NML - a Newgrf Meta Language

[Eddi]

in the context of cargodist, there is more to worry about than station rating. if passengers pile up at intermediate stations, they already used up some part of the ressources, but they have not paid you any money, which reduces your overall income significantly.

if you want to adjust capacities, you can decompile a GRF into NFO, and change the values there. you can't decompile it into NML.

also, there are several passenger-reducing patches in the development forum.

[ColdIce]

Thanks guys for answers. I just managed to alter the grf(s) with grfcodec. It worked like a charm
I didn't know that you can decode/encode grfs written in nml. thank you

[Transportman]

I have a question regarding Dual-headed vehicles. Which properties are shared between the front head and the back head and which properties are only set for the front head (and need a switch-block to also be set for the back head)? It seems to me that power and costs are not set for the back head, but the other properties are.

[Eddi]

what about the "available for articulated part" column in this table?
http://newgrf-specs.tt-wiki.net/wiki/NM ... icle_types

[Transportman]

what about the "available for articulated part" column in this table?
http://newgrf-specs.tt-wiki.net/wiki/NM ... icle_types

It follows the list mostly, but for example weight and TE coefficient are not set to 0 for dual-headed vehicles, while they are set to 0 for articulated parts.

[Wahazar]

I want to implement finite resources of mines by using permanent storage:

Code: Select all

switch(FEAT_INDUSTRIES, SELF, core_mine_resources_on_build, STORE_PERM(initial_resource,1)) {
 return 16;
}
switch(FEAT_INDUSTRIES, SELF, core_mine_monthly_prod_change, 
(STORE_PERM(LOAD_PERM(1)-produced_this_month_1,1))) { 
 return CB_RESULT_IND_PROD_NO_CHANGE; 
}

however seems that it is not working (I'm checking storage levels by means of industry extra text switch).
Should I push permanent storage to the temporary one during substraction, or there is my another mistake?

[planetmaker]

I want to implement finite resources of mines by using permanent storage:

Code: Select all

switch(FEAT_INDUSTRIES, SELF, core_mine_resources_on_build, STORE_PERM(initial_resource,1)) {
 return 16;
}
switch(FEAT_INDUSTRIES, SELF, core_mine_monthly_prod_change, 
(STORE_PERM(LOAD_PERM(1)-produced_this_month_1,1))) { 
 return CB_RESULT_IND_PROD_NO_CHANGE; 
}

however seems that it is not working (I'm checking storage levels by means of industry extra text switch).
Should I push permanent storage to the temporary one during substraction, or there is my another mistake?

You don't seem to actually check for the variable. You only assign a new value. Additionally you always return 'no production change', whatever your variable value.

Try

Code: Select all

switch(FEAT_INDUSTRIES, SELF, core_mine_monthly_prod_change, 
    [STORE_PERM(MAX(LOAD_PERM(1)-produced_this_month_1,0),1), LOAD_PERM(1)]
) { 
 0: return  CB_RESULT_IND_PROD_CLOSE;  // close when no ressource left anymore)
 return CB_RESULT_IND_PROD_NO_CHANGE; 
}

(Totally untested though)

[Wahazar]

You don't seem to actually check for the variable. You only assign a new value. Additionally you always return 'no production change', whatever your variable value.

I'm testing via:

Code: Select all

switch(FEAT_INDUSTRIES, SELF, core_mine_extra_text, (LOAD_PERM(1) > 0 ? (LOAD_PERM(1)>initial_resource-1 ? 2 : 1 ): 0) ) {
 0: return string(STR_MINE_EXHAUSTED);     
 1: return string(STR_MINE_1);   
 2: return string(STR_MINE_2);     
 return string(STR_NUMBER_UNDEF);
}

and still STR_MINE_2 is returned, regardless how much cargo is delivered from mine to factory.
I removed all production change procedures to simplify code.

EDIT: there was funny mistake, I used produced_this_month in monthly_prod_change switch, wich is called at the beginning of each month - obviously this variable is equal zero.
With produced_last_month everything works OK.

