论述了Python语言中Pygame库的框架结构和一些常用的该库API,使用Python库进行2D游戏开发时需要注意的事项,以及进行2D游戏开发的常用技巧。
Python制作chrome断网游戏“小恐龙”,跟chrome断网时的游戏一样,用两根手指就能玩的小游戏,主要效果是实现地图滚动,事件随机生成,恐龙跳跃,下蹲,和记录成绩功能。
关键字:Pygame,游戏开发
电子游戏自上个世纪诞生以来,以不可思议的速度发展着,从最初的按钮丢硬币简单的游戏到如今的模拟的视频游戏,电子游戏从最初的纯娱乐产品到现在的游戏行业,他的生命力越发的旺盛和持久。Python语言的出现,也大大的增强了程序的创新和发展,各种方便的接口API和别人些好的库,更好的方便了开发人员的技术选择,从而加快了开发人员的开发进度。Pygame是python的一个开源游戏框架,继承了python开源,快速的优点,使得2D游戏开发进度大大的加快。
2.1游戏框架图
把恐龙类,鸟类,云类,仙人掌类实现并运用在游戏场景类中,实现这个恐龙酷跑的游戏。
图1 游戏框架图
2.2创建主场景
图2 主场景图
场景尺寸:800*350
标题:恐龙酷跑
运行帧数:60
对象:恐龙,云,仙人掌,鸟
2.3事件处理流程
图3 事件处理流程图
3.1 游戏背景类,生成一个地图
# 地图
class GameBackground:
image1 = None
image2 = None
main_scene = None
speed = 20 # 滚动速度
x1 = None
x2 = None
# 初始化地图
def __init__(self, scene):
# 加载相同张图片资源,做交替实现地图滚动
self.image1 = pygame.image.load("images/dragon/map.png") #加载第一张图的路径
self.image2 = self.image1
# 保存场景对象
self.main_scene = scene
# 辅助移动地图
self.x1 = 0
self.x2 = self.main_scene.size[0]
# 计算地图图片绘制坐标
def action(self):
self.x1 = self.x1 - self.speed
self.x2 = self.x2 - self.speed
if self.x1 <= -self.main_scene.size[0]:
self.x1 = 0
if self.x2 <= 0:
self.x2 = self.main_scene.size[0]
# 绘制地图的两张图片
def draw(self):
map_y = self.main_scene.size[1] - self.image1.get_height()
self.main_scene.scene.blit(self.image1, (self.x1, map_y))
self.main_scene.scene.blit(self.image2, (self.x2, map_y))
3.2 鸟类,生成一只鸟
# 鸟
class Bird:
speed = 10
image = None
x = None
y = None
width = None
height = None
index = 0
main_scene = None
ret = 1
def __init__(self, x, y, image, main_scene):
self.x = x
self.y = y
self.image = image
self.main_scene = main_scene
image = self.image[self.index]
self.width = image.get_width()
self.height = image.get_height()
def move(self):
self.x -= self.speed
def draw(self):
if self.ret <= 8:
self.index = 0
else:
self.index = 1
if self.ret == 16:
self.ret = 0
image = self.image[self.index]
self.main_scene.scene.blit(image, (self.x, self.y))
self.ret += 1
3.3 云类,生成云
# 云
class Cloud:
speed = 1
image = None
x = None
y = None
def __init__(self, x, y, image):
self.x = x
self.y = y
self.image = image
def move(self):
self.x -= self.speed
3.4 仙人掌类,生成仙人掌
# 仙人掌
class Cactus:
speed = 8
image = None
x = None
y = None
width = None
height = None
def __init__(self, x, y, image):
self.x = x
self.y = y
self.image = image
self.width = image.get_width()
self.height = image.get_height()
def move(self):
self.x -= self.speed
3.5 恐龙类生成恐龙
# 恐龙
class Dragon:
speed = 10
image = None
x = None
y = None
width = None
height = None
index = 0
main_scene = None
ret = 1
style = 0 # 0:站立,1:蹲下
jump = 0 # 0: 未起跳,1:开始上升,2:开始下降
jump_y_add = 0
is_hit = 0
def __init__(self, x, y, image, main_scene):
self.x = x
self.y = y
self.image = image
self.main_scene = main_scene
def set_jump(self):
if self.style == 0 and self.jump == 0:
self.jump = 1
self.main_scene.jump_sound.play()
def move(self):
if self.jump == 1:
self.y -= 10
self.jump_y_add += 10
if self.jump_y_add == 200:
self.jump = 2
if self.jump == 2:
self.y += 10
self.jump_y_add -= 10
if self.jump_y_add == 0:
self.jump = 0
def draw(self):
if self.ret <= 5:
