How to generate the food for a snake game - python-3.x

Question

I can not figure out how to generate the food for the snake to eat. I know the position of the snake at line 97 and 98, I have created a class to generate a pixel where I want to draw a peace of food at line 22 (EDIT: should probably be a function, commented #def (?) in the code). All I have to do is add 15 pixels at the x and y coordinates from the position that is randomly allocated and print it to get a block.
The problem is to check if I eat it or not. It should be something like:
if x >= x_food && x <= x_food + 15 || y >= y_food && y <= y_food + 15:
...add a point and make snake longer...
The problem is putting it all together for some reason.. Can some one give me a hint or solve how I should write this class so I can continue with other problems? Thank you!
import pygame
import random
#Global variables
#Color
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
#Start length of snake
snake_length = 3
#Set the width of the segments of the snake
segment_width = 15
segment_height = 15
# Margin within each segment
segment_margin = 3
#Set initial speed
x_change = segment_width + segment_margin
y_change = 0
#def (?)
class Food():
#Class to print food
x_food = random.randint(0, 785)
y_food = random.randint(0, 585)
class Segment(pygame.sprite.Sprite):
""" Class to represent the segment of the snake. """
# Methods
# Constructer function
def __init__(self, x, y):
#Call the parents constructor
super().__init__()
#Set height, width
self.image = pygame.Surface([segment_width, segment_height])
self.image.fill(WHITE)
#Make our top-left corner the passed-in location.
self.rect = self.image.get_rect()
self.rect.x = x
self.rect.y = y
#Call this function so the Pygame library can initialize itself
pygame.init()
#Create an 800x600 size screen
screen = pygame.display.set_mode([800, 600])
#Set the title of the window
pygame.display.set_caption("Snake")
allspriteslist = pygame.sprite.Group()
#Create an initial snake
snake_segments = []
for i in range(snake_length):
x = 250 - (segment_width + segment_margin) * i
y = 30
segment = Segment(x, y)
snake_segments.append(segment)
allspriteslist.add(segment)
clock = pygame.time.Clock()
done = False
while not done:
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
#Set the speed based on the key pressed
#We want the speed to be enough that we move a full
#Segment, plus the margin
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_LEFT:
x_change = (segment_width + segment_margin) * -1
y_change = 0
if event.key == pygame.K_RIGHT:
x_change = (segment_width + segment_margin)
y_change = 0
if event.key == pygame.K_UP:
x_change = 0
y_change = (segment_height + segment_margin) * -1
if event.key == pygame.K_DOWN:
x_change = 0
y_change = (segment_width + segment_margin)
#Get rid of last segment of the snake
#.pop() command removes last item in list
old_segment = snake_segments.pop()
allspriteslist.remove(old_segment)
#Figure out where new segment will be
x = snake_segments[0].rect.x + x_change
y = snake_segments[0].rect.y + y_change
segment = Segment(x, y)
#Insert new segment to the list
snake_segments.insert(0, segment)
allspriteslist.add(segment)
#Draw
#Clear screen
screen.fill(BLACK)
allspriteslist.draw(screen)
#Flip screen
pygame.display.flip()
#Pause
clock.tick(5)
pygame.quit()