[Wahazar]

How to change type of cargo produced?
There is cargo_output callback, but it is unclear for me how it works.
I want to have one cargo produced permanently and the second one switched from one type to another and back, repeatedly.

[planetmaker]

There are the cargo_input and cargo_output callbacks.

Code: Select all

switch (FEAT_INDUSTRIES, SELF, decide_output_cargo, extra_callback_info1) {
  0: return cargotype("WATR");
  1: return cargotype("OIL_");
  return 0xFF;
}

...

item (FEAT_INDUSTRIES, well) {
  graphics {
    cargo_output: decide_output_cargo;
  }
}

But think twice, better three times before you start making use of those. People generally expect that an industry always accepts the same cargo types and also produces the same cargo types. it also doesn't work well with the industry chain view which also assumes constant cargo chains. And it will possibly also break AIs.

[Transportman]

How to change type of cargo produced?
There is cargo_output callback, but it is unclear for me how it works.
I want to have one cargo produced permanently and the second one switched from one type to another and back, repeatedly.

Sounds like you are trying to work around a game limitation, and I'm not sure if this is the right way to do that.

[Wahazar]

There are the cargo_input and cargo_output callbacks.
...
But think twice, better three times before you start making use of those. People generally expect that an industry always accepts the same cargo types and also produces the same cargo types. it also doesn't work well with the industry chain view which also assumes constant cargo chains. And it will possibly also break AIs.

I need it to accept and produce passengers in case of farms, however let me redirect eventual discussion to another thread:
http://www.tt-forums.net/viewtopic.php?f=67&t=71105

I have another question related to parsing NML files and using variable substitution within #define sttement -
sometimes there is variable_name ## something, sometimes variable_name ##something_without_space - what is a difference?
Is it possible to make #define template for switches names within graphic statement or only explicit names can be used?

[Eddi]

space after ## does not make a difference.

you can make a #define containing a switch or any other text sequence, it will be replaced textually before nmlc processing. use \ at the end of line to make a define cover multiple lines (for easier overview)

for more information about #define see https://gcc.gnu.org/onlinedocs/cpp/

[Transportman]

you can make a #define containing a switch or any other text sequence, it will be replaced textually before nmlc processing. use \ at the end of line to make a define cover multiple lines (for easier overview)

For an example of the use of \, see this code

[Transportman]

I have a question regarding running_cost_base. Is it for train vehicles fine to set it to RUNNING_COST_ROADVEH? According to the specifications it is, but are there side-effects I should be aware of?

[PikkaBird]

I have a question regarding running_cost_base. Is it for train vehicles fine to set it to RUNNING_COST_ROADVEH? According to the specifications it is, but are there side-effects I should be aware of?

It's "fine", but has exactly the drawbacks you've already identified in the 2cc thread.

If you want different cost bases with slightly less potential for other grfs buggering things up, you could do what I do in 10CC: use RUNNING_COST_STEAM for all locomotives, and RUNNING_COST_DIESEL for all wagons.

[Eddi]

the side effect of using RUNNING_COST_ROADVEH is that changes to it are going to be global, if you don't actually define a road vehicle (you can easily define a dummy road vehicle that never becomes available to avoid this)

[Transportman]

the side effect of using RUNNING_COST_ROADVEH is that changes to it are going to be global, if you don't actually define a road vehicle (you can easily define a dummy road vehicle that never becomes available to avoid this)

Okay, that is a bit of a downside, also because of the potential that base cost NewGRFs have to accidentally influence them as RVs. I'll stick to PikkaBirds suggestion to use one base for engines and stuff and one base for wagons/coaches. That still gives me the control I need, without the pesky side-effects.

Thanks for the information, saved me from a less handy decision.

[Wahazar]

Is it possible to create industry tile callback dependent on industry variables?
For example, I want to set industry tile anim_control callback dependent on industry production level.

[PikkaBird]

Certainly. Industry tiles can use the PARENT scope in switches to test the variables of the industry.