if self.style == 0:
self.index = 0
else:
self.index = 2
else:
if self.style == 0:
self.index = 1
else:
self.index = 3
if self.ret == 10:
self.ret = 0
image = self.image[self.index]
self.width = image.get_width()
self.height = image.get_height()
self.main_scene.scene.blit(image, (self.x, self.y))
self.ret += 1
3.6游戏主场景
# 主场景
class MainScene:
running = True
size = None
scene = None
bg = None
clouds = []
cloud_image = None
items = []
item_images = []
item_ret= 1
item_ret_num = 100
bird_images = []
birds = []
bird_ret= 1
bird_ret_num = 150
dragon = None
dragon_images = []
gameover_image = None
restart_image = None
restart_x = None
restart_y = None
score = 0.0
jump_sound = None
gameover_sound = None
# 初始化主场景
def __init__(self):
# 初始化 pygame,使用自定义字体必须用到
pygame.init()
# 场景尺寸
self.size = (800, 350)
# 场景对象
self.scene = pygame.display.set_mode([self.size[0], self.size[1]])
# 设置标题
pygame.display.set_caption("恐龙跑酷")
# 创建clock对象控制帧数
self.timer = pygame.time.Clock()
# 创建地图对象
self.bg = GameBackground(self)
# 创建云
self.cloud_image = pygame.image.load("images/dragon/cloud.png")
self.create_cloud()
# 创建仙人掌
for n in range(7):
self.item_images.append(pygame.image.load("images/dragon/item_" + str(n+1) + ".png"))
# 创建鸟
self.bird_images.append(pygame.image.load("images/dragon/bird_1.png"))
self.bird_images.append(pygame.image.load("images/dragon/bird_2.png"))
# 创建恐龙
for n in range(4):
self.dragon_images.append(pygame.image.load("images/dragon/dragon_" + str(n+1) + ".png"))
d_x = 50
d_y = self.size[1] - self.dragon_images[0].get_height()
self.dragon = Dragon(d_x, d_y, self.dragon_images, self)
# gameover
self.gameover_image = pygame.image.load("images/dragon/gameover.png")
self.restart_image = pygame.image.load("images/dragon/restart.png")
# 音效加载
self.jump_sound = pygame.mixer.Sound("sounds/dragon/jump.wav")
self.gameover_sound = pygame.mixer.Sound("sounds/dragon/gameover.wav")
# 生成两朵云
def create_cloud(self):
self.clouds.append(Cloud(350, 30, self.cloud_image))
self.clouds.append(Cloud(650, 100, self.cloud_image))
# 绘制
def draw_elements(self):
if self.dragon.is_hit == 1:
g_x = self.size[0] // 2 - self.gameover_image.get_width() // 2
self.scene.blit(self.gameover_image, (g_x, 120))
self.restart_x = self.size[0] // 2 - self.restart_image.get_width() // 2
self.restart_y = 170
self.scene.blit(self.restart_image, (self.restart_x, self.restart_y))
return
self.scene.fill((255, 255, 255)) # 填充背景色为白色
self.bg.draw() # 绘制背景
# 绘制云
for c in self.clouds[:]:
self.scene.blit(c.image, (c.x, c.y))
# 绘制仙人掌
for i in self.items[:]:
self.scene.blit(i.image, (i.x, i.y))
# 绘制鸟
for b in self.birds[:]:
b.draw()
# 绘制恐龙
self.dragon.draw()
# 绘制跑动距离
self.score += 0.1
font = pygame.font.Font("freesansbold.ttf", 20)
text = font.render(str(int(self.score)) + "m", True, (83, 83, 83))
text_rect = text.get_rect()
text_rect.right = self.size[0] - 10
text_rect.top = 10
self.scene.blit(text, text_rect)
# 计算元素坐标及生成元素
def action_elements(self):
if self.dragon.is_hit == 1:
return
# 地图
self.bg.action()
# 云
for c in self.clouds[:]:
c.move()
