python - 为什么仙人掌在改变速度时比地面移动得更快？

Question

我正在尝试制作一款类似于 google chrome 中的 Trex 游戏。我做了一个 SPEEDEVENT，这样每当 1 秒过去时，速度就会增加 0.1。在改变速度之前，仙人掌和地面都以相同的速度移动，但是一旦速度改变，仙人掌开始移动得更快（地面的速度也增加了）。当我将速度设置为增加 0.000000001 时也会发生这种情况，所以这不是关于速度的价值，而是关于我改变了速度的事实。无论如何，这是代码，您可能最需要关注的部分是move_cactus移动所有仙人掌并返回移动列表的函数，以及#Ground游戏循环中的注释下的内容（这就是我移动地面的地方）

import pygame
from random import choice, randint

def manage_surface():
    global current_surface
    if leg == 'rear':
        if crouching:
            current_surface = 3
        if not crouching:
            current_surface = 1
    if leg == 'front':
        if crouching:
            current_surface = 4
        if not crouching:
            current_surface = 2

def change_leg():
    global leg
    if leg == 'rear':
        leg = 'front'
        return
    else: leg = 'rear'

def spawn_cactus():
    cactus_count = randint(1, 3)
    x_position = screen_width + 200
    big_cactus = False
    for count in range(cactus_count):
        new_cactus_surface = choice(cactus_surfaces)
        if big_cactus: new_cactus_surface = choice(cactus_surfaces[5:-1])
        new_cactus_rect = new_cactus_surface.get_rect(midbottom = (x_position, ground_level))
        new_cactus_rect.left = x_position
        new_cactus_mask = pygame.mask.from_surface(new_cactus_surface)
        cactus_list.append([new_cactus_surface, new_cactus_rect, new_cactus_mask])
        x_position += new_cactus_rect.width
        if new_cactus_surface in cactus_surfaces[0:5]: big_cactus = True

def draw_cactus():
    for cactus in cactus_list:
        screen.blit(cactus[0], cactus[1])

def move_cactus(cactuses):
    moved_cactus_list = []
    for cactus in cactuses:
        if cactus[1].right < 0:
            continue
        cactus[1].centerx -= speed
        moved_cactus_list.append(cactus)
    return moved_cactus_list

def check_collision():
    trex_x, trex_y = trex_rect.topleft
    for cactus in cactus_list:
        cactus_x, cactus_y = cactus[1].topleft
        offset = (cactus_x - trex_x, cactus_y - trex_y)
        if trex_mask.overlap(cactus[2], offset):
            return True

pygame.init()

fps = 60
clock = pygame.time.Clock()
screen_width = 1280
screen_height = 720
screen = pygame.display.set_mode([screen_width, screen_height])

#Game Variables
initial_speed = 7
speed = initial_speed
initial_gravity = 1
gravity = initial_gravity
game_active = False
SPEEDEVENT = pygame.USEREVENT + 2
pygame.time.set_timer(SPEEDEVENT, 1000)

#Ground
ground_surface = pygame.image.load('assets/ground.png').convert_alpha()
ground_width, ground_height = ground_surface.get_size()
ground_last_x_pos = 0
crouch = False

#Trex
trex_surfaces = []
trex_images = ['trex0.png', 'trex1.png', 'trex2.png', 'trex1-1.png', 'trex2-1.png', 'trex3.png']
for trex in trex_images:
    trex_surfaces.append(pygame.image.load(f'assets/{trex}').convert_alpha())
ground_level = 710
leg = 'rear'
jumping = False
jump_power = 22
crouching = False
manage_surface()
trex_rect = trex_surfaces[current_surface].get_rect(center = (150, ground_level))
trex_mask = pygame.mask.from_surface(trex_surfaces[current_surface])
TREXSTEP = pygame.USEREVENT
pygame.time.set_timer(TREXSTEP, 200)


#cactus
cactus_surfaces = []
cactus_images = ['bigcactus1.png', 'bigcactus2.png', 'bigcactus3.png', 'bigcactus4.png', 'bigcactus5.png', 'cactus1.png', 'cactus2.png', 'cactus3.png', 'cactus4.png', 'cactus5.png', 'cactus6.png']
for cactus in cactus_images:
    cactus_surfaces.append(pygame.image.load(f'assets/{cactus}').convert_alpha())
cactus_list = []
SPAWNPIKE = pygame.USEREVENT + 1
pygame.time.set_timer(SPAWNPIKE, 2000)


running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_UP and not crouching:
                if not game_active: game_active = True
                jumping = True
            if event.key == pygame.K_DOWN and not jumping:
                trex_rect.bottom += 17
                crouching = True
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_DOWN:
                crouching = False
        if event.type == TREXSTEP and not jumping:
            change_leg()
        if event.type == SPAWNPIKE:
            spawn_cactus()
        if event.type == SPEEDEVENT and game_active and cactus_list:
            speed += 0.1

    if not game_active: continue

    #Background Color
    screen.fill((255, 255, 255))

    #Ground
    screen.blit(ground_surface, (ground_last_x_pos, 676))
    screen.blit(ground_surface, (ground_last_x_pos+ground_width, 676))
    if ground_last_x_pos < -ground_width:
        ground_last_x_pos = 0
    ground_last_x_pos -= speed

    
    #Cactus
    draw_cactus()
    cactus_list = move_cactus(cactus_list)
    
    

    #Trex
    manage_surface()
    trex_rect = trex_surfaces[current_surface].get_rect(center = trex_rect.center)
    trex_mask = pygame.mask.from_surface(trex_surfaces[current_surface])
    if jumping: trex_rect.bottom -= jump_power
    trex_rect.bottom += gravity
    gravity += initial_gravity
    if trex_rect.bottom > ground_level:
        trex_rect.bottom = ground_level
        gravity = initial_gravity
        jumping = False
    if check_collision():
        game_active = False
        current_surface = 5
        speed = initial_speed
    screen.blit(trex_surfaces[current_surface], trex_rect)



    pygame.display.update()
    clock.tick(fps)

pygame.quit()

标签： pythonpygame