Develop Reference

PyGame background color is not changing

I cannot find, what is wrong with background, even with debugger it is not doing nothing
#importing
from turtle import width
import pygame
#resolution
pygame.display.set_caption("Tanks")
WIDTH, HEIGHT = 900, 500
WIN = pygame.display.set_mode((WIDTH, HEIGHT))
#background color (my problem)
def draw_window():
WIN.fill((255, 0, 0))
pygame.display.update()
#main functions
def main():
run = True
while run:
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
pygame.quit()
#game start
if __name__ == "__main__":
main()

You have to call draw_window in the application loop:
#importing
import pygame
#resolution
pygame.display.set_caption("Tanks")
WIDTH, HEIGHT = 900, 500
WIN = pygame.display.set_mode((WIDTH, HEIGHT))
clock = pygame.time.Clock()
#background color (my problem)
def draw_window():
WIN.fill((255, 0, 0))
pygame.display.update()
#main functions
def main():
run = True
while run:
clock.tick(100)
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
draw_window()
pygame.quit()
#game start
if __name__ == "__main__":
main()
The typical PyGame application loop has to:
limit the frames per second to limit CPU usage with pygame.time.Clock.tick
handle the events by calling either pygame.event.pump() or pygame.event.get().
update the game states and positions of objects dependent on the input events and time (respectively frames)
clear the entire display or draw the background
draw the entire scene (blit all the objects)
update the display by calling either pygame.display.update() or pygame.display.flip()

When you write a function, it is just some instructions on memory, it doesn't run unless you call it. This is the case. You write a set of instructions, draw_window, but you never call it. What you need to do is before the game loop, call draw_window. So the code would be something like this.
#importing
from turtle import width
import pygame
#resolution
pygame.display.set_caption("Tanks")
WIDTH, HEIGHT = 900, 500
WIN = pygame.display.set_mode((WIDTH, HEIGHT))
#background color (my problem)
def draw_window():
WIN.fill((255, 0, 0))
pygame.display.update()
#main functions
def main():
run = True
while run:
draw_window()
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
pygame.quit()
#game start :)
if __name__ == "__main__":
main()
This way the result will be a red window which is rgb(0, 0).

How can i give my image an initial position before it starts moving with the mouse?

I'm working on this pygame game and i'm just getting started but got a bit confused because i want the image to move in the x-axis along with the mouse but when i run the program i want the image to show up at the center or the 'floor' but appears at the left side instead. This is my code and a screenshot of what's happening.
import pygame
import sys
pygame.init()
pygame.mixer.init()
WIDTH, HEIGHT = 400, 500
FPS = 60
TITLE = 'FOOD DROP'
SIZE = 190
# Colors
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
BLUE_SKY = (152, 166, 255)
# Display
SCREEN = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption(TITLE)
# Surfaces
floor_surface = pygame.Surface((WIDTH, 100))
floor_surface.fill(BLUE_SKY)
floor_rect = floor_surface.get_rect(midbottom=(200, 500))
# Images
LOAD_DITTO = pygame.image.load('Graphics/ditto.png')
DITTO = pygame.transform.scale(LOAD_DITTO, (SIZE, SIZE))
# Time
CLOCK = pygame.time.Clock()
class Figure:
def draw_figure(self, mouse_x):
SCREEN.blit(DITTO, (mouse_x - 90, 330))
# Game loop
SCREEN_UPDATE = pygame.USEREVENT
# main_game = Main()
figure = Figure()
running = True
while running:
CLOCK.tick(FPS)
mx, my = pygame.mouse.get_pos()
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
sys.exit()
SCREEN.fill(WHITE)
SCREEN.blit(floor_surface, floor_rect)
figure.draw_figure(mx)
pygame.display.update()
When i run the program, this happens:
And i want the image to appear right at the center or the x-axis, not the border, i don't know why is this happening. Just to state, that screenshot was taken when the mouse hadn't been placed over the display.

If the mouse pointer is not in the window (out of focus), the initial position of the mouse pointer is (0, 0). Therefore pygame.mouse.get_pos returns (0, 0). It is also not possible to set the mouse position with pygame.mouse.set_pos if it is not in the window.
Initialize the variables mx and mx with the center of the window. Change the mouse position only when the mouse pointer is in the window (in focus). pygame.mouse.get_focused can be used to test whether the mouse is in the window.
mx, my = SCREEN.get_rect().center
running = True
while running:
CLOCK.tick(FPS)
for event in pygame.event.get():
if event.type == pygame.QUIT:
running = False
if pygame.mouse.get_focused():
mx, my = pygame.mouse.get_pos()
SCREEN.fill(WHITE)
SCREEN.blit(floor_surface, floor_rect)
figure.draw_figure(mx)
pygame.display.update()
pygame.quit()
sys.exit()

Pygame black background has a distorted/broken image

I started a basic project with pygame and tried to set up the basics.
import pygame
BLACK = (0, 0, 0)
WHITE = (200, 200, 200)
SIZE = width, height = 500, 700
def main() -> None:
global SCREEN
pygame.init()
SCREEN = pygame.display.set_mode(SIZE)
pygame.display.set_caption('Tetronur')
running = True
SCREEN.fill(BLACK)
while running:
draw()
for event in pygame.event.get():
if event.type == pygame.QUIT:
running = False
def draw():
rect = pygame.Rect(100, 100, 400, 600)
pygame.draw.rect(SCREEN, WHITE, rect, 1)
if __name__ == '__main__':
main()
But the thing is, when I run the code, I get a screen looking like this:
PS: I use Python 3.9.6 and Pygame 2.0.1

Pygame draws to a hidden screen, you must call pygame.display.flip() or pygame.display.update() after drawing so that this hidden screen is displayed to the actual screen.

