如何在PyGame中模拟真实速度?

worker 物体。我该怎么做?

目前我有参数 speed 在密码里。此参数初始化为 randint(2, 4) -介于2和4之间的随机整数。但这个值并没有映射到真实的比例。

在我的例子中,1像素表示 0.038

METERS_PER_PIXEL = 0.038370147
AVG_WALK_SPEED = 1.4 # meters per second
MIN_RUN_SPEED = 2.0  # meters per second
MAX_RUN_SPEED = 5.0  # meters per second

有了这些常量,我想再引入一个名为 human_speed . 例如,我想初始化 人的速度 属于 工人 等于 1.4 . 我怎样才能转换 到 速度 以便 pygame 我需要 人的速度 一些后端计算。

import pygame, random
import sys

WHITE = (255, 255, 255)
GREEN = (20, 255, 140)
GREY = (210, 210 ,210)

SCREENWIDTH=1000
SCREENHEIGHT=578  


class Background(pygame.sprite.Sprite):
    def __init__(self, image_file, location, *groups):
        self._layer = -1
        pygame.sprite.Sprite.__init__(self, groups)

        self.image = pygame.transform.scale(pygame.image.load(image_file).convert(), (SCREENWIDTH, SCREENHEIGHT))
        self.rect = self.image.get_rect(topleft=location)


class Worker(pygame.sprite.Sprite):
    def __init__(self, image_file, location, *groups):

        self._layer = 1
        pygame.sprite.Sprite.__init__(self, groups)
        self.image = pygame.transform.scale(pygame.image.load(image_file).convert_alpha(), (40, 40))
        self.rect = self.image.get_rect(topleft=location)
        self.change_direction()
        self.speed = random.randint(2, 4)


    def change_direction(self):

        self.direction = pygame.math.Vector2(random.randint(-100, 100), random.randint(-100, 100))

        while self.direction.length() == 0:
            self.direction = pygame.math.Vector2(random.randint(-100, 100), random.randint(-100, 100)) 

        self.direction = self.direction.normalize()


    def update(self, screen):

        if random.uniform(0,1)<0.005:
            self.change_direction()

        vec = [int(v) for v in self.direction * self.speed]
        self.rect.move_ip(*vec)

        if not screen.get_rect().contains(self.rect):
            self.change_direction()
        self.rect.clamp_ip(screen.get_rect())

pygame.init()

all_sprites = pygame.sprite.LayeredUpdates()
workers = pygame.sprite.Group()

screen = pygame.display.set_mode((SCREENWIDTH, SCREENHEIGHT))
pygame.display.set_caption("TEST")

# create multiple workers
for pos in ((0,0), (100, 100), (200, 100)):
    Worker("worker.png", pos, all_sprites, workers)

Background("background.jpg", [0,0], all_sprites)

carryOn = True
clock = pygame.time.Clock()

while carryOn:
    for event in pygame.event.get():
        if event.type==pygame.QUIT:
            carryOn = False

    all_sprites.update(screen)
    all_sprites.draw(screen)

    pygame.display.flip()

    clock.tick(20)