如何实现粒子引擎

时间:2013-02-14 22:35:25

标签: python refactoring pygame particle-system

所以我制作了一个吸烟的粒子引擎,我很高兴我觉得它很适合我的游戏 我现在需要将它实现到我的游戏中,我遇到了一些麻烦。我想知道是否有人可以解释我将如何在游戏中使用我的粒子引擎 我在下面添加了我的代码(用于冒烟和我的游戏文件) 我希望将粒子与游戏文件分开,但在我的游戏中调用它 最终,我想在引擎中制作更多粒子效果,我也可以调用它。

有人可以帮忙吗?它可能需要一些调整才能工作。

粒子代码:

import pygame,random
from pygame.locals import *

xmax = 1000    #width of window
ymax = 600     #height of window

class Smoke():
    def __init__(self, startx, starty, col):
        self.x = startx
        self.y = random.randint(0, starty)
        self.col = col
        self.sx = startx
        self.sy = starty

    def move(self):
        if self.y < 0:
            self.x = self.sx
            self.y = self.sy
        else:
            self.y -= 1
        self.x += random.randint(-1, 2)

def main():
    pygame.init()
    screen = pygame.display.set_mode((xmax,ymax))
    black = (0,0,0)
    grey = (145,145,145)
    light_grey = (192,192,192)
    dark_grey = (183, 183, 183)

    clock = pygame.time.Clock()

    particles = []
    for part in range(600):
        if part % 2 > 0: col = grey
        #elif part % 5 > 0: col = dark_grey
        elif part % 3 > 0: col = dark_grey
        else: col = light_grey
        particles.append( Smoke(0, 500, col) )

    exitflag = False
    while not exitflag:
        for event in pygame.event.get():
            if event.type == QUIT:
                exitflag = True
            elif event.type == KEYDOWN:
                if event.key == K_ESCAPE:
                    exitflag = True

        screen.fill(black)
        for p in particles:
            p.move()
            pygame.draw.circle(screen, p.col, (p.x, p.y), 15)

        pygame.display.flip()
        clock.tick(80)
    pygame.quit()

if __name__ == "__main__":
    main()

游戏代码

import pygame
from pygame import *

WIN_WIDTH = 1120 - 320
WIN_HEIGHT = 960 - 320
HALF_WIDTH = int(WIN_WIDTH / 2)
HALF_HEIGHT = int(WIN_HEIGHT / 2)

DISPLAY = (WIN_WIDTH, WIN_HEIGHT)
DEPTH = 0
FLAGS = 0
CAMERA_SLACK = 30

levels = {0: {'level': [
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                         E  ",
                    "                            PPPPPPPPPPPPPPPP",
                    "                            PPPPPPPPPPPPPPPP",
                    "                            PPPPPPPPPPPPPPPP",
                    "               PPPPP        PPPPPPPPPPPPPPPP",
                    "                            PPPPPPPPPPPPPPPP",
                    "                            PPPP           P",
                    "                            PPPP           P",
                    "                            PPPP     PPPPPPP",
                    "                      PPPPPPPPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "       PPPP                 PPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "PPPPP                       PPPP     PPPPPPP",
                    "PPP                         PPPP     PPPPPPP",
                    "PPP                         PPPP     PPPPPPP",
                    "PPP                         PPPP     PPPPPPP",
                    "PPP         PPPPP           PPPP     PPPPPPP",
                    "PPP                                     PPPP",
                    "PPP                                     PPPP",
                    "PPP                                     PPPP",
                    "PPP                       PPPPPPPPPPPPPPPPPP",
                    "PPP                       PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",],
             'enemies': [(9, 38)]},
             1: {'level': [
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                         E  ",
                    "                            PPPPPPPPPPPPPPPP",
                    "                            PPPPPPPPPPPPPPPP",
                    "                            PPPPPPPPPPPPPPPP",
                    "               PPPPP        PPPPPPPPPPPPPPPP",
                    "                            PPPPPPPPPPPPPPPP",
                    "                            PPPP           P",
                    "                            PPPP           P",
                    "                            PPPP     PPPPPPP",
                    "                      PPPPPPPPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "       PPPP                 PPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "PPPPP                       PPPP     PPPPPPP",
                    "PPP                  PPPPPPPPPPP     PPPPPPP",
                    "PPP                         PPPP     PPPPPPP",
                    "PPP                         PPPP     PPPPPPP",
                    "PPP             PPPPPPPP    PPPP     PPPPPPP",
                    "PPP                                     PPPP",
                    "PPP                                     PPPP",
                    "PPP          PPPPP                      PPPP",
                    "PPP          P            PPPPPPPPPPPPPPPPPP",
                    "PPP          P    PPPPPPPPPPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",],
             'enemies': [(9, 38), (18, 38), (15, 15)]}}

