I tried adding gravity to my player in pygame, but I can move the player with key controls but gravity is not working, Here I used sprite class for making this. I got the rect of the image then add the x momentum and y momentum. X momentum worked while moving the player but y momentum didn't work while adding the gravity. Please help!
# Platformer
import pygame
# Basic Setup
pygame.init()
clock = pygame.time.Clock()
# Game Colors
white = (255, 255, 255)
light_blue = (105, 142, 255)
# Game Settings
game_title = "Platformer!"
screen_width = 1280
screen_height = 750
fps = 120
player_speed = 4
player_gravity = 0.2
# Main Window
screen = pygame.display.set_mode((screen_width, screen_height))
pygame.display.set_caption(game_title)
class Player(pygame.sprite.Sprite):
def __init__(self):
super().__init__()
self.image = pygame.image.load("IMGs/player.png")
self.image.set_colorkey(white)
self.rect = self.image.get_rect(center=(screen_width / 2, screen_height / 2))
self.x_momentum = 0
self.y_momentum = 0
self.moving_right = False
self.moving_left = False
def move(self):
# Set the movement to zero at first
self.x_momentum = 0
self.y_momentum = 0
# Move the player on key press
if self.moving_right:
self.x_momentum += player_speed
elif self.moving_left:
self.x_momentum -= player_speed
# Add Gravity
self.y_momentum += player_gravity
# Move the player
self.rect.x += self.x_momentum
self.rect.y += self.y_momentum
def update(self):
self.move()
class Main:
def __init__(self):
# Sprites
self.all_sprites = pygame.sprite.Group()
# Player Sprite
self.player = Player()
self.all_sprites.add(self.player)
def draw(self, surface):
self.all_sprites.draw(surface)
def update(self):
self.all_sprites.update()
main_game = Main()
def main_game_loop():
while True:
# Handling Inputs
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
exit(0)
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_RIGHT or event.key == pygame.K_d:
main_game.player.moving_right = True
elif event.key == pygame.K_LEFT or event.key == pygame.K_a:
main_game.player.moving_left = True
if event.type == pygame.KEYUP:
if event.key == pygame.K_RIGHT or event.key == pygame.K_d:
main_game.player.moving_right = False
elif event.key == pygame.K_LEFT or event.key == pygame.K_a:
main_game.player.moving_left = False
# Draw / Render
screen.fill(light_blue)
main_game.draw(screen)
main_game.update()
pygame.display.update()
# Manage Speed
clock.tick(fps)
main_game_loop()
The gravity doesn't work because self.y_momentum is set 0 at the begin of Player.move:
class Player(pygame.sprite.Sprite): # [...] def move(self): # Set the movement to zero at first self.x_momentum = 0 self.y_momentum = 0 # [...]
Since pygame.Rect is supposed to represent an area on the screen, a pygame.Rect object can only store integral data.
The coordinates for Rect objects are all integers. [...]
The fraction part of the coordinates gets lost when the position stored in the Rect object is decremented:
# Move the player self.rect.x += self.x_momentum self.rect.y += self.y_momentum
If you want to store object positions with floating point accuracy, you have to store the location of the object in separate variables respectively attributes and to synchronize the pygame.Rect object. round the coordinates and assign it to the location (e.g. .topleft) of the rectangle:
class Player(pygame.sprite.Sprite):
def __init__(self):
# [...]
self.x = screen_width // 2
self.y = screen_height // 2
self.rect = self.image.get_rect(center = (self.x, self.y))
# [...]
def move(self):
# [...]
# Move the player
self.x += self.x_momentum
self.y += self.y_momentum
self.rect.topleft = round(self.x), round(self.y)