我的角色不会在python中移动

Question

This is the code I used.

import pygame, sys

from pygame.locals import *

pygame.init()

def game():

width, height = 1000, 600
screen = pygame.display.set_mode((width,height))
pygame.display.set_caption('My game far now :P') #This command allows you make a title.
background=pygame.image.load('AE.jpg')
background = pygame.transform.scale(background, (width,height))
screen.blit(background, (0,0))

#Load target image and player



player = pygame.image.load('little.png')
player = pygame.transform.scale(player, (40,40))
px,py = width/2,height/2
screen.blit(player, (px,py))

movex = movey = 0

#Running of the game loop

while True:
    screen.blit(background, (0,0))
    #screen.blit(target,targetpos)
    screen.blit(player, (px,py))
    pygame.display.update()


    #keyboard an/or mouse movements
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()


        elif event.type == pygame.KEYDOWN:
            if event.key == K_RIGHT:
                movex = 2
            if event.key == K_LEFT:
                movex = -2
            if event.key == K_UP:
                movey = -2
            if event.key == K_DOWN:
                movey = 2

        elif event.type == pygame.KEYUP:
            if event.key == K_RIGHT:
                movex = 0
            if event.key == K_LEFT:
                movex = 0
            if event.key == K_UP:
                movey = 0
            if event.key == K_DOWN:
                movey = 0

                px = px + movex
                py = py + movey




#Python 's way of running the main routine

if __name__=='__main__':
   game()

When I run the program it all starts right, the screen opens with background and player spawning in the middle of the screen, but when I try to move nothing happends, no errors nothing.

Would apriciate any help I can get :)

Thx for taking time to help me.

Answer 1

You seem to have code indentation problem in last two lines which may be causing the bug.

Your curent code is equivalent to this if code block:

    elif event.type == pygame.KEYUP:
        if event.key == K_RIGHT:
            movex = 0
        if event.key == K_LEFT:
            movex = 0
        if event.key == K_UP:
            movey = 0
        if event.key == K_DOWN # IF BLOCK STARTS
            movey = 0

            px = px + movex  # THIS FALLS IN THE PREVIOUS IF BLOCK
            py = py + movey

Correct code would be :

  elif event.type == pygame.KEYUP:
        if event.key == K_RIGHT:
            movex = 0
        if event.key == K_LEFT:
            movex = 0
        if event.key == K_UP:
            movey = 0
        if event.key == K_DOWN # IF BLOCK STARTS
            movey = 0          #IF BLOCK ENDS

  px = px + movex  # NOW THIS IS OUT OF THE IF BLOCK
  py = py + movey

Answer 2

Two problems.

1. You don't render in your loop
2. You are updating the location only in the if statement.

fixed:

while True:
    # input    
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()

        elif event.type == pygame.KEYDOWN:
            # ...snip...

    # physics
    px += movex
    py += movey

    # drawing

    screen.blit(background, (0,0))
    screen.blit(player, (px,py))
    pygame.display.update()

Answer 3

Take this code, the movement is optimized. Useles code removed. I hope you understand it ;)

import pygame, sys
from pygame.locals import *

pygame.init()
width, height = 1000, 600
screen = pygame.display.set_mode((width,height))
pygame.display.set_caption('My game far now :P')
background=pygame.image.load('AE.png')
background = pygame.transform.scale(background, (width,height))
player = pygame.image.load('little.png')
player = pygame.transform.scale(player, (40,40))
px,py = width/2,height/2
movex = movey = 0

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

    keys = pygame.key.get_pressed()
    if keys[pygame.K_LEFT]: px -= 2
    if keys[pygame.K_RIGHT]: px += 2
    if keys[pygame.K_UP]: py -= 2
    if keys[pygame.K_DOWN]: py += 2

    screen.blit(background, (0,0))    
    screen.blit(player, (px,py))
    pygame.display.update()