class Scene(object):
    def __init__(self):
        pass

    def render(self, screen):
        raise NotImplementedError

    def update(self):
        raise NotImplementedError

    def handle_events(self, events):
        raise NotImplementedError

class GameScene(Scene):
    def __init__(self, levelno):
        super(GameScene, self).__init__()
        self.bg = Surface((32,32))
        self.bg.convert()
        self.bg.fill(Color("#0094FF"))
        up = left = right = False
        self.entities = pygame.sprite.Group()
        self.player = Player(5, 40)
        self.player.scene = self
        self.platforms = []

        self.levelno = levelno

        levelinfo = levels[levelno]
        self.enemies = [Enemy(*pos) for pos in levelinfo['enemies']]

        level = levelinfo['level']
        total_level_width = len(level[0]) * 32
        total_level_height = len(level) * 32

        # build the level
        x = 0
        y = 0
        for row in level:
            for col in row:
                if col == "P":
                    p = Platform(x, y)
                    self.platforms.append(p)
                    self.entities.add(p)
                if col == "E":
                    e = ExitBlock(x, y)
                    self.platforms.append(e)
                    self.entities.add(e)
                x += 32
            y += 32
            x = 0

        self.camera = Camera(complex_camera, total_level_width, total_level_height)
        self.entities.add(self.player)
        for e in self.enemies:
            self.entities.add(e)

    def render(self, screen):
        for y in range(20):
            for x in range(25):
                screen.blit(self.bg, (x * 32, y * 32))

        for e in self.entities:
            screen.blit(e.image, self.camera.apply(e))

    def update(self):
        pressed = pygame.key.get_pressed()
        up, left, right = [pressed[key] for key in (K_UP, K_LEFT, K_RIGHT)]
        self.player.update(up, left, right, self.platforms)

        for e in self.enemies:
            e.update(self.platforms)

        self.camera.update(self.player)

    def exit(self):
        if self.levelno+1 in levels:
            self.manager.go_to(GameScene(self.levelno+1))
        else:
            self.manager.go_to(CustomScene("You win!"))

    def die(self):
        self.manager.go_to(CustomScene("You lose!"))

    def handle_events(self, events):
        for e in events:
            if e.type == KEYDOWN and e.key == K_ESCAPE:
                self.manager.go_to(TitleScene())

class CustomScene(object):

    def __init__(self, text):
        self.text = text
        super(CustomScene, self).__init__()
        self.font = pygame.font.SysFont('Arial', 56)

    def render(self, screen):
        # ugly! 
        screen.fill((0, 200, 0))
        text1 = self.font.render(self.text, True, (255, 255, 255))
        screen.blit(text1, (200, 50))

    def update(self):
        pass

    def handle_events(self, events):
        for e in events:
            if e.type == KEYDOWN:
                self.manager.go_to(TitleScene())

class TitleScene(object):

    def __init__(self):
        super(TitleScene, self).__init__()
        self.font = pygame.font.SysFont('Arial', 56)
        self.sfont = pygame.font.SysFont('Arial', 32)

    def render(self, screen):
        # ugly! 
        screen.fill((0, 200, 0))
        text1 = self.font.render('Crazy Game', True, (255, 255, 255))
        text2 = self.sfont.render('> press space to start <', True, (255, 255, 255))
        screen.blit(text1, (200, 50))
        screen.blit(text2, (200, 350))

