pakt00

See /software/p5js/pakt-februari/pakt00/ for a JavaScript version and /software/supercollider/februari-pakt/pakt00/ for accompanying sound code.

#include "cinder/app/App.h"
#include "cinder/cairo/Cairo.h"

using namespace ci;
using namespace ci::app;
using namespace std;

const int WIDTH= 640;
const int HEIGHT= 480;

class pakt00App : public App {
public:
  void setup();
  void draw();
  int index;
};

void pakt00App::setup() {
  index= 0;
}

void pakt00App::draw() {

  float x= getWindowCenter().x;
  float y= getWindowCenter().y;
  float w= getWindowWidth()*0.25;
  float h= getWindowHeight()*0.25;

  cairo::Context ctx( cairo::createWindowSurface() );

  cairo::GradientRadial radialGrad(getWindowCenter(), 0, getWindowCenter(), getWindowWidth());
  radialGrad.addColorStop(0, Color( 1, 1, 0.8));
  radialGrad.addColorStop(1, Color( 0, 0, 0));
  ctx.setSource(radialGrad);
  ctx.paint();

  ctx.setLineWidth(1);

  ctx.setSourceRgba(1, 1, 0.8, 1);
  for(int i= 0; i<120; i++) {
    float start= sin((index+i)*0.006+i)*M_PI;
    float end= sin((index+i)*0.0123+i)*2*M_PI;
    if(start<end) {
      ctx.arc(x, y, sin(index*0.01+i)*70+75, start, end);
    } else {
      ctx.arc(x+(sin(i*0.21)*w), y+(cos(i*0.2)*h), sin(index*0.01+i)*50+55, end, start);
    }
  }
  ctx.stroke();

  index++;
}

CINDER_APP(pakt00App, Renderer2d, [&]( App::Settings *settings ) {
  settings->setWindowSize( WIDTH, HEIGHT );
  settings->setResizable( false );
})