ماهیت کد [شبیه‌سازی سیستم‌های طبیعی با پردازش]

How can we capture the unpredictable evolutionary and emergent properties of nature in software? How can understanding the mathematical principles behind our physical world help us to create digital worlds? This book focuses on a range of programming strategies and techniques behind computer simulations of natural systems, from elementary concepts in mathematics and physics to more advanced algorithms that enable sophisticated visual results. Readers will progress from building a basic physics engine to creating intelligent moving objects and complex systems, setting the foundation for further experiments in generative design. Subjects covered include forces, trigonometry, fractals, cellular automata, self-organization, and genetic algorithms. The book's examples are written in Processing, an open-source language and development environment built on top of the Java programming language. On the book's website ((http://www.natureofcode.com) http://www.natureofcode.com ), the examples run in the browser via Processing's JavaScript mode. The Nature of Code Dedication Acknowledgments A.1 A little bit of history A.2 Kickstarter Preface P.1 What is this book? P.2 A word about Processing P.3 What do you need to know? P.4 What are you using to read this book? P.5 The “story” of this book Part I: Inanimate Objects. Part II: It’s alive! Part III: Intelligence P.6 This book as a syllabus P.7 The Ecosystem Project P.8 Where do I find the code online and submit feedback? Table of Contents Introduction I.1 Random Walks I.2 The Random Walker Class Pseudo-Random Numbers Exercise I.1 I.3 Probability and Non-Uniform Distributions Exercise I.2 Exercise I.3 I.4 A Normal Distribution of Random Numbers Calculating Mean and Standard Deviation Exercise I.4 Exercise I.5 I.5 A Custom Distribution of Random Numbers Exercise I.6 I.6 Perlin Noise (A Smoother Approach) Noise Detail Mapping Noise Exercise I.7 Two-Dimensional Noise Exercise I.8 Exercise I.9 Exercise I.10 I.7 Onward Chapter 1. Vectors 1.1 Vectors, You Complete Me 1.2 Vectors for Processing Programmers 1.3 Vector Addition Exercise 1.1 Exercise 1.2 Exercise 1.3 1.4 More Vector Math Vector subtraction Basic Number Properties with Vectors Vector multiplication More Number Properties with Vectors 1.5 Vector Magnitude 1.6 Normalizing Vectors 1.7 Vector Motion: Velocity 1.8 Vector Motion: Acceleration Acceleration Algorithms! Exercise 1.4 Exercise 1.5 Exercise 1.6 1.9 Static vs. Non-Static Functions Exercise 1.7 1.10 Interactivity with Acceleration Exercise 1.8 The Ecosystem Project Chapter 2. Forces 2.1 Forces and Newton’s Laws of Motion Newton’s First Law Newton’s Third Law Newton’s Third Law (as seen through the eyes of Processing) 2.2 Forces and Processing—Newton’s Second Law as a Function Newton’s Second Law Weight vs. Mass 2.3 Force Accumulation Exercise 2.1 2.4 Dealing with Mass Units of Measurement Exercise 2.2 2.5 Creating Forces Exercise 2.3 2.6 Gravity on Earth and Modeling a Force Dealing with formulae 2.7 Friction Exercise 2.4 2.8 Air and Fluid Resistance Exercise 2.5 Exercise 2.6 Exercise 2.7 2.9 Gravitational Attraction Exercise 2.8 Exercise 2.9 2.10 Everything Attracts (or Repels) Everything Exercise 2.10 The Ecosystem Project Chapter 3. Oscillation 3.1 Angles What is PI? Exercise 3.1 3.2 Angular Motion Exercise 3.2 3.3 Trigonometry 3.4 Pointing in the Direction of Movement Exercise 