    def update(self):
        pass

    def handle_events(self, events):
        for e in events:
            if e.type == KEYDOWN and e.key == K_SPACE:
                self.manager.go_to(GameScene(0))

class SceneMananger(object):
    def __init__(self):
        self.go_to(TitleScene())

    def go_to(self, scene):
        self.scene = scene
        self.scene.manager = self

def main():
    pygame.init()
    screen = pygame.display.set_mode(DISPLAY, FLAGS, DEPTH)
    pygame.display.set_caption("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
    timer = pygame.time.Clock()
    running = True

    manager = SceneMananger()

    while running:
        timer.tick(60)

        if pygame.event.get(QUIT):
            running = False
            return
        manager.scene.handle_events(pygame.event.get())
        manager.scene.update()
        manager.scene.render(screen)
        pygame.display.flip()

class Camera(object):
    def __init__(self, camera_func, width, height):
        self.camera_func = camera_func
        self.state = Rect(0, 0, width, height)

    def apply(self, target):
        try:
            return target.rect.move(self.state.topleft)
        except AttributeError:
            return map(sum, zip(target, self.state.topleft))

    def update(self, target):
        self.state = self.camera_func(self.state, target.rect)

def complex_camera(camera, target_rect):
    l, t, _, _ = target_rect
    _, _, w, h = camera
    l, t, _, _ = -l + HALF_WIDTH, -t +HALF_HEIGHT, w, h

    l = min(0, l)                           # stop scrolling left
    l = max(-(camera.width - WIN_WIDTH), l)   # stop scrolling right
    t = max(-(camera.height-WIN_HEIGHT), t) # stop scrolling bottom

    return Rect(l, t, w, h)

class Entity(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)

class Player(Entity):
    def __init__(self, x, y):
        Entity.__init__(self)
        self.xvel = 0
        self.yvel = 0
        self.onGround = False
        self.image = Surface((32,32))
        self.image.fill(Color("#0000FF"))
        self.image.convert()
        self.rect = Rect(x*32, y*32, 32, 32)

    def update(self, up, left, right, platforms):
        if self.rect.top > 1440 or self.rect.top < 0:
            self.scene.die()
        if self.rect.left > 1408 or self.rect.right < 0:
            self.scene.die()
        if up:
            if self.onGround:
                self.yvel = 0
                self.yvel -= 10 # only jump if on the ground
        if left:
            self.xvel = -10
        if right:
            self.xvel = 10
        if not self.onGround:
            self.yvel += 0.3 # only accelerate with gravity if in the air
            if self.yvel > 80: self.yvel = 80 # max falling speed
        if not(left or right):
            self.xvel = 0

        self.rect.left += self.xvel # increment in x direction
        if self.collide(self.xvel, 0, platforms): # do x-axis collisions
            self.rect.top += self.yvel # increment in y direction
            self.onGround = False; # assuming we're in the air
            self.collide(0, self.yvel, platforms) # do y-axis collisions

    def collide(self, xvel, yvel, platforms):
        for p in platforms:
            if pygame.sprite.collide_rect(self, p):
                if isinstance(p, ExitBlock):
                    self.scene.exit()
                    return False
                if xvel > 0: self.rect.right = p.rect.left
                if xvel < 0: self.rect.left = p.rect.right
                if yvel > 0:
                    self.rect.bottom = p.rect.top
                    self.onGround = True
                if yvel < 0:
                    self.rect.top = p.rect.bottom
        return True

class Enemy(Entity):
    def __init__(self, x, y):
        Entity.__init__(self)
        self.yVel = 0
        self.xVel = 2 # start moving immediately
        self.image = Surface((32,32))
        self.image.fill(Color("#00FF00"))
        self.image.convert()
        self.rect = Rect(x*32, y*32, 32, 32)
        self.onGround = False

    def update(self, platforms):
        if not self.onGround:
            self.yVel += 0.3

        # no need for right_dis to be a member of the class,
        # since we know we are moving right if self.xVel > 0
        right_dis = self.xVel > 0

        # create a point at our left (or right) feet 
        # to check if we reached the end of the platform
        m = (1, 1) if right_dis else (-1, 1)
        p = self.rect.bottomright if right_dis else self.rect.bottomleft
        fp = map(sum, zip(m, p))

