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I cannot add gravity to my player in pygame [duplicate]

This question already has answers here:
Pygame doesn't let me use float for rect.move, but I need it
(2 answers)
Closed 2 years ago.
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)

OOP Pygame platform game: controlling and moving a square on a screen

import pygame
import random
import math
import sys
screenWidth = 1200
screenHeight = 600
class Hero:
def __init__(self, pos):
self.pos = pos
self.width = 30
self.height = 30
self.color = (0, 0, 0)
self.dirX = 0
self.dirY = 0
def move(self):
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
sys.exit()
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_RIGHT:
self.dirX = 1
elif event.key == pygame.K_LEFT:
self.dirX = -1
def draw(self, display):
x = self.pos[0]
y = self.pos[1]
pygame.draw.rect(display, self.color, (x + self.dirX, y + self.dirY, self.width, self.height))
print(self.pos, self.dirX, self.dirY)
def jump(self):
pass
def die(self):
pass
class Enemy:
pass
class Background:
pass
class Obstacles:
pass
class Camera:
pass
def score():
pass
def create(w, h):
display = pygame.display.set_mode((w, h))
display.fill((255, 255, 255))
#create background
#create Obstacles
#create Hero
heroOne = Hero([150, 450])
heroOne.move()
heroOne.draw(display)
#create Enemy
pygame.display.update()
def main():
pygame.init()
clock = pygame.time.Clock()
running = True
while running:
clock.tick(300)
create(screenWidth, screenHeight)
main()
Hi, I am making an OOP Game using Pygame in which a square would be controlled by the user and move along a floor, jump over obstacles and other enemy squares.
The way I want it to work:
When I press K_LEFT, dirX = 1 it will add to the x-coordinate of the pos and hence the x-position of the square will be updated and the square will begin to slide towards the right. When I press dir = -1and square will move to the left.
The way it is working:
No
I think the problem is the pos of the main cube does not seem to update and the dirX updates from 0 to 1 and goes back to 0.
I guess changing the values of the variables under the __init__() function is done as I am doing it or perhaps it is completely wrong.
Is this any way to make my code work the way I am trying to do it or is it completely a wrong way and there is some other way?
I am learning OOP and python, any additional advice or links regarding the best practices, relating to this code, would be highly appreciated.
Thank you.

First of all you've to invoke move in the main application loop:
def main():
pygame.init()
display = pygame.display.set_mode((screenWidth, screenHeight))
clock = pygame.time.Clock()
heroOne = Hero([150, 450])
running = True
while running:
clock.tick(300)
display.fill((255, 255, 255))
heroOne.move()
heroOne.draw(display)
pygame.display.update()
You have to change the position of the player by self.dirX and self.dirY, in every frame:
class Hero:
# [...]
def move(self):
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
sys.exit()
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_RIGHT:
self.dirX = 1
elif event.key == pygame.K_LEFT:
self.dirX = -1
new_x = self.pos[0] + self.dirX
new_y = self.pos[1] + self.dirY
self.pos = [new_x , new_y]
def draw(self, display):
pygame.draw.rect(display, self.color, (*self.pos, self.width, self.height))
If you wan to move the rectangle, just when a key is pressed, then I recommend to use pygame.key.get_pressed rather than the KEYDOWN event:
class Hero:
# [...]
def move(self):
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
sys.exit()
keys = pygame.key.get_pressed()
if keys[pygame.K_LEFT]:
self.pos[0] -= 1
if keys[pygame.K_RIGHT]:
self.pos[0] += 1
if keys[pygame.K_UP]:
self.pos[1] -= 1
if keys[pygame.K_DOWN]:
self.pos[1] += 1
Complete code:
import pygame
import random
import math
import sys
screenWidth = 1200
screenHeight = 600
class Hero:
def __init__(self, pos):
self.pos = pos
self.width = 30
self.height = 30
self.color = (0, 0, 0)
self.dirX = 0
self.dirY = 0
def move(self, events):
keys = pygame.key.get_pressed()
if keys[pygame.K_LEFT]:
self.pos[0] -= 1
if keys[pygame.K_RIGHT]:
self.pos[0] += 1
if keys[pygame.K_UP]:
self.pos[1] -= 1
if keys[pygame.K_DOWN]:
self.pos[1] += 1
def draw(self, display):
pygame.draw.rect(display, self.color, (*self.pos, self.width, self.height))
def jump(self):
pass
def die(self):
pass
class Enemy:
pass
class Background:
pass
class Obstacles:
pass
class Camera:
pass
def score():
pass
def main():
pygame.init()
display = pygame.display.set_mode((screenWidth, screenHeight))
clock = pygame.time.Clock()
heroOne = Hero([150, 450])
running = True
while running:
clock.tick(300)
events = pygame.event.get()
for event in events:
if event.type == pygame.QUIT:
pygame.quit()
sys.exit()
heroOne.move(events)
display.fill((255, 255, 255))
heroOne.draw(display)
pygame.display.update()
main()

