function Monster:fov()
    local x, y
    self.visible_tiles = {}

    for i = 1, self.current_dungeon.size.w do
        self.visible_tiles[i] = {}
        for j = 1, self.current_dungeon.size.h do
            self.visible_tiles[i][j] = 0
        end
    end

    for i = 0, 360 do
        x = math.cos(i * 0.01745)
        y = math.sin(i * 0.01745)
        self:do_fov(x, y)
    end
end

function Monster:do_fov(x, y)
    local ox, oy
    ox = self.pos.x + 0.5
    oy = self.pos.y + 0.5

    for i = 0, self.view_radius do
        self.visible_tiles[math.ceil(ox)][math.ceil(oy)] = self.view_radius - (i * 1.7)

        if self.visible_tiles[math.ceil(ox)][math.ceil(oy)] <= 0 then
            self.visible_tiles[math.ceil(ox)][math.ceil(oy)] = 0
        end

        if self.current_dungeon.tiles[math.ceil(ox)][math.ceil(oy)].solid then
            return
        end

        ox = ox + x
        oy = oy + y
    end
end