Pygame精灵援助

我基本上刚刚开始使用PyGame进行开发，而我在使用整个Sprite概念时遇到了麻烦 . 我一直在寻找关于如何使用它的指南，我似乎无法找到任何 . 我想知道一切如何运作的基本概念 . 这是我一直在研究的代码：

#!/usr/bin/python

import pygame, sys
from pygame.locals import *

size = width, height = 320, 320
clock = pygame.time.Clock()

xDirection = 0
yDirection = 0
xPosition = 32
yPosition = 256

blockAmount = width/32

pygame.init()
screen = pygame.display.set_mode(size)
screen.fill([0, 155, 255])
pygame.display.set_caption("Mario Test")
background = pygame.Surface(screen.get_size())

mainCharacter = pygame.sprite.Sprite()
mainCharacter.image = pygame.image.load("data/character.png").convert()
mainCharacter.rect = mainCharacter.image.get_rect()
mainCharacter.rect.topleft = [xPosition, yPosition]
screen.blit(mainCharacter.image, mainCharacter.rect)

grass = pygame.sprite.Sprite()
grass.image = pygame.image.load("data/grass.png").convert()
grass.rect = grass.image.get_rect()
for i in range(blockAmount):
    blockX = i * 32
    blockY = 288
    grass.rect.topleft = [blockX, blockY]
    screen.blit(grass.image, grass.rect)

grass.rect.topleft = [64, 256]  
screen.blit(grass.image, grass.rect.topleft )

running = False
jumping = False 
falling = False
standing = True

jumpvel = 22
gravity = -1

while True:

    for event in pygame.event.get():
        if event.type == KEYDOWN and event.key == K_ESCAPE:
            pygame.quit()
            sys.exit()
        elif event.type == QUIT:
            pygame.quit()
            sys.exit()
        if event.type == KEYDOWN:
            if event.key == K_LEFT:
                running = True
                xRun = -5
            elif event.key == K_RIGHT:
                running = True
                xRun = 5
            elif event.key == K_UP or event.key == K_SPACE:
                jumping = True
        elif event.type == KEYUP:
            if event.key == K_LEFT or event.key == K_RIGHT:
                running = False


    if running == True:
        xPosition += xRun

    if mainCharacter.rect.right >= width:
        xPosition = xPosition - 10
        print "hit"
        running = False
    elif mainCharacter.rect.left <= 0:
        xPosition = xPosition + 10
        print "hit"
        running = False

    screen.fill([0, 155, 255])

    for i in range(blockAmount):
        blockX = i * 32
        blockY = 288
        grass.rect.topleft = [blockX, blockY]
        screen.blit(grass.image, grass.rect)

    grass.rect.topleft = [64, 64]   
    screen.blit(grass.image, grass.rect.topleft )


    if jumping:
        yPosition -= jumpvel
        print jumpvel
        jumpvel += gravity
        if jumpvel < -22:
            jumping = False
        if mainCharacter.rect.bottom == grass.rect.top:
            jumping = False

    if not jumping:
        jumpvel = 22


    mainCharacter.rect.topleft = [xPosition, yPosition]
    screen.blit(mainCharacter.image,mainCharacter.rect)

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

基本上我只是想知道如何将这些草块变成一组中的精灵，这样当我添加我的玩家（也是一个精灵）时，我可以通过碰撞系统确定他是否在空中 . 有人可以向我解释我将如何做到这一点 . 我正在寻找的所有内容基本上都是一个启动，因为我认为有些文档非常糟糕，因为它并没有完全告诉你如何使用它 . 任何帮助是极大的赞赏 ：）