如何消除Pygame代码中使用Vector时的Rect拖尾移动问题

我正在探索Pygame中的Vector，尝试用它实现基础移动功能。目前已能控制Rect，但存在拖尾问题（类似贪吃蛇效果），希望仅保留初始单个Rect移动且无拖尾。我尝试过多种修复方法均无效，恳请帮忙指出错误并解决。

以下是我的代码：

import pygame, sys
from pygame.math import Vector2

class PLAYER:
    def __init__(self):
        self.x = cell_size
        self.y = cell_size
        self.pos = Vector2(self.x, self.y)
        self.direction = Vector2(0, 0)

    def draw_player(self):
        player_rect = pygame.Rect(int(self.pos.x * cell_size), int(self.pos.y * cell_size), cell_size, cell_size)
        pygame.draw.rect(win, colors["GREEN"], player_rect)

    def move_player(self):
        self.pos += self.direction

class MAIN:
    def __init__(self):
        self.player = PLAYER()

    def update(self):
        self.player.draw_player()
        self.player.move_player()

    def collision(self):
        pass

    def gameover(self):
        pass


pygame.init()
pygame.font.init()

# SCREEN SETUP
cell_size = 20
cell_number = 40
win = pygame.display.set_mode((cell_size * cell_number, cell_size * cell_number))
pygame.display.set_caption("Catch me")
icon = pygame.image.load("football.png")
pygame.display.set_icon(icon)

colors = {
    "RED":(255, 0, 0),
    "BLUE":(0, 0, 255),
    "GREEN":(0, 255, 0),
}

SCREEN_UPDATE = pygame.USEREVENT
pygame.time.set_timer(SCREEN_UPDATE, 150)

game = MAIN()
run = True
while run:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

        if event.type == SCREEN_UPDATE:
            game.update()
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_UP:
                game.player.direction = Vector2(0, -1)
            if event.key == pygame.K_DOWN:
                game.player.direction = Vector2(0, 1)
            if event.key == pygame.K_RIGHT:
                game.player.direction = Vector2(1, 0)
            if event.key == pygame.K_LEFT:
                game.player.direction = Vector2(-1, 0)

    pygame.display.update()

问题原因与修复方案 #

拖尾问题的核心是每次绘制新玩家Rect前未清空屏幕，旧的Rect会残留在画面中，叠加后形成类似贪吃蛇的拖尾效果。

修复步骤： #

1. 新增背景色（比如黑色），在每次绘制前用背景色填充整个窗口，覆盖之前的所有绘制内容。
2. 调整MAIN.update方法的执行顺序：先移动玩家更新位置，再绘制玩家，逻辑更合理。

修改后的完整代码： #

import pygame, sys
from pygame.math import Vector2

class PLAYER:
    def __init__(self):
        self.x = cell_size
        self.y = cell_size
        self.pos = Vector2(self.x, self.y)
        self.direction = Vector2(0, 0)

    def draw_player(self):
        player_rect = pygame.Rect(int(self.pos.x * cell_size), int(self.pos.y * cell_size), cell_size, cell_size)
        pygame.draw.rect(win, colors["GREEN"], player_rect)

    def move_player(self):
        self.pos += self.direction

class MAIN:
    def __init__(self):
        self.player = PLAYER()

    def update(self):
        # 先移动更新位置，再绘制
        self.player.move_player()
        self.player.draw_player()

    def collision(self):
        pass

    def gameover(self):
        pass


pygame.init()
pygame.font.init()

# SCREEN SETUP
cell_size = 20
cell_number = 40
win = pygame.display.set_mode((cell_size * cell_number, cell_size * cell_number))
pygame.display.set_caption("Catch me")
icon = pygame.image.load("football.png")
pygame.display.set_icon(icon)

colors = {
    "RED":(255, 0, 0),
    "BLUE":(0, 0, 255),
    "GREEN":(0, 255, 0),
    "BLACK":(0, 0, 0)  # 新增背景色
}

SCREEN_UPDATE = pygame.USEREVENT
pygame.time.set_timer(SCREEN_UPDATE, 150)

game = MAIN()
run = True
while run:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

        if event.type == SCREEN_UPDATE:
            # 每次更新前先清空屏幕
            win.fill(colors["BLACK"])
            game.update()
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_UP:
                game.player.direction = Vector2(0, -1)
            if event.key == pygame.K_DOWN:
                game.player.direction = Vector2(0, 1)
            if event.key == pygame.K_RIGHT:
                game.player.direction = Vector2(1, 0)
            if event.key == pygame.K_LEFT:
                game.player.direction = Vector2(-1, 0)

    pygame.display.update()

内容的提问来源于stack exchange，提问作者Adley Lafleur