Content
You can git clone learning project alien_invasion here:
git clone https://github.com/lance-lh/alien_invasion.git
1. class
class Alien(Sprite):
def __init__(self,ai_settings,screen):
super(Alien, self).__init__()
self.screen = screen
self.ai_settings = ai_settings
2. load image
self.image = pygame.image.load('images/alien.bmp')
3. get rectangular method
self.rect = self.image.get_rect() # rect method (center,centerx,middle,left,right...)
4. draw one image onto another
# blit(dest_image, location) location is obtained by rect method
self.screen.blit(self.image, self.rect)
5. initialize game
def run_game(): # initialize the game, screen object,setting
pygame.init()
ai_settings = Settings()
screen = pygame.display.set_mode(
(ai_settings.screen_width,ai_settings.screen_height)) # define a tuple which indicates screen size, width:1200, height:800.
pygame.display.set_caption("Alien Invasion")
6. Group
bullets = Group()
aliens = Group()
7. rect method
# create a bullet rectangular at (0,0) and then move it to proper location
self.rect = pygame.Rect(0,0,ai_settings.bullet_width, ai_settings.bullet_height)
self.rect.centerx = ship.rect.centerx
self.rect.top = ship.rect.top
def draw_bullet(self):
'''paint bullet in the screen'''
pygame.draw.rect(self.screen,self.color,self.rect)
8. Pygame font
self.font = pygame.font.SysFont(None,48)
9. score to image
def prep_score(self):
'''score to image'''
rounded_score = int(round(self.stats.score, -1))
score_str = "{:,}".format(rounded_score)
self.score_image = self.font.render(score_str,True,self.text_color,self.ai_settings.bg_color)
# put score image on the top right of screen
self.score_rect = self.score_image.get_rect()
self.score_rect.right = self.screen_rect.right - 20
self.score_rect.top = 20
10. reset game status
self.reset_stats()
11. quit game
import sys
def check_keydown_events(event,ai_settings,screen, ship,bullets):
if event.key == pygame.K_RIGHT:
ship.moving_right = True
elif event.key == pygame.K_LEFT:
ship.moving_left = True
elif event.key == pygame.K_SPACE:
fire_bullet(ai_settings,screen,ship,bullets)
elif event.key == pygame.K_q:
sys.exit()
12. collision check
def check_bullet_alien_collisons(ai_settings,screen,stats,sb,ship,aliens,bullets):
'''respond to collision between aliens and bullets'''
# delete crashed bullets and aliens
collissions = pygame.sprite.groupcollide(bullets,aliens,True, True) # return a dict , key is a bullet and value is an alien
if collissions:
for aliens in collissions.values():
stats.score += ai_settings.alien_points * len(aliens)
sb.prep_score()
check_high_score(stats,sb)
if len(aliens) == 0:
# delete existing bullets and create new aliens
bullets.empty()
ai_settings.increase_speed()
# level up
stats.level += 1
sb.prep_level()
create_fleet(ai_settings,screen,ship,aliens)
