在斜边上移动很可能需要您的对象在 y 轴或 x 轴上每帧移动少于一个像素,并且因为rects
只能保存整数,您需要一个新属性position
其中包含以浮点精度表示的精灵位置。您可以使用pygame.math.Vector2
使用有用的方法创建向量,例如normalize()
以及与其他向量的加、减、乘等。
假设您已经创建了一个属性self.position = pygame.math.Vector2(0, 0)
(或者你希望它开始的任何位置)你可以这样做:
def hunt_player(self, player):
player_position = pygame.math.Vector2(player.rect.topleft)
direction = player_position - self.position
velocity = direction.normalize() * self.speed
self.position += velocity
self.rect.topleft = self.position
通过将玩家的位置与敌人的位置相减,您将得到一个从敌人指向玩家的向量。如果我们将方向向量添加到我们的位置,我们将立即传送到玩家。相反,我们对向量进行归一化(使其长度为 1 像素)并乘以我们的速度属性。新创建的向量将是一个指向玩家的向量,其长度为我们的速度。
完整示例
import pygame
pygame.init()
SIZE = WIDTH, HEIGHT = 720, 480
FPS = 60
BACKGROUND_COLOR = pygame.Color('white')
screen = pygame.display.set_mode(SIZE)
clock = pygame.time.Clock()
class Hunter(pygame.sprite.Sprite):
def __init__(self, position):
super(Hunter, self).__init__()
self.image = pygame.Surface((32, 32))
self.image.fill(pygame.Color('red'))
self.rect = self.image.get_rect(topleft=position)
self.position = pygame.math.Vector2(position)
self.speed = 2
def hunt_player(self, player):
player_position = player.rect.topleft
direction = player_position - self.position
velocity = direction.normalize() * self.speed
self.position += velocity
self.rect.topleft = self.position
def update(self, player):
self.hunt_player(player)
class Player(pygame.sprite.Sprite):
def __init__(self, position):
super(Player, self).__init__()
self.image = pygame.Surface((32, 32))
self.image.fill(pygame.Color('blue'))
self.rect = self.image.get_rect(topleft=position)
self.position = pygame.math.Vector2(position)
self.velocity = pygame.math.Vector2(0, 0)
self.speed = 3
def update(self):
keys = pygame.key.get_pressed()
if keys[pygame.K_LEFT]:
self.velocity.x = -self.speed
elif keys[pygame.K_RIGHT]:
self.velocity.x = self.speed
else:
self.velocity.x = 0
if keys[pygame.K_UP]:
self.velocity.y = -self.speed
elif keys[pygame.K_DOWN]:
self.velocity.y = self.speed
else:
self.velocity.y = 0
self.position += self.velocity
self.rect.topleft = self.position
player = Player(position=(350, 220))
monster = Hunter(position=(680, 400))
running = True
while running:
clock.tick(FPS)
for event in pygame.event.get():
if event.type == pygame.QUIT:
running = False
player.update()
monster.update(player)
screen.fill(BACKGROUND_COLOR)
screen.blit(player.image, player.rect)
screen.blit(monster.image, monster.rect)
pygame.display.update()
Result