User:Andrew350/NML:Roadtypes

NewGRF Meta Language

Preface

Getting started

Graphics files

Blocks

Units

Expressions

Elementary values

Builtin functions

Language files

Lists of props, vars and CBs

Warnings

Additional references

NewGRF compatibility

Deprecated syntax

Changes from NML 0.2 to 0.3

Changes from NML 0.3 to 0.4

Changes from NML 0.4 to 0.5

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

NML Tutorial

Props, Vars and CBs

General

• variables

Vehicles

• common props | vars | CBs
• train | roadveh | ship | aircr props

Stations

• properties | variables | callbacks

Canals

• properties | variables | callbacks

Bridges

• properties | variables | callbacks

Towns

Houses

• properties | variables | callbacks

Industries

• common variables
• industry props | vars | CBs
• tile props | vars | CBs

Cargos

• properties | variables | callbacks

Airports

• airport props | vars | CBs
• tile props | vars | CBs

Objects

• properties | variables | callbacks

Railtypes

• properties | variables | callbacks

Roadtypes

• properties | variables | callbacks

Tramtypes

• properties | variables | callbacks

Roadtypes can only be defined in OpenTTD 1.10 or later.

Roadtype IDs

Roadtypes and Tramtypes share a pool of 64 IDs. Either feature can use as many IDs as needed (i.e. it is not limited to 32 per type), but both features combined are limited to 64 in total. NewGRF-local IDs may freely be chosen, but must be in the 0..63 range. If other roadtype/tramtype GRFs are loaded, it may be that there are not enough slots available. To prevent your entire NewGRF from being deactivated with the 'Attempt to use invalid ID'-error, you can use the following code:

if (roadtype_available("LABL") || loading_stage == LOADING_STAGE_RESERVE)
    ... item definition ...
} else if (loading_stage == LOADING_STAGE_ACTIVATE) {
    ... warning / error ...
}

The warning / error is optional, but can be used to inform the user about the missing roadtypes.

Vehicle and Roadtype availability

Vehicle and roadtype availability and compatibility is influenced by multiple properties. Generally, the vehicle defines which roadtype it is, and the roadtypes define the compatibility between each other.

• A vehicle exists, if its roadtype (road vehicle property track_type) is defined. Otherwise the vehicle is disabled.
• When a vehicle is introduced, it always introduces its roadtype (road vehicle property track_type).
• A roadtype is introduced, if at least one of the following conditions is met:
  • A vehicle is introduced, that references the roadtype (road vehicle property track_type).
  • Another roadtype is introduced, that references the roadtype via the introduced roadtype list (roadtype property introduces_roadtype_list).
  • The introduction date (roadtype property introduction_date) is passed and all required roadtypes (roadtype property requires_roadtype_list ) are available.

Via roadtype property compatible_roadtype_list multiple roadtypes can be defined, which shall be considered equivalent to a roadtype. This affects the interpretation of road vehicle property track_type. If road vehicle property track_type references an undefined roadtype, then roadtype property compatible_roadtype_list is checked for all defined roadtypes, whether the vehicle can be reassigned to some other roadtype. Otherwise the vehicle is disabled.

Roadtype properties

property	value range	comment
label	4-byte string	names of default road types: "ROAD" and "ELRD". See the List of roadtype labels in the NewGRF Specs for currently defined custom labels.
introduction_date	date(yyyy,mm,dd)	Valid range for yyyy is 0 ... 5000000.
name	string	Name of this roadtype
toolbar_caption	string	Caption of the build road toolbar
menu_text	string	Shown in the dropdown menu for all roadtypes
build_window_caption	string	Caption of the build vehicle window
autoreplace_text	string	String for the autoreplace window
new_engine_text	string	String for the "We have invented a new <road type> engine" news message
powered_roadtype_list	list of roadtype labels	Provide a list of road types that road vehicles of this type are powered on, e.g. ["ROAD", "ELRD"]. Note that there is no difference between "powered" and "compatible" for roadtypes
roadtype_flags	bitmask(ROADTYPE_FLAG_XXX, ...)	CATENARY Enable catenary NO_LEVEL_CROSSING Disable level crossings NO_HOUSES Disallows house construction
construction_cost	0 ... 65525	Per piece of road as multiplier to PR_BUILD_ROAD base cost. Default cost factors are 8 and 16 for ROAD and ELRD, respectively.
speed_limit	0 ... 65525 km/h (speed units)	A speed limit of 0 means unlimited speed
map_colour	0 ... 255	Entry in the colour palette.
requires_roadtype_list	list of roadtype labels	List of road types that need to be available to the company of the player for this road type to be introduced at (or after) the introduction date. This limit does not apply when the road type is introduced by the introduction of a vehicle.
introduces_roadtype_list	list of roadtype labels	List of road types that get introduced when this road type is introduced. For example, to make sure that when a fast road type is introduced the slow variant exists.
sort_order	0 ... 255	Number which defines the sort order among road types. If this entry is not defined, it gets assigned sort order n*10+7 for the n-th roadtype.
maintenance_cost	0 ... 255	Maintenance cost factor for each piece of road of this roadtype. Default cost factors are 16 and 24 for ROAD and ELRD, respectively.
alternative_roadtype_list	list of roadtype labels	List of road types which this road type will act as fallback for, if the corresponding road type is not defined separately

