Character moves slowly when grid is displayed in pygame

问题

I am making a snake game in pygame and I noticed a wierd thing. Whenever I am displaying a grid my character runs slowly.
Here is the main function of my program.
I have just started learning pygame!

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

    x = 0
    y = 0
    velocity = 20
    x_change = 0
    y_change = 0

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

            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_UP:
                    y_change = -velocity
                    x_change = 0
                if event.key == pygame.K_DOWN:
                    y_change = velocity
                    x_change = 0
                if event.key == pygame.K_LEFT:
                    x_change = -velocity
                    y_change = 0
                if event.key == pygame.K_RIGHT:
                    x_change = velocity
                    y_change = 0

        x += x_change
        y += y_change

        snake(x, y)
        pygame.display.update()
        SCREEN.fill(BLACK)
        CLOCK.tick(60)

def snake(x, y):
    head_rect = pygame.Rect(x, y, BLOCKSIZE, BLOCKSIZE)
    pygame.draw.rect(SCREEN, GREEN, head_rect)


def drawGrid():
    for x in range(WINDOW_WIDTH):
        for y in range(WINDOW_HEIGHT):
            rect = pygame.Rect(x*BLOCKSIZE, y*BLOCKSIZE,
                               BLOCKSIZE, BLOCKSIZE)
            pygame.draw.rect(SCREEN, WHITE, rect, 1)

Here are images for sample

回答1:

I don't think so there is any issue with re-drawing. The number of items being re-drawn is less.

I can see a possible bug in the draw function. You are drawing a box for each pixel. Try doing the following instead (divide the WINDOW_WIDTH with BLOCKSIZE):

def drawGrid():
    for x in range(WINDOW_WIDTH // BLOCKSIZE):
        for y in range(WINDOW_HEIGHT // BLOCKSIZE):
            rect = pygame.Rect(x*BLOCKSIZE, y*BLOCKSIZE,
                               BLOCKSIZE, BLOCKSIZE)
            pygame.draw.rect(SCREEN, WHITE, rect, 1)

来源：https://stackoverflow.com/questions/61061963/character-moves-slowly-when-grid-is-displayed-in-pygame

标签

python

pygame