pygame collissions between two groups - pygame

Question

I still have a problem with my software to check collisions between spaceship and asteroids. I have got no idea why I get a collision only in the top left corner of the screen.
any ideas ? any help please ?
import pygame, sys
import random
import math
from pygame.locals import KEYDOWN, K_SPACE
pygame.init()
pygame.display.set_caption("ASTROCRASH version 0.1 >>> DKR103 <<<")
clock = pygame.time.Clock()
SCREENH = 600
SCREENW = 800
SCREEN = pygame.display.set_mode((SCREENW, SCREENH))
sGRAD = math.pi/180
BLACK = (0,0,0)
WHITE = (255,255,255)
BBB = (0, 75, 230)
ASTEROIDS = []
MISSILES = []
SPACESHIPS = []
class AsteroidSprite(pygame.sprite.Sprite):
def __init__(self,posX,posY):
pygame.sprite.Sprite.__init__(self)
self.image = pygame.image.load("img/asteroid3.png").convert()
self.rect = self.image.get_rect()
self.x = posX
self.y = posY
self.speed = 2
self.dx = random.choice([1,-1]) * self.speed * random.random()
self.dy = random.choice([1,-1]) * self.speed * random.random()
def update(self):
if self.y > SCREENH:
self.y = (0 - self.rect[3])
if self.y < (0 - self.rect[3]):
self.y = SCREENH
if self.x > SCREENW:
self.x = (0 - self.rect[2])
if self.x < (0 - self.rect[2]):
self.x = SCREENW
self.x += self.dx
self.y += self.dy
class Ship(pygame.sprite.Sprite):
def __init__(self):
pygame.sprite.Sprite.__init__(self)
#load original image
self.imageMaster = pygame.image.load("img/spaceship.png")
self.imageMaster = self.imageMaster.convert()
###self.imageMaster.set_colorkey(WHITE)
#set Sprite attribute
self.image = self.imageMaster
#get Sprite rect
self.rect = self.image.get_rect()
self.rect.center = ((SCREEN.get_width()/2),(SCREEN.get_height()/2))
#initial rotation value
self.dir = 0
#ship movement speed
self.speed = 5
def rotation(self):
#set Sprite center before rotation
self.oldCenter = self.rect.center
#rotate Sprite
self.image = pygame.transform.rotate(self.imageMaster,self.dir)
self.rect= self.image.get_rect()
#set new Sprite center equal to old Center so it stays in place
self.rect.center = self.oldCenter
self.value = self.dir * math.pi / 180
def update(self):
#move
key = pygame.key.get_pressed()
if key[pygame.K_UP]:
self.rect[0] -= self.speed * math.sin(self.value)
self.rect[1] -= self.speed * math.cos(self.value)
#rotate
if key[pygame.K_LEFT]:
self.dir += 5
if self.dir > 360:
self.dir = 15
if key[pygame.K_RIGHT]:
self.dir -= 5
if self.dir < 0:
self.dir = 355
#outside SCREEN conditions
if self.rect[1] > SCREENH:
self.rect[1] = (0 - self.rect[3])
if self.rect[1] < (0 - self.rect[3]):
self.rect[1] = SCREENH
if self.rect[0] > SCREENW:
self.rect[0] = (0 - self.rect[2])
if self.rect[0] < (0 - self.rect[2]):
self.rect[0] = SCREENW
def draw(self):
SCREEN.blit(self.image,(self.rect[0],self.rect[1]))
def main():
#spaceship
spaceship = Ship()
SPACESHIPS.append(spaceship)
for i in range(8):
ASTEROIDS.append(AsteroidSprite(300,300))
runGame = True
while runGame:
clock.tick(60)
SCREEN.fill(BLACK)
for event in pygame.event.get():
if event.type == pygame.QUIT:
runGame = False
#update asteroids
for i in range(8):
ASTEROIDS[i].update()
SCREEN.blit(ASTEROIDS[i].image,(ASTEROIDS[i].x,ASTEROIDS[i].y))
for a in ASTEROIDS:
if pygame.sprite.spritecollide(a,SPACESHIPS,0):
SCREEN.fill(BBB)
spaceship.rotation()
spaceship.update()
spaceship.draw()
print spaceship.rect[0]
pygame.display.update()
main()
pygame.quit()

