Develop Reference

How do I implement sliding window algorithm on an image?

I'm making the Super Mario Bros. game on python using the pygame library. I wanted to fit only a portion of the map of mario bros level and I have no idea how am I supposed to do that. One of my seniors told me that I could use the sliding window algorithm. However, the problem is I don't know how to implement this algorithm on the image. If I can get any help that would be really appreciated.mario level world 1-1
I have also been able to print out the map to a suitable scaling:
map on code
edit: I am sorry I did not post my code. here it is:
import pygame
import pygame.transform
i = pygame.init()
X = 640
Y = 480
Window = pygame.display.set_mode ((X, Y))
pygame.display.set_caption ("Game")
Mario_Standing_Left = pygame.image.load("F:\\Mario in Python\\Mario_Standing_Left.png")
Mario_Standing_Right = pygame.image.load("F:\\Mario in Python\\Mario_Standing_Right.png")
x = 50
y = 430
width = 40
height = 60
speed = 5
isjump = False
jumpcount = 10
left = False
right = False
WalkCount = 0
ScreenWidth = X - width - speed
ScreenHeight = Y - height - speed
isjump = False
jumpcount = 10
run = True
while run:
pygame.time.delay (50) #time in pygame measured in milliseconds
for event in pygame.event.get ():
if event.type == pygame.QUIT:
run = False
keys = pygame.key.get_pressed()
if keys[pygame.K_LEFT] and x > speed:
x -= speed
if keys[pygame.K_RIGHT] and x <= ScreenWidth:
x += speed
if not (isjump):
if keys[pygame.K_SPACE]:
isjump = True
else:
if jumpcount >= -10:
neg = 1
if jumpcount < 0:
neg = -1
y -= (jumpcount ** 2) * 0.5 * neg
jumpcount -= 1
else:
isjump = False
jumpcount = 10
Window.fill ((0,0,0))
#(surface, (the window defined above, (colour), (the object being drawn)))
pygame.display.update()
world = pygame.image.load('World 1-1.png').convert()
world = pygame.transform.smoothscale(world,(8750,1400))
while True:
Window.blit(world,(0,0))
pygame.display.update()
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.display.quit()
pygame.quit()

You should use area in blit(..., area=...) to display only some part of world
I use area = pygame.Rect(0, 300, SCREEN_WIDTH, SCREEN_HEIGHT) to keep information what area to display. And I change area.x to scroll it right and left.
import pygame
# --- constants --- # PEP8: all constants directly after imports
SCREEN_WIDTH = 640
SCREEN_HEIGHT = 480
FPS = 60
# --- main --- # PEP8: `lower_case_names` for variables
pygame.init()
window = pygame.display.set_mode ((SCREEN_WIDTH, SCREEN_HEIGHT))
world_image = pygame.image.load('World 1-1.png').convert()
world_image = pygame.transform.smoothscale(world_image, (8750,1400))
world_rect = world_image.get_rect()
area = pygame.Rect(0, 300, SCREEN_WIDTH, SCREEN_HEIGHT)
direction = 'right'
# - mainloop -
clock = pygame.time.Clock()
run = True
while run:
for event in pygame.event.get ():
if event.type == pygame.QUIT:
run = False
if direction == 'right':
# move right
area.x += 2
# change direction
if area.right > world_rect.right:
area.right = world_rect.right
direction = 'left'
else:
# move left
area.x -= 2
# change direction
if area.left < world_rect.left:
area.left = world_rect.left
direction = 'right'
#window.fill((0, 0, 0))
window.blit(world_image, (0,0), area=area)
pygame.display.flip()
clock.tick(FPS) # keep speed 60 FPS (Frames Per Second)
# - end -
pygame.quit()
PEP 8 -- Style Guide for Python Code
EDIT:
If you will have other elements then you may need to create Surface with size of world to blit world and other elements before on this surface and later display it in window using area.
import pygame
# --- constants ---
SCREEN_WIDTH = 640
SCREEN_HEIGHT = 480
FPS = 60
# --- main --- # PEP8: `lower_case_names` for variables
pygame.init()
window = pygame.display.set_mode ((SCREEN_WIDTH, SCREEN_HEIGHT))
window_rect = window.get_rect()
world_image = pygame.image.load('World 1-1.png').convert()
world_image = pygame.transform.smoothscale(world_image, (8750,1400))
world_rect = world_image.get_rect()
player_image = pygame.Surface((40, 40))
player_image.fill((255, 0, 0)) # red
player_rect = player_image.get_rect(centerx=window_rect.centerx, centery=window_rect.centery+300 )
area = pygame.Rect(0, 300, SCREEN_WIDTH, SCREEN_HEIGHT)
direction = 'right'
buffer = pygame.Surface(world_rect.size)
# - mainloop -
clock = pygame.time.Clock()
run = True
while run:
for event in pygame.event.get ():
if event.type == pygame.QUIT:
run = False
if direction == 'right':
# move right
area.x += 5
player_rect.x += 5
# change direction
if area.right > world_rect.right:
area.x -= 5
player_rect.x -= 5
#area.right = world_rect.right
direction = 'left'
else:
# move left
area.x -= 5
player_rect.x -= 5
# change direction
if area.left < world_rect.left:
area.x += 5
player_rect.x += 5
#area.left = world_rect.left
direction = 'right'
#player_rect.center = area.center
buffer.blit(world_image, (0,0))
buffer.blit(player_image, player_rect)
# ---
#window.fill((0, 0, 0))
window.blit(buffer, (0,0), area=area)
pygame.display.flip()
clock.tick(FPS) # keep speed 60 FPS (Frames Per Second)
# - end -
pygame.quit()