Fill only one half of a display in Pygame?

I am new to Pygame and I wish to fill only certain parts of my screen, for example the half. Currently I am only able to fill the complete screen. Can someone help?
import pygame
color= (255, 0, 0)
screen = pygame.display.set_mode((740, 780))
screen.fill(color)

The 2nd parameter of .fill() is a rectangle, which defines the area to be filled.
The width and height of a pygame.Surface object can be get by .get_width() respectively .get_height():
e.g.
screen.fill(color, (0, 0, screen.get_width()// 2, screen.get_height()))

import pygame
size = w,h = 300, 400
scr = pygame.display.set_mode((w,h))
pygame.display.set_caption("Hello")
scr.fill((0,255,0), rect=(0,0,w,h/2))
pygame.display.flip()
running = True
while running:
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
running = False

One way to have partial fill may include "drawing" a shape (i.e. rectangle) on half of the screen.
import sys
import pygame
def half_screen():
#Initialize game and create screen object.
pygame.init()
color= (255, 0, 0)
screen = pygame.display.set_mode((200, 400))
#Draw rectangle to fill the left half of the screen.
left_half = pygame.draw.rect(screen, color,(0,0, 100, 400))
#Start loop for game- keeps screen open until you decide to quit.
while True:
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
#Make the current screen visible.
pygame.display.flip()
half_screen()
You can find more information on the draw module - pygame.draw - by going to https://www.pygame.org/docs/ref/draw.html

Pygame moving image over rectangle with different colors

I am new to python and pygame and I'm trying to move a image over drawed rectangles with changing colors. Whenever I run this code the image moves but it creates a track of the image.
I know that I need to blit the background of the image in the game loop but how can I blit the background if the background is not an image?
Or do I need to draw my rectangles in a different way?
Full code:
import pygame
pygame.init()
screen = pygame.display.set_mode((600,200))
pygame.draw.rect(screen, (175,171,171), [0, 0, 600, 200])
pygame.draw.rect(screen, (255,192,0), [200, 0, 200, 200])
clock = pygame.time.Clock()
# load your own image here (preferably not wider than 30px)
truck = pygame.image.load('your_image.png').convert_alpha()
class Truck:
def __init__(self, image, x, y, speed):
self.speed = speed
self.image = image
self.pos = image.get_rect().move(x, y)
def move(self):
self.pos = self.pos.move(self.speed, 0)
def game_loop():
newTruck = Truck(truck, 0, 50, 1)
gameExit = False
while not gameExit:
for event in pygame.event.get():
if event.type == pygame.QUIT:
gameExit = True
newTruck.move()
screen.blit(newTruck.image, newTruck.pos)
clock.tick(60)
pygame.display.update()
game_loop()

You have to somehow redraw all the objects (rectangles) in your background at every update.
The simplest way to do this is just to call all the drawing code again, before updating your foreground object. Another way, if the background does not change after created, is to blit these background objects into a separate Surface object, and blit that one to the screen on every update.
More sophisticated ways would be to save the background under your foreground objects are prior to drawing them, and then, on the next redraw, first redraw the background and then save the background again and draw the foreground objects on the new position. It is easier to do one of the former methods.
Your code could be written like this:
import pygame
pygame.init()
SIZE = (600,200)
screen = pygame.display.set_mode(SIZE)
bg_image = None
def draw_background(screen):
global bg_image
if not bg_image:
bg_image = pygame.Surface((SIZE))
pygame.draw.rect(bg_image, (175,171,171), [0, 0, 600, 200])
pygame.draw.rect(bg_image, (255,192,0), [200, 0, 200, 200])
...
# Draw whatever you want inside this if body
screen.blit(bg_image, (0, 0))
...
class Truck:
...
def game_loop():
newTruck = Truck(truck, 0, 50, 1)
gameExit = False
while not gameExit:
for event in pygame.event.get():
if event.type == pygame.QUIT:
gameExit = True
newTruck.move()
draw_background()
screen.blit(newTruck.image, newTruck.pos)
clock.tick(60)
pygame.display.update()
game_loop()

You can just move the two lines that draw your rects into the main while loop:
def game_loop():
newTruck = Truck(truck, 0, 50, 1)
gameExit = False
while not gameExit:
for event in pygame.event.get():
if event.type == pygame.QUIT:
gameExit = True
newTruck.move()
# Draw the background items first, then the foreground images.
# If the rects don't cover the whole screen, you can use
# `screen.fill(some_color)` to clear it.
pygame.draw.rect(screen, (175,171,171), [0, 0, 600, 200])
pygame.draw.rect(screen, (255,192,0), [200, 0, 200, 200])
screen.blit(newTruck.image, newTruck.pos)
clock.tick(60)
pygame.display.update()
If the background should be static, you could also draw the rects onto a background surface once and then blit this surf onto the screen in the main loop as jsbueno suggests.