這次用Python實現的是一個接球打磚塊的小遊戲，需要導入pygame模塊，有以下兩條經驗總結：
1.多父類的繼承
2.碰撞檢測的數學模型
知識點稍後再說，我們先看看遊戲的效果和實現：
一、遊戲效果
二、遊戲代碼
#導入模塊
import pygame
from pygame.locals import *
import sys,random,time,math
class GameWindow(object):
'''創建遊戲窗口類'''
def __init__(self,*args,**kw):
self.window_length = 600
self.window_wide = 500
#繪製遊戲窗口，設置窗口尺寸
self.game_window = pygame.display.set_mode((self.window_length,self.window_wide))
#設置遊戲窗口標題
pygame.display.set_caption("CatchBallGame")
#定義遊戲窗口背景顏色參數
self.window_color = (135,206,250)
def backgroud(self):
#繪製遊戲窗口背景顏色
self.game_window.fill(self.window_color)
class Ball(object):
'''創建球類'''
def __init__(self,*args,**kw):
#設置球的半徑、顏色、移動速度參數
self.ball_color = (255,215,0)
self.move_x = 1
self.move_y = 1
self.radius = 10
def ballready(self):
#設置球的初始位置、
self.ball_x = self.mouse_x
self.ball_y = self.window_wide-self.rect_wide-self.radius
#繪製球，設置反彈觸發條件
pygame.draw.circle(self.game_window,self.ball_color,(self.ball_x,self.ball_y),self.radius)
def ballmove(self):
#繪製球，設置反彈觸發條件
pygame.draw.circle(self.game_window,self.ball_color,(self.ball_x,self.ball_y),self.radius)
self.ball_x += self.move_x
self.ball_y -= self.move_y
#調用碰撞檢測函數
self.ball_window()
self.ball_rect()
#每接5次球球速增加一倍
if self.distance < self.radius:
self.frequency += 1
if self.frequency == 5:
self.frequency = 0
self.move_x += self.move_x
self.move_y += self.move_y
self.point += self.point
#設置遊戲失敗條件
if self.ball_y > 520:
self.gameover = self.over_font.render("Game Over",False,(0,0,0))
self.game_window.blit(self.gameover,(100,130))
self.over_sign = 1
class Rect(object):
'''創建球拍類'''
def __init__(self,*args,**kw):
#設置球拍顏色參數
self.rect_color = (255,0,0)
self.rect_length = 100
self.rect_wide = 10
def rectmove(self):
#獲取鼠標位置參數
self.mouse_x,self.mouse_y = pygame.mouse.get_pos()
#繪製球拍，限定橫向邊界
if self.mouse_x >= self.window_length-self.rect_length//2:
self.mouse_x = self.window_length-self.rect_length//2
if self.mouse_x <= self.rect_length//2:
self.mouse_x = self.rect_length//2
pygame.draw.rect(self.game_window,self.rect_color,((self.mouse_x-self.rect_length//2),(self.window_wide-self.rect_wide),self.rect_length,self.rect_wide))
class Brick(object):
def __init__(self,*args,**kw):
#設置磚塊顏色參數
self.brick_color = (139,126,102)
self.brick_list = [[1,1,1,1,1,1],[1,1,1,1,1,1],[1,1,1,1,1,1],[1,1,1,1,1,1],[1,1,1,1,1,1]]
self.brick_length = 80
self.brick_wide = 20
def brickarrange(self):
for i in range(5):
for j in range(6):
self.brick_x = j*(self.brick_length+24)
self.brick_y = i*(self.brick_wide+20)+40
if self.brick_list[i][j] == 1:
#繪製磚塊
pygame.draw.rect(self.game_window,self.brick_color,(self.brick_x,self.brick_y,self.brick_length,self.brick_wide))
#調用碰撞檢測函數
self.ball_brick()
