在圆形路径中移动对象

Question

这个问题与

有关

我的代码如下。您可以为我的图像使用任何小图像。

import sys, os, pygame, itertools
from math import sin,cos,pi, radians
from pygame.locals import *

os.environ['SDL_VIDEO_WINDOW_POS'] = "%d,%d" % (50,50) #Set window position

pygame.init()
clock = pygame.time.Clock()
FPS = 1000

SCREENW = 800   #screen width
SCREENH = 740   #screen height

BLACK = (0, 0, 0)
BLUE = (0, 0, 255)
ORANGE = (128, 100, 30)
FONT1= "Cookie-Regular.ttf"

SCREEN = pygame.display.set_mode((SCREENW, SCREENH), 0, 32) #display screen
clock = pygame.time.Clock()

#-------------------------------------------------------------------------------
def maketext(msg,fontsize, colour = ORANGE, font = FONT1):
    mafont = pygame.font.Font(font, fontsize)
    matext = mafont.render(msg, True, colour)
    matext = matext.convert_alpha()
    return matext

#-------------------------------------------------------------------------------
def print_info():
    """"""
    textcos = maketext(str(round(obj.rect.x, 2)) + "   " + str(round(obj.rect.y, 2)), 30)
    SCREEN.blit(textcos, (obj.rect.x, obj.rect.y + 30))

#-------------------------------------------------------------------------------
class object_factory(pygame.sprite.Sprite):

    def __init__(self, imagelist, xpos, ypos, speedx = 0, speedy = 0, value = 0):
        """Constructor"""
        pygame.sprite.Sprite.__init__(self)
        self.name = ""
        self.frame = 0
        self.imagelist = imagelist
        self.image = imagelist[self.frame]
        self.mask = pygame.mask.from_surface(self.image) # pixelmask
        self.rect = self.image.get_rect()
        self.rect.x = xpos
        self.rect.y = ypos
        #self.speedx = speedx
        #self.speedy = speedy
        self.timer = 0
        self.timerlimit = 10

        #----------------------------------------------------------------------
    #def move(self):  # wallsprites, Herosprite, looptime
        #self.rect.x += self.speedx
        #self.rect.y += self.speedy

    #----------------------------------------------------------------------
    def update(self):
        """"""
        self.image = self.imagelist[self.frame]
        if self.timer >= self.timerlimit:
            self.frame += 1
            if self.frame >= len(self.imagelist):
                self.frame = 0
            self.timer = 0
        self.timer += 1

plat = pygame.image.load("plt0.png").convert_alpha()
star = pygame.image.load("gemp0.png").convert_alpha()
#box = pygame.image.load("crateB.png").convert_alpha()

platforms = pygame.sprite.Group()
boxes = pygame.sprite.Group()

rotcenx = SCREENW/2
rotceny = SCREENH/2

radius = 200
angle = radians(90)  #pi/4 # starting angle 45 degrees
omega = radians(5) #Angular velocity

m = rotcenx + radius * cos(angle) #Starting position x
n = rotceny - radius * sin(angle) #Starting position y

for _ in itertools.repeat(None, 1):
    madyax = SCREENW/2
    madyay = SCREENH/2

    araya = 200
    konaya = radians(180)  #pi/4 # starting angle 45 degrees
    konika_pravegaya = radians(5) #Angular velocity

    a = madyax + (araya * cos(konaya)) #Starting position x
    b = madyay - (araya * sin(konaya)) #Startinh position y

    plat = object_factory([plat], a, b)
    plat.araya = araya
    plat.konaya = konaya
    plat.kp = konika_pravegaya


    platforms.add(plat)

while True:
    ms = clock.tick(FPS)  # milliseconds passed since last frame
    #looptime = milliseconds / 1000.0 # seconds passed since last frame

    SCREEN.fill((BLACK))

    pygame.draw.circle(SCREEN, BLUE, (SCREENW / 2, SCREENH / 2), 5)

    ##-----------------------------------------------------------
    SCREEN.blit(star, (m, n)) # Draw current x,y

    angle = angle + omega # New angle, we add angular velocity
    m = m + radius * omega * cos(angle + pi / 2) # New x
    n = n - radius * omega * sin(angle + pi / 2) # New y
    ##-----------------------------------------------------------
    # show object anchored to center of rotation
    pygame.draw.line(SCREEN, ORANGE, (rotcenx, rotceny), (m, n))

    text = maketext(str(radius), 30)
    SCREEN.blit(text, (m, n - 40))

    text = maketext((str(round(m, 2)) + "  " + str(round(n, 2))), 30)
    SCREEN.blit(text, (m, n + 40)) # Draw current x,y

    ##------------------------------------------------------------------
    for plat in platforms:

        plat.konaya = plat.konaya + plat.kp
        plat.rect.x = plat.rect.x + plat.araya * plat.kp * cos(plat.konaya + pi / 2)
        plat.rect.y = plat.rect.y - plat.araya * plat.kp * sin(plat.konaya + pi / 2)
    ##------------------------------------------------------------------------
    pygame.draw.line(SCREEN, ORANGE, (madyax, madyay), (plat.rect.x, plat.rect.y))

    platforms.update()
    platforms.draw(SCREEN)

    pygame.event.pump()
    keys = pygame.key.get_pressed()

    for event in pygame.event.get():
        if event.type == QUIT or (event.type == KEYDOWN and event.key == K_ESCAPE):
            pygame.quit()
            sys.exit()

    pygame.display.update()
    pygame.time.wait(100)

为什么代码在课外使用而不是在课堂时使用？我根本找不到我做错了什么。 请不要让我阅读任何谷歌文件或在互联网上搜索，因为我这样做后发现并没有找到我的问题的答案。我不是数学专家，只想知道这个问题的解决方案。请帮忙。 视频链接如下 http://youtu.be/0oRDX246aj8