I am creating Snake game in pygame using Sprite logic
how do i chain the movement of the snake? another question on this has been answered here but i cant apply it to my code: see here
the minimal example above works. try it first and you will see my issue :) the snake grows on collision with the red food… but its movement does not chain
thank you
import pygame
from random import randint
from sys import exit
pygame.init()
game_active = True #start the game on the Welcome Screen
clock = pygame.time.Clock() #an object to track time, for fps
def display_surface():
"""function to create the main window"""
disp_surface = pygame.display.set_mode(size = (610, 700)) #creates a main display window
pygame.display.set_caption("Snake")
return disp_surface
disp_surface = display_surface() #MUST return this immediately so it can be pushed to pygame.display.update()
class snake(pygame.sprite.Sprite):
def __init__(self, x_pos = 300, y_pos = 300):
#Access the super class of Sprite
super().__init__()
image1 = pygame.image.load("square1.png").convert_alpha()
self.x_pos = x_pos
self.y_pos = y_pos
self.image = image1
self.rect = self.image.get_rect(x = x_pos, y = y_pos)
def update(self, left, right, up, down):
"""defines the movement of the snake using arrow keys"""
if left:
self.rect.left -= 1
if right:
self.rect.right += 1
if up:
self.rect.top -= 1
if down:
self.rect.bottom += 1
snakegroup = pygame.sprite.Group()
original_snake = snake()
snakegroup.add(original_snake)
class food(pygame.sprite.Sprite):
"""class to control food action"""
def __init__(self):
super().__init__() #access the Sprite super class methods
food1 = pygame.image.load("food1.png").convert_alpha()
x_pos = randint(50,600)
y_pos = randint(50,650)
self.image = food1
self.rect = self.image.get_rect(x = x_pos,y = y_pos)
foods = pygame.sprite.GroupSingle()
foods.add(food())
multiplier_x_pos = 1
while True:
"""EVENT LOOP CODE"""
for eachevent in pygame.event.get():
if eachevent.type == pygame.QUIT:
pygame.quit()
exit()
game_active = True
if pygame.sprite.spritecollideany(foods.sprite, snakegroup):
foods.empty()
foods.add(food())
foods.draw(disp_surface)
snakegroup.add(snake(original_snake.rect.x-(25*multiplier_x_pos),original_snake.rect.y))
multiplier_x_pos += 1
snakegroup.update(left, right, up, down)
keys = pygame.key.get_pressed()
events = pygame.event.get()
left = keys[pygame.K_LEFT]
right = keys[pygame.K_RIGHT]
up = keys[pygame.K_UP]
down = keys[pygame.K_DOWN]
snakegroup.update(left,right,up,down)
"""PYGAME EVENT CODE"""
if game_active:
disp_surface = display_surface()
snakegroup.draw(disp_surface)
foods.draw(disp_surface)
else:
disp_surface.fill((64,64,64))
pygame.display.update() #update all the surfaces on each frame
clock.tick(120) #fps
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Answer
See the answer referenced in your question How do I chain the movement of a snake’s body?.
You need to use the 2nd solution and adjust the function that creates the snake body. The new function needs to update the positions of the Snakes body Sprites:
def update_body(track, distance):
body = snakegroup.sprites()
no_parts = len(body)
body[0].update(*track[0])
track_i = 1
next_i = 1
for i in range(1, no_parts):
while track_i < len(track):
pos = track[track_i]
track_i += 1
dx, dy = body[i-1].x_pos-pos[0], body[i-1].y_pos-pos[1]
if math.sqrt(dx*dx + dy*dy) >= distance:
body[i].update(*pos)
next_i = i+1
break
while next_i < no_parts:
body[next_i].update(*track[-1])
next_i += 1
del track[track_i:]
return body
Example based on your (revised) code:
import pygame
import math
from random import randint
from sys import exit
pygame.init()
clock = pygame.time.Clock()
disp_surface = pygame.display.set_mode(size = (610, 700))
class Snake(pygame.sprite.Sprite):
def __init__(self, x_pos = 300, y_pos = 300):
#Access the super class of Sprite
super().__init__()
#self.image = pygame.image.load("square1.png").convert_alpha()
self.image = pygame.Surface((20, 20), pygame.SRCALPHA)
pygame.draw.circle(self.image, (0, 255, 0), (10, 10), 10)
self.x_pos = x_pos
self.y_pos = y_pos
self.rect = self.image.get_rect(x = x_pos, y = y_pos)
def update(self, x_pos, y_pos):
self.x_pos = x_pos
self.y_pos = y_pos
self.rect = self.image.get_rect(center = (x_pos, y_pos))
class Food(pygame.sprite.Sprite):
"""class to control food action"""
def __init__(self):
super().__init__() #access the Sprite super class methods
#self.image = pygame.image.load("food1.png").convert_alpha()
self.image = pygame.Surface((20, 20), pygame.SRCALPHA)
pygame.draw.circle(self.image, (255, 0, 0), (10, 10), 10)
x_pos = randint(50,600)
y_pos = randint(50,650)
self.rect = self.image.get_rect(x = x_pos,y = y_pos)
def update(self, pos):
x_pos = randint(50,600)
y_pos = randint(50,650)
self.rect = self.image.get_rect(x = x_pos,y = y_pos)
def update_body(track, distance):
body = snakegroup.sprites()
no_parts = len(body)
body[0].update(*track[0])
track_i = 1
next_i = 1
for i in range(1, no_parts):
while track_i < len(track):
pos = track[track_i]
track_i += 1
dx, dy = body[i-1].x_pos-pos[0], body[i-1].y_pos-pos[1]
if math.sqrt(dx*dx + dy*dy) >= distance:
body[i].update(*pos)
next_i = i+1
break
while next_i < no_parts:
body[next_i].update(*track[-1])
next_i += 1
del track[track_i:]
return body
snakegroup = pygame.sprite.Group()
original_snake = Snake()
snakegroup.add(original_snake)
track = [(original_snake.x_pos, original_snake.y_pos)]
foods = pygame.sprite.GroupSingle()
foods.add(Food())
direction = (0, 0)
speed = 1
run = True
while run:
for eachevent in pygame.event.get():
if eachevent.type == pygame.QUIT:
run = False
if eachevent.type == pygame.KEYDOWN:
if eachevent.key == pygame.K_LEFT and direction[0] != 1:
direction = (-1, 0)
if eachevent.key == pygame.K_RIGHT and direction[0] != -1:
direction = (1, 0)
if eachevent.key == pygame.K_UP and direction[1] != 1:
direction = (0, -1)
if eachevent.key == pygame.K_DOWN and direction[1] != -1:
direction = (0, 1)
track.insert(0, track[0][:])
track[0] = (track[0][0] + direction[0] * speed) % disp_surface.get_width(), (track[0][1] + direction[1] * speed) % disp_surface.get_height()
update_body(track, 20)
if pygame.sprite.spritecollideany(foods.sprite, snakegroup):
foods.empty()
foods.add(Food())
last_part = snakegroup.sprites()[-1]
snakegroup.add(Snake(last_part.x_pos, last_part.y_pos))
speed = min(10, speed + 1)
disp_surface.fill((64,64,64))
snakegroup.draw(disp_surface)
foods.draw(disp_surface)
pygame.display.update()
clock.tick(120)