I'd like to create a moving background in my Python game, with an image, that moves up until it reaches the end, then it goes back to its first position. I'm still in my learning process and this is really troublesome, because I don't even know the approach it.
image:
What I have for now:
import pygame, random, sys
def main():
pygame.init()
global screenSize, allColors, FPS, clock, surface
screenSize = (640, 480)
surface = pygame.display.set_mode(screenSize)
pygame.display.set_caption('Space Shooters')
black = (0 , 0 , 0 )
white = (255, 255, 255)
gray = (100, 100, 100)
navyblue = (60 , 60 , 100)
red = (255, 0 , 0 )
green = (0 , 255, 0 )
blue = (0 , 0 , 255)
yellow = (255, 255, 0 )
orange = (255, 155, 55 )
purple = (255, 0 , 255)
cyan = (0 , 255, 255)
# 0 1 2 3 4 5 6 7 8 9
allColors = [white,red, green, blue, yellow, orange, purple, cyan, navyblue, gray]
clock = pygame.time.Clock()
FPS = 64
#-------------------------------------------------------------------------------
spaceship = Spaceship()
bullets = Bullet(spaceship)
while True:
#step1 SetDelay
clock.tick(FPS)
#step2 reactOnPlayerInput
for event in pygame.event.get():
if event.type == pygame.QUIT:
terminate()
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_ESCAPE:
terminate()
if event.key == pygame.K_UP:
spaceship.moveUp = True
spaceship.moveDown = False
if event.key == pygame.K_DOWN:
spaceship.moveUp = False
spaceship.moveDown = True
if event.key == pygame.K_LEFT:
spaceship.moveRight = False
spaceship.moveLeft = True
if event.key == pygame.K_RIGHT:
spaceship.moveRight = True
spaceship.moveLeft = False
if event.key == pygame.K_SPACE:
bullets.isShooting = True
if event.type == pygame.KEYUP:
if event.key == pygame.K_UP:
spaceship.moveUp = False
if event.key == pygame.K_DOWN:
spaceship.moveDown = False
if event.key == pygame.K_LEFT:
spaceship.moveLeft = False
if event.key == pygame.K_RIGHT:
spaceship.moveRight = False
if event.key == pygame.K_SPACE:
bullets.isShooting = False
#step3 updateClasses/Variables
spaceship.update()
bullets.update(spaceship)
#step4 renderEverything
surface.fill((255,255,255))
bullets.render()
spaceship.render()
pygame.display.update()
def terminate():
pygame.quit()
sys.exit()
class Spaceship():
def __init__(self):
self.height = 32
self.width = 28
self.ssIMG = pygame.image.load("/home/bucky/Dokumente/Computing/Python/scripts/pygame/spaceShooter/spaceShip.png")
self.centerx = screenSize[0] / 2
self.centery = screenSize[1] / 2
self.speed = 5
self.color = allColors[9]
self.moveLeft, self.moveRight, self.moveUp, self.moveDown = False, False, False, False
self.rect = pygame.Rect(self.centerx - self.width / 2, self.centery - self.height / 2, self.width, self.height)
def update(self):
if self.moveLeft and self.rect.left > 0:
self.rect.centerx -= self.speed
if self.moveRight and self.rect.right < screenSize[0] - 1:
self.rect.centerx += self.speed
if self.moveUp and self.rect.top > 0:
self.rect.centery -= self.speed
if self.moveDown and self.rect.bottom < screenSize[1] - 1:
self.rect.centery += self.speed
def render(self):
surface.blit(self.ssIMG, self.rect)
class Bullet():
def __init__(self, spaceship):
self.bulletIMG = pygame.image.load("/home/bucky/Dokumente/Computing/Python/scripts/pygame/spaceShooter/bullet.png")
self.width = 8
self.height = 12
self.centerx = spaceship.rect.centerx
self.centery = spaceship.rect.centery
self.color = allColors[4]
self.speed = 16
self.isShooting = False
self.listOfBullets = []
def update(self, spaceship):
for i in range(len(self.listOfBullets)):
if i >= len(self.listOfBullets):
break
if self.listOfBullets[i]['counter'] >= 64:
del self.listOfBullets[i]
continue
self.listOfBullets[i]['rect'].centery -= self.speed
self.listOfBullets[i]['counter'] += 1
if self.isShooting:
self.listOfBullets.append({
'rect':pygame.Rect(spaceship.rect.centerx - self.width / 2, spaceship.rect.centery - self.height, self.width, self.height),
'counter':0
})
def render(self):
for i in range(len(self.listOfBullets)):
surface.blit(self.bulletIMG, self.listOfBullets[i]['rect'])
main()
[Edit]:
With the right approach of Areeb I could figure out how to move the background permanently. I added a Background class, with a 'bgY'-variable, which is permanently decreasing, until it goes out of the screen, than it goes back to its first position. But I had to add the same picture twice with the diffrence of a little displacement, because when the background runs out of the screen there will not be any background at all:
class Background():
def __init__(self):
self.bgimage = pygame.image.load('/home/bucky/Dokumente/Computing/Python/scripts/pygame/spaceShooter/weltraum.png')
self.rectBGimg = self.bgimage.get_rect()
self.bgimage = pygame.transform.scale(self.bgimage, (int(screenSize[0] / self.rectBGimg.width * self.rectBGimg.width), int(screenSize[0] / self.rectBGimg.width * self.rectBGimg.height)))
self.rectBGimg = self.bgimage.get_rect()
self.bgY1 = 0
self.bgX1 = 0
self.bgY2 = self.rectBGimg.height
self.bgX2 = 0
self.movingUpSpeed = 5
def update(self):
self.bgY1 -= self.movingUpSpeed
self.bgY2 -= self.movingUpSpeed
if self.bgY1 <= -self.rectBGimg.height:
self.bgY1 = self.rectBGimg.height
if self.bgY2 <= -self.rectBGimg.height:
self.bgY2 = self.rectBGimg.height
def render(self):
surface.blit(self.bgimage, (self.bgX1, self.bgY1))
surface.blit(self.bgimage, (self.bgX2, self.bgY2))
Watch the result: https://youtu.be/dhuPA2v8gG0
