沿对角线移动使玩家走得更快

Question

我有这个简单的移动脚本。

if x > 0:
    if key[pygame.K_a] or key[pygame.K_LEFT]:
        rect_player.move_ip(-1 * speed, 0)
if x < SCREEN_WIDTH - 110:
    if key[pygame.K_d] or key[pygame.K_RIGHT]:
        rect_player.move_ip(speed, 0)
if y > 0:
    if key[pygame.K_w] or key[pygame.K_UP]:
        rect_player.move_ip(0, -1 * speed)
if y < SCREEN_HEIGHT - 110:
    if key[pygame.K_s] or key[pygame.K_DOWN]:
        rect_player.move_ip(0, speed)

当玩家向一个方向移动时，一切正常。但是当他们沿对角线行驶时，速度会更快。有什么办法可以解决这个问题吗？

Answer 1

感谢@Rabbid76 帮助我解决了这个问题，但这对我来说很有效：

    count  = 0
    if x > 0:
        if key[pygame.K_a] or key[pygame.K_LEFT]:
            count += 1
    if x < SCREEN_WIDTH - 110:
        if key[pygame.K_d] or key[pygame.K_RIGHT]:
            count += 1
    if y > 0:
        if key[pygame.K_w] or key[pygame.K_UP]:
            count += 1
    if y < SCREEN_HEIGHT - 110:
        if key[pygame.K_s] or key[pygame.K_DOWN]:
            count += 1

    if count >= 2:
        speed = speed/math.sqrt(2)

    if x > 0:
        if key[pygame.K_a] or key[pygame.K_LEFT]:
            rect_player.move_ip(-1 * speed, 0)
    if x < SCREEN_WIDTH - 110:
        if key[pygame.K_d] or key[pygame.K_RIGHT]:
            rect_player.move_ip(speed, 0)
    if y > 0:
        if key[pygame.K_w] or key[pygame.K_UP]:
            rect_player.move_ip(0, -1 * speed)
    if y < SCREEN_HEIGHT - 110:
        if key[pygame.K_s] or key[pygame.K_DOWN]:
            rect_player.move_ip(0, speed)

Answer 2

由于pygame.Rect应该表示屏幕上的一个区域，因此pygame.Rect对象只能存储整数数据。

The coordinates for Rect objects are all integers. [...]

我建议使用 pygame.math.Vector2 来解决这个问题。将对象的位置存储在一个pygame.math.Vector2对象中：

pos = pygame.math.Vector2(start_x, start_y)

根据按键设置方向矢量。使用 scale_to_length 将矢量缩放到 speed 的长度。移动对象并更新 rect_player:

key = pygame.key.get_pressed()
up = key[pygame.K_w] or key[pygame.K_UP]
down = key[pygame.K_s] or key[pygame.K_DOWN]
left = key[pygame.K_a] or key[pygame.K_LEFT]
right = key[pygame.K_d] or key[pygame.K_RIGHT]

move = pygame.math.Vector2(right - left, down - up)
if move.length_squared() > 0:
    move.scale_to_length(speed)
    pos += move  
    rect_player.topleft = round(pos.x), round(pos.y)

如果您不关心浮点精度，只需移动矩形即可：

key = pygame.key.get_pressed()
up = key[pygame.K_w] or key[pygame.K_UP]
down = key[pygame.K_s] or key[pygame.K_DOWN]
left = key[pygame.K_a] or key[pygame.K_LEFT]
right = key[pygame.K_d] or key[pygame.K_RIGHT]

move = pygame.math.Vector2(right - left, down - up)
if move.length_squared() > 0:
    move.scale_to_length(speed)
    rect_player.move_ip(round(move.x), round(move.y))

最小示例：

import pygame

pygame.init()
window = pygame.display.set_mode((500, 500))
clock = pygame.time.Clock()

rect_player = pygame.Rect(0, 0, 20, 20)
rect_player.center = window.get_rect().center
speed = 5

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

    key = pygame.key.get_pressed()
    up = key[pygame.K_w] or key[pygame.K_UP]
    down = key[pygame.K_s] or key[pygame.K_DOWN]
    left = key[pygame.K_a] or key[pygame.K_LEFT]
    right = key[pygame.K_d] or key[pygame.K_RIGHT]

    move = pygame.math.Vector2(right - left, down - up)
    if move.length_squared() > 0:
        move.scale_to_length(speed)
        rect_player.move_ip(round(move.x), round(move.y))       

    window.fill(0)
    pygame.draw.rect(window, (255, 0, 0), rect_player)
    pygame.display.flip()
    clock.tick(60)

pygame.quit()
exit()

沿对角线移动使玩家走得更快

moving diagonally makes player go faster

python

pygame