Method VehicleResolverObject

src/newgrf_engine.cpp:1073–1103

* Resolver of a vehicle (chain). * @param engine_type Engine type * @param v %Vehicle being resolved. * @param wagon_override Application of wagon overrides. * @param rotor_in_gui Helicopter rotor is drawn in GUI. * @param callback Callback ID. * @param callback_param1 First parameter (var 10) of the callback. * @param callback_param2 Second parameter (var 18) of the callback. */

 * @param callback_param2 Second parameter (var 18) of the callback.
 */
VehicleResolverObject::VehicleResolverObject(EngineID engine_type, const Vehicle *v, WagonOverride wagon_override, bool rotor_in_gui,
		CallbackID callback, uint32_t callback_param1, uint32_t callback_param2)
	: SpecializedResolverObject<VehicleRandomTriggers>(GetEngineGrfFile(engine_type), callback, callback_param1, callback_param2),
	self_scope(*this, engine_type, v, rotor_in_gui),
	parent_scope(*this, engine_type, ((v != nullptr) ? v->First() : v), rotor_in_gui),
	relative_scope(*this, engine_type, v, rotor_in_gui),
	cached_relative_count(0)
{
	if (wagon_override == WO_SELF) {
		this->root_spritegroup = GetWagonOverrideSpriteSet(engine_type, CargoGRFFileProps::SG_DEFAULT, engine_type);
	} else {
		if (wagon_override != WO_NONE && v != nullptr && v->IsGroundVehicle()) {
			assert(v->engine_type == engine_type); // overrides make little sense with fake scopes

			/* For trains we always use cached value, except for callbacks because the override spriteset
			 * to use may be different than the one cached. It happens for callback 0x15 (refit engine),
			 * as v->cargo_type is temporary changed to the new type */
			if (wagon_override == WO_CACHED && v->type == VEH_TRAIN) {
				this->root_spritegroup = Train::From(v)->tcache.cached_override;
			} else {
				this->root_spritegroup = GetWagonOverrideSpriteSet(v->engine_type, v->cargo_type, v->GetGroundVehicleCache()->first_engine);
			}
		}

		if (this->root_spritegroup == nullptr) {
			const Engine *e = Engine::Get(engine_type);
			CargoType cargo = v != nullptr ? v->cargo_type : CargoGRFFileProps::SG_PURCHASE;
			this->root_spritegroup = e->grf_prop.GetFirstSpriteGroupOf({cargo, CargoGRFFileProps::SG_DEFAULT});
		}
	}
}

static void GetCustomEngineSprite(EngineID engine, const Vehicle *v, Direction direction, EngineImageType image_type, VehicleSpriteSeq *result)
{