3.3 3.5 Polar vs. Cartesian Coordinates Exercise 3.4 Exercise 3.5 3.6 Oscillation Amplitude and Period Exercise 3.6 3.7 Oscillation with Angular Velocity Exercise 3.7 Exercise 3.8 3.8 Waves Exercise 3.9 Exercise 3.10 Exercise 3.11 3.9 Trigonometry and Forces: The Pendulum Exercise 3.12 Exercise 3.13 Exercise 3.14 3.10 Spring Forces Exercise 3.15 Exercise 3.16 The Ecosystem Project Chapter 4. Particle Systems 4.1 Why We Need Particle Systems 4.2 A Single Particle Exercise 4.1 Exercise 4.2 4.3 The ArrayList 4.4 The Particle System Class Exercise 4.3 Exercise 4.4 4.5 A System of Systems Exercise 4.5 Exercise 4.6 4.6 Inheritance and Polymorphism: An Introduction 4.7 Inheritance Basics 4.8 Particles with Inheritance Exercise 4.7 4.9 Polymorphism Basics 4.10 Particle Systems with Polymorphism Exercise 4.8 4.11 Particle Systems with Forces 4.12 Particle Systems with Repellers Exercise 4.9 Exercise 4.10 4.13 Image Textures and Additive Blending Exercise 4.11 Exercise 4.12 Exercise 4.13 Exercise 4.14 The Ecosystem Project Chapter 5. Physics Libraries 5.1 What Is Box2D and When Is It Useful? 5.2 Getting Box2D in Processing 5.3 Box2D Basics SETUP DRAW Core elements of a Box2D world: 5.4 Living in a Box2D World 5.5 Building a Box2D body Step 1: Define a body. Step 2: Configure the body definition. Step 3: Create the body. Step 4: Set any other conditions for the body’s starting state. 5.6 Three’s Company: Bodies and Shapes and Fixtures Step 1: Define a shape. Step 2: Create a fixture. Step 3: Attach the shape to the body with the fixture. Exercise 5.1 5.7 Box2D and Processing: Reunited and It Feels So Good Step 1: Add Box2D to our main program (i.e. setup() and draw()). Step 2: Link every Processing Box object with a Box2D Body object. Exercise 5.2 5.8 Fixed Box2D Objects 5.9 A Curvy Boundary Step 1: Define a body. Step 2: Define the Shape. Step 3: Configure the Shape. Step 4: Attach the Shape to the body with a Fixture. Exercise 5.3 5.10 Complex Forms Exercise 5.4 Exercise 5.5 5.11 Feeling Attached—Box2D Joints Exercise 5.6 Step 1: Make sure you have two bodies ready to go. Step 2: Define the joint. Step 3: Configure the joint’s properties. Step 4: Create the joint Exercise 5.7 Exercise 5.8 Exercise 5.9 5.12 Bringing It All Back Home to Forces Exercise 5.10 5.13 Collision Events Step 1: Contact, could you tell me what two things collided? Step 2: Fixtures, could you tell me which body you are attached to? Step 3: Bodies, could you tell me which Particles you are associated with? Exercise 5.11 Exercise 5.12 5.14 A Brief Interlude—Integration Methods 5.15 Verlet Physics with toxiclibs Getting toxiclibs Core Elements of VerletPhysics Vectors with toxiclibs Building the toxiclibs physics world 5.16 Particles and Springs in toxiclibs 5.17 Putting It All Together: A Simple Interactive Spring 5.18 Connected Systems Part I: String Exercise 5.13 5.19 Connected Systems Part II: Force-Directed Graph Exercise 5.14 Exercise 5.15 5.20 Attraction and Repulsion Behaviors Exercise 5.16 Exercise 5.17 The Ecosystem Project Chapter 6. Autonomous Agents 6.1 Forces from Within 6.2 Vehicles and Steering Why Vehicle? 