Spiral with Gradient

Compiled with Processing (www.proce55ing.org)

Rick Companje (www.companje.nl)

October 1^st, 2005

int xMax, xMin, yMax, yMin, xCenter, yCenter;

int x=0,y=0;

int xr=1,yr=1;

float rMin,rMax,r,rr=.1;

void setup() {

framerate(20);

size(200,200);

xMin = -width/2; xCenter = 0; xMax = width/2;

yMin = -height/2; yCenter = 0; yMax = height/2;

rMin = 4*PI; rMax = 12*PI; r=rMin;

}

void draw() {

background(100);

translate(xMax,yMax);

stroke(50);

line(xMin,0,xMax,0);

line(0,yMin,0,yMax);

spiral(0,0,getMouseX(),getMouseY(),r);

x+=xr; y+=yr; r+=rr;

if (r>rMax || r<rMin) rr=-rr;

if (x>xMax || x<xMin) xr=-xr;

if (y>yMax || y<yMin) yr=-yr;

}

int getMouseX() { return mouseX-width/2; }

int getMouseY() { return mouseY-height/2; }

void mouseMoved() { r=rMax; }

void spiral(float xc,float yc,float xm,float ym,float rmax) {

float x,y,xp=0,yp=0;

float d=dist(xc,yc,xm,ym);

float r=atan2(ym, xm) + rmax;

while (r>0) {

x=-sin(r-HALF_PI)*(r/rmax)*d + xc;

y= cos(r-HALF_PI)*(r/rmax)*d + yc;

stroke(255-255*(r/rmax));

line(0,0,x,y);

stroke(255);

line(x,y,xp,yp);

xp=x;

yp=y;

r-=.02;

}

}