Classes of Loading Screens

There are two classes of loading screens:

• Unconditional: These loading screens have no condition, so they can show up any time. Most vanilla loading screens are like that.
• Conditional: These loading screens have specific conditions under which they can be used. Vanilla uses conditions to implement location specific loading screens
  

If there are conditional loading screens, whose conditions are met, they will be prioritized over unconditional loading screens. This means, as long as there is at least one conditional loading screen, whose conditions are met, unconditional loading screens are ignored. Conditional loading screens, whose conditions are met, will be called valid.

Understanding conditional Loading Screens

This makes it very hard to control the frequency of loading screens, because as soon as you try to control them with conditions, they are prioritized over vanilla loading screens. Because of that, conditional loading screens often have additional random conditions, so that their conditions are only met rarely.

Mods that replace vanilla loading screens, generally give their loading screens a 100% chance, so that unconditional loading screens are never used. In theory, conditional vanilla loading screens could still be used, but due to small random chances and location or quest specific conditions, usually only 1 or 2 conditional vanilla loading screens are valid. On the other hand, the replacer mod might add 20 loading screens, of which all have a 100% chance. So in the rare cases, where a conditional vanilla loading screen could be chosen, it still has to fight against 20 mod added loading screens. As a result vanilla loading screens are extremely rare and the replacer mod works as a replacer mod.

Frequency and Compatibility

Now the question is: How do you make a mod configurable, so that you can select how frequently its loading screens will be used and how can you use that frequency to make it compatible with other mods?
In order to be compatible with a replacer mod, you essentially make your own mod a replacer mod as well. Then all loading screens are conditional and valid, so each loading screen has the same chance to be used. Mods with more loading screens will be chosen more frequently because of that.

In order to be compatible with vanilla loading screens, you have 2 options. First, you can use unconditional loading screens. The disadvantage of this approach is, that you cannot control the frequency and all loading screens are equally likely. You will probably get more vanilla loading screens, because there are simply a lot of vanilla loading screens. Another option is to use conditional loading screens, which have a tiny chance to be used.

Starting with version 2.0.0 of this mod, it uses a new system to implement loading screen frequency. All added loading screens have a synchronized chance, which means they will all be valid at the same time. This happens randomly at a rate equal to the frequency. If all loading screens are valid at the same, the chance of a conditional vanilla loading screen being picked over them is extremely low.