        # if there's no platform in front of us, change the direction
        collide = any(p for p in platforms if p.rect.collidepoint(fp))
        if not collide:
            self.xVel *= -1

        self.rect.left += self.xVel # increment in x direction
        self.collide(self.xVel, 0, platforms) # do x-axis collisions
        self.rect.top += self.yVel # increment in y direction
        self.onGround = False; # assuming we're in the air
        self.collide(0, self.yVel, platforms) # do y-axis collisions

    def collide(self, xVel, yVel, platforms):
        for p in platforms:
            if pygame.sprite.collide_rect(self, p):
                if xVel > 0: 
                    self.rect.right = p.rect.left
                    self.xVel *= -1 # hit wall, so change direction
                if xVel < 0: 
                    self.rect.left = p.rect.right
                    self.xVel *= -1 # hit wall, so change direction
                if yVel > 0:
                    self.rect.bottom = p.rect.top
                    self.onGround = True
                if yVel < 0:
                    self.rect.top = p.rect.bottom

class Platform(Entity):
    def __init__(self, x, y):
        Entity.__init__(self)
        #self.image = Surface([32, 32], pygame.SRCALPHA, 32) #makes blocks invisible for much better artwork
        self.image = Surface((32,32)) #makes blocks visible for building levels
        self.image.convert()
        self.rect = Rect(x, y, 32, 32)

    def update(self):
        pass

class ExitBlock(Platform):
    def __init__(self, x, y):
        Platform.__init__(self, x, y)
        self.image = Surface((32,32)) #makes blocks visible for building levels
        self.image.convert()
        self.rect = Rect(x, y, 32, 32)




if __name__ == "__main__":
    main()

1 个答案:

答案 0 :(得分:14)

小心!很长的帖子!

粒子

首先,让我们来看看你的Smoke课程。它包含一些 smoke 行为,但你的主循环也是如此。让我们通过创建一个通用Particle类来解决这个问题,该类除了表示粒子外什么都不做:

class Particle():
    def __init__(self, col, size, *strategies):
        self.x, self.y = 0, 0
        self.col = col
        self.alive = 0
        self.strategies = strategies
        self.size = size

    def kill(self):
        self.alive = -1 # alive -1 means dead

    def move(self):
        for s in self.strategies:
            s(self)   

这门课做的不多。它是通用的,它将所有行为(简单函数)传递给它的__init__函数,并且粒子在move方法中将这些函数应用于自身。

粒子的行为

现在我们的粒子类是灵活的,让我们考虑粒子应该如何表现,以便它们看起来像烟雾。

烟雾粒子应该上升,所以让我们创建一个向上移动粒子的函数:

def ascending(speed):
    def _ascending(particle):
        particle.y -= speed
    return _ascending

烟雾粒子应该在某个时刻死亡,所以让我们写一个在某种条件下杀死的函数:

def kill_at(max_x, max_y):
    def _kill_at(particle):
        if particle.x < -max_x or particle.x > max_x or particle.y < -max_y or particle.y > max_y:
            particle.kill()
    return _kill_at

我们需要跟踪粒子的存活时间(后来派上用场),所以我们需要一个让粒子 age 的函数:

def age(amount):
    def _age(particle):
        particle.alive += amount
    return _age

当烟雾上升时,它不应该直线(多么无聊!),但它应该散开:

def fan_out(modifier):
    def _fan_out(particle):
        d = particle.alive / modifier
        d += 1
        particle.x += random.randint(-d, d)
    return _fan_out

尼斯!现在我们的烟雾可以散开,但它仍然有点无聊,所以让我们写一个模拟一点风的功能:

def wind(direction, strength):
    def _wind(particle):
        if random.randint(0,100) < strength:
            particle.x += direction
    return _wind

我们现在有一堆描述粒子行为的函数。所有这些都很小而且独立。您可以创建无限量的它们并根据需要组合它们以创建不同的粒子。

烟雾

实际创建一些粒子的时间:进入烟雾机!

