialog that stops the game and explains the player various things. Minimization of the amount of things the player can interact with to absolute minimum, so he can't start doing other things before the basics are clear. The possible drawbacks: The constant interruptions can get really annoying (typically around 22 message dialogs before the player starts to play relatively freely in the 2nd level). The possibility, that the player will mindlessly follow the step-by step tasks without understanding it, so he can become really lost later on, and the tutorial basically wouldn't help him to understand things. So the question is: Can we make a tutorial that makes these problems go away?, and alternatively, How big are these problems actually? The current direction of the new tutorial attempt is to never use the message dialogs, so the player can learn the game more fluently, and to leave way more things to explore, as learning things yourself has a better chance of success than force-feeding generally. We made a few tests of the new approach with a few people, the main takeaway, is that nothing is for free, and this approach created new drawbacks. If the player doesn't figure out something basic, it can be very frustrating for him to figure out what is going on when not moving forward for a long time. It might be possible, that some things are just not fun to learn by exploration, and it is more comfortable if they are force fed to you. I would compare this to a friend explaining you how to play a game for 5 minutes compared to 2 hours of trial and error. There are more possible outcomes from this, and we shall see how different tweaks of both strategies work in the testings. It might be interesting if you mentioned your experience with the tutorial in the comment section as well.

Hello, We have another exciting batch of facts for you today.