NML:Parameter assignment

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Vehicles, Stations, Roadstops, Canals, Towns, Houses, Industries (Tiles), Cargos, Airports+Tiles, Objects, Railtypes, Roadtypes, Tramtypes, Bridges, Badges, Terrain

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Block Syntax

GRF

• GRF parameters

Item

• Property
• Graphics
• Livery override

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Railtypetable / Roadtypetable / Tramtypetable

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Testing for other NewGRFs

Overriding vehicles in other NewGRFs

Sprite replacement

• Replace TTD sprites
• Replace new sprites
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Alternative (32bpp) sprites

Town names

• Town names parts

Snow line

Parameter assignment

Setting base costs

Sorting vehicles in the purchase list

Parameters

param[<expression>] = <expression>;

Set a parameter to the given expression. Neither of the two expressions has to be constant, the following is perfectly valid:

 param[param[2] + 1] = param[3] * param[4];

Parameters can also be named, then it is possible to access them by that name instead of index.

 custom_bit_mask = add_trains + (add_planes << 1);

Note: When assigning value to named parameter that has not been used/defined earlier it is given an unused index, therefore it is better not to mix named parameters with unnamed ones in one grf.

Compile time values

Since NML 0.7.6 it is possible to create user defined constants. They work the same way as default ones.

 const <expression> = <expression>;

 const CC_WEIRD = 12;

It is adviced to use screaming snake case for constants to distinguish them from runtime expressions.