• Mini projects #7 ---- Spaceship


    课程全名:An Introduction to Interactive Programming in Python,来自 Rice University

    授课教授:Joe Warren, Scott Rixner, John Greiner, Stephen Wong

    工具:http://www.codeskulptor.org/, simplegui 模块

    最后两周就要结束了~~~

    第七周:

    先上图,这周完成Spaceship游戏的一部分。

    image

    在这图里面有什么?飞船,陨石,子弹,背景图….

    用OO的对象来看,他们都对应一幅图像,那么抽象一个类ImageInfo来操作这些图像信息,它包括图像的center(中心位置),size(图像大小),radius(半径),lifespan(时间周期),animated(动画)。可能有些属性比较陌生,有些针对到具体的对象才有用。

    class ImageInfo:
        def __init__(self, center, size, radius = 0, lifespan = None, animated = False):
            self.center = center
            self.size = size
            self.radius = radius
            if lifespan:
                self.lifespan = lifespan
            else:
                self.lifespan = float('inf')
            self.animated = animated
    
        def get_center(self):
            return self.center
    
        def get_size(self):
            return self.size
    
        def get_radius(self):
            return self.radius
    
        def get_lifespan(self):
            return self.lifespan
    
        def get_animated(self):
            return self.animated

    有了图像的表示,那么我们还需要飞船,用Ship来表示

    Ship有什么属性和方法呢?

    pos:位置

    vel:加速度

    thrust:冲刺状态

    angle:飞船旋转的角度

    angle_vel:飞船旋转角速度

    image:飞船图像

    image_cener:飞船图像的中心位置

    image_size:飞船图像的大小

    image_radius:飞船半径?(这周作业没用到,不知道干嘛的)

    飞船的方法:

    draw(canvas): 绘制飞船,要求绘制根据是否在冲刺状态,绘制图像不同。所给的飞船image是tiled图像,所以绘制时候计算一下偏移就好

    image

    update():更新当前飞船位置以及角度。基本所有涉及到简单数学计算的公式,课上以及相关ppt都给出来,都比较简单,直接拿来用。对于角度的更新和Pong那周一样,用左右按键按下增加旋转角速度,放开减少旋转角速度,每次更新的时候就只用把飞船的角度加上旋转角速度。

    image

    飞船的位置更新同理,使用位置加上加速度,但是要考虑飞出边界,所以对WIDTH和HEIGHT分别取模。

    image

    这边与Pong不同的是加速度的计算,Pong只有上下方向,但这里飞船可以旋转指向各个方向,所以加速度修改飞船向着它转角的方向,原理还是一样,把转角方向向水平和垂直方向做投影乘以常量,然后加到原有的加速度上。

    image

    最后剩下的一个问题就是,外太空有<阻力>,所以飞船会不断减速直到速度为0,那么不断按照一定的比例缩小飞船的加速度,直到加速度为0,飞船的位置就不更新了。

    image

    update()的代码如下:

    def update(self):
        self.angle += self.angle_vel
        self.pos[0] = (self.pos[0] + self.vel[0]) % WIDTH
        self.pos[1] = (self.pos[1] + self.vel[1]) % HEIGHT
        c = 0.05
        self.vel[0] *= (1 - c)
        self.vel[1] *= (1 - c)
        forward = angle_to_vector(self.angle)
        if self.thrust:
            self.vel[0] += forward[0] * 1.2
            self.vel[1] += forward[1] * 1.2

    change_angle_vel(ori, key_state):根据按键是left或者right和按键当前状态是按下或者松开,来改变飞船的旋转角速度

    set_thruster(thruster_state):根据up按键来改变飞船的冲刺状态,并且播放和暂停响应的声音效果

    shoot(): 飞船发子弹,初始化子弹,它的位置在飞船的炮孔位置,然后子弹的加速度等于,飞船的加速度,加上飞船角度在水平垂直分量的常量倍,这与飞船的加速思路一样的,子弹的角度和旋转角速度设置成0就好。

    飞船处理完了,剩下的就是陨石和子弹,给的template中用sprite来抽象表示他们。

    imageimage

    基本的属性和飞船差不多,pos, vel, angle, angle_vel, image, image_center, image_size, radius,多了lifespan, animated, age还有sound

    主要方法:

    draw(canvas): 直接根据image的信息进行绘制

    update(canvas): 更新角度和位置,与飞船类似。超出边界要取模

    其他的部分就是frame的draw事件模板里已经写好,key_up,key_down事件,上面也都提到处理方法。

    这周的任务也就这样完工了。

    完整的代码如下:

