using controlp5 example

Knob controlling a ring of points.pde

/**
* ControlP5 Knob - modified by Steve
*
*
* find a list of public methods available for the Knob Controller
* at the bottom of this sketch.
*
* by Andreas Schlegel, 2012
* www.sojamo.de/libraries/controlp5
*
*/

import controlP5.*;


ControlP5 cp5;

float radius=150;

int knobValue = 100;
int knobRadius;

Knob myKnobA;

void setup() {
  size(700,400);
  smooth();
  noStroke();
  
  cp5 = new ControlP5(this);
  
  myKnobA = cp5.addKnob("knob")
               .setRange(0,255)
               .setValue(50)
               .setPosition(100,height-150)
               .setRadius(50)
               .setDragDirection(Knob.VERTICAL)
               .setColorForeground(color(255))
               .setColorBackground(color(0, 160, 100))
               .setColorActive(color(255,255,0))
               ;
                     
}
void draw() {
  background(0);

  
  //fill(255,0,0);
  //rect(100,100,myColorBackground+300,myColorBackground+100);
    stroke(255);
    strokeWeight(3);
      pushMatrix();
      translate(width/2, height/2);
    
    float angle=TWO_PI/(float)knobRadius;
    for(int i=0;i<knobRadius;i++)
    {
      point(radius*sin(angle*i),radius*cos(angle*i));
    } 
    
    popMatrix();
    
    noStroke();
    

}


void knob(int theValue) {
  knobRadius = theValue;
  println("a knob event. setting background to "+theValue);
}


void keyPressed() {
  switch(key) {
    case('1'):myKnobA.setValue(50);break;
    case('2'):myKnobA.shuffle();break;
  }
  
}