pakt20

See /software/p5js/pakt-februari/pakt20/ for a JavaScript version and /software/supercollider/februari-pakt/pakt20/ 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 pakt20App : public App {
public:
  void setup();
  void draw();
  cairo::SurfaceImage srfOff;
  cairo::Context ctxOff;
  int index, n;
  float w, h;
  float spread;
};

void pakt20App::setup() {
  srfOff= cairo::SurfaceImage(WIDTH, HEIGHT, false);
  ctxOff= cairo::Context(srfOff);
  ctxOff.setSourceRgb(0, 0, 0);
  ctxOff.paint();
  ctxOff.setLineWidth(1);
  ctxOff.setAntiAlias(0);
  index= 0;
  w= getWindowWidth();
  h= getWindowHeight();
  n= 150;
}

void pakt20App::draw() {
  cairo::Context ctx(cairo::createWindowSurface());
  spread= sin(index*0.002f);
  for(int i= 0; i<n; i++) {
    float tx= sin(0.012f*(index+(i*spread)));
    float ty= sin(0.014f*(index+(i*spread)));
    float tz= sin(0.016f*(index+(i*spread)))*0.5f+0.5f;
    ctxOff.setSourceRgba(tz, tz*0.9f, tz, 0.05f);
    ctxOff.moveTo(vec2(sin(tx+sin(index*0.001f))*(sin(tx)*0.001f+1.0f)*w*0.46f+(w*0.5f), sin(ty+cos(index*0.001f*i))*(cos(ty)*0.001f+1.0f)*h*0.46f+(h*0.5f)));
    ctxOff.lineTo(vec2(cos(ty+sin(index*0.001f))*(sin(tx)*0.001f+1.0f)*w*0.36f+(w*0.5f), sin(tx+cos(index*0.001f*i))*(cos(ty)*0.001f+1.0f)*h*0.36f+(h*0.5f)));
    ctxOff.stroke();
  }
  index++;
  ctx.copySurface(srfOff, srfOff.getBounds());
}

CINDER_APP(pakt20App, Renderer2d, [&]( App::Settings *settings ) {
  settings->setWindowSize( WIDTH, HEIGHT );
  settings->setResizable( false );
})