def smoke_machine():
    colors = {0: grey,
              1: dark_grey,
              2: light_grey}
    def create():
        for _ in xrange(random.choice([0,0,0,0,0,0,0,1,2,3])):
            behaviour = age(1), ascending(1), fan_out(400), wind(1, 15), kill_at(1000, 1000)
            p = Particle(colors[random.randint(0, 2)], random.randint(10, 15), *behaviour)
            yield p

    while True:
        yield create()

那到底是什么意思?简单。它是一个不断发射新粒子的发生器。每当有人想要检索下一个项目时,它就会调用它的嵌套create函数。该函数依次返回0到3个粒子,基于输入列表random.choice。这是一个很好的方式,它说它返回0粒子,有70%的几率,1或2或3粒子,每粒粒子有10%的几率。

在下一行中,我们定义粒子的行为。它只是一个功能元组。注意每个函数调用如何返回其嵌套函数。这样就可以参数化这些函数。

最后一步是为粒子随机分配颜色和大小。

您可以从命令行进行测试,看看它是如何工作的:

>>> s=smoke_machine()
>>> list(next(s))
[]
>>> list(next(s))
[<particle.Particle instance at 0x02AD94B8>, <particle.Particle instance at 0x02
AD9030>]
>>> list(next(s))
[]
>>> list(next(s))
[]
>>> list(next(s))
[<particle.Particle instance at 0x02AD9030>]
>>> list(next(s))
[<particle.Particle instance at 0x02AD9418>, <particle.Particle instance at 0x02
AD93C8>]
>>> list(next(s))
[<particle.Particle instance at 0x02AD9030>]

看看每次我们在生成器上调用next时,它最多返回3个粒子。

全部放在一起

我们如何将我们的烟雾机与我们的游戏结合起来?让我们写一个为我们处理它的类:

class Emitter(object):
    def __init__(self, pos=(0, 0)):
        self.particles = []
        self.pos = pos
        self.factories = []

    def add_factory(self, factory, pre_fill=300):
        self.factories.append(factory)
        tmp = []
        for _ in xrange(pre_fill):
            n = next(factory)
            tmp.extend(n)
            for p in tmp:
                p.move()
        self.particles.extend(tmp)

    def update(self):
        for f in self.factories:
            self.particles.extend(next(f))

        for p in self.particles[:]:
            p.move()
            if p.alive == -1:
                self.particles.remove(p)

    def draw(self, screen, position_translater_func):
        for p in self.particles:
            target_pos = position_translater_func(map(sum, zip((p.x, p.y), self.pos)))
            pygame.draw.circle(screen, p.col, target_pos, int(p.size))

发射器可以容纳一堆工厂函数(比如我们的smoke_machine),每次更新时都可以将这些工厂的粒子添加到self.particles中,这样就可以将它们绘制到屏幕上。让我们详细看一些函数:

如果我们使用add_factory添加新工厂,我们会调用factory并提前移动其粒子300(或任何pre_fill)。这样,一些粒子已经存在。

如果我们想绘制粒子,我们必须使用Emitter的位置计算其位置。此外,我们需要使用游戏相机调整此位置,因此我们只接受一个函数作为参数,将我们的位置转换为正确的最终位置,以便我们的粒子在游戏中相应滚动。

我们现在不需要对游戏类进行大的更改即可使用Emitter。我们只需在名为GameScene的{​​{1}}和self.emitter中创建一个新列表,然后将Emitter工厂添加到其中。

在我们调用的smoke_machine方法中

render

并在for e in self.emitter: e.draw(screen, self.camera.apply) 方法中调用

update

我们完成了!