Sort order

The sort_order influences the sort order of the drop down lists with road types. Default values are as follows:

Value	Meaning
07	normal road
17	electrified road
n7	roadtype #n

Thus the road type that (internally) gets index 8 will get a default value of 87. These defaults are to keep the ordering when this property is not supported as they were.

Roadtype variables

name	value range	comment
terrain_type	TILETYPE_NORMAL, TILETYPE_DESERT, TILETYPE_RAIN_FOREST, TILETYPE_SNOW
level_crossing_status	LEVEL_CROSSING_CLOSED, LEVEL_CROSSING_OPEN
build_date	0 .. 5000000	for depots only: build date of the depot in days since 0
town_zone	town zone	Town zone of the tile
random_bits		2 pseudo random bits

Roadtype callbacks

For road types a number of callbacks are used to define road type graphics. Each should refer to a sprite set containing the relevant sprites. Refer to the example sprites or the example roadtype grf in the NML repository, for an example on what sprites are needed in what order.

callbacks	number of sprites	meaning
gui	12	6 gui icons, 6 cursors
track_overlay	19	11 roadbit combinations, 4 slopes, and 4 dead ends. These sprites are optional for roadtypes.
underlay	19	11 roadbit combinations, 4 slopes, and 4 dead ends. These sprites are required.
tunnels	4	1 sprite for each direction. Sprite is overlay for road in existing tunnel graphics. The original ground sprite is drawn, then the overlay, then possibly a road vehicle and the original tunnel head is drawn over the top. This keeps compatibility with different landscape types. Sprite order: SW, NW, NE, SE.
catenary_front	29	11 roadbit combinations, 4 slopes, 4 dead ends, 4 tunnels, 2 bridge middle, 4 bridge ramps
catenary_back	29	11 roadbit combinations, 4 slopes, 4 dead ends, 4 tunnels (unused), 2 bridge middle, 4 bridge ramps
bridge_surfaces	6	2 bridge middle, 4 bridge ramps
depots	6	If not present, the default depot sprites (depending on catenary flag) plus track overlay are drawn. If present, the depot sprites are expected to include track overlay graphics.
roadstops	4	Overlays for drive-in road stops

Note that there is no "default graphics" callback.

Example sprites

gui

underlay

catenary_front

catenary_back

depots

Sprite Number	Usage
0	NE wall for SE-entry depot.
1	Depot building for SE-entry depot.
2	NW wall for SW-entry depot.
3	Depot building for SW-entry depot.
4	Depot building for NE-entry depot.
5	Depot building for NW-entry depot.

bridge_surfaces

roadstops

Example code

A typical implementation for roadtypes can look like:

 item(FEAT_ROADTYPES, highway, 0x01) {
     property {
         label:                      "HWY_";
         name:                       string(STR_HWY);
         menu_text:                  string(STR_HWY);
         build_window_caption:       string(STR_BUILD_CAPTION);
         autoreplace_text:           string(STR_AUTOREPLACE);
         new_engine_text:            string(STR_NEW_ENGINE);
         powered_roadtype_list:      ["HWY_","ROAD"];                          // Highways are compatible with other roads
         roadtype_flags:             bitmask(ROADTYPE_FLAG_NO_LEVEL_CROSSING, ROADTYPE_FLAG_NO_HOUSES); // Highways should not have level crossings or houses
         construction_cost:          32;                                       // Highways are expensive
         speed_limit:                100 km/h;
     }
     graphics {
         underlay:        ground_switch_underlay;    // defines the usual roads
         tunnels:         tunnel_switch;             // defines the roads drawn on a tunnel tile
         depots:          depot_switch;              // defines the depot sprites
         bridge_surfaces: bridge_terrain_switch;     // defines the overlay drawn over bridges depending on climate
         roadstops:       roadstops_switch;          // defines the look of roadstop pavement
     }
 }

The switches and graphics blocks are defined in the usual way as described in sections switches, random switches and graphics block sections.