问题
After I hit a platform my character can't move along the x-axis anymore unless you press the left or right keys again. For example, if I jump and I clip the corner of the platform the character doesn't continue moving and I have to either do the jump again or react quickly and press the corresponding key. When I remove the player.friction() in the collision detecting system, if I stop pressing the right key it ends up clipping into the edge of the block, which causes the player to get permanently stuck unless they press the right and jump keys at the same time. I presume this could be fixed by changing the blocks position again, but as of now I don't know how to implement this.
Here is my code:
import pygame
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
GREEN = (0, 255, 0)
RED = (255, 0, 0)
BLUE = (0, 255, 255)
DISPLAY_WIDTH = 800
DISPLAY_HEIGHT = 600
gameDisplay = pygame.display.set_mode((DISPLAY_WIDTH, DISPLAY_HEIGHT))
def textObjects(text, font):
textSurface = font.render(text, True, BLACK)
return textSurface, textSurface.get_rect()
def messageDisplay(text):
largeText = pygame.font.Font('freesansbold.ttf', 115)
textSurf, textRect = textObjects(text, largeText)
textRect.center = ((DISPLAY_WIDTH/2), (DISPLAY_HEIGHT/2))
gameDisplay.blit(textSurf, textRect)
class Player(pygame.sprite.Sprite):
def __init__(self):
super().__init__()
width = 100
height = 150
self.image = pygame.Surface([width, height])
self.image.fill(RED)
self.rect = self.image.get_rect()
self.xVel = 0
self.yVel = 0
self.level = None
def update(self):
self.calc_grav()
self.level.bgX += self.xVel
correction = 0
block_hit_list = pygame.sprite.spritecollide(self, self.level.platform_list, False)
for block in block_hit_list:
if self.xVel < 0:
self.friction()
correction = self.rect.right - block.rect.left
elif self.xVel > 0:
self.friction()
correction = self.rect.left - block.rect.right
if correction != 0:
for block in self.level.platform_list:
block.rect.x += correction
self.rect.y += self.yVel
block_hit_list = pygame.sprite.spritecollide(self, self.level.platform_list, False)
for block in block_hit_list:
if self.yVel > 0:
self.rect.bottom = block.rect.top
if self.yVel < 0:
self.rect.top = block.rect.bottom
self.yVel = 0
if isinstance(block, MovingPlatform):
self.level.bgX += block.xVel
def calc_grav(self):
if self.yVel == 0:
self.yVel = 1
else:
self.yVel +=0.3
if self.rect.y >= DISPLAY_HEIGHT - self.rect.height and self.yVel >= 0:
self.yVel = 0
self.rect.y = DISPLAY_HEIGHT - self.rect.height
def jump(self):
self.rect.y += 2
platform_hit_list = pygame.sprite.spritecollide(self, self.level.platform_list, False)
self.rect.y -= 2
if len(platform_hit_list) > 0 or self.rect.bottom >= DISPLAY_HEIGHT:
self.yVel = -10
def moveLeft(self):
self.xVel = 10
def moveRight(self):
self.xVel = -10
def friction(self):
self.xVel = 0
class Platform(pygame.sprite.Sprite):
def __init__(self, width, height):
super().__init__()
self.image = pygame.Surface([width, height])
self.image.fill(GREEN)
self.rect = self.image.get_rect()
class MovingPlatform(Platform):
xVel = 0
yVel = 0
boundary_top = 0
boundary_bottom = 0
boundary_left = 0
boundary_right = 0
player = None
level = None
def update(self):
self.rect.x += self.xVel
correction = 0
hit = pygame.sprite.collide_rect(self, self.player)
if hit:
if self.xVel < 0:
self.player.friction()
correction = self.player.rect.right - self.rect.left
elif self.xVel > 0:
self.player.friction()
correction = self.player.rect.left - self.rect.right
if correction != 0:
for block in self.level.platform_list:
block.rect.x += correction
self.rect.y += self.yVel
hit = pygame.sprite.collide_rect(self, self.player)
if hit:
if self.yVel < 0:
self.player.rect.bottom = self.rect.top
else:
self.player.rect.top = self.rect.bottom
if self.rect.bottom > self.boundary_bottom or self.rect.top < self.boundary_top:
self.yVel *= -1
cur_pos = self.rect.x - self.level.bgX
if cur_pos < self.boundary_left or cur_pos > self.boundary_right:
self.xVel *= -1
class Level(object):
def __init__(self, player):
self.platform_list = pygame.sprite.Group()
self.enemy_list = pygame.sprite.Group()
self.player = player
self.background = None
self.bgX = 0
self.level_limit = -1000
def update(self):
self.platform_list.update()
self.enemy_list.update()
def draw(self, screen):
screen.fill(BLUE)
self.platform_list.draw(screen)
self.enemy_list.draw(screen)
for platform in self.platform_list:
platform.rect.x += self.player.xVel
for enemy in self.enemy_list:
enemy.rect.x += self.player.xVel
class Level_01(Level):
