Mixing
I cant move my sprite unless I shoot first?
I cant move my sprite unless I shoot first?
I'm developing a basic game, where you can move around and shoot projectiles to kill randomly spawned enemies, but if I boot the game and I try to move before I do anything else, the game crashes. If I shoot a projectile first, however, the game runs perfectly and I can move around without any problems, but I can't seem to figure out why this is.
import pygame
import random
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)
#Classes
class Player(pygame.sprite.Sprite):
def __init__(self, filename, x, y):
super().__init__()
self.image = pygame.image.load(filename).convert()
self.image.set_colorkey(BLACK)
self.rect = self.image.get_rect()
self.rect.y = y
self.rect.x = x
self.change_x = 0
self.change_y = 0
self.walls = None
def changespeed(self, x, y):
self.change_x += x
self.change_y += y
def update(self):
self.rect.x += self.change_x
block_hit_list = pygame.sprite.spritecollide(self, self.walls, False)
for block in block_hit_list:
if self.change_x > 0:
self.rect.right = block.rect.left
else:
self.rect.left = block.rect.right
self.rect.y += self.change_y
block_hit_list = pygame.sprite.spritecollide(self, self.walls, False)
for block in block_hit_list:
if self.change_y > 0:
self.rect.bottom = block.rect.top
else:
self.rect.top = block.rect.bottom
class Wall(pygame.sprite.Sprite):
def __init__(self, x, y, width, height):
super().__init__()
self.image = pygame.Surface([width, height])
self.image.fill(BLACK)
self.rect = self.image.get_rect()
self.rect.y = y
self.rect.x = x
class Enemy(pygame.sprite.Sprite):
def __init__(self, filename):
super().__init__()
self.image = pygame.image.load(filename).convert()
self.image.set_colorkey(BLACK)
self.rect = self.image.get_rect()
class ProjectileUp(pygame.sprite.Sprite):
def __init__(self, filename):
super().__init__()
self.image = pygame.image.load(filename).convert()
self.image.set_colorkey(BLACK)
self.rect = self.image.get_rect()
def update(self):
self.rect.y -= 5
class ProjectileDown(pygame.sprite.Sprite):
def __init__(self, filename):
super().__init__()
self.image = pygame.image.load(filename).convert()
self.image.set_colorkey(BLACK)
self.rect = self.image.get_rect()
def update(self):
self.rect.y += 5
class ProjectileLeft(pygame.sprite.Sprite):
def __init__(self, filename):
super().__init__()
self.image = pygame.image.load(filename).convert()
self.image.set_colorkey(BLACK)
self.rect = self.image.get_rect()
def update(self):
self.rect.x -= 5
class ProjectileRight(pygame.sprite.Sprite):
def __init__(self, filename):
super().__init__()
self.image = pygame.image.load(filename).convert()
self.image.set_colorkey(BLACK)
self.rect = self.image.get_rect()
def update(self):
self.rect.x += 5
# --- Create the window
#Initialise pygame
pygame.init()
#Window dimensions
screen_width = 1080
screen_height = 607
screen = pygame.display.set_mode([screen_width, screen_height])
#Window display name
pygame.display.set_caption('Labyrinth')
#Sprite Lists
all_sprite_list = pygame.sprite.Group()
block_list = pygame.sprite.Group()
wall_list = pygame.sprite.Group()
projectile_list = pygame.sprite.Group()
#Define game borders
wall = Wall(-32, 0, 10, 607)
wall_list.add(wall)
all_sprite_list.add(wall)
wall = Wall(0 , -64, 1080, 10)
wall_list.add(wall)
all_sprite_list.add(wall)
wall = Wall(1100, 0, 10, 607)
wall_list.add(wall)
all_sprite_list.add(wall)
wall = Wall(0 , 600, 1080, 10)
wall_list.add(wall)
all_sprite_list.add(wall)
#Create player sprite
player = Player("Isaac.png", 420, 150)
all_sprite_list = pygame.sprite.Group()
all_sprite_list.add(player)
player.walls = wall_list
#Create enemies
for i in range(7):
block = Enemy("Judas.png")
block.rect.x = random.randrange(50, 950)
block.rect.y = random.randrange(50, 450)
block_list.add(block)
all_sprite_list.add(block)
#Manage screen updates
clock = pygame.time.Clock()
#Load background image
background_position = [0, 0]
background_image = pygame.image.load("Floor.png").convert()
