pygame.mouse.get_pos（）没有更新

Question

So I'm trying to make this button change color when I hover over it, but pygame.mouse.get_pos() is not updating after I open the program.

I'm a novice to both python and program so any assistance would be a appreciated greatly.

import pygame

pygame.init()

gameDisplay = pygame.display.set_mode((800,600))
pygame.display.set_caption('Click to Adventure')
clock = pygame.time.Clock()

black = (0,0,0)
white = (255,255,255)
red = (255,0,0)
green = (0,255,0)

gameDisplay.fill(white)


def text_objects(text, font):
    textSurface = font.render(text, True, black)
    return textSurface, textSurface.get_rect()

def button(msg,x,y,w,h,ic,ac,action=None):
    mouse = pygame.mouse.get_pos()
    click = pygame.mouse.get_pressed()
    ycrd = int((y+(h/2)))
    r = int(h/2)
    print(mouse)
    if x+(w+(h/2)) > mouse[0] > x-(h/2) and y+h > mouse[1] > y:
        pygame.draw.rect(gameDisplay,ac,(x,y,w,h))
        pygame.draw.circle(gameDisplay,ac,(x,ycrd),r,0)
        pygame.draw.circle(gameDisplay,ac,(x+w,ycrd),r,0)
        if click[0] == 1 and action != None:
            action()    
    else:
        pygame.draw.rect(gameDisplay,ic,(x,y,w,h))
        pygame.draw.circle(gameDisplay,ic,(x,ycrd),r,0)
        pygame.draw.circle(gameDisplay,ic,(x+w,ycrd),r,0)
        smallText = pygame.font.SysFont("comicsansms",20)
        textSurf, textRect = text_objects(msg, smallText)
        textRect.center = ((x+(w/2)),(y+(h/2)))
        gameDisplay.blit(textSurf, textRect)

button("Hi",300,200,100,50,red,green,None)

gameExit = False

while not gameExit:

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            quit()

        #print(event)

    pygame.display.update()
    clock.tick(60)


pygame.quit()
quit()

I'm not really sure why pygame.mouse.get_pos() isn't updating as I have both pygame.time.Clock() and clock.tick(60).

Answer 1

I'm not a pygame expert myself but what i can see is that you're calling the button() function only once when the game is starting. You need to make a function that will be called in every frame which will wait for an event to happen, in your case, changing the button's color. Make a normal button on the screen. Then, make a function which will be called when the mouse is on top of the button and change color. Something like,

Button = MakeButton(); #This function will create a button and show on the screen

In while not gameExit:

if Button.get_rect().collidepoint(pygame.mouse.get_pos()): #This line will wait for the mouse to hover over the button
    ChangeButtonColor(); #This function will change the button color

These are pseudo codes to get you started.

Answer 2

pygame uses the "update/draw loop" pattern, commonly found in game development frameworks. This pattern consists of a loop that is mostly non-terminating, and you have it in your code as while not gameExit: . Inside this loop, you must handle all of the user input, through the usage of event flags. For example, your code deals with the QUIT event.

However, your button code is not particularly tailored for this pattern. Instead, it hopes to create a "button" as some sort of static object on the screen, like event-based GUIs.

First, you should separate the update step and the draw step. The update changes the game state, and the draw step simply checks the state and draw things on screen. In your case, the update step should check if the mouse is over the button or not, and define which color is used.

Let's do that separation:

# to be used in the draw step
def draw_button(msg, x, y, width, height, color):
    ycrd = int((y + (h / 2)))
    r = int(h / 2)
    pygame.draw.rect(gameDisplay, color, (x, y, width, height))
    pygame.draw.circle(gameDisplay, color, (x, ycrd), r, 0)
    pygame.draw.circle(gameDisplay, color, (x + w, ycrd), r, 0)
    smallText = pygame.font.SysFont("comicsansms",20)
    textSurf, textRect = text_objects(msg, smallText)
    textRect.center = ((x + (w / 2)), (y + (h / 2)))

# to be used in the update step
def check_mouse_state_over_box(x, y, width, height):
    # I'm returning strings here, but you should use something else like an enum
    mouse = pygame.mouse.get_pos()
    click = pygame.mouse.get_pressed()
    if x + (w + (h / 2)) > mouse[0] > x - (h / 2) and y + h > mouse[1] > y:
       if click[0] == 1:
           return 'click'
       else:
           return 'hover'
    else:
       return 'no-relation'

Now that the button() function separates the update and draw steps, you can properly use it in the game loop:

while not game_exit:
    # UPDATE STEP
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            quit() # this function is undefined it seems?
        # you can also use 'elif event.type == pygame.MOUSEMOTION:' if you wish, but then the logic is a bit different

     button_state = check_mouse_over_box(300, 200, 100, 50)
     if button_state = 'no-relation':
         button_color = red
     else:
         button_color = green
     if button_state = 'click':
         action() # define whatever action you want

     # DRAW STEP
     draw_button('Hi', 300, 200, 100, 50, button_color)
     gameDisplay.blit() # I think this is mandatory in pygame

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Now, this should work. But if you know object-oriented programming (OOP), you could define a class Button that holds its position and color, an update method that checks the mouse and change the button state properly, and a draw method that draws the button. If you don't know OOP, this is a great opportunity to learn it :)