if self.distanceb < self.radius:
self.brick_list[i][j] = 0
self.score += self.point
#設置遊戲勝利條件
if self.brick_list == [[0,0,0,0,0,0],[0,0,0,0,0,0],[0,0,0,0,0,0],[0,0,0,0,0,0],[0,0,0,0,0,0]]:
self.win = self.win_font.render("You Win",False,(0,0,0))
self.game_window.blit(self.win,(100,130))
self.win_sign = 1
class Score(object):
'''創建分數類'''
def __init__(self,*args,**kw):
#設置初始分數
self.score = 0
#設置分數字體
self.score_font = pygame.font.SysFont('arial',20)
#設置初始加分點數
self.point = 1
#設置初始接球次數
self.frequency = 0
def countscore(self):
#繪製玩家分數
my_score = self.score_font.render(str(self.score),False,(255,255,255))
self.game_window.blit(my_score,(555,15))
class GameOver(object):
'''創建遊戲結束類'''
def __init__(self,*args,**kw):
#設置Game Over字體
self.over_font = pygame.font.SysFont('arial',80)
#定義GameOver標識
self.over_sign = 0
class Win(object):
'''創建遊戲勝利類'''
def __init__(self,*args,**kw):
#設置You Win字體
self.win_font = pygame.font.SysFont('arial',80)
#定義Win標識
self.win_sign = 0
class Collision(object):
'''碰撞檢測類'''
#球與窗口邊框的碰撞檢測
def ball_window(self):
if self.ball_x <= self.radius or self.ball_x >= (self.window_length-self.radius):
self.move_x = -self.move_x
if self.ball_y <= self.radius:
self.move_y = -self.move_y
#球與球拍的碰撞檢測
def ball_rect(self):
#定義碰撞標識
self.collision_sign_x = 0
self.collision_sign_y = 0
if self.ball_x < (self.mouse_x-self.rect_length//2):
self.closestpoint_x = self.mouse_x-self.rect_length//2
self.collision_sign_x = 1
elif self.ball_x > (self.mouse_x+self.rect_length//2):
self.closestpoint_x = self.mouse_x+self.rect_length//2
self.collision_sign_x = 2
else:
self.closestpoint_x = self.ball_x
self.collision_sign_x = 3
if self.ball_y < (self.window_wide-self.rect_wide):
self.closestpoint_y = (self.window_wide-self.rect_wide)
self.collision_sign_y = 1
elif self.ball_y > self.window_wide:
self.closestpoint_y = self.window_wide
self.collision_sign_y = 2
else:
self.closestpoint_y = self.ball_y
self.collision_sign_y = 3
#定義球拍到圓心最近點與圓心的距離
self.distance = math.sqrt(math.pow(self.closestpoint_x-self.ball_x,2)+math.pow(self.closestpoint_y-self.ball_y,2))
#球在球拍上左、上中、上右3種情況的碰撞檢測
if self.distance < self.radius and self.collision_sign_y == 1 and (self.collision_sign_x == 1 or self.collision_sign_x == 2):
if self.collision_sign_x == 1 and self.move_x > 0:
self.move_x = - self.move_x
self.move_y = - self.move_y
if self.collision_sign_x == 1 and self.move_x < 0:
self.move_y = - self.move_y
if self.collision_sign_x == 2 and self.move_x < 0:
self.move_x = - self.move_x
self.move_y = - self.move_y
if self.collision_sign_x == 2 and self.move_x > 0:
self.move_y = - self.move_y
if self.distance < self.radius and self.collision_sign_y == 1 and self.collision_sign_x == 3:
