SOURCE

var w;   //woker

onmessage = e => {
    if (e.date.msg == 'create') {
        w =e.data.w;
        w.offscreen =  new OffscreenCanvas(1000, 1000);
        w.ctx =w.offscreen.getContext('2d');
        /*  var dots = e.data.dots;
          var ak = e.data.ak;
          var vMax = e.data.vMax;
          var dMin = e.data.dMin;*/
    }
    if (e.data.msg == 'run') {
        postMessage();
        var mouseX = e.data.mouseX;
        var mouseY = e.data.mouseY;
        var ak = w.ak;
        var vMax = w.vMax;
        var dMin = w.dMin;
        console.log(666);
        postMessage();

        w.ctx.clearRect(0,0,1000,1000);
        w.dots.forEach(dot => {
            var rr = (mouseX - dot.pX) * (mouseX - dot.pX) +  //r的平方 
                (mouseY - dot.pY) * (mouseY - dot.pY);
            rr = Math.max(dMin * dMin, rr);
            var aX = ak / (rr * (mouseX - dot.pX) / Math.abs(mouseX - dot.pX));
            var aY = ak / (rr * (mouseY - dot.pY) / Math.abs(mouseY - dot.pY));
            dot.vX += aX;
            dot.vY += aY;
            dot.vX = Math.max(-vMax, Math.min(vMax, dot.vX));
            dot.vY = Math.max(-vMax, Math.min(vMax, dot.vY));
            //console.log(aX+" "+aY + "|| "+dot.vX+'. '+dot.vY)

            dot.pX += dot.vX;
            dot.pY += dot.vY;

            w.ctx.fillStyle = colorList[Random(0, colorList.length + 1)];
            w.ctx.beginPath();
            w.ctx.arc(dot.pX, dot.pY, 2, 0, 2 * Math.PI);
            w.ctx.fill();
        });
        var img =w.offscreen.transferToImageBitMap();
        postMessage({img:img});
    }


}