Rail Type Introduction & its relationship to Introduction Date

[Gwyd]

So I was playing around with making some of my own railtypes, and to make some railtypes that were required from a technical standpoint but should not available to the player (let's call it railtype X), I set the property "introduction_date" of the tracktype to the year 5000000, the quoted maximum from: https://newgrf-specs.tt-wiki.net/wiki/NML:Railtypes.

When I compiled this into a NewGRF regardless of the date, once the first train for railtype X was made available (~1980) railtype X was made available.

Some more digging on that same page tells me that the game will basically ignore the "introduction_date" property, unless no trains are explicitly allowed on it. To me this seem unintuitive and unhelpful. Yes, I am pushing the limits of the design for a specific use case, but nonetheless this implication does not appear to be the best possible.

[Eddi]

with openttd 1.9 was added the ability to hide railtypes from the construction menu. that sounds like what you're looking for here. (property 10 bit 2)

[Erato]

with openttd 1.9 was added the ability to hide railtypes from the construction menu. that sounds like what you're looking for here. (property 10 bit 2)

Is there a way to implement this using NML?

[Eddi]

yes, property 10 is called "railtype_flags" there. i imagine it hasn't got a name for the bit, though, so you'd have to use the raw number, like

Code: Select all

bitmask(2)

[Gwyd]

I tried to do something like that after reading the nfo specs about it, but I couldn't seem to get the desired result.

[Eddi]

i'm afraid you need to provide us with more details

[Gwyd]

What I'm trying to ask is how would I set flags in the item block of some item which doesn't have a name implemented into NML like RAILTYPE_FLAG_CATENARY, but rather one that is defined under property 10 for NFO.
In this particular case, I want to set the railtype to have the "hidden in construction menu" flag enabled, which in NFO is defined as bit 2 with a value of 4 in property 10. I have attempted this in NML by trying the code

Code: Select all

bitmask(4)

In the item block of the railtype in question, but this didn't seem to work.
This suggests either:
I wasn't being rigorous in testing the change
or I'm doing it wrong.


EDIT: I just had to copy Eddi's post to hide the track type, thank you for your help. Still unsure on the behaviour of railtype releases.

[Transportman]

What I'm trying to ask is how would I set flags in the item block of some item which doesn't have a name implemented into NML like RAILTYPE_FLAG_CATENARY, but rather one that is defined under property 10 for NFO.
In this particular case, I want to set the railtype to have the "hidden in construction menu" flag enabled, which in NFO is defined as bit 2 with a value of 4 in property 10. I have attempted this in NML by trying the code

Code: Select all

bitmask(4)

In the item block of the railtype in question, but this didn't seem to work.
This suggests either:
I wasn't being rigorous in testing the change
or I'm doing it wrong.


EDIT: I just had to copy Eddi's post to hide the track type, thank you for your help. Still unsure on the behaviour of railtype releases.

It didn't work because you misunderstood how the bitmask() function works, it sets the bit at the position you provide. So if you need to set a property to value 4, you can do that by setting bit 2 (1x2^n, where n is the bit you set, in this case 2).

I think the railtype release behavior is a bit of a safeguard against several things (vehicle introduction dates randomization, different vehicle and track NewGRFs), so the safe behavior is to forcefully introduce the railtype when a vehicle becomes available for it. But there are cases where a railtype should not become available as it is a technical type, which is now covered with the "hidden in construction menu" flag.

[Eddi]

which in NFO is defined as bit 2 with a value of 4

this is the important information. if you use the "bitmask" function, you need to use the bit number (2), if you don't use the bitmask function, you can use the value (4). in other words, bitmask(2) == 4