    # program template for Spaceship
    import simplegui
    import math
    import random
    
    # globals for user interface
    WIDTH = 800
    HEIGHT = 600
    score = 0
    lives = 3
    time = 0.5
    
    class ImageInfo:
        def __init__(self, center, size, radius = 0, lifespan = None, animated = False):
            self.center = center
            self.size = size
            self.radius = radius
            if lifespan:
                self.lifespan = lifespan
            else:
                self.lifespan = float('inf')
            self.animated = animated
    
        def get_center(self):
            return self.center
    
        def get_size(self):
            return self.size
    
        def get_radius(self):
            return self.radius
    
        def get_lifespan(self):
            return self.lifespan
    
        def get_animated(self):
            return self.animated
    
        
    # art assets created by Kim Lathrop, may be freely re-used in non-commercial projects, please credit Kim
        
    # debris images - debris1_brown.png, debris2_brown.png, debris3_brown.png, debris4_brown.png
    #                 debris1_blue.png, debris2_blue.png, debris3_blue.png, debris4_blue.png, debris_blend.png
    debris_info = ImageInfo([320, 240], [640, 480])
    debris_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/debris2_blue.png")
    
    # nebula images - nebula_brown.png, nebula_blue.png
    nebula_info = ImageInfo([400, 300], [800, 600])
    nebula_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/nebula_blue.f2014.png")
    
    # splash image
    splash_info = ImageInfo([200, 150], [400, 300])
    splash_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/splash.png")
    
    # ship image
    ship_info = ImageInfo([45, 45], [90, 90], 35)
    ship_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/double_ship.png")
    
    # missile image - shot1.png, shot2.png, shot3.png
    missile_info = ImageInfo([5,5], [10, 10], 3, 50)
    missile_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/shot2.png")
    
    # asteroid images - asteroid_blue.png, asteroid_brown.png, asteroid_blend.png
    asteroid_info = ImageInfo([45, 45], [90, 90], 40)
    asteroid_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/asteroid_blue.png")
    
    # animated explosion - explosion_orange.png, explosion_blue.png, explosion_blue2.png, explosion_alpha.png
    explosion_info = ImageInfo([64, 64], [128, 128], 17, 24, True)
    explosion_image = simplegui.load_image("http://commondatastorage.googleapis.com/codeskulptor-assets/lathrop/explosion_alpha.png")
    
    # sound assets purchased from sounddogs.com, please do not redistribute
    soundtrack = simplegui.load_sound("http://commondatastorage.googleapis.com/codeskulptor-assets/sounddogs/soundtrack.mp3")
    missile_sound = simplegui.load_sound("http://commondatastorage.googleapis.com/codeskulptor-assets/sounddogs/missile.mp3")
    missile_sound.set_volume(.5)
    ship_thrust_sound = simplegui.load_sound("http://commondatastorage.googleapis.com/codeskulptor-assets/sounddogs/thrust.mp3")
    explosion_sound = simplegui.load_sound("http://commondatastorage.googleapis.com/codeskulptor-assets/sounddogs/explosion.mp3")
    
    # helper functions to handle transformations
    def angle_to_vector(ang):
        return [math.cos(ang), math.sin(ang)]
    
    def dist(p,q):
        return math.sqrt((p[0] - q[0]) ** 2+(p[1] - q[1]) ** 2)
    
    
    # Ship class
    class Ship:
        def __init__(self, pos, vel, angle, image, info):
            self.pos = [pos[0],pos[1]]
            self.vel = [vel[0],vel[1]]
            self.thrust = False
            self.angle = angle
            self.angle_vel = 0
            self.image = image
            self.image_center = info.get_center()
            self.image_size = info.get_size()
            self.radius = info.get_radius()
            
        def draw(self,canvas):
            if self.thrust:
                center = (self.image_center[0]+self.image_size[0], self.image_center[1])
                canvas.draw_image(self.image, center, self.image_size, self.pos, self.image_size, self.angle)        
            else:
                canvas.draw_image(self.image, self.image_center, self.image_size, self.pos, self.image_size, self.angle)
    
    
        def update(self):
            self.angle += self.angle_vel
            self.pos[0] = (self.pos[0] + self.vel[0]) % WIDTH
            self.pos[1] = (self.pos[1] + self.vel[1]) % HEIGHT
            c = 0.05
            self.vel[0] *= (1 - c)
            self.vel[1] *= (1 - c)
            forward = angle_to_vector(self.angle)
            if self.thrust:
                self.vel[0] += forward[0] * 1.2
                self.vel[1] += forward[1] * 1.2
    
    
        def change_angle_vel(self, ori, key_state):
            if ((ori == "right" and key_state == "keyup") or
                (ori == "left" and key_state == "keydown")):
                self.angle_vel -= 0.1
            elif ((ori == "right" and key_state == "keydown") or
                (ori == "left" and key_state == "keyup")):
                self.angle_vel += 0.1
    
        def set_thruster(self, thruster_state):
            self.thrust = thruster_state
            if self.thrust:
                ship_thrust_sound.rewind()
                ship_thrust_sound.play()    
            else:
                ship_thrust_sound.rewind()
    
        def shoot(self):
            global a_missile
            offset = self.image_size[0] / 2.0
            forward = angle_to_vector(self.angle)
            pos = [self.pos[0] + offset * forward[0], self.pos[1] + offset * forward[1]]
            vel = [self.vel[0] + 4 * forward[0], self.vel[1] + 4 * forward[1]]
            ang = 0
            ang_vel = 0
            a_missile = Sprite(pos, vel, ang, ang_vel, missile_image, missile_info, missile_sound)
        