6.3 The Steering Force Exercise 6.1 Exercise 6.2 Exercise 6.3 6.4 Arriving Behavior 6.5 Your Own Desires: Desired Velocity Exercise 6.4 Exercise 6.5 6.6 Flow Fields Exercise 6.6 Exercise 6.7 Exercise 6.8 6.7 The Dot Product Exercise 6.9 6.8 Path Following 6.9 Path Following with Multiple Segments Exercise 6.10 Exercise 6.11 6.10 Complex Systems 6.11 Group Behaviors (or: Let’s not run into each other) Exercise 6.12 Exercise 6.13 6.12 Combinations Exercise 6.14 6.13 Flocking Exercise 6.15 Exercise 6.16 Exercise 6.17 Exercise 6.18 Exercise 6.19 6.14 Algorithmic Efficiency (or: Why does my $@(*%! run so slowly?) 6.15 A Few Last Notes: Optimization Tricks 1) Magnitude squared (or sometimes distance squared) 2) Sine and cosine lookup tables 3) Making gajillions of unnecessary PVector objects Exercise 6.20 Exercise 6.21 The Ecosystem Project Chapter 7. Cellular Automata 7.1 What Is a Cellular Automaton? 7.2 Elementary Cellular Automata 7.3 How to Program an Elementary CA 7.4 Drawing an Elementary CA Exercise 7.1 Exercise 7.2 Exercise 7.3 Exercise 7.4 7.5 Wolfram Classification Exercise 7.5 7.6 The Game of Life 7.7 Programming the Game of Life Exercise 7.6 Exercise 7.7 Exercise 7.8 7.8 Object-Oriented Cells 7.9 Variations of Traditional CA Exercise 7.9 Exercise 7.10 Exercise 7.11 Exercise 7.12 Exercise 7.13 Exercise 7.14 Exercise 7.15 The Ecosystem Project Chapter 8. Fractals 8.1 What Is a Fractal? 8.2 Recursion 8.3 The Cantor Set with a Recursive Function Exercise 8.1 8.4 The Koch Curve and the ArrayList Technique The “Monster” Curve Exercise 8.2 Exercise 8.3 Exercise 8.4 Exercise 8.5 8.5 Trees Exercise 8.6 Exercise 8.7 Exercise 8.8 Exercise 8.9 Exercise 8.10 Exercise 8.11 8.6 L-systems Exercise 8.12 Exercise 8.13 Exercise 8.14 The Ecosystem Project Chapter 9. The Evolution of Code 9.1 Genetic Algorithms: Inspired by Actual Events 9.2 Why Use Genetic Algorithms? Exercise 9.1 9.3 Darwinian Natural Selection 9.4 The Genetic Algorithm, Part I: Creating a Population 9.5 The Genetic Algorithm, Part II: Selection 9.6 The Genetic Algorithm, Part III: Reproduction 9.7 Code for Creating the Population Step 1: Initialize Population Step 2: Selection Exercise 9.2 Exercise 9.3 Step 3: Reproduction Exercise 9.4 Exercise 9.5 9.8 Genetic Algorithms: Putting It All Together Exercise 9.6 9.9 Genetic Algorithms: Make Them Your Own Key #1: Varying the variables Key #2: The fitness function Exercise 9.7 Key #3: Genotype and Phenotype 9.10 Evolving Forces: Smart Rockets 9.11 Smart Rockets: Putting It All Together Exercise 9.8 Exercise 9.9 Exercise 9.10 Exercise 9.11 Exercise 9.12 9.12 Interactive Selection Exercise 9.14 9.13 Ecosystem Simulation Genotype and Phenotype Selection and Reproduction The Ecosystem Project Chapter 10. Neural Networks 10.1 Artificial Neural Networks: Introduction and Application 10.2 The Perceptron 10.3 Simple Pattern Recognition Using a Perceptron 10.4 Coding the Perceptron Exercise 10.1 Exercise 10.2 10.5 A Steering Perceptron Exercise 10.3 Exercise 10.4 10.6 It’s a “Network,” Remember? 10.7 Neural Network Diagram 10.8 Animating Feed Forward Exercise 10.5 Exercise 10.6 Exercise 10.7 The Ecosystem Project The end Further Reading Books Papers and Articles Index Introduction -- Ch. 1. Vectors -- Ch. 2. Forces -- Ch. 3. Oscillation -- Ch. 4. Particle Systems -- Ch. 5. Physics Libraries -- Ch. 6. Autonomous Agents -- Ch. 7. Cellular Automata -- Ch. 8. Fractals -- Ch. 9. The Evolution Of Code -- Ch. 10. Neural Networks -- Further Reading. By Daniel Shiffman ; Editor, Shannon Fry ; Illustrations, Zannah Marsh. This Work Is Licensed Under The Creative Commons Attribution-noncommercial 3.0 Unported License--page Iii. Includes Bibliographical References And Index.