Pygame character jump speed problems

I'm currently trying to make my first game. I am trying to make my character jump, but my code doesn't have errors but when my character jump it just happens to fast. I don't know which part to change. I have not been able to figure this out on my own as I am still learning. Here is my code:
import pygame
pygame.init()
screen = pygame.display.set_mode((1200, 600))
WinHeight = 600
WinWidth = 1200
# player
player = pygame.image.load("alien.png")
x = 50
y = 450
vel = 0.3
playerSize = 32
# title
pygame.display.set_caption("First Game")
# Jump
isJump = False
jumpCount = 10
running = True
while running:
screen.fill((255, 255, 255))
for event in pygame.event.get():
if event.type == pygame.QUIT:
running = False
break
keys = pygame.key.get_pressed()
if keys[pygame.K_a] and x > vel:
x -= vel
if keys[pygame.K_d] and x < WinWidth - vel - playerSize:
x += vel
if not (isJump):
if keys[pygame.K_w] and y > vel:
y -= vel
if keys[pygame.K_s] and y < WinHeight - vel - playerSize:
y += vel
if keys[pygame.K_SPACE]:
isJump = True
else:
if jumpCount >= -10:
neg = 1
if jumpCount < 0:
neg = -1
y -= (jumpCount ** 2) * 0.5 * neg
jumpCount -= 1
else:
isJump = False
jumpCount = 10
screen.blit(player, (x, y))
pygame.display.update()

Use pygame.time.Clock to control the frames per second and thus the game speed.
The method tick() of a pygame.time.Clock object, delays the game in that way, that every iteration of the loop consumes the same period of time. See pygame.time.Clock.tick():
This method should be called once per frame.
That means that the loop:
clock = pygame.time.Clock()
running = True
while running:
clock.tick(60)
# [...]

How do I fix my code with Pygame to jump correctly?

EDIT:
I've now updated indentation and a few other numbers (to get player to start at the floor and not jump so high). Now it jumps up to a good height, but it doesn't come down back to the floor. Any ideas on how to fix this new problem?
Messing around some more, if I put player_movement = 2 in last else (resetting variables) it slowly goes down, but then I'd need to set a barrier so it doesn't go off the bottom of the screen. But, the code I already have is supposed to do that for me...right?
Updated code:
if not(isJump):
if keys[pygame.K_UP]:
isJump = True
else:
if jumpCount >= -10:
neg = 1
if jumpCount < 0:
neg = -1
player_movement -= (jumpCount ** 2) * 0.5 * neg
jumpCount -= 10
# This will execute when jump is finished
else:
# Resetting Variables
jumpCount = 10
isJump = False
I originally started following this tutorial: https://www.youtube.com/watch?v=UZg49z76cLw
(Learning pygame by making Flappy Bird). But I decided I just wanted the "player" to be on the floor and be able to jump (instead of gravity/jumping like flappy bird).
So I then combined that tutorial with: https://techwithtim.net/tutorials/game-development-with-python/pygame-tutorial/jumping/ . Before adding in the jump, the 'player' is resting on the floor. With the jump, the 'player' is flashing at the top of the screen. How do I fix this so it works correctly? I tried looking it up and all I can find is how to jump with like a box being drawn on screen, versus using screen.blit().
See my code below:
import pygame
def draw_floor():
"""Sets one floor after the first"""
screen.blit(floor_surface, (floor_x_pos, 900))
screen.blit(floor_surface, (floor_x_pos + 576, 900))
# Needed to start pygame
pygame.init()
# Creating the screen ((width, height))
screen = pygame.display.set_mode((576, 1024))
# Creating FPS
clock = pygame.time.Clock()
# Game variables
isJump = False
jumpCount = 10
player_movement = 0
# Importing background image into game
bg_surface = pygame.image.load('assets/bg_day.png').convert()
# Making background image larger
bg_surface = pygame.transform.scale2x(bg_surface)
# Importing floor image into the game
floor_surface = pygame.image.load('assets/base.png').convert()
# Making floor image larger
floor_surface = pygame.transform.scale2x(floor_surface)
# Floor variable to move floor
floor_x_pos = 0
# Importing player image into the game
player_surface = pygame.image.load('assets/player.png').convert()
# Making player image larger
player_surface = pygame.transform.scale2x(player_surface)
# Make a collision box around player -- center of rectangle x,y
player_rect = player_surface.get_rect(center=(100, 899))
run = True
while run:
# Checks for all events running
for event in pygame.event.get():
# if event type is quitting:
if event.type == pygame.QUIT:
# set run to False to close loop
run = False
keys = pygame.key.get_pressed()
if not(isJump):
if keys[pygame.K_UP]:
isJump = True
else:
if jumpCount >= -10:
player_movement -= (jumpCount * abs(jumpCount)) * 0.5
jumpCount -= 1
# This will execute when jump is finished
else:
# Resetting Variables
jumpCount = 10
isJump = False
# Setting the background (screen_bg,(x,y)) : (0,0) = top left
screen.blit(bg_surface, (0, 0))
player_rect.centery = player_movement
# Putting player on screen
screen.blit(player_surface, player_rect)
# Moving the floor
floor_x_pos += -1
# Setting the floor surface to go infinitely
draw_floor()
if floor_x_pos <= -576:
floor_x_pos = 0
# Draws anything from above in while loop and draws on the screen
pygame.display.update()
# Setting FPS - won't run faster than [120] frames per second
clock.tick(120)
# Quits game
pygame.quit()