    # Sprite class
    class Sprite:
        def __init__(self, pos, vel, ang, ang_vel, image, info, sound = None):
            self.pos = [pos[0],pos[1]]
            self.vel = [vel[0],vel[1]]
            self.angle = ang
            self.angle_vel = ang_vel
            self.image = image
            self.image_center = info.get_center()
            self.image_size = info.get_size()
            self.radius = info.get_radius()
            self.lifespan = info.get_lifespan()
            self.animated = info.get_animated()
            self.age = 0
            if sound:
                sound.rewind()
                sound.play()
       
        def draw(self, canvas):
            canvas.draw_image(self.image, self.image_center, self.image_size, self.pos, self.image_size, self.angle)
    
        def update(self):
            self.angle += self.angle_vel
            self.pos[0] = (self.pos[0] + self.vel[0]) % WIDTH
            self.pos[1] = (self.pos[1] + self.vel[1]) % HEIGHT
    
    def draw(canvas):
        global time
        
        # animiate background
        time += 1
        wtime = (time / 4) % WIDTH
        center = debris_info.get_center()
        size = debris_info.get_size()
        canvas.draw_image(nebula_image, nebula_info.get_center(), nebula_info.get_size(), [WIDTH / 2, HEIGHT / 2], [WIDTH, HEIGHT])
        canvas.draw_image(debris_image, center, size, (wtime - WIDTH / 2, HEIGHT / 2), (WIDTH, HEIGHT))
        canvas.draw_image(debris_image, center, size, (wtime + WIDTH / 2, HEIGHT / 2), (WIDTH, HEIGHT))
    
        # draw ship and sprites
        my_ship.draw(canvas)
        a_rock.draw(canvas)
        a_missile.draw(canvas)
        
        # update ship and sprites
        my_ship.update()
        a_rock.update()
        a_missile.update()
    
        # draw lives
        canvas.draw_text("Lives", [WIDTH / 12, HEIGHT / 12], 30, "White")
        canvas.draw_text(str(lives), [WIDTH / 12, HEIGHT / 12 + 40], 30, "White")
    
        # draw score
        canvas.draw_text("Score", [10 * WIDTH / 12, HEIGHT/12], 30, "White")
        canvas.draw_text(str(score), [10 * WIDTH /12, HEIGHT/12 + 40], 30, "White")
    
    # timer handler that spawns a rock    
    def rock_spawner():
        global a_rock
        pos = [random.randint(0, WIDTH-1), random.randint(0, HEIGHT-1)]
        vel = [random.randrange(1, 5, 1)*random.choice([1, -1]), random.randrange(1, 5, 1)*random.choice([1, -1])]
        ang = 0
        ang_vel = random.randrange(5, 10, 1) / 100.0 * random.choice([1, -1])
        a_rock = Sprite(pos, vel, ang, ang_vel, asteroid_image, asteroid_info)
        
    def key_up(key):
        if simplegui.KEY_MAP['left'] == key:
            my_ship.change_angle_vel("left", "keyup")
        elif simplegui.KEY_MAP['right'] == key:
            my_ship.change_angle_vel("right", "keyup")
        elif simplegui.KEY_MAP['up'] == key:
            my_ship.set_thruster(False)
    
    def key_down(key):
        if simplegui.KEY_MAP['left'] == key:
            my_ship.change_angle_vel("left", "keydown")
        elif simplegui.KEY_MAP['right'] == key:
            my_ship.change_angle_vel("right", "keydown")
        elif simplegui.KEY_MAP['up'] == key:
            my_ship.set_thruster(True)
        elif simplegui.KEY_MAP['space'] == key:
            my_ship.shoot()
    
    # initialize frame
    frame = simplegui.create_frame("Asteroids", WIDTH, HEIGHT)
    
    # initialize ship and two sprites
    my_ship = Ship([WIDTH / 2, HEIGHT / 2], [0, 0], 0, ship_image, ship_info)
    a_rock = Sprite([WIDTH / 3, HEIGHT / 3], [1, 1], 0, 0, asteroid_image, asteroid_info)
    a_missile = Sprite([2 * WIDTH / 3, 2 * HEIGHT / 3], [-1, 1], 0, 0, missile_image, missile_info, missile_sound)
    
    # register handlers
    frame.set_draw_handler(draw)
    frame.set_keydown_handler(key_down)
    frame.set_keyup_handler(key_up)
    
    timer = simplegui.create_timer(1000.0, rock_spawner)
    
    # get things rolling
    timer.start()
    frame.start()

    期待着最后一周,游戏完整的代码。就要完成Coursera的一门这么有意思的课,课程难度很小,乐趣十足。

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  • 原文地址:https://www.cnblogs.com/tiny656/p/4079865.html
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