#javascript-processing-example-basic-math-graphing2dequation.htm / htm
<!DOCTYPE html> <html><head> <script src="javascript-processing-example-processing.js"></script> <script src="javascript-processing-example-init.js"></script> <link rel="stylesheet" href="javascript-processing-example-style.css"> </head><body><h1><a href="http://ejohn.org/blog/processingjs/">Processing.js</a></h1> <h2>Graphing2DEquation</h2> <p>by Daniel Shiffman. Graphics the following equation: sin(n*cos(r) + 5*theta) where n is a function of horizontal mouse location.</p> <p><a href="http://processing.org/learning/basics/graphing2dequation.html"><b>Original Processing.org Example:</b> Graphing2DEquation</a><br> <script type="application/processing"> void setup() { size(50,50); frameRate(30); } void draw() { loadPixels(); float n = (mouseX * 10.0) / width; float w = 16.0; // 2D space width float h = 16.0; // 2D space height float dx = w / width; // Increment x this amount per pixel float dy = h / height; // Increment y this amount per pixel float x = -w/2; // Start x at -1 * width / 2 for (int i = 0; i < width; i++) { float y = -h/2; // Start y at -1 * height / 2 for (int j = 0; j < height; j++) { float r = sqrt((x*x) + (y*y)); // Convert cartesian to polar float theta = atan2(y,x); // Convert cartesian to polar // Compute 2D polar coordinate function float val = sin(n*cos(r) + 5 * theta); // Results in a value between -1 and 1 //float val = cos(r); // Another simple function //float val = sin(theta); // Another simple function // Map resulting vale to grayscale value pixels[i+j*width] = color((val + 1.0) * 255.0/2.0); // Scale to between 0 and 255 y += dy; // Increment y } x += dx; // Increment x } updatePixels(); } </script><canvas width="50" height="50"></canvas></p> <div style="overflow: hidden; height: 0px; width: 0px;"></div> <pre><b>// All Examples Written by <a href="http://reas.com/">Casey Reas</a> and <a href="http://benfry.com/">Ben Fry</a> // unless otherwise stated.</b> void setup() { size(200,200); frameRate(30); } void draw() { loadPixels(); float n = (mouseX * 10.0) / width; float w = 16.0; // 2D space width float h = 16.0; // 2D space height float dx = w / width; // Increment x this amount per pixel float dy = h / height; // Increment y this amount per pixel float x = -w/2; // Start x at -1 * width / 2 for (int i = 0; i < width; i++) { float y = -h/2; // Start y at -1 * height / 2 for (int j = 0; j < height; j++) { float r = sqrt((x*x) + (y*y)); // Convert cartesian to polar float theta = atan2(y,x); // Convert cartesian to polar // Compute 2D polar coordinate function float val = sin(n*cos(r) + 5 * theta); // Results in a value between -1 and 1 //float val = cos(r); // Another simple function //float val = sin(theta); // Another simple function // Map resulting vale to grayscale value pixels[i+j*width] = color((val + 1.0) * 255.0/2.0); // Scale to between 0 and 255 y += dy; // Increment y } x += dx; // Increment x } updatePixels(); }</pre> </body></html>
(C) Æliens 20/2/2008
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