I have made a list of bullets and a list of sprites using the classes below. How do I detect if a bullet collides with a sprite and then delete that sprite and the bullet?
# Define the sprite class
class Sprite:
def __init__(self, x, y, image_file):
# Define the position of the sprite.
self.x = x
self.y = y
# Load the sprite image and get it's rect.
self.image = pygame.image.load(image_file)
self.rect = self.image.get_rect()
def render(self, window):
# Render the sprite onscreen
window.blit(self.image, (self.x, self.y))
# Define the bullet class to create bullets
class Bullet:
def __init__(self, x, y):
# Define the position of the bullet.
self.x = x + 23 # Offset it
self.y = y
# Load the bullet image and get it's rect.
self.bullet = pygame.image.load("user_bullet.BMP")
self.rect = self.bullet.get_rect()
def render(self, window):
# Render the bullet onscreen.
window.blit(self.bullet, (self.x, self.y))
In PyGame, collision detection is done using pygame.Rect
objects. The Rect
object offers various methods for detecting collisions between objects. Even the collision between a rectangular and circular object such as a paddle and a ball can be detected by a collision between two rectangular objects, the paddle and the bounding rectangle of the ball.
Some examples:
Test if a point is inside a rectangle
repl.it/@Rabbid76/PyGame-collidepoint
import pygame
pygame.init()
window = pygame.display.set_mode((250, 250))
rect = pygame.Rect(*window.get_rect().center, 0, 0).inflate(100, 100)
run = True
while run:
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
point = pygame.mouse.get_pos()
collide = rect.collidepoint(point)
color = (255, 0, 0) if collide else (255, 255, 255)
window.fill(0)
pygame.draw.rect(window, color, rect)
pygame.display.flip()
pygame.quit()
exit()
Test if two rectangles overlap
See also How to detect collisions between two rectangular objects or images in pygame
repl.it/@Rabbid76/PyGame-colliderect
import pygame
pygame.init()
window = pygame.display.set_mode((250, 250))
rect1 = pygame.Rect(*window.get_rect().center, 0, 0).inflate(75, 75)
rect2 = pygame.Rect(0, 0, 75, 75)
run = True
while run:
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
rect2.center = pygame.mouse.get_pos()
collide = rect1.colliderect(rect2)
color = (255, 0, 0) if collide else (255, 255, 255)
window.fill(0)
pygame.draw.rect(window, color, rect1)
pygame.draw.rect(window, (0, 255, 0), rect2, 6, 1)
pygame.display.flip()
pygame.quit()
exit()
Furthermore, pygame.Rect.collidelist
and pygame.Rect.collidelistall
can be used for the collision test between a rectangle and a list of rectangles. pygame.Rect.collidedict
and pygame.Rect.collidedictall
can be used for the collision test between a rectangle and a dictionary of rectangles.
The collision of pygame.sprite.Sprite
and pygame.sprite.Group
objects, can be detected by pygame.sprite.spritecollide()
, pygame.sprite.groupcollide()
or pygame.sprite.spritecollideany()
. When using these methods, the collision detection algorithm can be specified by the collided
argument:
The collided argument is a callback function used to calculate if two sprites are colliding.
Possible collided
callables are collide_rect
, collide_rect_ratio
, collide_circle
, collide_circle_ratio
, collide_mask
Some examples:
repl.it/@Rabbid76/PyGame-spritecollide
import pygame
pygame.init()
window = pygame.display.set_mode((250, 250))
sprite1 = pygame.sprite.Sprite()
sprite1.image = pygame.Surface((75, 75))
sprite1.image.fill((255, 0, 0))
sprite1.rect = pygame.Rect(*window.get_rect().center, 0, 0).inflate(75, 75)
sprite2 = pygame.sprite.Sprite()
sprite2.image = pygame.Surface((75, 75))
sprite2.image.fill((0, 255, 0))
sprite2.rect = pygame.Rect(*window.get_rect().center, 0, 0).inflate(75, 75)
all_group = pygame.sprite.Group([sprite2, sprite1])
test_group = pygame.sprite.Group(sprite2)
run = True
while run:
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
sprite1.rect.center = pygame.mouse.get_pos()
collide = pygame.sprite.spritecollide(sprite1, test_group, False)
window.fill(0)
all_group.draw(window)
for s in collide:
pygame.draw.rect(window, (255, 255, 255), s.rect, 5, 1)
pygame.display.flip()
pygame.quit()
exit()
For a collision with masks, see How can I make a collision mask? or Pygame mask collision
See also Collision and Intersection
pygame.sprite.spritecollide()
/ collide_circle
repl.it/@Rabbid76/PyGame-spritecollidecollidecircle
import pygame
pygame.init()
window = pygame.display.set_mode((250, 250))
sprite1 = pygame.sprite.Sprite()
sprite1.image = pygame.Surface((80, 80), pygame.SRCALPHA)
pygame.draw.circle(sprite1.image, (255, 0, 0), (40, 40), 40)
sprite1.rect = pygame.Rect(*window.get_rect().center, 0, 0).inflate(80, 80)
sprite1.radius = 40
sprite2 = pygame.sprite.Sprite()
sprite2.image = pygame.Surface((80, 89), pygame.SRCALPHA)
pygame.draw.circle(sprite2.image, (0, 255, 0), (40, 40), 40)
sprite2.rect = pygame.Rect(*window.get_rect().center, 0, 0).inflate(80, 80)
sprite2.radius = 40
all_group = pygame.sprite.Group([sprite2, sprite1])
test_group = pygame.sprite.Group(sprite2)
run = True
while run:
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
sprite1.rect.center = pygame.mouse.get_pos()
collide = pygame.sprite.spritecollide(sprite1, test_group, False, pygame.sprite.collide_circle)
window.fill(0)
all_group.draw(window)
for s in collide:
pygame.draw.circle(window, (255, 255, 255), s.rect.center, s.rect.width // 2, 5)
pygame.display.flip()
pygame.quit()
exit()
What does this all mean for your code?
pygame.Surface.get_rect.get_rect()
returns a rectangle with the size of the Surface object, that always starts at (0, 0) since a Surface object has no position. The position of the rectangle can be specified by a keyword argument. For example, the centre of the rectangle can be specified with the keyword argument center
. These keyword arguments are applied to the attributes of the pygame.Rect
before it is returned (see pygame.Rect
for a list of the keyword arguments).
See *Why is my collision test always returning 'true' and why is the position of the rectangle of the image always wrong (0, 0)?
You do not need the x
and y
attributes of Sprite
and Bullet
at all. Use the position of the rect
attribute instead:
#Define the sprite class
class Sprite:
def __init__(self, x, y, name):
self.image = pygame.image.load(name)
self.rect = self.image.get_rect(topleft = (x, y))
def render(self):
window.blit(self.image, self.rect)
# Define the bullet class to create bullets
class Bullet:
def __init__(self, x, y):
self.bullet = pygame.image.load("user_bullet.BMP")
self.rect = self.bullet.get_rect(topleft = (x + 23, y))
def render(self):
window.blit(self.bullet, self.rect)
Use pygame.Rect.colliderect()
to detect collisions between instances of Sprite
and Bullet
.
See How to detect collisions between two rectangular objects or images in pygame:
my_sprite = Sprite(sx, sy, name)
my_bullet = Bullet(by, by)
while True:
# [...]
if my_sprite.rect.colliderect(my_bullet.rect):
printe("hit")