In your create function you are creating new instance of the Hero each time its being called.
Instead, init heroOne in the main, and pass it as an argument so you can use it:
def main():
pygame.init()
heroOne = Hero([150, 450])
clock = pygame.time.Clock()
running = True
while running:
clock.tick(30)
create(screenWidth, screenHeight, heroOne)
Also add increment in the move method:
self.dirX += 1
and:
self.dirX -= 1
Now the object will move by one on each keypress.
And if you want continuous movement you should put some flag, e.g. if it is True +=1 and "False" -=1 and key presses will change the flag state.

Pygame: bullets sticks to the screen

My problem is very simple. The bullets I fire sticks to the screen if I shoot fast. If I shoot slowly, they don't stick. Anyone have an idea how this phenomenon occurs?
screenshot of the bullets sticking to the screen
Below I have entered the code. I follow this default game flowchart:
I am curious about the origin of the problem. Is it the code or hardware?
import sys
import pygame
from pygame.sprite import Sprite
from pygame.sprite import Group
# pygame initializing
pygame.init()
#create the screen surface
screen = pygame.display.set_mode((800, 700))
class Color():
def __init__(self):
self.black = (0, 0, 0)
self.white = (255, 255, 255)
self.red = (255, 0, 0)
self.green = (0, 255, 0)
self.green_lambda = (10, 255, 150)
self.blue = (0, 0, 255)
# set up the colors
color = Color() # make an instance of this class - this makes some colors available
class Spaceship(Sprite):
"""
This class represents the Spaceship.
It derives from the "Sprite" class in Pygame.
"""
def __init__(self):
""" Constructor"""
# Call the parent class (Sprite) constructor
super().__init__()
width = 22
height = 32
self.screen = screen
self.image = pygame.Surface((width, height))
self.image.fill(color.black)
self.image.set_colorkey(color.black)
pygame.draw.polygon(self.image, color.green_lambda, [[10,0],[15,22],[20,30],[10,27],[0,30],[5,22]],2)
self.rect = self.image.get_rect()
self.screen_rect = self.screen.get_rect()
self.rect.centerx = self.screen_rect.centerx
self.rect.bottom = self.screen_rect.bottom
# As the rect method only take integers we store a
# This value is only used at the beginning, i.e. before the game loop starts
self.center_x = self.rect.centerx
self.center_y = self.rect.centery
class Bullet(Sprite):
"""
This class represents the bullets.
It derives from the "Sprite" class in Pygame.
"""
def __init__(self):
# Call the parent class (Sprite) constructor
super().__init__()
self.image = pygame.Surface((8,10))
self.image.fill(color.red)
self.image.set_colorkey((color.red))
pygame.draw.ellipse(self.image, color.green, [1, 0, 5, 8], 2)
self.rect = self.image.get_rect()
self.rect.centerx = defender.rect.centerx
self.rect.bottom = defender.rect.top
# def function to move the bullets
def update_pos(self):
self.rect.y -= bullet_speed
# create spaceship instance
defender = Spaceship()
# create group to store sprites in
all_sprites_list = Group()
all_sprites_list.add(defender)
ship_speed = 0.5
bullet_speed = 3
def run_game():
m_right = False
m_left = False
m_up = False
m_down = False
new_bullet = False
while True:
"""This is the user interaction section"""
for event in pygame.event.get():
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_ESCAPE:
sys.exit()
elif event.key == pygame.K_RIGHT:
m_right = True
elif event.key == pygame.K_LEFT:
m_left = True
elif event.key == pygame.K_UP:
m_up = True
elif event.key == pygame.K_DOWN:
m_down = True
elif event.key == pygame.K_SPACE:
new_bullet = Bullet()
#print(dir(new_bullet))
all_sprites_list.add(new_bullet)
if event.type == pygame.KEYUP:
if event.key == pygame.K_RIGHT:
m_right = False
elif event.key == pygame.K_LEFT:
m_left = False
elif event.key == pygame.K_UP:
m_up = False
elif event.key == pygame.K_DOWN:
m_down = False
"""Below is the game logic, which gets input from the user interaction
section and more"""
# Movement of spaceship depending on the flag boolean value and on screen width and height
if m_right and defender.rect.right < defender.screen_rect.right:
defender.center_x += ship_speed
if m_left and defender.rect.left > defender.screen_rect.left:
defender.center_x -= ship_speed
if m_up and defender.rect.top > defender.screen_rect.top:
defender.center_y -= ship_speed
if m_down and defender.rect.bottom < defender.screen_rect.bottom:
defender.center_y += ship_speed
# The cumulative value (which is a float number) for the spaceships movement
# is given to the spaceship rect variable (which can only be integer) now.
# This enables fine adjusting of the speed
defender.rect.centerx = defender.center_x
defender.rect.centery = defender.center_y
all_sprites_list.update()
screen.fill(color.black)
if new_bullet:
new_bullet.update_pos()
# Below the bullets which leaves the screen display are deleted
if new_bullet.rect.bottom < defender.screen_rect.top:
all_sprites_list.remove(new_bullet)
all_sprites_list.draw(screen)
print(all_sprites_list)
pygame.display.flip()
run_game()

