a port of the Processing Visualization Language

Graphing2DEquation

by Daniel Shiffman. Graphics the following equation: sin(n*cos(r) + 5*theta) where n is a function of horizontal mouse location.

Original Processing.org Example: Graphing2DEquation

// All Examples Written by Casey Reas and Ben Fry

// unless otherwise stated.

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();

}
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