Function VehicleGetVariable

src/newgrf_engine.cpp:415–970

}

static uint32_t VehicleGetVariable(Vehicle *v, const VehicleScopeResolver *object, uint8_t variable, uint32_t parameter, bool &available)
{
	/* Calculated vehicle parameters */
	switch (variable) {
		case 0x25: // Get engine GRF ID
			return v->GetGRFID();

		case 0x40: // Get length of consist
			if (!HasBit(v->grf_cache.cache_valid, NCVV_POSITION_CONSIST_LENGTH)) {
				v->grf_cache.position_consist_length = PositionHelper(v, false);
				SetBit(v->grf_cache.cache_valid, NCVV_POSITION_CONSIST_LENGTH);
			}
			return v->grf_cache.position_consist_length;

		case 0x41: // Get length of same consecutive wagons
			if (!HasBit(v->grf_cache.cache_valid, NCVV_POSITION_SAME_ID_LENGTH)) {
				v->grf_cache.position_same_id_length = PositionHelper(v, true);
				SetBit(v->grf_cache.cache_valid, NCVV_POSITION_SAME_ID_LENGTH);
			}
			return v->grf_cache.position_same_id_length;

		case 0x42: { // Consist cargo information
			if (!HasBit(v->grf_cache.cache_valid, NCVV_CONSIST_CARGO_INFORMATION)) {
				std::array<uint8_t, NUM_CARGO> common_cargoes{};
				uint8_t cargo_classes = 0;
				uint8_t user_def_data = 0;

				for (const Vehicle *u = v; u != nullptr; u = u->Next()) {
					if (v->type == VEH_TRAIN) user_def_data |= Train::From(u)->tcache.user_def_data;

					/* Skip empty engines */
					if (!u->GetEngine()->CanCarryCargo()) continue;

					cargo_classes |= CargoSpec::Get(u->cargo_type)->classes.base();
					common_cargoes[u->cargo_type]++;
				}

				/* Pick the most common cargo type */
				auto cargo_it = std::max_element(std::begin(common_cargoes), std::end(common_cargoes));
				/* Return INVALID_CARGO if nothing is carried */
				CargoType common_cargo_type = (*cargo_it == 0) ? INVALID_CARGO : static_cast<CargoType>(std::distance(std::begin(common_cargoes), cargo_it));

				/* Count subcargo types of common_cargo_type */
				std::array<uint8_t, UINT8_MAX + 1> common_subtypes{};
				for (const Vehicle *u = v; u != nullptr; u = u->Next()) {
					/* Skip empty engines and engines not carrying common_cargo_type */
					if (u->cargo_type != common_cargo_type || !u->GetEngine()->CanCarryCargo()) continue;

					common_subtypes[u->cargo_subtype]++;
				}

				/* Pick the most common subcargo type*/
				auto subtype_it = std::max_element(std::begin(common_subtypes), std::end(common_subtypes));
				/* Return UINT8_MAX if nothing is carried */
				uint8_t common_subtype = (*subtype_it == 0) ? UINT8_MAX : static_cast<uint8_t>(std::distance(std::begin(common_subtypes), subtype_it));

				/* Note: We have to store the untranslated cargotype in the cache as the cache can be read by different NewGRFs,
				 *       which will need different translations */