NML:GRF
Vehicles, Stations, Canals, Bridges, Towns, Houses, Industries (Tiles), Cargos, Airports+Tiles, Objects, Railtypes, Roadtypes, Tramtypes, Terrain
GRF block
Syntax:
grf {
grfid: <literal-string>;
name: <string>;
desc: <string>;
version: <expression>;
min_compatible_version: <expression>;
<param { ... }>
}
Example:
grf {
grfid: "AB\03\02";
name: string(STR_GRF_NAME);
desc: string(STR_GRF_DESC);
version: 1;
min_compatible_version: 1;
}
GRF parameters
As part of the grf block you can specify some parameter settings that the user will be able to change as part of the newgrf configuration. These can for example be used to disable parts of your NewGRF or to change between multiple graphics in case that's not possible at runtime. In general the settings (sub-)block looks like
param {
<name> {
type: <type>;
name: <string>;
desc: <string>;
min_value: <expression>;
max_value: <expression>;
def_value: <expression>;
names: {
0: <string>;
1: <string>;
.
.
.
};
}
}
Looking at the single entries:
type
This defines the parameter type. Possible values are bool for on/off statements or int for positive integer values
name
This gives the parameter name as shown in the parameter configuration dialogue of OpenTTD.
desc
This gives the description which is displayed when the parameter is selected. Here you can explain the meaning and impact it will have
min_value
The minimum acceptable value for the parameter (makes only sense for type int)
max_value
The maximum acceptable value for the parameter (makes only sense for type int)
def_value
This sets the default value for this parameter. If left out, the default value of 0 will be used.
names
If you chose type int and the numbers themselves are only used internally, have no direct numerical meaning and are better explained in words, you can use this to associate the single numbers with a string which describes it and is shown to the user instead of the value. A simple example:
param {
param_provide {
type: int;
name: string(STR_PARAM_PROVIDE);
desc: string(STR_PARAM_PROVIDE_DESC);
min_value: 0;
max_value: 1;
def_value: 0;
names: {
0: string(STR_PARAM_PROVIDE_ENGINES_AND_WAGONS);
1: string(STR_PARAM_PROVIDE_WAGONS_ONLY);
};
}