instead of just updating the position of new_bullet
# if new_bullet:
# new_bullet.update_pos()
# # Below the bullets which leaves the screen display are deleted
# if new_bullet.rect.bottom < defender.screen_rect.top:
# all_sprites_list.remove(new_bullet)
update the position of all bullets
for bullet in all_sprites_list:
if isinstance(bullet,Bullet):
bullet.update_pos()
if bullet.rect.bottom < defender.screen_rect.top:
all_sprites_list.remove(bullet)
del bullet

Joran Beasley's answer is correct. I'd just like to point out that you can also put the behavior of the sprites into their update methods which get called automatically when you call all_sprites_list.update(). You can actually move most of the code in the while loop to the update methods.
I've got an example with these changes and some more tips in the comments (a quick code review):
import pygame
from pygame.sprite import Sprite
from pygame.sprite import Group
# I'd just define some global constants for the colors.
BLACK = (0, 0, 0)
GREEN = (0, 255, 0)
GREEN_LAMBDA = (10, 255, 150)
class Spaceship(Sprite):
"""This class represents the Spaceship."""
def __init__(self, screen):
"""Constructor"""
super().__init__()
self.screen = screen
# pygame.SRCALPHA makes the surface transparent.
self.image = pygame.Surface((22, 32), pygame.SRCALPHA)
pygame.draw.polygon(
self.image, GREEN_LAMBDA,
[[10,0],[15,22],[20,30],[10,27],[0,30],[5,22]], 2
)
self.screen_rect = self.screen.get_rect()
# You can pass the position as the midbottom argument to `get_rect`.
self.rect = self.image.get_rect(midbottom=self.screen_rect.midbottom)
self.center_x = self.rect.centerx
self.center_y = self.rect.centery
# I've removed the `m_right`, etc. variables and just set the speed
# of the sprite in the event loop.
self.max_speed = 3.5
self.speed_x = 0
self.speed_y = 0
def update(self):
# Move the sprite.
self.center_x += self.speed_x
self.center_y += self.speed_y
self.rect.centerx = self.center_x
self.rect.centery = self.center_y
# Keep the sprite on the screen.
if not self.screen_rect.contains(self.rect):
self.rect.clamp_ip(self.screen_rect)
self.center_x, self.center_y = self.rect.center
class Bullet(Sprite):
"""This class represents the bullets."""
def __init__(self, pos):
super().__init__()
self.image = pygame.Surface((8, 10), pygame.SRCALPHA)
pygame.draw.ellipse(self.image, GREEN, [1, 0, 5, 8], 2)
self.rect = self.image.get_rect(midbottom=pos)
self.speed = 3 # The speed is now an attribute.
def update(self):
self.rect.y -= self.speed
if self.rect.top < 0:
self.kill() # Remove the sprite from all groups.
def run_game():
pygame.init()
screen = pygame.display.set_mode((800, 700))
clock = pygame.time.Clock() # Use a clock to limit the frame rate.
defender = Spaceship(screen)
all_sprites = Group() # Changed the name because groups are not lists.
all_sprites.add(defender)
while True:
for event in pygame.event.get():
if event.type == pygame.QUIT:
return
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_ESCAPE:
return
elif event.key == pygame.K_RIGHT:
defender.speed_x = defender.max_speed
elif event.key == pygame.K_LEFT:
defender.speed_x = -defender.max_speed
elif event.key == pygame.K_UP:
defender.speed_y = -defender.max_speed
elif event.key == pygame.K_DOWN:
defender.speed_y = defender.max_speed
elif event.key == pygame.K_SPACE:
new_bullet = Bullet(defender.rect.midtop) # Pass the pos.
all_sprites.add(new_bullet)
elif event.type == pygame.KEYUP:
if event.key == pygame.K_RIGHT and defender.speed_x > 0:
defender.speed_x = 0
elif event.key == pygame.K_LEFT and defender.speed_x < 0:
defender.speed_x = 0
elif event.key == pygame.K_UP and defender.speed_y < 0:
defender.speed_y = 0
elif event.key == pygame.K_DOWN and defender.speed_y > 0:
defender.speed_y = 0
all_sprites.update() # Calls the update methods of all sprites.
screen.fill(BLACK)
all_sprites.draw(screen)
pygame.display.flip()
clock.tick(60) # Limit the frame rate to 60 FPS.
run_game()

