# Processing.js

## SineWave

by Daniel Shiffman. Render a simple sine wave.

Original Processing.org Example: SineWave

```// All Examples Written by Casey Reas and Ben Fry
// unless otherwise stated.
int xspacing = 8;   // How far apart should each horizontal location be spaced
int w;              // Width of entire wave

float theta = 0.0;       // Start angle at 0
float amplitude = 75.0;  // Height of wave
float period = 500.0;    // 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)

void setup() {
size(200,200);
frameRate(30);
colorMode(RGB,255,255,255,100);
smooth();
w = width+16;
dx = (TWO_PI / period) * xspacing;
yvalues = new float[w/xspacing];
}

void draw() {
background(0);
calcWave();
renderWave();

}

void calcWave() {
// Increment theta (try different values for 'angular velocity' here
theta += 0.02;

// 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;
}
}

void renderWave() {
// A simple way to draw the wave with an ellipse at each location
for (int x = 0; x < yvalues.length; x++) {
noStroke();
fill(255,50);
ellipseMode(CENTER);
ellipse(x*xspacing,width/2+yvalues[x],16,16);
}
}```