VariationalAction2/Vehicles

Variational Action 2 Variables for Vehicles

Variational Action 2 Variables for Vehicles

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||Variable|Size|Content|Available in purchase list

40|D|Position in consist and length of consist|no

41|D|Position in and length of chain of consecutive vehicles with same ID|no

42|D|Cargo types transported by consist|no

43|D|Player info|TTDP 2.5 beta2, OTTD r4611

44|D|Aircraft info|no

45|D|Curvature info|no

46|D|Motion counter|no

47|D|Vehicle cargo info|OTTD r15542

48|D|Vehicle type information|TTDP 2.5 beta 2, OTTD r5338

49 a|D|Year of construction (long format, 0 based)|OTTD r13376 (current date)

60|D|Count Veh.ID occurence|no

97|B|Tick counter, increased every engine tick|no

B4|W|Current speed (note, units different for each vehicle type)|no

B9|B|Cargo type (type B from the list at CargoTypes; climate dependent)|no

C0|W|Vehicle age in days (not valid for wagons bought before alpha 61)|no

C4|B|Year built (counted from 1920), note this is modified when Cht: Year is used|OTTD r4611 (current date)

C6|W|Vehicle type ID (useful for Callback 1D)|no

C8|B|Sprite type; FD for trains forward, FE or FF when reversed|no

C9|B|Day counter; increased daily|no

DA|W|Next wagon index, FFFF if last wagon (use shift-num=08 and check for FF)|no

F2|B|Refit cycle, how many times refitted to the same cargo type|OTTD r15542 (currently always zero)

FE|W|Modflags|no

FF|B|Modflags|no||

<nowiki>a</nowiki> OpenTTD r13376, TTDPatch r2216

For other 80+x variables confer the vehicle structure.

Variables 40, 41, 42 and 43 are cached. This means that while they are in principle computationally expensive, they can be used without impacting performance. Variables 45 and 60 are also computationally expensive but cannot be cached, and should therefore be used sparingly. If possible 80+x variables are to be preferred.

Cached variables are updated when the game is loaded, when the consist enters or is rearranged in a depot, and when the train reverses.

Position and length (40, 41)

Format: 00nnbbff

||Variable|Value

ff|position of vehicle within the consist counted from the engine (front), e.g. the engine would have ff=0, the 1st wagon or mail compartment of planes would have ff=1, the 2nd wagon or the rotor of helicopters would have ff=2, the 3rd wagon would have ff=3 etc

bb|same as ff, but counted from the end, i.e. the last wagon has bb=0, the next-to-last wagon has bb=1 etc.

nn|total number of vehicles in the consist minus one (i.e. a train with engine and three wagons has nn=3), including shadow and rotor for aircraft.||

For variable 40, these numbers refer to the whole consist, but for variable 41, they only refer to the chain of consecutive vehicles with the same ID as the current wagon (including itself).

Consist cargo (42)

Format: uuiicctt

||Variable|Value

tt|a bit mask of all cargo classes transported by the consist

cc|the most common cargo type (from the column for type A)

ii|the most common refit cycle (var. F2) of cargo type cc

uu|the result of ORing the bits of prop. 25 from all vehicles in the train||

Note that even if the grf file has installed a cargo translation table, the value in "cc" is the actual bit number of that cargo. The reason for this is that it cannot be translated in general, because different vehicles can be from different .grf files and have different translation tables. Use variable 47 if you want the translated cargo type.

The bits of tt are:

||Bit|Cargo class

0|Passengers

1|Mail

2|Express cargo (Goods,Food,Candy)

3|Armored cargo (Valuables/Gold/Diamonds)

4|Bulk freight (Coal,Grain etc.,Ore,Fruit)

5|Piece goods (Livestock,Wood,Steel,Paper)

6|Liquids (Oil,Rubber)

7|Refrigerated cargo (Food, Fruit)||

If used with variational action 2 type 81 (vehicle) it returns only cargo from this vehicle on, with type 82 (engine) that of the whole consist.

Player info (43)

Format: Ccttmmnn

||Variable|Value

nn|the number of the current player from 0 to 7 (up to E (14) in OpenTTD since r14735)

mm|the multiplayer player number with the host player (or the single player) being 0 and the client player being 1

tt|the player type, see below for possible values

c|the primary player colour

C|the secondary player colour, equal to c if none (since r1405)||

||tt value|Meaning

0|Player is human player (permanent company)

1|Player is AI player (not managed)

2|Player is a human managing an AI company

3|Player is human player's original company, now temporarily AI controlled||

This variable is available in the purchase list as well (since 2.5 beta 2).