Answer 1

The pygame.sprite.groupcollide() function finds collisions between all sprites of the two passed sprite-groups and returns a dictionary containing the collision information, as the documentation states.
Because the collision is determined by comparing the sprite.rect attribute of each sprite, every time you call an update() method of an sprite instance you need to update the position of self.rect object, instead of changing its self.x and self.y attributes.
Your Ship class is ok, because you change the self.rect object and its own .x or .y attributes. (e.g. self.rect[1] = (0 - self.rect[3])).But in your AsteroidSprite class you create a rect object in the __init__() method and only change the self.x and self.y attributes of an instance when you call the .update() method.
What you need to change:
The .update() method of the AsteroidSprite class, because you need to change the self.rect objects position, which is used for collision detection.
The if statement where you check for a collision, because pygame.sprite.groupcollide() returns a dict object, not a Boolean value.
I hope this helps you a little bit :)

Answer 2

Many thanks. Your answer helped me to solve the problem.
updated code:
import pygame, sys
import random
import math
from pygame.locals import KEYDOWN, K_SPACE
pygame.init()
pygame.display.set_caption("ASTROCRASH version 0.1 >>> DKR103 <<<")
clock = pygame.time.Clock()
SCREENH = 600
SCREENW = 800
SCREEN = pygame.display.set_mode((SCREENW, SCREENH))
sGRAD = math.pi/180
BLACK = (0,0,0)
WHITE = (255,255,255)
BBB = (0, 75, 230)
ASTEROIDS = []
MISSILES = []
SPACESHIPS = []
class AsteroidSprite(pygame.sprite.Sprite):
def __init__(self,posX,posY):
pygame.sprite.Sprite.__init__(self)
self.image = pygame.image.load("img/asteroid3.png").convert()
self.rect = self.image.get_rect()
self.rect.x = posX
self.rect.y = posY
self.speed = 2
self.dx = random.choice([1,-1]) * self.speed * random.random()
self.dy = random.choice([1,-1]) * self.speed * random.random()
def update(self):
if self.rect.y > SCREENH:
self.rect.y = (0 - self.rect[3])
if self.rect.y < (0 - self.rect[3]):
self.rect.y = SCREENH
if self.rect.x > SCREENW:
self.rect.x = (0 - self.rect[2])
if self.rect.x < (0 - self.rect[2]):
self.rect.x = SCREENW
self.rect.x += self.dx
self.rect.y += self.dy
class Ship(pygame.sprite.Sprite):
def __init__(self):
pygame.sprite.Sprite.__init__(self)
#load original image
self.imageMaster = pygame.image.load("img/spaceship.png")
self.imageMaster = self.imageMaster.convert()
###self.imageMaster.set_colorkey(WHITE)
#set Sprite attribute
self.image = self.imageMaster
#get Sprite rect
self.rect = self.image.get_rect()
self.rect.center = ((SCREEN.get_width()/2),(SCREEN.get_height()/2))
#initial rotation value
self.dir = 0
#ship movement speed
self.speed = 5
def rotation(self):
#set Sprite center before rotation
self.oldCenter = self.rect.center
#rotate Sprite
self.image = pygame.transform.rotate(self.imageMaster,self.dir)
self.rect= self.image.get_rect()
#set new Sprite center equal to old Center so it stays in place
self.rect.center = self.oldCenter
self.value = self.dir * math.pi / 180
def update(self):
#move
key = pygame.key.get_pressed()
if key[pygame.K_UP]:
self.rect[0] -= self.speed * math.sin(self.value)
self.rect[1] -= self.speed * math.cos(self.value)
#rotate
if key[pygame.K_LEFT]:
self.dir += 5
if self.dir > 360:
self.dir = 15
if key[pygame.K_RIGHT]:
self.dir -= 5
if self.dir < 0:
self.dir = 355
#outside SCREEN conditions
if self.rect[1] > SCREENH:
self.rect[1] = (0 - self.rect[3])
if self.rect[1] < (0 - self.rect[3]):
self.rect[1] = SCREENH
if self.rect[0] > SCREENW:
self.rect[0] = (0 - self.rect[2])
if self.rect[0] < (0 - self.rect[2]):
self.rect[0] = SCREENW
def draw(self):
SCREEN.blit(self.image,(self.rect[0],self.rect[1]))
def main():
#spaceship
spaceship = Ship()
SPACESHIPS.append(spaceship)
for i in range(8):
ASTEROIDS.append(AsteroidSprite(300,300))
runGame = True
while runGame:
clock.tick(60)
SCREEN.fill(BLACK)
for event in pygame.event.get():
if event.type == pygame.QUIT:
runGame = False
#update asteroids
for i in range(8):
ASTEROIDS[i].update()
SCREEN.blit(ASTEROIDS[i].image,(ASTEROIDS[i].rect.x,ASTEROIDS[i].rect.y))
for a in ASTEROIDS:
if pygame.sprite.spritecollide(a,SPACESHIPS,0):
SCREEN.fill(BBB)
spaceship.rotation()
spaceship.update()
spaceship.draw()
print spaceship.rect[0]
pygame.display.update()
main()
pygame.quit()