行动!

enter image description here

完整列表:

game.py

省略了一些类,因为我达到了30000个字符限制: - )

for e in self.emitter:
   e.update()

particle.py

import pygame
from pygame import *
from particle import Emitter, smoke_machine
WIN_WIDTH = 1120 - 320
WIN_HEIGHT = 960 - 320
HALF_WIDTH = int(WIN_WIDTH / 2)
HALF_HEIGHT = int(WIN_HEIGHT / 2)

DISPLAY = (WIN_WIDTH, WIN_HEIGHT)
DEPTH = 0
FLAGS = 0
CAMERA_SLACK = 30

levels = {0: {'level': [
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                         E  ",
                    "                            PPPPPPPPPPPPPPPP",
                    "                            PPPPPPPPPPPPPPPP",
                    "                            PPPPPPPPPPPPPPPP",
                    "               PPPPP        PPPPPPPPPPPPPPPP",
                    "                            PPPPPPPPPPPPPPPP",
                    "                            PPPP           P",
                    "                            PPPP           P",
                    "                            PPPP     PPPPPPP",
                    "                      PPPPPPPPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "       PPPP                 PPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "PPPPP                       PPPP     PPPPPPP",
                    "PPP                         PPPP     PPPPPPP",
                    "PPP                         PPPP     PPPPPPP",
                    "PPP                         PPPP     PPPPPPP",
                    "PPP         PPPPP           PPPP     PPPPPPP",
                    "PPP                                     PPPP",
                    "PPP                                     PPPP",
                    "PPP                                     PPPP",
                    "PPP                       PPPPPPPPPPPPPPPPPP",
                    "PPP                       PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP    S      PPPPPPPPPPPPPPPPPP",],
             'enemies': [(9, 38)]},
             1: {'level': [
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                            ",
                    "                                         E  ",
                    "                            PPPPPPPPPPPPPPPP",
                    "                            PPPPPPPPPPPPPPPP",
                    "                            PPPPPPPPPPPPPPPP",
                    "               PPPPP        PPPPPPPPPPPPPPPP",
                    "                            PPPPPPPPPPPPPPPP",
                    "                            PPPP           P",
                    "                            PPPP           P",
                    "                            PPPP     PPPPPPP",
                    "                      PPPPPPPPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "       PPPP                 PPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "                            PPPP     PPPPPPP",
                    "PPPPP                       PPPP     PPPPPPP",
                    "PPP                  PPPPPPPPPPP     PPPPPPP",
                    "PPP                         PPPP     PPPPPPP",
                    "PPP                         PPPP     PPPPPPP",
                    "PPP             PPPPPPPP    PPPP     PPPPPPP",
                    "PPP                                     PPPP",
                    "PPP                                     PPPP",
                    "PPP          PPPPP                      PPPP",
                    "PPP          P            PPPPPPPPPPPPPPPPPP",
                    "PPP          P    PPPPPPPPPPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",
                    "PPPPPPPPPPPPPPP           PPPPPPPPPPPPPPPPPP",],
             'enemies': [(9, 38), (18, 38), (15, 15)]}}

...

class GameScene(Scene):
    def __init__(self, levelno):
        super(GameScene, self).__init__()
        self.bg = Surface((32,32))
        self.bg.convert()
        self.bg.fill(Color("#0094FF"))
        up = left = right = False
        self.entities = pygame.sprite.Group()
        self.player = Player(5, 40)
        self.player.scene = self
        self.platforms = []

        self.levelno = levelno

        levelinfo = levels[levelno]
        self.enemies = [Enemy(*pos) for pos in levelinfo['enemies']]

        level = levelinfo['level']
        total_level_width = len(level[0]) * 32
        total_level_height = len(level) * 32

        self.emitter = []

        # build the level
        x = 0
        y = 0
        for row in level:
            for col in row:
                if col == "P":
                    p = Platform(x, y)
                    self.platforms.append(p)
                    self.entities.add(p)
                if col == "E":
                    e = ExitBlock(x, y)
                    self.platforms.append(e)
                    self.entities.add(e)
                if col == "S":
                    e = Emitter((x, total_level_height))
                    e.add_factory(smoke_machine())
                    self.emitter.append(e)
                x += 32
            y += 32
            x = 0

        self.camera = Camera(complex_camera, total_level_width, total_level_height)
        self.entities.add(self.player)
        for e in self.enemies:
            self.entities.add(e)

    def render(self, screen):
        for y in range(20):
            for x in range(25):
                screen.blit(self.bg, (x * 32, y * 32))

        for e in self.emitter:
            e.draw(screen, self.camera.apply)

        for e in self.entities:
            screen.blit(e.image, self.camera.apply(e))

    def update(self):
        for e in self.emitter:
            e.update()

        pressed = pygame.key.get_pressed()
        up, left, right = [pressed[key] for key in (K_UP, K_LEFT, K_RIGHT)]
        self.player.update(up, left, right, self.platforms)

        for e in self.enemies:
            e.update(self.platforms)

        self.camera.update(self.player)

    def exit(self):
        if self.levelno+1 in levels:
            self.manager.go_to(GameScene(self.levelno+1))
        else:
            self.manager.go_to(CustomScene("You win!"))

