How to make a grid in pygame

Question

I am trying to create a basic snake game with Python and I am not familiar with Pygame. I have created a window and I am trying to split that window up into a grid based on the size of the window and a set square size.

def get_initial_snake( snake_length, width, height, block_size ):
    window = pygame.display.set_mode((width,height))
    background_colour = (0,0,0)
    window.fill(background_colour)

    return snake_list

What should I add inside window.fill function to create a grid based on width, height, and block_size? Any info would be helpful.

Answer 1

You can draw rectangles

for y in range(height):
    for x in range(width):
        rect = pygame.Rect(x*block_size, y*block_size, block_size, block_size)
        pygame.draw.rect(window, color, rect)

I assumed that the height and width is the number of blocks.

---

if you need one pixel gap between rectangles then use

rect = pygame.Rect(x*(block_size+1), y*(block_size+1), block_size, block_size)

---

To draw snake you can use list and head_color, tail_color

snake = [(0,0), (0,1), (1,1), (1,2), (1,3)]

# head

x, y = snake[0]
rect = pygame.Rect(x*block_size, y*block_size, block_size, block_size)
pygame.draw.rect(window, head_color, rect)

# tail

for x, y in snake[1:]:
    rect = pygame.Rect(x*block_size, y*block_size, block_size, block_size)
    pygame.draw.rect(window, tail_color, rect)

Answer 2

Using the for loop as a reference from the answer: https://stackoverflow.com/a/33963521/9715289

This is what I did when I was trying to make a snake game.

BLACK = (0, 0, 0)
WHITE = (200, 200, 200)
WINDOW_HEIGHT = 400
WINDOW_WIDTH = 400


def main():
    global SCREEN, CLOCK
    pygame.init()
    SCREEN = pygame.display.set_mode((WINDOW_WIDTH, WINDOW_HEIGHT))
    CLOCK = pygame.time.Clock()
    SCREEN.fill(BLACK)

    while True:
        drawGrid()
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                sys.exit()

        pygame.display.update()


def drawGrid():
    blockSize = 20 #Set the size of the grid block
    for x in range(0, WINDOW_WIDTH, blockSize):
        for y in range(0, WINDOW_HEIGHT, blockSize):
            rect = pygame.Rect(x, y, blockSize, blockSize)
            pygame.draw.rect(SCREEN, WHITE, rect, 1)

How the result looks like: