Function forget_map

crawl-ref/source/player.cc:2368–2420

}

void forget_map(bool rot)
{
    ASSERT(!crawl_state.game_is_arena());

    // If forgetting was intentional, clear the travel trail.
    if (!rot)
        clear_travel_trail();

    const bool rot_resist = player_in_branch(BRANCH_ABYSS)
                            && have_passive(passive_t::map_rot_res_abyss);
    const double geometric_chance = 0.99;
    const int radius = (rot_resist ? 200 : 100);

    const int scalar = 0xFF;
    for (rectangle_iterator ri(0); ri; ++ri)
    {
        const coord_def &p = *ri;
        if (!env.map_knowledge(p).known() || you.see_cell(p))
            continue;

        if (player_in_branch(BRANCH_ABYSS)
            && env.map_knowledge(p).item()
            && env.map_knowledge(p).item()->is_type(OBJ_RUNES, RUNE_ABYSSAL))
        {
            continue;
        }

        if (rot)
        {
            const int dist = grid_distance(you.pos(), p);
            int chance = pow(geometric_chance,
                             max(1, (dist * dist - radius) / 40)) * scalar;
            if (x_chance_in_y(chance, scalar))
                continue;
        }

        if (you.see_cell(p))
            continue;

        env.map_knowledge(p).clear();
        if (env.map_forgotten)
            (*env.map_forgotten)(p).clear();
        StashTrack.update_stash(p);
#ifdef USE_TILE
        tile_forget_map(p);
#endif
    }

    ash_detect_portals(is_map_persistent());
#ifdef USE_TILE
    tiles.update_minimap_bounds();
#endif
}

int get_exp_progress()
{