    def die(self):
        self.manager.go_to(CustomScene("You lose!"))

    def handle_events(self, events):
        for e in events:
            if e.type == KEYDOWN and e.key == K_ESCAPE:
                self.manager.go_to(TitleScene())

...

if __name__ == "__main__":
    main()

结论

我们已成功将粒子集成到游戏中。我们通过编写描述不同行为模式的小型自包含函数来完成此任务,并使用工厂函数对它们进行组合。

在执行此操作时,我们了解了closuresgeneratorsSRPfactory-strategy pattern

我们现在可以轻松添加新行为,例如改变颜色,或创建表现完全不同的新粒子工厂,但使用我们现有的功能。

例如,尝试使用此功能让粒子生长

import pygame,random

def ascending(speed):
    def _ascending(particle):
        particle.y -= speed
    return _ascending

def kill_at(max_x, max_y):
    def _kill_at(particle):
        if particle.x < -max_x or particle.x > max_x or particle.y < -max_y or particle.y > max_y:
            particle.kill()
    return _kill_at

def age(amount):
    def _age(particle):
        particle.alive += amount
    return _age

def fan_out(modifier):
    def _fan_out(particle):
        d = particle.alive / modifier
        d += 1
        particle.x += random.randint(-d, d)
    return _fan_out

def wind(direction, strength):
    def _wind(particle):
        if random.randint(0,100) < strength:
            particle.x += direction
    return _wind

class Particle():
    def __init__(self, col, size, *strategies):
        self.x, self.y = 0, 0
        self.col = col
        self.alive = 0
        self.strategies = strategies
        self.size = size

    def kill(self):
        self.alive = -1 # alive -1 means dead

    def move(self):
        for s in self.strategies:
            s(self)        

black = (0,0,0)
grey = (145,145,145)
light_grey = (192,192,192)
dark_grey = (183, 183, 183)

def smoke_machine():
    colors = {0: grey,
              1: dark_grey,
              2: light_grey}
    def create():
        for _ in xrange(random.choice([0,0,0,0,0,0,0,1,2,3])):
            behaviour = ascending(1), kill_at(1000, 1000), fan_out(400), wind(1, 15), age(1)
            p = Particle(colors[random.randint(0, 2)], random.randint(10, 15), *behaviour)
            yield p

    while True:
        yield create()

class Emitter(object):
    def __init__(self, pos=(0, 0)):
        self.particles = []
        self.pos = pos
        self.factories = []

    def add_factory(self, factory, pre_fill=300):
        self.factories.append(factory)
        tmp = []
        for _ in xrange(pre_fill):
            n = next(factory)
            tmp.extend(n)
            for p in tmp:
                p.move()
        self.particles.extend(tmp)

    def update(self):
        for f in self.factories:
            self.particles.extend(next(f))

        for p in self.particles[:]:
            p.move()
            if p.alive == -1:
                self.particles.remove(p)

    def draw(self, screen, position_translater_func):
        for p in self.particles:
            target_pos = position_translater_func(map(sum, zip((p.x, p.y), self.pos)))
            pygame.draw.circle(screen, p.col, target_pos, int(p.size))

def grow(amount): def _grow(particle): if random.randint(0,100) < particle.alive / 20: particle.size += amount return _grow 添加到grow(0.5)

中的行为列表中

enter image description here

微小的变化,令人印象深刻的效果。

多么美好的一天!

P.S。:您可以在this repository找到更快的版本(以及错误修正)。它使用numpyitertoolspsycopygame.surfarray并避开smoke_machine模块以提高速度。