防止角色离开屏幕

Question

所以我有一个非常简单的问题，但我找不到解决方案。

我尝试使用“clamp_ip”来阻止我的角色离开屏幕，但我不确定为什么这不起作用，因为我遵循了我看到的所有示例，但仍然遇到这个问题

这是我的代码：

import math
from random import randint
import pygame
from pygame.math import Vector2

pygame.init()

screen = pygame.display.set_mode((600, 600))
screen_width = 600
screen_height = 600
black = (0, 0, 0)
pygame.display.set_caption("gang")
clock = pygame.time.Clock()


class Character:
    def __init__(self, x, y, width, height):
        self.x = x
        self.y = y
        self.width = width
        self.height = height


class Player(pygame.sprite.Sprite):

    def __init__(self, pos):
        super().__init__()
        self.image = pygame.Surface((50, 30), pygame.SRCALPHA)
        pygame.draw.polygon(self.image, pygame.Color('steelblue2'), [(0, 0), (50, 15), (0, 30)])
        self.original_image = self.image
        self.rect = self.image.get_rect(center=pos)
        self.pos = Vector2(pos)
        self.velocityx = Vector2(6, 0)
        self.velocityy = Vector2(0, 6)

    def update(self):
        self.rect.center = (int(self.pos.x), int(self.pos.y))
        self.rotate()

    def rotate(self):
        direction = pygame.mouse.get_pos() - self.pos
        radius, angle = direction.as_polar()
        self.image = pygame.transform.rotate(self.original_image, -angle)
        self.rect = self.image.get_rect(center=self.rect.center)


class Enemy(Character):
    def __init__(self, x, y, width, height):
        Character.__init__(self, x, y, width, height)

    def draw(self, win):
        pygame.draw.rect(win, (0, 255, 0), (enemy1.x, enemy1.y, enemy1.width, enemy1.height))


class Projectile(pygame.sprite.Sprite):
    def __init__(self, pos):
        super().__init__()
        self.image = pygame.Surface((9, 15), pygame.SRCALPHA)
        pygame.draw.circle(self.image, (0, 0, 0), (30, 50), 14)
        self.rect = self.image.get_rect(center=pos)
        self.pos = Vector2(pos)
        self.velocityx = Vector2(9, 0)
        self.velocityy = Vector2(0, 9)

    def update(self):
        self.pos += self.velocityx
        self.rect.center = self.pos


def draw_window():
    screen.fill((30, 30, 30))
    enemy1.draw(screen)
    all_sprites.update()
    all_sprites.draw(screen)
    bullets.update()
    bullets.draw(screen)
    pygame.display.update()


def xor(a, b):
    if bool(a) != bool(b):
        return True
    else:
        return False


def game_end():
    pygame.font.init()
    text = pygame.font.Font('freesansbold.ttf', 32)
    text_surface = text.render('Game Over', False, (0, 0, 0))
    text_rect = text_surface.get_rect()
    text_rect.center = (86, 86)
    screen.blit(text_surface, (172, 172))
    pygame.display.update()



player = Player((150, 150))
enemy1 = Enemy(randint(300, 500), randint(300, 500), 60, 60)
projectile = Projectile((150, 150))
player_sprite = pygame.sprite.RenderPlain(player)
bullet_sprites = pygame.sprite.RenderPlain(projectile)
bullets = pygame.sprite.Group(projectile)
all_sprites = pygame.sprite.Group(player, projectile)


def main():
    screen_rect = screen.get_rect()

    run = True
    while run:
        clock.tick(60)

        keys = pygame.key.get_pressed()

        for e in pygame.event.get():
            if e.type == pygame.QUIT:
                run = False


        if keys[pygame.K_SPACE]:
            if len(bullets) < 5:
                projectile.pos += projectile.velocityx
        if xor(keys[pygame.K_a], keys[pygame.K_LEFT]):
            player.pos -= player.velocityx
        elif xor(keys[pygame.K_d], keys[pygame.K_RIGHT]):
            player.pos += player.velocityx
        elif xor(keys[pygame.K_w], keys[pygame.K_UP]):
            player.pos -= player.velocityy
        elif xor(keys[pygame.K_s], keys[pygame.K_DOWN]):
            player.pos += player.velocityy

        player.rect.clamp_ip(screen_rect)

        draw_window()


main()

程序运行没有问题，但只是没有做我想让它做的事情，而且我可能不明白clamp的工作原理。

我希望我的角色不会离开屏幕。我需要做出哪些改变才能做到这一点？

Answer 1

player.pos 和 player.rect 必须先同步。钳制player.rect是不够的，因为player.rect不断被player.pos更新。
将player.rect 夹在Player.update 中。如果player.rect 被钳位，则必须将更改的位置写回player.pos。

class Player(pygame.sprite.Sprite):

    # [...]

    def update(self):
        self.rect.center = (int(self.pos.x), int(self.pos.y))
        self.rotate()
        clamp_rect = self.rect.clamp(screen.get_rect())
        if clamp_rect != self.rect:
            self.rect = clamp_rect
            self.pos.x, self.pos.y = self.rect.center

Answer 2

在main函数中，为什么不对玩家x、y的位置做一些限制呢？比如：

    if keys[pygame.K_SPACE]:
        if len(bullets) < 5:
            projectile.pos += projectile.velocityx

    if xor(keys[pygame.K_a], keys[pygame.K_LEFT]):
        if player.pos - player.velocityx >= 0:
            player.pos -= player.velocityx

Answer 3

它不起作用，因为在每一帧中：

• 你打电话给clamp_ip
• 然后你改变玩​​家精灵的位置
• 然后将玩家精灵绘制到屏幕上。

只需在播放器的更新方法中使用clamp_ip即可：

def update(self):
    self.rect.center = (int(self.pos.x), int(self.pos.y))
    self.rect.clamp_ip(pygame.display.get_surface().get_rect())
    self.rotate()