Function propagate_vertical_flags

plugins/dig-now.cpp:213–242

propagate light, outside, and subterranean flags to open tiles below this one

// propagate light, outside, and subterranean flags to open tiles below this one
static void propagate_vertical_flags(MapExtras::MapCache &map,
                                     const DFCoord &pos) {
    df::tile_designation td = map.designationAt(pos);

    if (!map.ensureBlockAt(DFCoord(pos.x, pos.y, pos.z+1))) {
        // only the sky above
        td.bits.light = true;
        td.bits.outside = true;
        td.bits.subterranean = false;
    }

    int32_t zlevel = pos.z;
    df::tiletype_shape shape =
            tileShape(map.tiletypeAt(DFCoord(pos.x, pos.y, zlevel)));
    while ((shape == df::tiletype_shape::EMPTY
            || shape == df::tiletype_shape::RAMP_TOP)
           && map.ensureBlockAt(DFCoord(pos.x, pos.y, --zlevel))) {
        DFCoord pos_below(pos.x, pos.y, zlevel);
        df::tile_designation td_below = map.designationAt(pos_below);
        if (td_below.bits.light == td.bits.light
                && td_below.bits.outside == td.bits.outside
                && td_below.bits.subterranean == td.bits.subterranean)
            break;
        td_below.bits.light = td.bits.light;
        td_below.bits.outside = td.bits.outside;
        td_below.bits.subterranean = td.bits.subterranean;
        map.setDesignationAt(pos_below, td_below);
        shape = tileShape(map.tiletypeAt(pos_below));
    }
}

static bool can_dig_default(df::tiletype tt) {
    df::tiletype_shape shape = tileShape(tt);