Player Jump Sample

playerJump.py

import pygame

"""
    Solution for reddit user found at:
    https://www.reddit.com/r/pygame/comments/3uw9ja/player_jumps_but_cannot_be_seen_going_upwards/
"""

pygame.init()
HEIGHT = 360
WIDTH = 480
screen = pygame.display.set_mode((WIDTH, HEIGHT))
GROUND = HEIGHT - 100
BLOCK_DIM = 50


class Block:

    def __init__(self, x, y):
        self.image = pygame.Surface((50,50))
        self.image.fill((128,0,0))
        self.rect = self.image.get_rect()
        self.rect.x = x
        self.rect.y = y
        self.speedx = 0
        self.speedy = 0
        self.gravity = 3.5
        self.jumpvel = 35
        
    def update(self):
        self.speedx = 0
        # self.speedy = 0  #THE LINE WITH THE PROBLEM
        self.onGround = True

        keystate = pygame.key.get_pressed()

        if self.rect.y < GROUND - BLOCK_DIM:
            self.speedy += self.gravity
            self.onGround = False
        elif self.rect.y >= GROUND - BLOCK_DIM:
            self.speedy = 0
            self.onGround = True

        if keystate[pygame.K_LEFT]:
            self.speedx = -5
        if keystate[pygame.K_RIGHT]:
            self.speedx = 5
        if keystate[pygame.K_UP]:
            self.jump()
        self.rect.x += self.speedx
        self.rect.y += self.speedy

    def jump(self):
        if self.onGround == False:
            return
        if self.onGround == True:
            self.speedy -= self.jumpvel


def main():
    
    block = Block(40, GROUND - BLOCK_DIM)
    clock = pygame.time.Clock()
    while True:
        clock.tick(50)
        e = pygame.event.poll()
        if e.type == pygame.QUIT:
            break
        elif e.type == pygame.KEYUP and e.key in [pygame.K_q, pygame.K_ESCAPE]:
            break
    
        screen.fill((255,255,255))
        block.update()
        screen.blit(block.image, block.rect)
        pygame.display.flip()
    pygame.quit()

if __name__ == '__main__':
    main()