NML:General

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

General variables

A number of global variables are available. Some are only available in switch-blocks, while others can be used in any expression. This is indicated by the second column in the following table:

name	Available outside switch blocks	Value range	Comment
ttd_platform	Yes	PLATFORM_TTDPATCH or PLATFORM_OPENTTD
ttdpatch_version	Yes
openttd_version	Yes		use version_openttd(MAJOR, MINOR, BUILD) to test and compare for a release version and version_openttd(MAJOR, MINOR, BUILD, REVISION) to test for a specific svn version of OpenTTD
current_palette	Yes	PALETTE_DOS or PALETTE_WIN
current_date	No	days since year 0	Use date (year, month, day) to compare with.
current_year	No	years since year 0
current_month	No	0 .. 11
current_day_of_month	No	0 .. 30
current_day_of_year	No	0 .. 364 (365 in leap years)
is_leapyear	No	0 or 1
date_loaded	Yes	days since year 0	Set to the time of game load, which is the current date in single player, and the date the server started in multiplayer. This to prevent desyncs.
year_loaded	Yes	years since year 0	See date_loaded.
starting_year	Yes	years since year 0	Years before 1920 are clamped to 1920
animation_counter	No	0 .. 65535	Increased by 1 each tick
climate	Yes (a)	ARCTIC | TROPICAL | TOYLAND]
game_mode	Yes	GAME | EDITOR]
loading_stage	Yes	RESERVE | ACTIVATE | TEST]	'Phase' of the GRF loading process.
difficulty_level	Yes (a)	MEDIUM | HARD | CUSTOM]
display_options	No	STATION_NAMES | SIGNS | ANIMATION | FULL_DETAIL]	Use hasbit(display_options, DISPLAY_XXX) to test a particular bit.
desert_paved_roads	Yes (b)	0 or 1	If 1, desert roads have pavement and street lights.
train_width_32_px	Yes (b)	0 or 1	If 1, train vehicles are 32 instead of 29 pixels wide in the depot view.
traininfo_y_offset	Yes (b)	-128 .. 127	Used to correctly position the depot view of trains.
snowline_height	No	16 .. 120 in steps of 8, or 0xFF if no snow.	One tile height is equivalent to 8 units.
traffic_side	Yes (a)	TRAFFIC_SIDE_LEFT or TRAFFIC_SIDE_RIGHT
freight_trains	Yes	1 .. 255	Weight multiplier for freight trains
plane_speed	Yes	1 .. 4	Speed multiplier for planes. Value of 1 is equal to the original speed (1/4), while 4 means that planes move at full speed (4/4)
ttdpatch_flags	Yes
current_callback	No		Set to the ID of the current callback, useful for old-style callbacks.
extra_callback_info1	No	Varies	Extra callback information, meaning differs per callback.
extra_callback_info2	No	Varies	Extra callback information, meaning differs per callback.
last_computed_result	No		Result of the last (previously evaluated) switch block.
base_sprite_2cc	Yes	0 .. 65535	Base sprite for 2cc (dual company colour) colour-maps
map_type	Yes	X_BIGGER | Y_BIGGER]
map_min_edge	Yes	64 .. 2048	Length of the smallest map edge (in tiles)
map_max_edge	Yes	64 .. 2048	Length of the biggest map edge (in tiles)
map_x_edge	Yes	64 .. 2048	Length of the x (top-left) map edge (in tiles)
map_y_edge	Yes	64 .. 2048	Length of the y (top-right) map edge (in tiles)
map_size	Yes	64*64 .. 2048*2048	Total number of tiles on the map
long_bridges	Yes	0 or 1
gradual_loading	Yes	0 or 1
bridge_speed_limits	Yes	0 or 1
signals_on_traffic_side	Yes	0 or 1
electrified_railways	Yes	0 or 1
unified_maglev	Yes	0 .. 3
temperate_snowline	Yes	0 or 1
dynamic_engines	Yes	0 or 1
variable_runningcosts	Yes	0 or 1
newtrains	Yes	0 or 1
newrvs	Yes	0 or 1
newships	Yes	0 or 1
newplanes	Yes	0 or 1
newhouses	Yes	0 or 1
newindustries	Yes	0 or 1
newcargos	Yes	0 or 1

(a) The value of these variables can change during the game. Reading them from a switch block (which reads the current value) may result in a different value than in the rest of the code (which is evaluated when the game is loaded).

(b) These variables can be written as well as read. Use a normal assignment, for example:

 traininfo_y_offset = -2;