Pygame In a Few Minutes

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Imogen Russell
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1 Pygame In a Few Minutes By: Paul W. Yost Updated: 22 January 2016 Using Pygame: To use pygame, it must be imported and then initialized. import pygame pygame.init() # load the module # must be initialized before we do anything else with it. Surfaces: In pygame, graphical entities are called surfaces. We perform most operations on and with surfaces. We can make many surfaces and they can be of any size we'd like. Display Surface: One surface is special because it is the surface that is connected to the screen - this is called the display surface. pygame.display.set_mode((800,600),pygame.swsurface,24) # create the display surfaces There are other functions that relate to the display surface: pygame.display.list_modes() pygame.display.flip() pygame.display.update( rectangle ) pygame.display.update( rectangle_list ) pygame.display.set_caption( My Game ) # return a list of resolutions to use. # update the screen. # update an area of the screen # update multiple areas of the screen # set the window caption Creating Other Surfaces: Surfaces from an image file: mario = pygame.image.load( mario.jpg ) # create a surface for the image and load the image into it. Surfaces from a text string / font: To render text, first we must load a font by using a font object: or font = pygame.font.sysfont( Arial,20) font = pygame.font.font( myfont.ttf,size) # make a font object using a system installed font. # make a font object using a font file. Once we've created the font object, we can use it to create surfaces that are made from rendered text. text_surface = font.render( Game Over, anti_alias_0_1, fore_color, back_color )

2 Surfaces that are blank: It is often useful to create blank surfaces that can be used as our program runs. my_surface = pygame.surface((200,100)) # make a blank surface that is 200 x 100 pixels big Doing Stuff With Surfaces: Blitting: To copy image data from one surface onto another surface, we use the blit method on the surface we want to blit to. disp_surf.blit(mario, (10,10)) # blit from the mario surface to the disp_surface at offset 10,10. disp_surf.blit(game_over,(300,200)) #blit from game_over surface to disp_surface at offset 300,200. Drawing: Any of the drawing functions can be used to draw on any surface, including the display surface. Also, drawing can be performed on other surfaces that are off-screen. pygame.draw.line(disp_surf, color, (p1_x, p1_y), (p2_x, p2_y), width) # draw a line from p1 to p2. pygame.draw.circle(disp_surf, color, (center_x, center_y), radius, width) # draw circle The other drawing functions work similarly. Here is a list of some others: pygame.draw.ellipse pygame.draw.rect pygame.draw.arc pygame.draw.aaline pygame.draw.lines pygame.draw.polygon Pixel Operations: Pygame allows per-pixel manipulation on any surface. To get and set individual pixel values on a surface, you can do the following: surf.set_at((x, y), color) # set the pixel at (x,y) to the specified color. color = surf.get_at((x,y)) # get the color of the pixel at (x,y). Surface Transforms: Surfaces can be transformed in a number of ways: new_surf = pygame.transform.rotate(source_surface, angle) new_surf = pygame.transform.scale(source_surface, (width,height)) new_surf = pygame.transform.flip(source_surface, flip_x, flip_y ) new_surf = pygame.transform.rotozoom(source_surface, angle, zoom_factor)

3 Keyboard: Keyboard Input Overview: The keyboard gets events from the event queue for the application window. This means that to receive and update the set of all key states, something in the program needs to cause these events to be processed. This is done with the pygame.event.pump() function. pygame.event.pump() # process the events in the event queue. pygame.key.get_pressed() # returns a giant tuple that contains the state of each key on the keyboard. pygame.key.name( position ) # looks up the name associated with the key at the position in the tuple. You can also see if a key is pressed by checking it's location in the tuple like this: keyspressed = pygame.key.get_pressed() if keyspressed[pygame.k_escape]: #thing to do if key is pressed. Keyboard Helper Functions: I use helper functions to aid in checking the state of the keys. def keygetpressedlist(): pygame.event.pump() keyspressed = pygame.key.get_pressed() result = [] for i in range(0,len(keyspressed)): if keyspressed[i]: result.append(pygame.key.name(i)) return result def keyispressed( keysymbol ): if keysymbol in keygetpressedlist(): return True else: return False def keyisnotpressed( keysymbol ): if keysymbol not in keygetpressedlist(): return True else: return False Mouse: Overview: The mouse also gets events from the event queue for the application window. This means that to receive mouse positions from pygame the program needs to cause these events to be processed. Generally, if you are using keyboard input already ( such as calling one my keyboard helper functions ) in your game loop, the events are already being processed. If you have no keyboard input, you'll need to put a pygame.event.pump() call in your loop. (mouse_x,mouse_y) = pygame.mouse.get_pos() # returns a 2 element tuple containing the mouse position. (m_left,m_middle,m_right) = pygame.mouse.get_pressed() # returns the mouse button states. pygame.mouse.set_visible( True ) # show the mouse pointer.