#Loop until game_exit
done = False
#---------- MAIN PROGRAM LOOP ----------#
while not done:
# --- Event processing
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
#Projectile spawn
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_UP:
projectile = ProjectileUp("LightningUp.png")
projectile.rect.x = player.rect.x+65
projectile.rect.y = player.rect.y
elif event.key == pygame.K_DOWN:
projectile = ProjectileDown("LightningDown.png")
projectile.rect.x = player.rect.x+65
projectile.rect.y = player.rect.y+100
elif event.key == pygame.K_LEFT:
projectile = ProjectileLeft("LightningLeft.png")
projectile.rect.x = player.rect.x+35
projectile.rect.y = player.rect.y+100
elif event.key == pygame.K_RIGHT:
projectile = ProjectileRight("LightningRight.png")
projectile.rect.x = player.rect.x+115
projectile.rect.y = player.rect.y+100
all_sprite_list.add(projectile)
projectile_list.add(projectile)
#Movement controls
if event.type == pygame.KEYDOWN:
if event.key == ord('a'):
player.changespeed(-7, 0)
elif event.key == ord('d'):
player.changespeed(7, 0)
elif event.key == ord('w'):
player.changespeed(0, -7)
elif event.key == ord('s'):
player.changespeed(0, 7)
elif event.type == pygame.KEYUP:
if event.key == ord('a'):
player.changespeed(7, 0)
elif event.key == ord('d'):
player.changespeed(-7, 0)
elif event.key == ord('w'):
player.changespeed(0, 7)
elif event.key == ord('s'):
player.changespeed(0, -7)
# --- Game logic
#Update sprites
all_sprite_list.update()
#Projectile mechanics
for projectile in projectile_list:
block_hit_list = pygame.sprite.spritecollide(projectile, block_list, True)
for block in block_hit_list:
projectile_list.remove(projectile)
#Determine if player hits enemy
blocks_hit_list = pygame.sprite.spritecollide(player, block_list, True)
#Call on background image
screen.blit(background_image, background_position)
# --- Draw the window
all_sprite_list.draw(screen)
pygame.display.flip()
clock.tick(60)
pygame.quit()
1 Answer
1
It's because your if/elif/else logic is messed up a bit. You have two paths for the KEYDOWN event. If the first event happens to be a movement command, your code runs through the projectile code first (without finding a valid projectile command) and then tries to reference a projectile object that doesn't exist. Try this instead:
#---------- MAIN PROGRAM LOOP ----------#
while not done:
# --- Event processing
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
elif event.type == pygame.KEYDOWN:
projectile = None # initialize
if event.key == pygame.K_UP:
projectile = ProjectileUp("LightningUp.png")
projectile.rect.x = player.rect.x+65
projectile.rect.y = player.rect.y
elif event.key == pygame.K_DOWN:
projectile = ProjectileDown("LightningDown.png")
projectile.rect.x = player.rect.x+65
projectile.rect.y = player.rect.y+100
elif event.key == pygame.K_LEFT:
projectile = ProjectileLeft("LightningLeft.png")
projectile.rect.x = player.rect.x+35
projectile.rect.y = player.rect.y+100
elif event.key == pygame.K_RIGHT:
projectile = ProjectileRight("LightningRight.png")
projectile.rect.x = player.rect.x+115
projectile.rect.y = player.rect.y+100
elif event.key == ord('a'):
player.changespeed(-7, 0)
elif event.key == ord('d'):
player.changespeed(7, 0)
elif event.key == ord('w'):
player.changespeed(0, -7)
elif event.key == ord('s'):
player.changespeed(0, 7)
if projectile: # did we create a valid projectile?
all_sprite_list.add(projectile)
projectile_list.add(projectile)
elif event.type == pygame.KEYUP:
if event.key == ord('a'):
player.changespeed(7, 0)
elif event.key == ord('d'):
player.changespeed(-7, 0)
elif event.key == ord('w'):
player.changespeed(0, 7)
elif event.key == ord('s'):
player.changespeed(0, -7)
@Goose_, no problem. If this answered your question, please click on the check mark to accept it.
– OregonJim
Jun 30 at 16:18
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Oh, that makes alot more sense, thatll help alot! thanks!
– Goose _
Jun 30 at 9:48