Hello!

Can anyone tell me why random() here seems to repeat? I would like the ellipse height and width to be between 0-200, it seems to keep making new values leading to odd animation.

1. void setup() {
       size(800, 800);
       ellipseMode(CENTER);
       smooth();
   }
   
   void draw() {
       background(255);
       ellipse( width/2, height/2, random(200), random(200));
   }

I know this is prob really simple but can't find an answer.

Many Thanks!

Hello All!

New to programming and Processing so thanks for your patience/help.

Trying to generate 15 squares oscillating with simple harmonic motion but with different periods, each is essentially a pendulum. Here is an example that works by entering the periods of each oscillator manually:

1. void setup() {
     size(800,340);
   }
   
   color c = color(255);
   float x = 400;
   
   void draw()
   
   {
     background(0);
     noStroke();
     int l = millis();
     fill(c);
     rectMode(CENTER);
2. 
     rect( x +( sin((cos((2*(PI*(millis())))/4013))))*300,20,20,20); 
3. 
   
4. /* generates a rect that moves along x axis under simple harmonic motion with period 4013 etc*/
    
   
5.   rect( x +( sin((cos((2*(PI*(millis())))/3822))))*300,40,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/3648))))*300,60,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/3489))))*300,80,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/3344))))*300,100,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/3210))))*300,120,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/3086))))*300,140,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/2973))))*300,160,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/2866))))*300,180,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/2768))))*300,200,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/2675))))*300,220,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/2589))))*300,240,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/2508))))*300,260,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/2432))))*300,280,20,20);
     rect( x +( sin((cos((2*(PI*(millis())))/2361))))*300,300,20,20);
   }
   

I am trying to do this with a for loop but am only getting the first oscillator:

1. void setup() {
     size(800,340);
   }
   
   color c = color(255);
   
   void draw() {
     background (0);
     noStroke();
     fill(c);
     for( int i = 0 ; i <= 14 ; i = i + 1 ) {
         float l_1 = 4;
         float x = 350;
         int m = millis();
         float l = l_1 * ( pow ( ( 20 / ( 20 + i )) , 2 ) );
         float t = TWO_PI * sqrt( ( l / 9.80665));
         float tn = t * 1000; // period of ith oscillator in milliseconds
         float p = sin ( ( cos ( ( 2 * ( PI * m ) ) / tn ) ) ); // x position of ith oscillator at millis() with values between +-1
         float pn = x + (p * 300); // centers each oscillator on screen and moves according to p through +-300
         rectMode(CENTER);
         rect( pn , (i + 1) * 20 , 20 , 20 );
     } 
   }
   

Any ideas? In my head this for loop generates each oscillator with initial coordinates (x = 350, y = (i +1) * 20), where am i going wrong?

Many thanks, processing is Great!