How to move my player sprite?

Here is my code. How can I move my class Player sprite? Would I add an x,y to my def __init__? like def __init__(self, x, y)? Thanks for the answers,
import pygame as pg
WIDTH = 800
HEIGHT = 600
CLOCK = pg.time.Clock()
FPS = 60
GREEN = (0, 255, 0)
LIGHTBLUE = (20, 130, 230)
BGCOLOR = LIGHTBLUE
class Player(pg.sprite.Sprite):
def __init__(self, x, y):
pg.sprite.Sprite.__init__(self)
self.image = pg.Surface((50, 50))
self.image.fill(GREEN)
self.rect = self.image.get_rect()
self.rect.center = ((WIDTH / 2, HEIGHT / 2))
self.x = x
self.y = y
player = Player()
pg.init()
screen = pg.display.set_mode((WIDTH, HEIGHT))
pg.display.set_caption('The Moon Smiles Back')
running = True
while running:
for event in pg.event.get():
if event.type == pg.QUIT:
running = False
if event.type == pg.KEYDOWN:
if event.key == pg.K_ESCAPE:
running = False
all_sprites = pg.sprite.Group()
all_sprites.add(player)
all_sprites.update()
screen.fill(BGCOLOR)
all_sprites.draw(screen)
pg.display.flip()
CLOCK.tick(FPS)
pg.quit()

Add two attributes to the Player class to store the current velocity of the player. In the update method, add the velocities to the x and y attributes and then set the rect to the new position.
class Player(pg.sprite.Sprite):
def __init__(self, x, y):
pg.sprite.Sprite.__init__(self)
self.image = pg.Surface((50, 50))
self.image.fill(GREEN)
self.rect = self.image.get_rect()
self.rect.center = (x, y)
self.x = x
self.y = y
self.velocity_x = 0
self.velocity_y = 0
def update(self):
self.x += self.velocity_x
self.y += self.velocity_y
self.rect.center = (self.x, self.y)
To move the player to the right, set the player.velocity_x to the desired speed if the 'd' key is pressed (in this example), and back to 0 if the key is released. Do the same for the other directions.
if event.type == pg.KEYDOWN:
if event.key == pg.K_ESCAPE:
running = False
elif event.key == pg.K_d:
player.velocity_x = 3
elif event.type == pg.KEYUP:
if event.key == pg.K_d:
player.velocity_x = 0

Is there a better way to move a sprite using the keyboard with Pygame?