It's a matter of Indentation. The else case belongs to if not(isJump)::
while run:
# [...]
if not(isJump):
if keys[pygame.K_UP]:
isJump = True
#<--| INDENTATION
else:
if jumpCount >= -10:
player_movement -= (jumpCount * abs(jumpCount)) * 0.5
jumpCount -= 1
# This will execute when jump is finished
else:
# Resetting Variables
jumpCount = 10
isJump = False

How to fix 'Couldn't open C:\GAME\R1.png' in pygame?

I'm trying to learn how to make a game using python and pygame, but I'm pretty new to this, so I can't understand the jargon that comes with the answers that are similar to my own question.
I'm following a video playlist on YouTube called Tech With Tim and I need to use some images for the character in the game, but the images simply won't load and keeps coming up with 'Couldn't open C:\GAME\R1.png'.
They're already in the same folder why is what makes this so confusing. All the images are also named correctly to the best of my understanding (i.e. they all have the names used in the code below:
import pygame
pygame.init()
win = pygame.display.set_mode((500, 480))
pygame.display.set_caption("First Game")
walkRight = [pygame.image.load('C:\GAME\R1.png'), pygame.image.load('C:\GAME\R2.png'), pygame.image.load('C:\GAME\R3.png'),
pygame.image.load('C:\GAME\R4.png'), pygame.image.load('C:\GAME\R5.png'), pygame.image.load('C:\GAME\R6.png'),
pygame.image.load('C:\GAME\R7.png'), pygame.image.load('C:\GAME\R8.png'), pygame.image.load('C:\GAME\R9.png')]
walkLeft = [pygame.image.load('C:\GAME\L1.png'), pygame.image.load('C:\GAME\L2.png'), pygame.image.load('C:\GAME\L3.png'),
pygame.image.load('C:\GAME\L4.png'), pygame.image.load('C:\GAME\L5.png'), pygame.image.load('C:\GAME\L6.png'),
pygame.image.load('C:\GAME\L7.png'), pygame.image.load('C:\GAME\L8.png'), pygame.image.load('C:\GAME\L9.png')]
bg = pygame.image.load('C:\GAME\Bg.jpg')
char = pygame.image.load('C:\GAME\standing.png')
x = 50
y = 425
width = 64
height = 64
vel = 5
clock = pygame.time.Clock()
isJump = False
jumpCount = 10
left = False
right = False
walkCount = 0
def redrawGameWindow():
global walkCount
win.blit(bg, (0, 0))
if walkCount + 1 >= 27:
walkCount = 0
if left:
win.blit(walkLeft[walkCount // 3], (x, y))
walkCount += 1
elif right:
win.blit(walkRight[walkCount // 3], (x, y))
walkCount += 1
else:
win.blit(char, (x, y))
walkCount = 0
pygame.display.update()
run = True
while run:
clock.tick(27)
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
keys = pygame.key.get_pressed()
if keys[pygame.K_LEFT] and x > vel:
x -= vel
left = True
right = False
elif keys[pygame.K_RIGHT] and x < 500 - vel - width:
x += vel
left = False
right = True
else:
left = False
right = False
walkCount = 0
if not (isJump):
if keys[pygame.K_SPACE]:
isJump = True
left = False
right = False
walkCount = 0
else:
if jumpCount >= -10:
y -= (jumpCount * abs(jumpCount)) * 0.5
jumpCount -= 1
else:
jumpCount = 10
isJump = False
redrawGameWindow()
pygame.quit()
I expect to see the game load and work, but instead, the error 'Couldn't open C:\GAME\R1.png' comes up.
I'd appreciate any help!