4 pygame.mouse.set_visible( False ) # hide the mouse pointer. pygame.mouse.set_pos((x,y)) # set the mouse position to the location (x,y). Don't do this. Please. Mouse Helper Functions: It can also be useful to make some helper functions for the mouse. def mousegetx( ): return pygame.mouse.get_pos()[0] def mousegety( ): return pygame.mouse.get_pos()[1] def mousegetbuttonl( ): return pygame.mouse.get_pressed()[0] def mousegetbuttonm( ): return pygame.mouse.get_pressed()[1] def mousegetbuttonr( ): return pygame.mouse.get_pressed()[2] Timing: Pygame has several functions that can help manage time specific aspects of your game, including delays, fps calculation, and functionality that makes it easier to preserve a constant frame-rate. pygame.time.wait( milli_seconds ) # like time.sleep(), but built-in to pygame pygame.time.delay( milli_seconds ) # same as wait, but more accurate timing. Uses CPU while waiting. pygame.time.get_ticks( ) # return the number of milliseconds since pygame was initialized. myclock = pygame.time.clock( ) # create a clock object myclock.tick( milli_seconds ) # slows down loop to attempt to keep a constant frame-rate myclock.get_fps() # returns the calculated frame-rate based upon calls to tick. Sound and Music: Pygame has two types of distinct sound sources: sounds and music. Both types go through the pygame mixer object, which is responsible for playing back both sounds and music. Mixer Functions: pygame.mixer.set_num_channels(8) # set the number of sounds that can play simultaneously pygame.mixer.pause( ) # pause sound playback from all sources pygame.mixer.unpause( ) # resume paused playback pygame.mixer.fadeout( milli_seconds ) # fadeout playback over the specified time pygame.mixer.stop( ) # stop all playback instantly Sounds: Loading a Sound: Pygame supports.wav files and.ogg files: bubbles = pygame.mixer.sound( bubbles.wav ) # create a sound object and load the sound into it. bang = pygame.mixer.sound( bang.ogg ) # create a sound object and load the sound into it.

5 Using Sounds: Once a sound object has been created, it can be used in various ways: bubbles.play( ) # send the sound to the mixer to be played bubbles.set_volume( 0.5 ) # set the volume of the sound to 50% bubbles_vol = bubbles.get_volume( ) # get the current volume setting bubbles.fade_out( milli_seconds ) # fade out the sound over the specified number of milliseconds bubles_length = bubbles.get_length( ) # get the duration of the sound. bubbles.stop( ) # stop the playback of the sound. Music: Loading Music: Pygame supports many formats for music files including:.wav,.ogg,.mp3,.mid, and.mod files: pygame.mixer.music.load( filename ) # load the music file. Using Music: Once a music file has been loaded, it can be used in various ways: pygame.mixer.music.play( loops=0, startpos=0.0) # play back the loaded music. Loops=-1 means forever. pygame.mixer.music.stop( ) # immediately halt music playback. pygame.mixer.music.pause( ) # pause music playback. pygame.mixer.music.unpause( ) # resume music playback. pygame.mixer.music.set_volume( 0.5 ) # set music volume to 50%. music_volume = pygame.mixer.music.get_volume( ) # get music volume. pygame.mixer.music.fadeout( milli_seconds ) # fadeout music over the time specified pygame.mixer.music.rewind( ) # restart music from the beginning pygame.mixer.music.queue( filename ) # start the specified file one the playing one has completed Other Functions: Pygame has many other capabilities that haven't been explained in this document. For example, pygame includes functionality for MIDI device interfacing, joystick input, live camera input, movie playback, CD-Rom interfacing, changing the mouse pointer, etc. Visit: for more details and additional documentation.

PYTHON NOTES (drawing.py and drawstuff.py)

PYTHON NOTES (drawing.py and drawstuff.py) INTRODUCTION TO PROGRAMMING USING PYGAME STEP 1: Importing Modules and Initialization All the Pygame functions that are required to implement features like graphics