在pygame中使块从线反弹

Question

Running the following code allows 3 squares to move about a screen, which are then supposed roam freely, bouncing off the edges, until they encounter a blue line. They are under strict orders to bounce off that line as well. I am able to do that when the block comes from the right and bounces off the line's right side, but not from the left and to bounce off the line's left side. Please see the code for more information.

import pygame, sys, time
from pygame.locals import *

pygame.init()
WINDOWWIDTH = 200
WINDOWHEIGHT = 300
screen = pygame.display.set_mode((WINDOWWIDTH, WINDOWHEIGHT), 0, 32)
pygame.display.set_caption('Animation')

DOWNLEFT = 1
DOWNRIGHT = 3
UPLEFT = 7
UPRIGHT = 9

MOVESPEED = 1

BLACK = (0, 0, 0)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)


b1 = {'rect':pygame.Rect(0, 50, 25, 25), 'color':RED, 'dir':DOWNRIGHT}
b2 = {'rect':pygame.Rect(0, 100, 25, 25), 'color':GREEN, 'dir':DOWNRIGHT}
b3 = {'rect':pygame.Rect(0, 150, 25, 25), 'color':BLUE, 'dir':DOWNRIGHT}
blocks = [b1, b2, b3]

while True:
    # check for the closing of the 'x' button
    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()
    screen.fill(BLACK)
    pygame.draw.line(screen,BLUE,(150,0),(150,150),5)


    for b in blocks:
        #moves the blocks
        if b['dir'] == DOWNLEFT:
            b['rect'].left -= MOVESPEED
            b['rect'].top += MOVESPEED
        if b['dir'] == DOWNRIGHT:
            b['rect'].left += MOVESPEED
            b['rect'].top += MOVESPEED
        if b['dir'] == UPLEFT:
            b['rect'].left -= MOVESPEED
            b['rect'].top -= MOVESPEED
        if b['dir'] == UPRIGHT:
            b['rect'].left += MOVESPEED
            b['rect'].top -= MOVESPEED

        # check if the block has move out of the window
        if b['rect'].top < 0:
            # block has moved past the top
            if b['dir'] == UPLEFT:
                b['dir'] = DOWNLEFT
            if b['dir'] == UPRIGHT:
                b['dir'] = DOWNRIGHT
        if b['rect'].bottom > WINDOWHEIGHT:
            # block has moved past the bottom
            if b['dir'] == DOWNLEFT:
                b['dir'] = UPLEFT
            if b['dir'] == DOWNRIGHT:
                b['dir'] = UPRIGHT
        if b['rect'].left < 0:
            # block has moved past the left side
            if b['dir'] == DOWNLEFT:
                b['dir'] = DOWNRIGHT
            if b['dir'] == UPLEFT:
                b['dir'] = UPRIGHT
        if b['rect'].right > WINDOWWIDTH:
            # block has moved past the right side
            if b['dir'] == DOWNRIGHT:
                b['dir'] = DOWNLEFT
            if b['dir'] == UPRIGHT:
                b['dir'] = UPLEFT
        if b['rect'].left < 150 and b['rect'].top > 0 and b['rect'].top < 150:
            if b['dir'] == DOWNLEFT:
                b['dir'] = DOWNRIGHT
            if b['dir'] == UPLEFT:
                b['dir'] = UPRIGHT
##        if b['rect'].right > 150 and b['rect'].top > 0 and b['rect'].top < 150:
##            if b['dir'] == DOWNLEFT:
##                b['dir'] = DOWNRIGHT
##            if b['dir'] == UPLEFT:
##                b['dir'] = UPRIGHT
        print(b['rect'].right)
        pygame.draw.rect(screen, b['color'], b['rect'])

    pygame.display.update()
    time.sleep(0.0001)

Answer 1

import pygame, sys, time
from pygame.locals import *

pygame.init()
WINDOWWIDTH = 200
WINDOWHEIGHT = 300
screen = pygame.display.set_mode((WINDOWWIDTH, WINDOWHEIGHT), 0, 32)
pygame.display.set_caption('Animation')

DOWNLEFT = 1
DOWNRIGHT = 3
UPLEFT = 7
UPRIGHT = 9

MOVESPEED = 1

BLACK = (0, 0, 0)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)


b1 = {'rect':pygame.Rect(0, 50, 25, 25), 'color':RED, 'dir':DOWNRIGHT}
b2 = {'rect':pygame.Rect(0, 100, 25, 25), 'color':GREEN, 'dir':DOWNRIGHT}
b3 = {'rect':pygame.Rect(0, 150, 25, 25), 'color':BLUE, 'dir':DOWNRIGHT}
blocks = [b1, b2, b3]


while True:
# check for the closing of the 'x' button
    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()
    screen.fill(BLACK)
    pygame.draw.line(screen,BLUE,(150,0),(150,150),5)


    for b in blocks:
    #moves the blocks
        if b['dir'] == DOWNLEFT:
            b['rect'].left -= MOVESPEED
            b['rect'].top += MOVESPEED
        if b['dir'] == DOWNRIGHT:
            b['rect'].left += MOVESPEED
            b['rect'].top += MOVESPEED
        if b['dir'] == UPLEFT:
            b['rect'].left -= MOVESPEED
            b['rect'].top -= MOVESPEED
        if b['dir'] == UPRIGHT:
            b['rect'].left += MOVESPEED
            b['rect'].top -= MOVESPEED

    # check if the block has move out of the window
        if b['rect'].top < 0:
        # block has moved past the top
            if b['dir'] == UPLEFT:
                b['dir'] = DOWNLEFT
            if b['dir'] == UPRIGHT:
                b['dir'] = DOWNRIGHT
        if b['rect'].bottom > WINDOWHEIGHT:
        # block has moved past the bottom
            if b['dir'] == DOWNLEFT:
                b['dir'] = UPLEFT
            if b['dir'] == DOWNRIGHT:
                b['dir'] = UPRIGHT
        if b['rect'].left < 0:
        # block has moved past the left side
            if b['dir'] == DOWNLEFT:
                b['dir'] = DOWNRIGHT
            if b['dir'] == UPLEFT:
                b['dir'] = UPRIGHT
        if b['rect'].right > WINDOWWIDTH:
        # block has moved past the right side
            if b['dir'] == DOWNRIGHT:
                b['dir'] = DOWNLEFT
            if b['dir'] == UPRIGHT:
                b['dir'] = UPLEFT
        if b['dir'] == UPLEFT or b['dir'] == DOWNLEFT: # In this case it's rather easy to check for the exact conditions when direction changes should be made. Being the movement speed is only 1, at some point the b['rect'].right/left will be exactly 150. It's easier to check for that than deal with greater than less than problems which tend to only work for one way. If movement was higher than one you'd have to switch to short ranges instead.
            if b['rect'].left == 150 and b['rect'].top > 0 and b['rect'].top < 150:
                if b['dir'] == DOWNLEFT:
                    b['dir'] = DOWNRIGHT
                if b['dir'] == UPLEFT:
                    b['dir'] = UPRIGHT

        if b['dir'] == DOWNRIGHT or b['dir'] == UPRIGHT:
            if b['rect'].right == 150 and b['rect'].top < 150:
                if b['dir'] == DOWNRIGHT:
                    b['dir'] = DOWNLEFT
                if b['dir'] == UPRIGHT:
                    b['dir'] = UPLEFT
        print(b['rect'].right)
        pygame.draw.rect(screen, b['color'], b['rect'])

    pygame.display.update()
    time.sleep(0.00001)

This corrected codes works more like you were hoping for I'm thinking.