Since r1497, when the vehicle sprite is being displayed in an exclusive offer window or new vehicle news message, or in other circumstances when no player is associated with the vehicle, nn will be FF.

Aircraft info (44)

Format: xxxxhhtt

(available from 2.0.1 alpha 48)

hh is the height of the aircraft above ground, or more properly above the height of its shadow. Buildings, including the heliport, don't count as "ground", i.e. to get the height above a heliport, you have to subtract the heliport height from hh.

tt is the type of the current airport: 0=small, 1=large, 2=heliport, 3=oil rig. The current airport is the target airport for aircraft that have finished the ascent and are in flight.

Curvature info (45)

Format: xxxTxBxF

(available from 2.0.1 alpha 58)

This returns the amount of curvature between the adjacent wagon pairs. It is useful for train vehicles that normally tilt in curves. The curvature is the difference in direction between the surrounding vehicles:

F = for the front pair (previous wagon to current wagon, 0 if vehicle is first)

B = for the back pair (current wagon to next wagon, 0 if wagon is last)

T = for the triplet (previous wagon to next wagon; is zero in an S-bend)

Possible values:

||Decimal|Hex|Meaning

-4|C|180° curve left (T only)

-3|D|135° curve left (T only)

-2|E|90° curve left

-1|F|45° curve left

0|0|no curve

1|1|45° curve right

2|2|90° curve right

3|3|135° curve right (T only)

4|4|180° curve right (T only)||

Motion counter (46)

Format: 32-bit value

(available from 2.0.1 alpha 59)

This variable counts the amount of motion that a vehicle has done.  It is only valid for the first vehicle in a consist (i.e. use var.action 2 type 82!).  Its value is in units of 1/4096 of a tile.  A vehicle actually moves visibly every time the motion counter increases by 256, and since a tile consists of 16 such subunits, 16*256=4096 motion units mean motion across one tile.

The most useful way to access it is probably with <shiftnum>=08 and an appropriate <andmask>.  For example, to achieve an animation with one frame per vehicle motion and 16 frames in total for motion across an entire tile, you would use <shiftnum>=08 and <andmask>=0F.  For an animation with one frame every two vehicle motions and 4 frames total, use <shiftnum>=09 and <andmask>=03.

If the vehicle is going very fast (>160 mph for trains), it may move by several 1/16ths of a tile at once, and thus some frames may be skipped, but the animation will still remain in sync with the motion.

Note that vehicle graphics are only updated every time the vehicle actually moves, so checking the lower byte is probably pointless, and only needed internally to achieve sufficient precision.

Vehicle cargo info (47)

Format: ccccwwtt

||Variable|Value

tt|the cargo type transported by the vehicle (from the column for type A); translated if a translation table has been installed

ww|cargo unit weight in 1/16 tons, same as cargo prop. 0F

cccc|the cargo class value of the cargo transported by the vehicle||

Note that if the grf has installed a cargo translation table, the value in "tt" is the slot number in that table, irrespective of which actual slot or bit the cargo is using in the game. If a table has been installed, but the current cargo is not listed there, "tt" will be set to FF.

Unlike variable 42, this variable returns the info of the current vehicle only, not the consist.

Vehicle type information (48)

Format: xxxxxxff

The bits of ff are:

||Bit|Value|Meaning

0|1|Vehicle type is available on the market

1|2|Vehicle type is in the testing phase

2|4|Exclusive testing offer for a human player active||

All other bits in ff are undefined and must be masked out.

This variable is available in the purchase list as well (since 2.5 beta 2).

Count Veh.ID occurence (60)

Format: xxxxxxnn

(available from 2.0.1 alpha 57)

The 60+x parameter is the vehicle ID to look for, and the returned nn is the number of vehicles in the consist that have this ID. If used with var.action 2 type 81, only the current vehicle and onwards will be check, with var.action 2 type 82, all vehicles in the consist will be counted.

Modflags (FE and FF)

The bits in FE mostly relate to gradualloading.  A few useful bits for grf authors are;

||Bit|Value of the bit

5|Vehicle is powered (engine or powered wagon, mainly useful for the latter)

6|Electric "engine" (incl. powered wagons) is unpowered here (for mixed trains)

8 *|This bit is flipped every time the train reverses direction

10|Vehicle was built during the exclusive preview (since 2.5 r1334)||

<nowiki>*</nowiki> This bit is only accurate for the first vehicle in the consist.

variable FF is actually the high byte of variable FE, so FE bit 8 is the same as FF bit 0.