Callback: Select colour mapping for vehicle

Select colour mapping for vehicle (2D)

Called while drawing the vehicle. Should return the number of the colour mapping to be used on the vehicle sprite, for example, 775 for blue->dark blue mapping. If the callback fails, the company colour of the owner is used. Since mapping 775 doesn't change any colours, you can return it to disable the company colours and leave all magic blue in your sprite alone.

If bit 14 is set, the company colour will be added to the resulting sprite number. This means the given sprite and the 15 following sprites must be colour maps, one for each of the 16 possible player colours. If the vehicle also has misc.flags bit 1 set (two company colours), the sprite and the 255 following sprites must be appropriate colour maps. Alternatively, use a return value of 00 C0 to use the default two-colour maps.

Uses 15 return bits.

The return value is cached to speed up sprite processing, and only updated via callback 32 bit 1 (or when loading/starting a game or rearranging the consist).