First, be sure that is the good path to your file.
Also, you should use '/' instead of '\'. Your path should be : 'C:/GAME/R1.png'

How do I fix my 'Jump'?

I am new to this website and pygame so bear with me. I am experimenting with pygame and made a simple platformer. However, whenever I 'Jump', the block jumps frame by frame, so I have to hold down the spacebar. Any help would be greatly appreciated!
here is my code:
import pygame
pygame.init()
win = pygame.display.set_mode((500, 500))
x = 0
y = 490
width = 10
height = 10
vel = 5
pygame.key.set_repeat(1)
isjump = False
jumpcount = 10
while True:
pygame.time.delay(30)
for event in pygame.event.get():
if event.type == pygame.QUIT:
break
keys = pygame.key.get_pressed()
if keys[pygame.K_a] and x>vel-5:
x -= vel
if keys[pygame.K_d] and x < 500 - width:
x += vel
if not(isjump):
if keys[pygame.K_SPACE]:
isjump = True
else:
if jumpcount >= -10:
neg = 1
if jumpcount < 0:
neg = -1
y -= (jumpcount ** 2) /2 * neg
jumpcount -= 1
else:
isjump = False
jumpcount = 10
win.fill((0, 0, 0))
pygame.draw.rect(win, (255, 255, 255), (x, y, width, height))
pygame.display.update()
pygame.quit()

You are mixing your keyboard event handling with your jump-logic. I've done two things, change the spacebar detection to trigger isjump and handle the jump logic irregardless of whether there is a key pressed or not:
import pygame
pygame.init()
win = pygame.display.set_mode((500, 500))
x = 0
y = 490
width = 10
height = 10
vel = 5
pygame.key.set_repeat(1)
isjump = False
jumpcount = 10
while True:
pygame.time.delay(30)
for event in pygame.event.get():
if event.type == pygame.QUIT:
break
keys = pygame.key.get_pressed()
if keys[pygame.K_a] and x>vel-5:
x -= vel
if keys[pygame.K_d] and x < 500 - width:
x += vel
# if we're not already jumping, check if space is pressed to start a jump
if not isjump and keys[pygame.K_SPACE]:
isjump = True
jumpcount = 10
# if we're supposed to jump, handle the jump logic
if isjump:
if jumpcount >= -10:
neg = 1
if jumpcount < 0:
neg = -1
y -= (jumpcount ** 2) /2 * neg
jumpcount -= 1
else:
isjump = False
jumpcount = 10
win.fill((0, 0, 0))
pygame.draw.rect(win, (255, 255, 255), (x, y, width, height))
pygame.display.update()
pygame.quit()

The line keys = pygame.key.get_pressed() and the whole game logic and drawing code should not be in the event loop (for event in pygame.event.get():), otherwise the code gets executed once per event in the queue, and if no events are in the queue, it won't be executed at all.
You could just dedent keys = pygame.key.get_pressed() and all lines beneath.
Alternatively, you could check in the event loop if the space key was pressed (with if event.type == pygame.KEYDOWN:) and then set isjump to True (that means the player will only jump once per keypress).
import pygame
pygame.init()
win = pygame.display.set_mode((500, 500))
clock = pygame.time.Clock()
x = 0
y = 490
width = 10
height = 10
vel = 5
isjump = False
jumpcount = 10
running = True
while running:
for event in pygame.event.get():
if event.type == pygame.QUIT:
running = False
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_SPACE:
isjump = True
keys = pygame.key.get_pressed()
if keys[pygame.K_a] and x > vel - 5:
x -= vel
elif keys[pygame.K_d] and x < 500 - width:
x += vel
if isjump:
if jumpcount >= -10:
neg = 1
if jumpcount < 0:
neg = -1
y -= jumpcount**2 / 2 * neg
jumpcount -= 1
else:
isjump = False
jumpcount = 10
win.fill((0, 0, 0))
pygame.draw.rect(win, (255, 255, 255), (x, y, width, height))
pygame.display.update()
clock.tick(30)
pygame.quit()
I also recommend adding a pygame.time.Clock instance and call clock.tick(FPS) to regulate the frame rate.
And I'd rather implement the jumping in this way, with a gravity constant which gets added to the y-velocity each frame.