Python Playground : Geeky Projects for the Curious Programmer

Python is a powerful programming language thats easy to learn and fun to play with. But once youve gotten a handle on the basics, what do you do next? Python Playground is a collection of imaginative programming projects that will inspire you to use Python to make art and music, build simulations of real-world phenomena, and interact with hardware like the Arduino and Raspberry Pi. Youll learn to use common Python tools and libraries like numpy, matplotlib, and pygame to do things like: Generate Spirograph-like patterns using parametric equations and the turtle module Create music on your computer by simulating frequency overtones Translate graphical images into ASCII art Write an autostereogram program that produces 3D images hidden beneath random patterns Make realistic animations with OpenGL shaders by exploring particle systems, transparency, and billboarding techniques Construct 3D visualizations using data from CT and MRI scans Build a laser show that responds to music by hooking up your computer to an Arduino Programming shouldnt be a chore. Have some solid, geeky fun with Python Playground . The projects in this book are compatible with both Python 2 and 3. Brief Contents Contents in Detail Acknowledgments Introduction Who Is This Book For? What’s in This Book? Part I: Warming Up Part II: Simulating Life Part III: Fun with Images Part IV: Enter the 3D Part V: Hardware Hacking Why Python? Python Versions The Code in This Book Part I: Warming Up Chapter 1: Parsing iTunes Playlists Anatomy of the iTunes Playlist File Requirements The Code Finding Duplicates Extracting Duplicates Finding Tracks Common Across Multiple Playlists Collecting Statistics Plotting Your Data Command Line Options The Complete Code Running the Program Summary Experiments! Chapter 2: Spirographs Parametric Equations Spirograph Equations Turtle Graphics Requirements The Code The Spiro Constructor The Setup Functions The restart() Method The draw() Method Creating the Animation The SpiroAnimator Class The genRandomParams() Method Restarting the Program The update() Method Showing or Hiding the Cursor Saving the Curves Parsing Command Line Arguments and Initialization The Complete Code Running the Spirograph Animation Summary Experiments! Part II: Simulating Life Chapter 3: Conway’s Game of Life How It Works Requirements The Code Representing the Grid Initial Conditions Boundary Conditions Implementing the Rules Sending Command Line Arguments to the Program Initializing the Simulation The Complete Code Running the Game of Life Simulation Summary Experiments! Chapter 4: Generating Musical Overtones with the Karplus-Strong Algorithm How It Works The Simulation Creating WAV Files The Minor Pentatonic Scale Requirements The Code Implementing the Ring Buffer with deque Implementing the Karplus-Strong Algorithm Writing a WAV File Playing WAV Files with pygame The main() Method The Complete Code Running the Plucked String Simulation Summary Experiments! Chapter 5: Boids: Simulating a Flock How It Works Requirements The Code Computing the Position and Velocities of the Boids Setting Boundary Conditions Drawing a Boid Applying the Rules of the Boids Adding a Boid Scattering the Boids Command Line Arguments The Boids Class The Complete Code Running the Boids Simulation Summary Experiments! Part III: Fun with Images Chapter 6: ASCII Art How It Works Requirements The Code Defining the Grayscale Levels and Grid Computing the Average Brightness Generating the ASCII Content from the Image Command Line Options Writing the ASCII Art Strings to a Text File The Complete Code Running the ASCII Art Generator Summary Experiments! Chapter 7: Photomosaics How It Works Splitting the Target Image Averaging Color Values Matching Images Requirements The Code Reading in the Tile Images Calculating the Average Color Value of the Input Images Splitting the Target Image into a Grid Finding the Best Match for a Tile Creating an Image Grid Creating the Photomosaic Adding the Command Line Options Controlling the Size of the Photomosaic The Complete Code Running the Photomosaic Generator Summary Experiments! Chapter 8: Autostereograms How It Works Perceiving Depth in an Autostereogram Depth Maps Requirements The Code Repeating a Given Tile Creating a Tile from Random Circles Creating Autostereograms Command Line Options The Complete Code Running the Autostereogram Generator Summary Experiments! Part IV: Enter 3D Chapter 9: Understanding OpenGL Old-School OpenGL Modern OpenGL: The 3D Graphics Pipeline Geometric Primitives 3D Transformations Shaders Vertex Buffers Texture Mapping Displaying OpenGL Requirements The Code Creating an OpenGL Window Setting Callbacks The Scene Class The Complete Code Running the OpenGL Application