目的

本文介绍一个简单的案例。目标如下：

image.png
我们的机器人在上面的地图上行走，目的是要找到宝藏，如果进入骷髅头，游戏就失败。

定义状态空间

我们对地图上的小方格进行编号： 1 - 8

image.png

代码简单表示如下：

self.states = [1,2,3,4,5,6,7,8] #状态空间

同时定义终止状态：

self.terminate_states = dict()  #终止状态为字典格式
self.terminate_states[6] = 1
self.terminate_states[7] = 1
self.terminate_states[8] = 1

定义动作空间

动作空间很简单：上，下，左，右

self.actions = ['n','e','s','w']

定义回报函数

self.rewards = dict();        #回报的数据结构为字典
self.rewards['1_s'] = -1.0
self.rewards['3_s'] = 1.0
self.rewards['5_s'] = -1.0

构造我们的环境，目的如下：

(如果不知道怎么用 gym 画图，请跳转：https://www.jianshu.com/p/b3c4d2b95c58)
代码如下：

    def render(self, mode='human', close=False):
        # 创建地图
        lines = []
        line1 = rendering.Line((0, 0), (0, 200))
        lines.append(line1)
        line2 = rendering.Line((120, 0), (120, 200))
        lines.append(line2)
        line3 = rendering.Line((0, 200), (600, 200))
        lines.append(line3)
        line4 = rendering.Line((0, 100), (600, 100))
        lines.append(line4)
        line5 = rendering.Line((240, 0), (240, 200))
        lines.append(line5)
        line6 = rendering.Line((360, 0), (360, 200))
        lines.append(line6)
        line7 = rendering.Line((480, 0), (480, 200))
        lines.append(line7)
        line8 = rendering.Line((600, 0), (600, 200))
        lines.append(line8)
        line9 = rendering.Line((0, 0), (120, 0))
        lines.append(line9)
        line10 = rendering.Line((240, 0), (360, 0))
        lines.append(line10)
        line11 = rendering.Line((480, 0), (600, 0))
        lines.append(line11)
        # 创建骷髅
        kulos = []
        kulo1 = rendering.make_circle(40)
        kulo1_transiform = rendering.Transform(translation=(60, 50))
        kulo1.add_attr(kulo1_transiform)
        kulo1.set_color(0, 0, 0)
        kulos.append(kulo1)

        kulo2 = rendering.make_circle(40)
        kulo2_transiform = rendering.Transform(translation=(540, 50))
        kulo2.add_attr(kulo2_transiform)
        kulo2.set_color(0, 0, 0)
        kulos.append(kulo2)

        # 创建宝藏
        golds = []
        gold = rendering.make_circle(40)
        circletrans = rendering.Transform(translation=(300, 50))
        gold.add_attr(circletrans)
        gold.set_color(1, 0.9, 0)
        golds.append(gold)

        # 创建机器人
        robots = []
        robot = rendering.make_circle(40)
        robot.set_color(0.8, 0.6, 0.4)
        robot_transilation = rendering.Transform(translation=(420, 150))
        robot.add_attr(robot_transilation)
        robots.append(robot)

        transiform = rendering.Transform(translation=(50, 50))
        for line_ in lines:
            line_.set_color(0, 0, 0)
            line_.add_attr(transiform)
            self.viewer.add_geom(line_)
        for kulo_ in kulos:
            kulo_.add_attr(transiform)
            self.viewer.add_geom(kulo_)
        for gold_ in golds:
            gold_.add_attr(transiform)
            self.viewer.add_geom(gold_)
        for robot_ in robots:
            robot_.add_attr(transiform)
            self.viewer.add_geom(robot_)

        return self.viewer.render(return_rgb_array=mode == 'rgb_array')