In my below code using PyGame, the character won't move left or right and the bullet won't shoot. I'm not sure what's causing this. It works without the whole start menu with buttons concept so I was wondering if that is the issue?
import pygame
from pygame import mixer
import math
import random
import time
# Initialize pygame module
pygame.init()
# Create the screen
screen = pygame.display.set_mode((800, 600))
display_width = 800
display_height = 600
# Background
background = pygame.image.load('space1.jpg')
# Background Sound
mixer.music.load('background.wav')
mixer.music.play(-1)
# Title and Icon
pygame.display.set_caption('Space Invaders')
icon = pygame.image.load('ufo.png')
pygame.display.set_icon(icon)
# Player
playerImg = pygame.image.load('space-invaders.png')
playerX = 370
playerY = 480
player_change = 0
playerX += player_change
# Enemy
enemyImg = []
enemyX = []
enemyY = []
enemyX_change = []
enemyY_change = []
num_of_enemies = 6
# Colours
WHITE = (255, 255, 255)
BLACK = (0, 0, 0)
RED = (150, 0, 0)
GREEN = (0, 150, 0)
BRIGHT_RED = (255, 0,0)
BRIGHT_GREEN = (0, 255, 0)
for i in range(num_of_enemies):
enemyImg.append(pygame.image.load('alien.png'))
enemyX.append(random.randint(0, 736))
enemyY.append(random.randint(50, 150))
enemyX_change.append(2)
enemyY_change.append(40)
# Bullet
# Ready - You cant see the bullet on the screen
# Fire - The bullet is current moving
bulletImg = pygame.image.load('bullet.png')
bulletX = 0
bulletY = 480
bulletY_change = 10
bullet_state = 'ready'
# Score
score_value = 0
font = pygame.font.Font('freesansbold.ttf', 32)
textX = 10
textY = 10
# Game Over Text
over_font = pygame.font.Font('freesansbold.ttf', 64)
# Clock
clock = pygame.time.Clock()
def show_score(x, y):
score = font.render('score : ' + str(score_value), True, (0, 255, 0))
screen.blit(score, (x, y))
def game_over_text():
over_text = over_font.render('GAME OVER', True, (0, 255, 0))
screen.blit(over_text, (200, 250))
def player(x, y):
screen.blit(playerImg, (x, y))
def enemy(x, y, i):
screen.blit(enemyImg[i], (x, y))
def fire_bullet(x, y):
global bullet_state
bullet_state = 'fire'
screen.blit(bulletImg, (x + 16, y + 10))
def isCollision(enemyX, enemyY, bulletX, bulletY):
distance = math.sqrt((math.pow(enemyX - bulletX, 2)) + (math.pow(enemyY - bulletY, 2)))
if distance < 27:
return True
else:
return False
def text_objects(text, font):
textSurface = font.render(text, True, WHITE)
return textSurface, textSurface.get_rect()
def game_intro():
intro = True
while intro:
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
quit()
screen.fill(BLACK)
largeText = pygame.font.Font('freesansbold.ttf', 105)
TextSurf, TextRect = text_objects('Space Invaders', largeText)
TextRect.center = ((display_width/2), 200)
screen.blit(TextSurf, TextRect)
button('Start Invasion', 325, 350, 150, 50, GREEN, BRIGHT_GREEN, 'play')
button('Quit Mission', 325, 450, 150, 50, RED, BRIGHT_RED, 'quit')
pygame.display.update()
clock.tick(15)
#Game Loop
def game_loop(playerX, playerY, player_change, bulletX, bulletY, bulletX_change, bulletY_change, bullet_state, bulletImg):
running = True
while running:
playerX = 370
playerY = 480
player_change = 0
playerX += player_change
# RGB R G B
screen.fill((0, 0, 0))
# Background Image
screen.blit(background, (0, 0))
for event in pygame.event.get():
if event.type == pygame.QUIT:
running = False
# If keystroke is pressed check whether its left or right
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_LEFT:
player_change = -5
if event.key == pygame.K_RIGHT:
player_change = 5
if event.key == pygame.K_SPACE:
if bullet_state is 'ready':
bullet_sound = mixer.Sound('laser.wav')
bullet_sound.play()
# Get the current x coordinate of the spaceship
bulletX = playerX