Currently, I have small image that I move using the D and A keys on the keyboard. The code works just how I want it to, but it seems to be a bit unnecessarily complicated. Is there a more efficient way of doing this?
In the main loop, my code checks to see what key is pressed through the events, but after that, if a key is no longer pressed, it checks to see if another key is pressed, just in case a user pressed a key while another key was initially pressed.
Here is my code:
import pygame
import sys
from pygame.locals import *
SCREENX = 640
SCREENY = 480
LEFT = 'left'
RIGHT = 'right'
class Character(pygame.sprite.Sprite):
def __init__(self, image_file):
super().__init__()
temp_image = pygame.image.load(image_file)
self.image = pygame.transform.scale(temp_image, (100, 100))
self.rect = self.image.get_rect()
self.moving = False
self.direction = RIGHT
def start_move(self, direction):
self.moving = True
if direction != self.direction:
self.image = pygame.transform.flip(self.image, True, False)
self.direction = direction
def stop_move(self):
if self.moving:
self.moving = False
def move(self):
if self.direction == RIGHT:
self.rect.x += 5
if self.direction == LEFT:
self.rect.x -= 5
def update(self):
if self.moving:
self.move()
def main():
pygame.init()
surface = pygame.display.set_mode((SCREENX, SCREENY))
clock = pygame.time.Clock()
sprites = pygame.sprite.Group()
girl = Character("assets/girl.png")
girl.rect.x = SCREENX/2
girl.rect.y = SCREENY - girl.rect.height
sprites.add(girl)
while True:
for event in pygame.event.get():
if event.type == QUIT:
pygame.quit()
sys.exit()
if event.type == KEYDOWN:
if not girl.moving:
if event.key == K_d:
girl.start_move(RIGHT)
if event.key == K_a:
girl.start_move(LEFT)
if event.type == KEYUP:
if event.key == K_a or event.key == K_d:
girl.stop_move()
keys_pressed = pygame.key.get_pressed()
if keys_pressed[K_d]:
girl.start_move(RIGHT)
if keys_pressed[K_a]:
girl.start_move(LEFT)
surface.fill((255, 255, 255))
sprites.update()
sprites.draw(surface)
pygame.display.update()
clock.tick(60)
if __name__ == '__main__':
main()

Yes, you can get rid of most of the event handling, you can generalize your main loop, and you can get rid of some fields of your Character class.
See my explanatory notes in the comments:
import pygame
import sys
from pygame.locals import *
SCREENX = 640
SCREENY = 480
class Character(pygame.sprite.Sprite):
def __init__(self, image_file):
pygame.sprite.Sprite.__init__(self)
temp_image = pygame.image.load(image_file)
# only to the flipping of the image once
self.image_r = pygame.transform.scale(temp_image, (100, 100))
self.image_l = pygame.transform.flip(self.image_r, True, False)
self.image = self.image_l
self.rect = self.image.get_rect()
def update(self, pressed_keys):
move = 0
if pressed_keys[K_d]: move += 1
if pressed_keys[K_a]: move -= 1
self.rect.move_ip(move*5, 0)
# check which direction we're facing and set the image
self.image = self.image_l if move < 0 else self.image_r
def main():
pygame.init()
surface = pygame.display.set_mode((SCREENX, SCREENY))
clock = pygame.time.Clock()
sprites = pygame.sprite.Group()
girl = Character("assets/girl.png")
girl.rect.x = SCREENX / 2
girl.rect.y = SCREENY - girl.rect.height
sprites.add(girl)
while True:
for event in pygame.event.get():
# since we are in a function, we can simply return.
# we don't care here what happens after we quit the main loop
if event.type == QUIT: return pygame.quit()
# get all pressed keys, and just let all sprites
# decide what they want to do with it
keys_pressed = pygame.key.get_pressed()
# you could wrap this information in a more
# general container represeting the game state
# See how the game loop does not care what a
# Sprite does with this information
sprites.update(keys_pressed)
surface.fill((255, 255, 255))
sprites.draw(surface)
pygame.display.update()
clock.tick(60)
if __name__ == '__main__':
main()