Rainbow Waves

// Sine Wave

// Daniel Shiffman <http://www.shiffman.net>

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// Render a simple sine wave

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// Created 2 May 2005

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int xspacing = 8;   // How far apart should each horizontal location be spaced

int w;              // Width of entire wave

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float theta = 0.0f;       // Start angle at 0

float amplitude = 175.0f;  // Height of wave

float period = 500.0f;    // How many pixels before the wave repeats

float dx;                 // Value for incrementing X, to be calculated as a function of period and xspacing

float[] yvalues;          // Using an array to store height values for the wave (not entirely necessary)

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void setup() {

  size(600,600);

  colorMode(HSB);

  smooth();

  w = width+16;

  dx = (TWO_PI / period) * xspacing;

  yvalues = new float[w/xspacing];

  println(yvalues.length);

}

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void draw() {

  //background(255);

  fill(255,10);

  rect(0,0,width,height);

  calcWave();

  renderWave();

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}

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void calcWave() {

  // Increment theta (try different values for 'angular velocity' here

  theta += 0.02;

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  // For every x value, calculate a y value with sine function

  float x = theta;

  for (int i = 0; i < yvalues.length; i++) {

    yvalues[i] = sin(x)*amplitude;

    x+=dx;

  }

}

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void renderWave() {

  // A simple way to draw the wave with an ellipse at each location

  for ( int x = 0; x < yvalues.length; x++ ) {

    stroke( x, 255, 255, 50 );

    fill( yvalues[x], 155, 255, 1 );

    ellipseMode( CENTER );

    ellipse( x*xspacing,width/2+yvalues[x],yvalues[(x+x)%77],yvalues[(x+x+x)%77] );

  }

}

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