Function GetCountAndDistanceOfClosestInstance

src/newgrf_object.cpp:235–259

* Implementation of var 65 * @param object ResolverObject owning the temporary storage. * @param local_id Parameter given to the callback, which is the set id, or the local id, in our terminology. * @param grfid The object's GRFID. * @param tile The tile to look from. * @param current Object for which the inquiry is made * @return The formatted answer to the callback : rr(reserved) c

 * @return The formatted answer to the callback : rr(reserved) cc(count) dddd(manhattan distance of closest sister)
 */
static uint32_t GetCountAndDistanceOfClosestInstance(const ResolverObject &object, uint8_t local_id, uint32_t grfid, TileIndex tile, const Object *current)
{
	uint32_t grf_id = static_cast<uint32_t>(object.GetRegister(0x100)); // Get the GRFID of the definition to look for in register 100h
	uint32_t idx;

	/* Determine what will be the object type to look for */
	switch (grf_id) {
		case 0:  // this is a default object type
			idx = local_id;
			break;

		case 0xFFFFFFFF: // current grf
			grf_id = grfid;
			[[fallthrough]];

		default: // use the grfid specified in register 100h
			idx = _object_mngr.GetID(local_id, grf_id);
			break;
	}

	/* If the object type is invalid, there is none and the closest is far away. */
	if (idx >= NUM_OBJECTS) return 0 | 0xFFFF;

	return Object::GetTypeCount(idx) << 16 | ClampTo<uint16_t>(GetClosestObject(tile, idx, current));
}

/** Used by the resolver to get values for feature 0F deterministic spritegroups. */
/* virtual */ uint32_t ObjectScopeResolver::GetVariable(uint8_t variable, [[maybe_unused]] uint32_t parameter, bool &available) const