self.move_y = - self.move_y
#球在球拍左、右兩側中間的碰撞檢測
if self.distance < self.radius and self.collision_sign_y == 3:
self.move_x = - self.move_x
#球與磚塊的碰撞檢測
def ball_brick(self):
#定義碰撞標識
self.collision_sign_bx = 0
self.collision_sign_by = 0
if self.ball_x < self.brick_x:
self.closestpoint_bx = self.brick_x
self.collision_sign_bx = 1
elif self.ball_x > self.brick_x+self.brick_length:
self.closestpoint_bx = self.brick_x+self.brick_length
self.collision_sign_bx = 2
else:
self.closestpoint_bx = self.ball_x
self.collision_sign_bx = 3
if self.ball_y < self.brick_y:
self.closestpoint_by = self.brick_y
self.collision_sign_by = 1
elif self.ball_y > self.brick_y+self.brick_wide:
self.closestpoint_by = self.brick_y+self.brick_wide
self.collision_sign_by = 2
else:
self.closestpoint_by = self.ball_y
self.collision_sign_by = 3
#定義磚塊到圓心最近點與圓心的距離
self.distanceb = math.sqrt(math.pow(self.closestpoint_bx-self.ball_x,2)+math.pow(self.closestpoint_by-self.ball_y,2))
#球在磚塊上左、上中、上右3種情況的碰撞檢測
if self.distanceb < self.radius and self.collision_sign_by == 1 and (self.collision_sign_bx == 1 or self.collision_sign_bx == 2):
if self.collision_sign_bx == 1 and self.move_x > 0:
self.move_x = - self.move_x
self.move_y = - self.move_y
if self.collision_sign_bx == 1 and self.move_x < 0:
self.move_y = - self.move_y
if self.collision_sign_bx == 2 and self.move_x < 0:
self.move_x = - self.move_x
self.move_y = - self.move_y
if self.collision_sign_bx == 2 and self.move_x > 0:
self.move_y = - self.move_y
if self.distanceb < self.radius and self.collision_sign_by == 1 and self.collision_sign_bx == 3:
self.move_y = - self.move_y
#球在磚塊下左、下中、下右3種情況的碰撞檢測
if self.distanceb < self.radius and self.collision_sign_by == 2 and (self.collision_sign_bx == 1 or self.collision_sign_bx == 2):
if self.collision_sign_bx == 1 and self.move_x > 0:
self.move_x = - self.move_x
self.move_y = - self.move_y
if self.collision_sign_bx == 1 and self.move_x < 0:
self.move_y = - self.move_y
if self.collision_sign_bx == 2 and self.move_x < 0:
self.move_x = - self.move_x
self.move_y = - self.move_y
if self.collision_sign_bx == 2 and self.move_x > 0:
self.move_y = - self.move_y
if self.distanceb < self.radius and self.collision_sign_by == 2 and self.collision_sign_bx == 3:
self.move_y = - self.move_y
#球在磚塊左、右兩側中間的碰撞檢測
if self.distanceb < self.radius and self.collision_sign_by == 3:
self.move_x = - self.move_x
class Main(GameWindow,Rect,Ball,Brick,Collision,Score,Win,GameOver):
'''創建主程序類'''
def __init__(self,*args,**kw):
super(Main,self).__init__(*args,**kw)
super(GameWindow,self).__init__(*args,**kw)
super(Rect,self).__init__(*args,**kw)
super(Ball,self).__init__(*args,**kw)