def __init__(self, player):
Level.__init__(self, player)
self.level_limit = -1500
level = [[210, 70, 500, 500],
[210, 70, 800, 400],
[210, 70, 1000, 500],
[210, 70, 1120, 280],
]
for platform in level:
block = Platform(platform[0], platform[1])
block.rect.x = platform[2]
block.rect.y = platform[3]
block.player = self.player
self.platform_list.add(block)
block = MovingPlatform(100, 40)
block.rect.x = 1350
block.rect.y = 280
block.boundary_left = 1350
block.boundary_right = 1600
block.xVel = -1
block.player = self.player
block.level = self
self.platform_list.add(block)
class Level_02(Level):
def __init__(self, player):
Level.__init__(self, player)
self.level_limit = -1000
level = [[210, 70, 500, 550],
[210, 70, 800, 400],
[210, 70, 1000, 500],
[210, 70, 1120, 280],
]
for platform in level:
block = Platform(platform[0], platform[1])
block.rect.x = platform[2]
block.rect.y = platform[3]
block.player = self.player
self.platform_list.add(block)
block = MovingPlatform(70, 70)
block.rect.x = 1500
block.rect.y = 300
block.boundary_top = 100
block.boundary_bottom = 550
block.yVel = -1
block.player = self.player
block.level = self
self.platform_list.add(block)
def main():
pygame.init()
size = [DISPLAY_WIDTH, DISPLAY_HEIGHT]
screen = pygame.display.set_mode(size)
pygame.display.set_caption("Platformer with moving platforms")
player = Player()
level_list = []
level_list.append(Level_01(player))
level_list.append(Level_02(player))
current_level_no = 0
current_level = level_list[current_level_no]
active_sprite_list = pygame.sprite.Group()
player.level = current_level
player.rect.x = 350
player.rect.y = DISPLAY_HEIGHT - player.rect.height
active_sprite_list.add(player)
done = False
clock = pygame.time.Clock()
# -------- Main Program Loop -----------
while not done:
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_LEFT:
player.moveLeft()
if event.key == pygame.K_RIGHT:
player.moveRight()
if event.key == pygame.K_UP:
player.jump()
if event.type == pygame.KEYUP:
if event.key == pygame.K_LEFT and player.xVel > 0:
player.friction()
if event.key == pygame.K_RIGHT and player.xVel < 0:
player.friction()
active_sprite_list.update()
current_level.update()
current_position = current_level.bgX
if current_position < current_level.level_limit:
if current_level_no < len(level_list)-1:
player.rect.x = 350
current_level_no += 1
current_level = level_list[current_level_no]
player.level = current_level
else:
done = True
current_level.draw(screen)
active_sprite_list.draw(screen)
clock.tick(60)
pygame.display.flip()
pygame.quit()
if __name__ == "__main__":
main()
Here is the part of my code that controls the movement and the platform collision system:
Collision (located within the player class):
hit = pygame.sprite.collide_rect(self, self.player)
if hit:
if self.xVel < 0:
self.player.friction()
correction = self.player.rect.right - self.rect.left
elif self.xVel > 0:
self.player.friction()
correction = self.player.rect.left - self.rect.right
if correction != 0:
for block in self.level.platform_list:
block.rect.x += correction
Movement (located within the game loop):
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_LEFT:
player.moveLeft()
if event.key == pygame.K_RIGHT:
player.moveRight()
if event.key == pygame.K_UP:
player.jump()
if event.type == pygame.KEYUP:
if event.key == pygame.K_LEFT and player.xVel > 0:
player.friction()
if event.key == pygame.K_RIGHT and player.xVel < 0:
player.friction()
回答1:
For the problem of having to re-press a left/right key to continue in the desired direction:
You should be acting on key state (pressed/released) not key changes (up/down). Here is the modified event loop you are probably looking for:
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_LEFT:
player.left_pressed=True
#player.moveLeft()
if event.key == pygame.K_RIGHT:
player.right_pressed=True
#player.moveRight()
if event.key == pygame.K_UP:
player.jump()
if event.type == pygame.KEYUP:
if event.key == pygame.K_LEFT:
player.left_pressed=False
if player.xVel > 0:
player.friction()
if event.key == pygame.K_RIGHT:
player.right_pressed=False
if player.xVel < 0:
player.friction()
if player.left_pressed:
player.moveLeft()
if player.right_pressed:
player.moveRight()
Make sure to add left_pressed and right_pressed variables in your player class, initialized to False. Also I haven't used pygame in a while, so there may already be a key state variable available so you don't need key change events.
来源：https://stackoverflow.com/questions/59525136/how-would-i-fix-my-characters-position-after-hitting-a-block