int MapView::calcFirstVisibleFloor()
{
    int z = 7;
    // return forced first visible floor
    if(m_lockedFirstVisibleFloor != -1) {
        z = m_lockedFirstVisibleFloor;
    } else {
        Position cameraPosition = getCameraPosition();

        // this could happens if the player is not known yet
        if(cameraPosition.isValid()) {
            // avoid rendering multifloors in far views
            if(!m_multifloor) {
                z = cameraPosition.z;
            } else {
                // if nothing is limiting the view, the first visible floor is 0
                int firstFloor = 0;

                // limits to underground floors while under sea level
                if(cameraPosition.z > Otc::SEA_FLOOR)
                    firstFloor = std::max<int>(cameraPosition.z - Otc::AWARE_UNDEGROUND_FLOOR_RANGE, (int)Otc::UNDERGROUND_FLOOR);

                // loop in 3x3 tiles around the camera
                for(int ix = -1; ix <= 1 && firstFloor < cameraPosition.z; ++ix) {
                    for(int iy = -1; iy <= 1 && firstFloor < cameraPosition.z; ++iy) {
                        Position pos = cameraPosition.translated(ix, iy);

                        // process tiles that we can look through, e.g. windows, doors
                        if((ix == 0 && iy == 0) || ((std::abs(ix) != std::abs(iy)) && g_map.isLookPossible(pos))) {
                            Position upperPos = pos;
                            Position coveredPos = pos;

                            while(coveredPos.coveredUp() && upperPos.up() && upperPos.z >= firstFloor) {
                                // check tiles physically above
                                TilePtr tile = g_map.getTile(upperPos);
                                if(tile && tile->limitsFloorsView(!g_map.isLookPossible(pos))) {
                                    firstFloor = upperPos.z + 1;
                                    break;
                                }

                                // check tiles geometrically above
                                tile = g_map.getTile(coveredPos);
                                if(tile && tile->limitsFloorsView(g_map.isLookPossible(pos))) {
                                    firstFloor = coveredPos.z + 1;
                                    break;
                                }
                            }
                        }
                    }
                }
                z = firstFloor;
            }
        }
    }

    // just ensure the that the floor is in the valid range
    z = stdext::clamp<int>(z, 0, (int)Otc::MAX_Z);
    return z;
}

int MapView::calcLastVisibleFloor()
{
    if(!m_multifloor)
        return calcFirstVisibleFloor();

    int z = 7;

    Position cameraPosition = getCameraPosition();
    // this could happens if the player is not known yet
    if(cameraPosition.isValid()) {
        // view only underground floors when below sea level
        if(cameraPosition.z > Otc::SEA_FLOOR)
            z = cameraPosition.z + Otc::AWARE_UNDEGROUND_FLOOR_RANGE;
        else
            z = Otc::SEA_FLOOR;
    }

    if(m_lockedFirstVisibleFloor != -1)
        z = std::max<int>(m_lockedFirstVisibleFloor, z);

    // just ensure the that the floor is in the valid range
    z = stdext::clamp<int>(z, 0, (int)Otc::MAX_Z);
    return z;
}