fire_bullet(bulletX, bulletY)
if event.type == pygame.KEYUP:
if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
player_change = 0
# boundary for spaceship
if playerX <= 0:
playerX = 0
elif playerX >= 736:
playerX = 736
# Enemy movement
for i in range(num_of_enemies):
# Game Over
if enemyY[i] > 440:
for j in range(num_of_enemies):
enemyY[j] = 2000
game_over_text()
break
enemyX[i] += enemyX_change[i]
if enemyX[i] <= 0:
enemyX_change[i] = 2
enemyY[i] += enemyY_change[i]
elif enemyX[i] >= 736:
enemyX_change[i] = -2
enemyY[i] += enemyY_change[i]
# Collision
collision = isCollision(enemyX[i], enemyY[i], bulletX, bulletY)
if collision:
explosion_sound = mixer.Sound('explosion.wav')
explosion_sound.play()
bulletY = 480
bullet_state = "ready"
score_value += 1
enemyX[i] = random.randint(0, 736)
enemyY[i] = random.randint(50, 150)
enemy(enemyX[i], enemyY[i], i)
# Bullet movement
if bulletY <= 0:
bulletY = 480
bullet_state = 'ready'
if bullet_state is 'fire':
fire_bullet(bulletX, bulletY)
bulletY -= bulletY_change
player(playerX, playerY)
show_score(textX, textY)
pygame.display.update()
def button(msg, x, y, w, h, inactivecolour, activecolour, action=None):
mouse = pygame.mouse.get_pos()
click = pygame.mouse.get_pressed()
if x + w > mouse[0] > x and y + h > mouse[1] > y:
pygame.draw.rect(screen, activecolour, (x, y, w, h))
if click[0] == 1 and action != None:
if action == 'play':
game_loop(370, 480, 0, 0, 480, 0, 10, 'ready', pygame.image.load('bullet.png'))
if action == 'quit':
pygame.quit()
quit()
else:
pygame.draw.rect(screen, inactivecolour, (x, y, w, h))
smallText = pygame.font.Font('freesansbold.ttf', 20)
textSurf, textRect = text_objects(msg, smallText)
textRect.center = ((x + (w / 2)), (y + (h / 2)))
screen.blit(textSurf, textRect)
game_intro()
the character won't move
The movement of the player player_change is continuously set 0, in the main application loop. Further more, the position of the player is continuously initialized:
def game_loop(playerX, playerY, player_change, bulletX, bulletY, bulletX_change, >bulletY_change, bullet_state, bulletImg): running = True while running: playerX = 370 playerY = 480 player_change = 0
Initialize playerX, playerY and player_change before the loop:
def game_loop(playerX, playerY, player_change, bulletX, bulletY, bulletX_change, bulletY_change, bullet_state, bulletImg):
running = True
player_change = 0
playerX = 370
playerY = 480
while running:
playerX += player_change
# [...]
the bullet won't shoot
If you want to fire a bullet, then you have to set the initial position of the bullet bulletX, bulletY = playerX, playerY and set bullet_state = 'fire':
def game_loop(playerX, playerY, player_change, bulletX, bulletY, bulletX_change, bulletY_change, bullet_state, bulletImg):
# [...]
while running:
playerX += player_change
for event in pygame.event.get():
if event.type == pygame.QUIT:
running = False
# If keystroke is pressed check whether its left or right
if event.type == pygame.KEYDOWN:
# [...]
if event.key == pygame.K_SPACE:
if bullet_state is 'ready':
#bullet_sound = mixer.Sound('laser.wav')
#bullet_sound.play()
# Get the current x coordinate of the spaceship
bulletX, bulletY = playerX, playerY
bullet_state = 'fire'
Note, the global variable bullet_state
def fire_bullet(x, y): global bullet_state bullet_state = 'fire'
is different to the local variable bullet_state in game_loop, because bullet_state is an argument to game_loop and thus a completely different variable in a different scope, which has casually the same name:
def game_loop(playerX, playerY, player_change, bulletX, bulletY,
bulletX_change, bulletY_change,
bullet_state, # <--- that is a new variable in local scope
# and not the "global" bullet_state
bulletImg):
# [...]