if c.x < - self.cloud_image.get_width():
self.clouds.remove(c)
if len(self.clouds) == 0:
self.create_cloud()
# 仙人掌
if self.item_ret % self.item_ret_num == 0:
image = self.item_images[random.randint(0, len(self.item_images) - 1)]
x = self.size[0]
y = self.size[1] - image.get_height()
self.items.append(Cactus(x, y, image))
self.item_ret += 1
if self.item_ret == self.item_ret_num:
self.item_ret = 0
self.item_ret_num = random.randint(60, 110)
for i in self.items[:]:
i.move()
if i.x < -i.width:
self.items.remove(i)
# 鸟
if int(self.score) > 100:
if self.bird_ret % self.bird_ret_num == 0:
x = self.size[0]
y = 210
self.birds.append(Bird(x, y, self.bird_images, self))
self.bird_ret += 1
if self.bird_ret == self.bird_ret_num:
self.bird_ret = 0
self.bird_ret_num = random.randint(150, 300)
for b in self.birds[:]:
b.move()
if b.x < -b.width:
self.birds.remove(b)
# 恐龙
self.dragon.move()
# 处理事件
def handle_event(self):
for event in pygame.event.get():
# 检测松开键盘事件
if event.type == pygame.KEYUP:
if event.key == K_DOWN:
if self.dragon.style == 1:
self.dragon.style = 0
self.dragon.y -= 34
# 检测按下鼠标事件
if event.type == pygame.MOUSEBUTTONDOWN:
if pygame.mouse.get_pressed()[0]:
if self.dragon.is_hit == 1:
pos = event.pos # 点击位置坐标
# 判断点击范围是否是重启图片上
x1 = self.restart_x
x2 = self.restart_x + self.restart_image.get_width()
y1 = self.restart_y
y2 = self.restart_y + self.restart_image.get_height()
if pos[0] >= x1 and pos[0] <= x2 and pos[1] >= y1 and pos[1] <= y2:
self.dragon.is_hit = 0
self.score = 0
self.items.clear()
self.birds.clear()
# 检测到事件为退出时
if event.type == pygame.QUIT:
self.running = False
# 碰撞检测
def detect_collision(self):
if self.dragon.is_hit == 0:
for i in self.items[:]:
if self.collision(self.dragon, i) or self.collision(i, self.dragon):
self.dragon.is_hit = 1
break
for b in self.birds[:]:
if self.collision(self.dragon, b) or self.collision(b, self.dragon):
self.dragon.is_hit = 1
break
if self.dragon.is_hit == 1:
self.gameover_sound.play()
# 验证是否碰撞
def collision(self, a, b):
offset = 30 # 增加20误差,降低难度
temp1 = (b.x + offset <= a.x + a.width <= b.x + offset + b.width)
temp2 = (b.y + offset <= a.y + a.height <= b.y + offset + b.height)
return temp1 and temp2
# 处理按键
def key_pressed(self):
# 获取按下按键信息
key_pressed = pygame.key.get_pressed()
if key_pressed[K_DOWN]:
if self.dragon.jump == 0:
if self.dragon.style == 0:
self.dragon.style = 1
self.dragon.y += 34
if key_pressed[K_SPACE]:
self.dragon.set_jump()
# 处理帧数
def set_fps(self):
# 刷新显示
pygame.display.update()
# 设置帧率为60fps
self.timer.tick(60)
# 主循环,主要处理各种事件
def run_scene(self):
while self.running:
# 计算元素坐标及生成元素
self.action_elements()
# 绘制元素图片
self.draw_elements()
# 处理事件
self.handle_event()
# 碰撞检测
self.detect_collision()
# 按键处理
self.key_pressed()
# 更新画布设置fps
self.set_fps()
pygame是刚开始学习,不是很熟悉,游戏实现是参照别人的代码改的,自己的能力还不是很足。对于游戏的坐标计算还是存在问题,有时候鸟和仙人掌会一起出现,这会导致游戏可玩性很差,因为容易死,而且游戏退出有问题,经常游戏会崩溃,这是我还没有解决的一个大问题。而且chome上面的游戏会随着行走的距离的增加而增加行进速度,从而增加游戏的整体难度,而我这个小游戏并不可以做到这一点,他只能在刚开始的时候设定一个初始速度,然后会一直这个速度运行下去。后面我会继续花费时间去研究pygame争取写出完整属于自己的2D小游戏。
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