super(Brick,self).__init__(*args,**kw)
super(Collision,self).__init__(*args,**kw)
super(Score,self).__init__(*args,**kw)
super(Win,self).__init__(*args,**kw)
#定義遊戲開始標識
start_sign = 0
while True:
self.backgroud()
self.rectmove()
self.countscore()
if self.over_sign == 1 or self.win_sign == 1:
break
#獲取遊戲窗口狀態
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
if event.type == MOUSEBUTTONDOWN:
pressed_array = pygame.mouse.get_pressed()
if pressed_array[0]:
start_sign = 1
if start_sign == 0:
self.ballready()
else:
self.ballmove()
self.brickarrange()
#更新遊戲窗口
pygame.display.update()
#控制遊戲窗口刷新頻率
time.sleep(0.010)
if __name__ == '__main__':
pygame.init()
pygame.font.init()
catchball = Main()
三、知識點
1.多父類的繼承
Python的繼承方式分爲深度優先和廣度優先，Python2分經典類的深度優先搜索繼承方式（class A:）、 新式類的廣度優先搜索繼承方式（class A(object):）2種，Python3經典類與新式類的繼承方式與python2的新式類繼承方式一致，都爲廣度優先的繼承方式。
經典類的深度優先搜索繼承方式：
如圖所示
class B(A)
class C(A)
class D(B,C)
（1）若D類有構造函數，則重寫所有父類的繼承
（2）若D類沒有構造函數，B類有構造函數，則D類會繼承B類的構造函數
（3）若D類沒有構造函數，B類也沒有構造函數，則D類會繼承 A類的構造函數，而不是C類的構造函數
（4）若D類沒有構造函數，B類也沒有構造函數，A類也沒有構造函數，則D類纔會繼承C類的構造函數
新式類的廣度優先搜索繼承方式：
如圖所示
class B(A)
class C(A)
class D(B,C)
（1）若D類有構造函數，則重寫所有父類的繼承
（2）若D類沒有構造函數，B類有構造函數，則D類會繼承B類的構造函數
（3）若D類沒有構造函數，B類也沒有構造函數，則D類會繼承 C類的構造函數，而不是A類的構造函數
（4）若D類沒有構造函數，B類也沒有構造函數，C類也沒有構造函數，則D類纔會繼承A類的構造函數
通過上面的分析，大家應該清楚了Python中類的繼承順序，那麼問題來了，如果我不想重寫父類的構造函數，要子類和父類的構造函數都生效怎麼辦？解決辦法需要用到super關鍵字，對直接父類對象的引用,可以通過super來訪問父類中被子類覆蓋的方法或屬性。
class A(object):
def __init__(self,*args,**kw)
class B(A):
def __init__(self,*args,**kw)
super(B,self).__init__(*args,**kw)
class C(A):
def __init__(self,*args,**kw)
super(C,self).__init__(*args,**kw)
class D(B,C):
def __init__(self,*args,**kw)
super(D,self).__init__(*args,**kw)
super(B,self).__init__(*args,**kw)
2.碰撞檢測的數學模型
其實，編程問題到最後就是數學問題，這個遊戲涉及到2D圓形與矩形的碰撞檢測問題：
碰撞檢測原理：通過找出矩形上離圓心最近的點，然後通過判斷該點與圓心的距離是否小於圓的半徑，若小於則爲碰撞。
那如何找出矩形上離圓心最近的點呢？下面我們從 x 軸、y 軸兩個方向分別進行尋找。爲了方便描述，我們先約定以下變量：
（1）矩形上離圓心最近的點爲變量：closestpoint = [x, y]
（2）矩形 rect = [x, y, l, w] 左上角與長寬 length,wide
（3）圓形 circle = [x, y, r] 圓心與半徑
首先是 x 軸：
如果圓心在矩形的左側（if circle_x < rect_x），那麼 closestpoint_x = rect_x。
如果圓心在矩形的右側（elif circle_x > rect_x + rect_l），那麼 closestpoint_x = rect_x + rect_l。
如果圓心在矩形的正上下方（else），那麼 closestpoint_x = circle_x。
同理，對於 y 軸：
如果圓心在矩形的上方（if circle_y < rect_y），那麼 closestpoint_y = rect_y。
如果圓心在矩形的下方（elif circle_y > rect_y + rect_w)），那麼 closestpoint_y = rect_y + rect_w。
圓形圓心在矩形的正左右兩側（else），那麼 closestpoint_y = circle_y。
因此，通過上述方法即可找出矩形上離圓心最近的點了，然後通過“兩點之間的距離公式”得出“最近點”與“圓心”的距離，最後將其與圓的半徑相比，即可判斷是否發生碰撞。
distance=math.sqrt(math.pow(closestpoint_x-circle_x,2)+math.pow(closestpoint_y-circle_y,2))
if distance < circle.r :
return True – 發生碰撞
else :
return False – 未發生碰撞