Callback: Change vehicle properties
Change vehicle properties (36)
This common callback allows modification of certain properties of a vehicle for which there exists no specific callback (like CBs 10, 11, 12). The low byte of variable 10 holds the property number from Action 0.
The following properties are supported:
| Feature | Property | Minimum version | OpenTTD rev | |
|---|---|---|---|---|
| Trains (00) | 07 (Load amount) | - | - | Changeable via callback 12 |
| 09 (Speed) | 2.5 beta 6 | r9671 | ||
| 0B (Power) | 2.5 beta 6 | r9671 | ||
| 0D (Running cost factor) | 2.6 rev 1420 | r9671 | ||
| 14 (Cargo capacity) | 2.6 rev 1966 | r9828 | See also callback 15 | |
| 16 (Weight) | 2.6 rev 1887 | r9780 | ||
| 17 (Cost factor) | r9806 | |||
| 1F (Tractive effort) | 2.5 beta 6 | r9671 | ||
| 21 (Short wagons) | - | - | Changeable via callback 11 | |
| 22 (Visual effect & powered wagons) | - | - | Changeable via callback 10 | |
| 25 (User data) | 2.5 beta 6 | r11431 | ||
| Road Vehicles (01) | 07 (Load amount) | - | - | Changeable via callback 12 |
| 09 (Running cost factor) | r18011 | |||
| 0F (Cargo capacity) | r9828 | See also callback 15 | ||
| 11 (Cost factor) | r9806 | |||
| 13 (Power) | r21058 | |||
| 14 (Weight) | r21058 | |||
| 15 (Speed) | r21100 | |||
| 18 (Tractive effort) | r21058 | |||
| 21 (Visual effect) | - | - | Changeable via callback 10 | |
| Ships (02) | 07 (Load amount) | - | - | Changeable via callback 12 |
| 0A (Cost factor) | TTDPatch 2.6 rev 1990 | r9806 | ||
| 0B (Speed) | 2.5 beta 6 | r9671 | ||
| 0D (Cargo capacity) | TTDPatch 2.6 rev 1990 | r9828 | See also callback 15 | |
| 0F (Running cost factor) | TTDPatch 2.6 rev 1510 | r9808 | ||
| 1C (Visual effect) | - | - | Changeable via callback 10 | |
| Planes (03) | 07 (Load amount) | - | - | Changeable via callback 12 |
| 0B (Cost factor) | r9806 | |||
| 0C (Speed) | 2.5 beta 6 | r9671 | ||
| 0E (Running cost factor) | 2.6 r1507 | r9678 | ||
| 0F (Passenger capacity) | r19218 | See also callback 15 | ||
| 11 (Mail capacity) | r19218 |
Most properties will only change when the vehicle is bought, serviced (enters a depot), visits a station or on loading of a saved game. Other ones such as TE are called every time a TE calculation is run.
If the callback fails, the corresponding value from the action 0 property will be used. The callback is always used when defined, no bit in the action 0 property needs to be set to activate it.
Before r1758 (both 2.5 and TTDPatch 2.6), callback 36 was sometimes called with the 40+x and 80+x variables unavailable when they should have been available, or with not all 80+x variables properly initialized, causing some 40+x variables to be unsafe.
About the capacity properties see also the summary page about vehicle refitting.