Answer 1

i took your code and i think i work something out, pls note that this only monitors when the snake goes over the block, then it prints: yummy, so you will have to add the detail, also note that i dont use your class to generate the food:
import pygame
import random
#Global variables
#Color
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
#Start length of snake
snake_length = 3
#Set the width of the segments of the snake
segment_width = 15
segment_height = 15
# Margin within each segment
segment_margin = 3
#Set initial speed
x_change = segment_width + segment_margin
y_change = 0
#def (?)
class Food():
#Class to print food
x_food = random.randint(0, 785)
y_food = random.randint(0, 585)
class Segment(pygame.sprite.Sprite):
""" Class to represent the segment of the snake. """
# Methods
# Constructer function
def __init__(self, x, y):
#Call the parents constructor
super().__init__()
#Set height, width
self.image = pygame.Surface([segment_width, segment_height])
self.image.fill(WHITE)
#Make our top-left corner the passed-in location.
self.rect = self.image.get_rect()
self.rect.x = x
self.rect.y = y
#Call this function so the Pygame library can initialize itself
pygame.init()
#Create an 800x600 size screen
screen = pygame.display.set_mode([800, 600])
#Set the title of the window
pygame.display.set_caption("Snake")
allspriteslist = pygame.sprite.Group()
#Create an initial snake
snake_segments = []
for i in range(snake_length):
x = 250 - (segment_width + segment_margin) * i
y = 30
segment = Segment(x, y)
snake_segments.append(segment)
allspriteslist.add(segment)
clock = pygame.time.Clock()
done = False
x_food = random.randint(0, 785)
y_food = random.randint(0, 585)
while not done:
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
#Set the speed based on the key pressed
#We want the speed to be enough that we move a full
#Segment, plus the margin
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_LEFT:
x_change = (segment_width + segment_margin) * -1
y_change = 0
if event.key == pygame.K_RIGHT:
x_change = (segment_width + segment_margin)
y_change = 0
if event.key == pygame.K_UP:
x_change = 0
y_change = (segment_height + segment_margin) * -1
if event.key == pygame.K_DOWN:
x_change = 0
y_change = (segment_width + segment_margin)
if y < y_food+30:
if x > x_food and x < x_food+30 or x+20 > x_food and x+20<x_food+30:
print('yummy')
#Get rid of last segment of the snake
#.pop() command removes last item in list
old_segment = snake_segments.pop()
allspriteslist.remove(old_segment)
#Figure out where new segment will be
x = snake_segments[0].rect.x + x_change
y = snake_segments[0].rect.y + y_change
segment = Segment(x, y)
#Insert new segment to the list
snake_segments.insert(0, segment)
allspriteslist.add(segment)
#Draw
#Clear screen
screen.fill(BLACK)
pygame.draw.rect(screen, WHITE, [x_food, y_food, 30, 30])
allspriteslist.draw(screen)
#Flip screen
pygame.display.flip()
#Pause
clock.tick(5)
pygame.quit()
hope this helped, thanks!

Answer 2

if x >= x_food && x <= x_food + 15 || y >= y_food && y <= y_food + 15:
Why do you OR these pairs of conditions? Don't all 4 tests have to be true at the same time?
if x >= x_food && x <= x_food + 15 && y >= y_food && y <= y_food + 15:

Answer 3

how about using:
if snake_headx == foodx and snake_heady == foody:
food_eated()
snake_grow()
just a suggestion though
didnt read all ur code, just thought u might find it usefull.
actuely ive came to a solution, so basicly what you want is a square, and when the snake comes near that square something should happen?, well ive got a racegame that makes you crash when you hit a square car, so il just copy the code here:
if y < thing_starty+thing_height:
if x > thing_startx and x < thing_startx+thing_width or x+car_width > thing_startx and x+car_width<thing_startx+thing_width:
snake_eated()
snake_grow()
this monitors the x and y of your car (or snake) and checks when the thing (or food) 's y is smaller than your car, then it checks the x's and alot of other things, and basicly it creates a big line all around your square that you cannot cross in your case you'd just need to add the rest, would this work?

Answer 4

Make your food a sprite with a simple filled rectangle as the image, and then use sprite collision pygame.sprite.spritecollide() to check if your snake collides with your food. Pygame will take care of the actual logic whether two rectangles overlap for you.
Also, since you are already using sprite groups, I suggest you write an update function for your snake segments which moves them instead of creating a new segment every turn. Then you can simply call allspriteslist.update() in your main game loop, which will call the update function for every snake segment.
Finally, you might want to have a look at the numerous snake examples on the pygame website.