Summary Experiments! Chapter 10: Particle Systems How It Works Modeling the Motion of a Particle Setting a Maximum Spread Rendering the Particles Using OpenGL Blending to Create More Realistic Sparks Using Billboarding Animating the Sparks Requirements The Code for the Particle System Defining the Particle Geometry Defining the Time-Lag Array for the Particles Setting the Initial Particle Velocities Creating the Vertex Shader Creating the Fragment Shader Rendering The Camera Class The Complete Particle System Code The Box Code The Code for the Main Program Updating the Particles at Each Step The Keyboard Handler Managing the Main Program Loop The Complete Main Program Code Running the Program Summary Experiments! Chapter 11: Volume Rendering How It Works Data Format Generating Rays Displaying the OpenGL Window Requirements An Overview of the Project Code Generating a 3D Texture The Complete 3D Texture Code Generating Rays Defining the Color Cube Geometry Creating the Frame Buffer Object Rendering the Back-Faces of the Cube Rendering the Front-Faces of the Cube Rendering the Whole Cube The Resize Handler The Complete Ray Generation Code Volume Ray Casting The Vertex Shader The Fragment Shader The Complete Volume Ray Casting Code 2D Slicing The Vertex Shader The Fragment Shader A User Interface for 2D Slicing The Complete 2D Slicing Code Putting the Code Together The Complete Main File Code Running the Program Summary Experiments! Part V: Hardware Hacking Chapter 12: Introduction to the Arduino The Arduino The Arduino Ecosystem Language IDE Community Peripherals Requirements Building the Light-Sensing Circuit How the Circuit Works The Arduino Sketch Creating the Real-Time Graph The Python Code The Complete Python Code Running the Program Summary Experiments! Chapter 13: Laser Audio Display Generating Patterns with a Laser Motor Control The Fast Fourier Transform Requirements Constructing the Laser Display Wiring the Motor Driver The Arduino Sketch Configuring the Arduino’s Digital Output Pins The Main Loop Stopping the Motors The Python Code Selecting the Audio Device Reading Data from the Input Device Computing the FFT of the Data Stream Extracting Frequency Information from the FFT Values Converting Frequency to Motor Speed and Direction Testing the Motor Setup Command Line Options Manual Testing The Complete Python Code Running the Program Summary Experiments! Chapter 14: A Raspberry Pi–Based Weather Monitor The Hardware The DHT11 Temperature and Humidity Sensor The Raspberry Pi Setting Up Your Pi Installing and Configuring Software The Operating System Initial Configuration Wi-Fi Setup Setting Up the Programming Environment Connecting via SSH The Bottle Web Framework Plotting with flot Shutting Down the Pi Building the Hardware The Code Handling Sensor Data Requests Plotting the Data The update() Method The JavaScript Handler for the LED Adding Interactivity The Complete Code Running the Program Summary Experiments! Appendix A: Software Installation Installing Source Code for the Book’s Projects Installing on Windows Installing GLFW Installing Prebuilt Binaries for Each Module Other Options Installing on OS X Installing Xcode and MacPorts Installing Modules Installing on Linux Appendix B: Basic Practical Electronics Common Components Essential Tools Building Circuits Going Further Appendix C: Raspberry Pi Tips & Tricks Setting Up Wi-Fi Checking Whether Your Pi Is Connected Preventing the Wi-Fi Adapter from Going to Sleep Backing Up Your Code and Data from the Pi Backing Up Your Entire Pi OS Logging In to Your Pi with SSH Using the Raspberry Pi Camera Enabling Sound on Your Pi Making Your Pi Talk Making HDMI Work Making Your Pi Mobile Checking Your Raspberry Pi Hardware Version Index Resources More No-nonsense Books from No Starch Press About the Author Python is a powerful programming language that's fun to play around with. Getting to know Python isn't just about hammering syntax into your brain--it's about discovering new tools to explore whatever excites you. Python Playground is a collection of fun programming projects that will inspire you to new heights as a Pythonista. Inside, you'll learn to use Python for all kinds of playful purposes. You'll manipulate images, build simulations, and interact with hardware using Arduino and Raspberry Pi. As you work through each project, you'll power up your programming skills as you learn how to leverage external libraries for specialized tasks, how to break problems into smaller, solvable pieces, and how to translate an algorithm into code Provides instructions for programming projects using Python that teach such programming skills as how to leverage external libraries for specialized tasks, how to break problems into solvable pieces, and how to translate an algorithm into code