Learn to Code via Tutorials on Repl.it

← Back to all posts
56
🚀 A Starter Guide to Pygame 📀

🚀 A Starter Guide to Pygame 📀

Pygame is an open-source library for making graphical applications with Python. Learn more about it on the official website.

This tutorial is intended to help you setup a very basic Pygame interface. It's for Python beginners or people who want to quickly bootstrap a Pygame project. Find more about Repl.it's GFX public beta announcement here. So let's get started!

We're going to be building a simple screen saver. The final result will look like the following

Starting out

When creating a new project, be sure to select "PyGame" when creating a project.

Now we're ready to start writing some code!

Painting the Screen Red 🎨

First, we're importing Pygame and initializing all the imported pygame modules with pygame.init().

Second, we're declaring width and height variables that represent the size of the screen.
Third, we're setting backgroundColor to a tuple of 3 elements that represent the RGB numbers.

Fourth, screen is a display Surface, or an initialized window or screen for display with the set_mode() method.

Lastly, in the infinite loop, we're filling the screen to the backGroundColor and updatiang the display Surface to the screen. In other words pygame.display.flip() "refreshes" the screen with changes you made to the grahpics.

import pygame

pygame.init()
width, height = 800,  600
backgroundColor = 255,  0,  0

screen = pygame.display.set_mode((width, height))

while True:
	screen.fill(backgroundColor)
	pygame.display.flip()

So, we get a red background!

Adding the DVD

Right before you while loop, import an image of your DVD. Feel free to use the same image I used, in the repl below.

dvdLogo = pygame.image.load("dvd-logo-white.png")

Then, create a rectangle from the Surface, or from the image you just loaded with get_rect()

dvdLogoRect = dvdLogo.get_rect()

Now, inside of the while loop (after filling the background color), "map" the imported image to the dvdLogoRect rectangle using the blit() method. That way, the image stays inside of the invisible dvdLogoRect rectangle.

screen.blit(dvdLogo, dvdLogoRect)

Now, we get a DVD!

Moving the DVD Logo

To move the DVD logo, simply use move() by a speed:

dvdLogoRect = dvdLogoRect.move(dvdLogoSpeed)

Make sure you also declare and initialie dvdLogoSpeed at the top of the file. dvdLogoSpeed[0] represents the speed in the x direction.

dvdLogoSpeed = [1,  1]

Finally, I added a time.sleep(10 / 1000) so the logo moves slower.

So my code ended up looking like

The DVD logo will move off the screen because there is no bouncing.
To implement a check for bouncing, add the following:

if dvdLogoRect.left < 0  or dvdLogoRect.right > width:
	dvdLogoSpeed[0] = -dvdLogoSpeed[0]
if dvdLogoRect.top < 0  or dvdLogoRect.bottom > height:
	dvdLogoSpeed[1] = -dvdLogoSpeed[1]

The .left and .right properties don't seem to be documented, but it's implied that .left measures the distance from the left part of the dvdLogoRect Rect (rectangle) to the left part of the screen. And so on and so fourth for .right, .top, and .bottom.

Here is the final result

Now let me know when the logo hits the corner!

Loading Repl
Commentshotnewtop
6

no avaiable video device what

Traceback (most recent call last):
File "main.py", line 11, in <module>
screen = pygame.display.set_mode((width, height))
pygame.error: No available video device

1

Hmm. I'll have to check this error out. Do you get the error when forking the project?

1

@RishabhDey make sure you made a repl under "pygame" and not "python" category when you create a new repl. That was my problem.

1

@Neo_ Oh! Thanks for finding the problem - I'll add that to this guide.

1

@eankeen also by the way, in the code box under the section "painting the screen red" you misspelled display on the last line. I couldn't figure out what was wrong and it was that.

1

@Neo_ Sorry about that! Not sure how I glossed over that when checking everything over - fixed now.

6

The example works when I open it in your repl, but when I fork to my own it doens't work :-(
I wanted to test it because I find pygame and love2d kind of slow responding/ laggy when I move a picture around (with keyboard input)
Some of the error code:
Display is not capable of DPMS
ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM default
^CTraceback (most recent call last):
File "main.py", line 25, in <module>
time.sleep(10 / 1000)
KeyboardInterrupt
XIO: fatal IO error 11 (Resource temporarily unavailable) on X server ":0"
after 123 requests (123 known processed) with 12 events remaining.
exit status 1

2

Great tutorial, very easy for a beginner like me to follow!

3

It gives me the error message couldn't open dvd-logo-white.png when I run the program I don't know why.

1

@FilipH I had the same issue. The filename is case-sensitive (the code was looking for "dvd-logo-white.png" but my file uploaded as "dvd-logo-white.PNG").

2

Get in the corner!

1

I don't know if anyone else had this issue, but when I run the program it gives the message:
nohup: redirecting stderr to stdout
and then doesn't run it further.

1

this is so coooooooooooooooooooooooooollllll!!

1

There is a bug in this code, the logo doesn't change color.

1

@ChristianGlacet Hm. Well the logo was not supposed to change color. I put the other color in there just in case you wanted to use a white background. 🙂

1

@eankeen Ah don't worry that was just a joke as the typical bouncing DVD logo changes color :p

1

@eankeen A neat trick you could try to implement is to make sure it can't hit any corner but still have it to bounce all around with kind of uniform probability, that'd be super cool. Note sure if that's hard or not tho :p

1

@ChristianGlacet Yeah that sounds pretty cool. Heh, sometimes I have trouble detecting jokes myself.

1

So cool, check out our website https://jalcon.co.uk !

1

if dvdLogoRect.left < 0 or dvdLogoRect.right > width:
dvdLogoSpeed[0] = -dvdLogoSpeed[0]
if dvdLogoRect.top < 0 or dvdLogoRect.bottom > height:
dvdLogoSpeed[1] = -dvdLogoSpeed[1]

can anyone explain this part for me
thanks

1

@boohoo If it's touching the edge of the screen, invert its speed

1

Whenever I try to use another image, it gives an error that "couldn't open [imagename].png". I imported the image into the project directly from my computer. Is there another thing I have to do?

1

@Korkin Hm. Not that I know of. I tried loading a jpg and it worked fine. Maybe prepend a ./ to the filename, or use os.path.join?

1

An amazing job as always! Keep up the good work man.

1

My game is lagging too much in this what do i do to increase frame rate