/*
    Written by Alex Young

    Based on:
        http://astronomy.swin.edu.au/~pbourke/fractals/peterdejong/
*/

int width = 400, height = 400;
int iteration;
int colourRate = 6;

color defaultColour;
color colour;

float x = 0, y = 0, x2, y2;
int px, py;
float a, b, c, d;

void setup()
{
    defaultColour = color(100, 100, 140);

    size(width, height);
    colorMode(RGB, 255);
    stroke(defaultColour);

    // Make a nice gradient    
    for (y = 0; y < height; y++)
    {
        stroke(red(defaultColour) - (y / 3), green(defaultColour) - (y / 3), blue(defaultColour) - (y / 3));
        line(0, y, width, y);
    }
    a = random_coord();
    b = random_coord();
    c = random_coord();
    d = random_coord();
}

void loop()
{
    for (iteration = 0; iteration < 150; iteration++)
    {
    	if (mousePressed == true)
	    {
		    setup();
	    }
	                  
        x2 = cos(a * x) - sin(c * y);
        y2 = sin(b * x) - cos(d * y);

        // Convert to screen co-ords
        px = int((x2 + 1) * 70) + 70;
        py = int((y2 + 1) * 70) + 70;
 
        // Get the colour of the pixel
        colour = get(px, py);
        colour = color(red(colour) + colourRate, green(colour) + colourRate, blue(colour) + colourRate);
        set(px, py, colour);
        
        x = x2;
        y = y2;
     }
}

float random_coord()
{
    if (random(1) > 0.7)
    {
        return random(4)  * -1;
    }
    else
    {
        return random(4);
    }
}