Pygame Windows
Program Arcade Games With Python And Pygame. Program Arcade Games. With Python And Pygame. Now that you can create loops, it is time to move on to learning how to create graphics. This chapter covers. How the computer handles x, y coordinates. It isnt like the coordinate system you learned in math class. How to specify colors. With millions of colors to choose from, telling the computer what color to use isnt as easy as just saying red. How to open a blank window for drawing. Every artist needs a canvas. Spelling Blizzard Game there. How to draw lines, rectangles, ellipses, and arcs. Video The coordinate system for computer graphics. The Cartesian coordinate system, shown in. Figure 5. 1 Wikimedia Commons. This is the system taught in school. The computer uses a similar, but somewhat different, coordinate system. Understanding. why it is different requires a quick bit of computer history. Not many people are trying to capture images from their webcam using Python under Linux and blogging about it. In fact, I could find nobody who did that. This video shows how to enable pip for use via command line. Pip is a package manager for Python. It is used to install and uninstall packages that you. Figure 5. 1 Cartesian coordinate system. During the early 8. Figure 5. 2 Wikimedia Commons. Apple computer that was popular in the 8. More silly nonsense about Pygame Silliness built in. Pygame is meant to make software things fun. New silliness is added every 3. Source is a 3D video game engine developed by Valve Corporation as the successor of GoldSrc. It debuted with CounterStrike Source in June 2004, followed shortly by. When positioning text on the screen, programmers started. The screen continued down for 2. Figure 5. 2 Early Apple text screen. Even with plain text, it was possible to make rudimentary graphics by just using. See this kitten shown in Figure 5. When making this art, characters. Figure 5. 3 Text screen. Later the character set was expanded to include boxes and other primitive drawing. Pygame Windows' title='Pygame Windows' />Pygame is a crossplatform set of Python modules designed for writing video games. It includes computer graphics and sound libraries designed to be used with the. I recently installed Python 3. Pygame module for Python 3. When I type import python in the console I get the following error Traceback most recent call. Important The import pygame looks for a library file named pygame. If a programmer creates a new program named pygame. Characters could be drawn in different colors. As shown in. Figure 5. Search the web for. ASCII art and many more examples can be found. Figure 5. 4 Spaceware text screen. Once computers moved to being able to control individual pixels. Figure 5. 5 Computer coordinate system. The x coordinates work the same as the Cartesian coordinates system. But the y coordinates. Rather than the zero y coordinate at the bottom of the graph like in Cartesian. As the y values go up, the computer coordinate position moved down the screen, just like. Cartesian graphics. See Figure 5. 5. Also, note the screen covers the lower right quadrant, where the Cartesian coordinate system. It is possible to draw items at negative coordinates. This can be useful when part of a shape is off screen. The computer. figures out what is off screen and the programmer does not need to worry too much about it. Video Opening a Window. To make graphics easier to work with, well use Pygame. Pygame is a library of code other people have written. Draw graphic shapes. Display bitmapped images. Interact with keyboard, mouse, and gamepad. Detect when objects collide. The first code a Pygame program needs to do is. Pygame library. Every program that uses Pygame should. Import a library of functions called pygame. Initialize the game engine. If you havent installed Pygame yet, directions for installing. Pygame are available in. If Pygame is not installed on your computer, you will get an error. Dont name any file pygame. Important The import pygame looks for a library file named pygame. If a programmer creates a new program named pygame. This will prevent any pygame programs from working until. Next, we need to add variables that define. Colors are defined in a list of three colors red, green, and blue. Have you ever heard of an RGB monitor This is where the term comes. Red Green Blue. With older monitors, you could sit really close to the monitor and make out the. RGB colors. At least before your mom told you not to sit so close. TV. This is hard to do with todays high resolution monitors. Each element of the RGB triad is a number ranging from 0 to 2. Zero means there is none of the color, and 2. The colors combine in an additive. This is different. Lists in Python are surrounded by either square brackets or parentheses. Chapter 7 covers lists in detail and the difference between the two types. Individual numbers in the list are separated by commas. Below is an example that creates variables and sets them equal to lists of three numbers. These lists will be used later to specify colors. Define some colors. BLACK 0, 0, 0. WHITE 2. GREEN 0, 2. RED 2. BLUE 0, 0, 2. Why are these variables in upper caseRemember back from chapter one, a. We dont expect. the color of black to change it is a constant. We signify that variables are. If we expect a color to change, like. Using the interactive shell in IDLE, try defining these variables and printing them. If the five colors above arent the colors you are looking for, you can define your. To pick a color, find an on line color picker like the one shown in. Figure 5. 6. One such color picker is at http www. Figure 5. 6 Color picker. Extra Some color pickers specify colors in hexadecimal. You can enter hexadecimal. For example. WHITE 0x. FF, 0x. FF, 0x. FF. Eventually the program will need to use the value of pi when. It is also possible. PI 3. 1. 41. 59. So far, the programs we have created only printed text out to the screen. The code to open a window is not complex. Below is the required code. Why setmode Why not openwindow The reason is that. It can also create. This removes the start menu, title bars. Because this mode is slightly. But if you want to find out more about full screen. Also, why size 7. The same reason. why we put parentheses around the color definitions. Python cant. normally store two numbers a height and width into one variable. The only way it. can is if the numbers are stored as a list. Lists need either parentheses. Technically, parenthesis surrounding a set of numbers is. Lists surrounded by square brackets. An experienced Python developer would cringe at calling a. Also you can actually say size 7. I prefer to use parentheses. Lists are covered in detail in Chapter 7. To set the title of the window which is shown in the title bar use the following line of code. Professor Cravens Cool Game. With just the code written so far. The user cant interact with the window, even to close it. All of this needs to be programmed. Code needs to be added so that the program waits in a loop until. This is the most complex part of the program, and a complete understanding. But it is necessary to have an idea of what it does. Loop until the user clicks the close button. Used to manage how fast the screen updates. Clock. Main Program Loop. Main event loop. for event in pygame. User did something. QUIT If user clicked close. True Flag that we are done so we exit this loop. Game logic should go here. Drawing code should go here. First, clear the screen to white. Dont put other drawing commands. WHITE. Go ahead and update the screen with what weve drawn. Limit to 6. 0 frames per second. Eventually we will add code to handle the keyboard and mouse clicks. That code will go below the comment for main event loop on line 9. Code for. determining when bullets are fired and how objects move will go below the comment. Well talk about that in later chapters. Code to draw will go in below where the screen is filled with white on line 2. Keep that processing loop together. Alert One of the most frustrating problems programmers have. This event processing code handles all the keystrokes. For example your loop might look like. QUIT. printUser asked to quit. KEYDOWN. printUser pressed a key. KEYUP. printUser let go of a key. MOUSEBUTTONDOWN. printUser pressed a mouse button. The events like pressing keys all go together in a list. The program uses. Using a. chain of if statements the code figures out what type of event occurred, and the code to.